07 Technical Session Seven

FIRST INDIA INTERNATIONAL ENERGY SUMMIT-2011

1 Energy Conservation & Management




ENERGY CONSERVATION & MANAGEMENT

TECHNICAL SESSION – VII



Detailed Energy Audit Report on

11/0.4 kV Distribution Transformer and

33/11kV Power Transformer

of Pushkar, Ajmer

Er. R.N.Vaishnawa & Er. P.C. Tiwari

Definition & Description of terms

Primary winding: The winding where incoming power supply is connected. Usually this refers to High

Voltage side in distribution transformers

Secondary winding: the winding where the principal load is connected. Usually this refers to Low Voltage

side in Distribution transformers.

No load loss: The losses taking place in a transformer when only primary winding is energized and all

secondary windings are open. They represent constant losses in a transformer.

Dielectric loss: The losses taking place in a stressed dielectric medium (insulation) subjected to stress

reversals.

Iron losses: The losses taking place in the magnetic core. There are two types; hysterisis losses and eddy

current losses.

Hysteresis losses: This loss depends upon the area of the hysteresis loop, which is depending upon the

maximum flux density, the type of material and frequency. It is independent of the waveform

Eddy current losses in core: This is loss due to circulating currents induced by voltage in the thickness of

core laminations. It depends upon thickness of lamination, path resistance which is depended upon the type of

material, R.M.S. flux density i.e. waveform and square of frequency

Eddy losses in a conductor: For a thick conductor, the induced voltage within the conductor cross section

due to self linkage and due to current in other conductor varies. The difference in induced voltage in the local

path in the thickness of the conductor causes extra eddy current loss : This loss varies with square of current and

square of frequency.



Stray losses: All current dependant losses in a winding other than the basic I2R losses. Stray losses include

eddy loss in the conductor, eddy losses in structural paths in close proximity to outgoing conductor and the eddy

loss in general in the structural parts. In dry type transformers, the last two mentioned types of stray losses are

absent.

Form factor: It is the ratio of the r.m.s. value of a waveform to the average value over one half cycle. For a

sine wave the value of form factor is 1.11. For distorted waves with higher peak values, the form factor is

higher.

Harmonics: Frequencies other than the main fundamental frequency of current or voltage which are present in

a distorted wave as multiples of base fundamental frequency.

Ajmer Discom Profile

Ajmer Vidyut Vitran nigam Limited (ERSTWHILE RSEB) has been established under the Companies Act,

1956 by Govt. of Rajasthan. AVVNL has been created with the principal object of engaging in the business of

distribution and supply of electricity in 11 districts of Rajasthan viz., Ajmer, Bhilwara, Nagaur, Sikar,

Jhunjhunu, Udaipur, Banswara, Chittorgarh, Rajsamand, Dungarpur and Pratapgarh. The area of operation of

AVVNL is 87,256 sq km. The population in this area is 19.8 million as per 2001 census with population density

of 227 persons/sq km. The power supply in the AVVNL is managed by 9 distribution circles i.e. Ajmer,

Bhilwara, Nagaur, Udaipur, Chittorgarh, Banswara, Sikar, Rajsamand & Jhunjhunu. AVVNL has 3 Zones, 9

O&M Circles, 34 Divisions, 153 Sub-Divisions and 375 Sub Offices. The total consumers of various tariff

categories are around 2.95 million.

Inception Report

Distribution transformers are very efficient, with losses of less than 0.5% in large units. Smaller units have

efficiencies of 97% or above. It is estimated that transformer losses in power distribution networks are 15 billion

kWh i.e. 3% of the total electrical power generated in India. Reducing losses can increase transformer

efficiency. There are two components that make up transformer losses. The first is "core" loss (also called no-

load loss), which is the result of the magnetizing and de-magnetizing of the core during normal operation. Core

loss occurs whenever the transformer is energized; core loss does not vary with load. The second component of

loss is called coil or load loss, because the efficiency losses occur in the primary and secondary coils of the

transformer. Coil loss is a function of the resistance of the winding materials and varies withthe load on the

transformer.

In selecting equipments, one often conveniently avoids the concept of life cycle costing. But the truth is that

even the most efficient energy transfer equipment like a transformer, concept of life cycle cost is very much

relevant. The total cost of owning and operating a transformer must be evaluated, since the unit will be in

service for decades.



Estimation of transformer efficiency The total losses in a transformer at base kVA as well as at the actual

load are estimated. The losses in a transformer are as under.

1. Dielectric Loss

2. Hysteresis Losses in the Core

3. Eddy current losses in the Core

4. Resistive Losses in the winding conductors

5. Increased resistive losses due to Eddy Current Losses in conductors.

6. For oil immersed transformers, extra eddy current losses in the tank structure.

From the rated output and measured output, transformer efficiency is calculated as follows.

Reduction of losses due to improvement of power factor-

Transformer load losses vary as square of current. Industrial power factor vary from 0.6 to 0.8. Thus the loads

tend to draw 60% to 25% excess current due to poor power factor. For the same kW load, current drawn is

proportional to KW/pf. If p.f. is improved to unity at load end or transformer secondary, the saving in load

losses is as under.

Saving in load losses = (Per unit loading as per kW)2 X Load losses at full load X {(1/pf)2-1)} Thus, if p.f is 0.8

and it is improved to unity, the saving will be 56.25% over existing level of load losses. This is a relatively

simple opportunity to make the most of the existing transformer and it should not be missed. It should also be

kept in mind that correction of p.f downstream saves on cable losses, which may be almost twice in value

compared to transformer losses.



Core Material- Losses in Core:-

There are two important core materials used in transformer manufacturing. Amorphous metal and CRGO. It can

be seen that losses in amorphous metal core is less than 25% of that in CRGO.

The objective of this study is to find out how the technical losses varies with the % loading as well as

unbalancing and power factor in the 11/0.4kV Distribution Transformers and 33/11kV Power Transformers. The

area for case study has been choosen is the Pushkar Sub-station. The 33/11kV Substation at Pushkar (Ganaheda)

is having 4 nos. of 33/11kV Power Transformers of 3X3.15MVA + 1X1.5MVA Capacity. Total 9 nos. 11kV

feeders are emanating from these power transformers feeding the area.

• _ Transformer No.1 of 3.15MVA

o 11 kV Banseli feeder

o 11 kV Budha Pushkar


o 11 kV Mela Ground Feeder

o 11 kV Pushkar city Pushkar


o 11 kV Dev Nagar Feeder

o 11 kV Ganahera (Rural)

o 11 kV Kishanpura




o 11 kV Leela Sevadi Feeder (24 Hrs.)

o 11 kV Ganahera (24 Hrs.)

The 33/11kV Sub-station is fed from 132/33kV MDSU Grid Sub-station, Ajmer.





Case Study #1

For the 56 nos. DT’s studied, the total loss due to over/ under sizing and improper loading/ unbalancing as well

as poor power factor is 1.47LU per year. The Power saving is around 34kW. The CO2 emission saving shall be

around 300 tons per year. The national saving against power plant cost shall be Rs.27 Lacs.

If these transformers are replaced by appropriate size amorphous core distribution transformers, then 1.83 LU of

electrical energy can be saved. The CO2 emission saving shall be around 382 tons per year. The national saving

against power plant cost shall be Rs.35 Lacs.









Case Study#2

A sample of 56 Transformers are studied for their phasewise % loading and neutral current due to unbalance

loading is measured. Neutral current flows in the neutral conductor having some resistance depending on the

size of the conductor. This current cause losses in the conductor in the form of heat and proportional to the

square of the neutral current.

The average value of neutral current in all 56 Transformers is found to be 15.4Amps. Assuming 500m length of

neutral conductor per transformer, the calculation for losses occurring is as follows:

15.4AX15.4AX0.9116 ohm/kmX56 Nos. of DT X 0.5 km/TransformerX50%(Distribution factor)=3.026kW

=3.026X8760 = 26514 kWh/annum

This can save 53 tons of CO2/annum.



As the Discom as a whole, if this figure is calculated, it can be million of tons of CO2/ nnum that can be saved

by proper balancing of transformers to some extent.





Case Study #3

Power Transformer #1 for 11kV Banseli & Budha Pushkar Feeder of 3.15MVA The no-load loss is 3kW and

Copper loss is 16kW at unity power factor. The maximum efficiency of the transformer is achieved at the load

where no load loss and copper loss are equal i.e.

Loading for maximum efficiency of the transformer = (No load loss/Copper loss)1/2

For this transformer, the maximum efficiency is achieved at (3/16)1/2= 43.3% loading i.e.

1364kVA.

The loading pattern of this power transformer for 26-7-10 to 22-09-10 (1503 Hrs) is as follows-

It is found that the loading average loading on the transformer is 722kVA and the transformer is loaded for only

20-30% of its rate capacity. The technical loss of the transformer at 23% loading and 0.9 PF is 0.59%. If the

load of transformer #4 is connected with this transformer (225kVA) then the loading on this transformer shall be

950kVA, then loss of 1.5MVA Transformer will be saved which is equal to 1.9kWx8760 = 16644kWh per

annum. This can save 33 tons of CO2 per annum. Also this will improve efficiency of the existing 3.15MVA

Power Transformer.



Case Study #4

Power Transformer # 2 for 11kV Mela Feeder and Pushkar City Feeder of 3.15MVA

Capacity of Power Transformer # 2 is 3.15MVA. Two nos. 11kv Urban feeders emanates from this transformer

namely 11kV Mela Ground Feeder and 11kV Pushkar City Feeder. The no-load loss is 3kW and Copper loss is

16kW at unity power factor. The maximum efficiency of the transformer is achieved at the load where no load

loss and copper loss are equal i.e. Loading for maximum efficiency of the transformer = (No load loss/Copper

loss)1/2 For this transformer, the maximum efficiency is achieved at (3/16)1/2= 43.3% loading i.e. 1364kVA.

The loading pattern of this power transformer for 26-7-10 to 22-09-10 (1392 Hours) is as follows-

From the loading pattern, it is clear that the transformer is mainly have 70-80% loading for more than 45%

period and average loading on the transformer is 2125kVA and maximum load is 3600kVA.

The Technical losses at 0.9PF for 3.15MVA Power Transformer at 2125kVA (75%) loading is 0.56% while the

loss for 5MVA Transformer for 2125kVA(42.5%) loading is 0.42% i.e. an improvement of 0.14% improvement

in efficiency.

It is therefore proposed to augment the 3.15MVA Power transformer by 5MVA Power Transformer.

The total saving of Energy shall be ~34000kWh per year. It will save 68 ton of CO2 per annum.



Case Study # 5

Power Transformer #3 is 3.15MVA for 11kV Devnagar, Ganaheda and kishanpura feeder

Capacity of Power Transformer #3 is 3.15MVA. Three nos. 11kv Rural area feeders emanates from this

transformer. The no-load loss is 3kW and Copper loss is 16kW at unity power factor. The maximum efficiency

of the transformer is achieved at the load where no load loss and copper loss are equal i.e.

Loading for maximum efficiency of the transformer = (No load loss/Copper loss)1/2

For this transformer, the maximum efficiency is achieved at (3/16)1/2= 43.3% loading i.e.

1364kVA.

The loading pattern of this power transformer for 28-3-10 to 23-09-10 (4320 Hours) is as follows-

From the loading pattern, it is clear than for more than 11% of period, the Power Transformer is idle and around

3000kWh/annum are lost due to no load losses. This can be saved if GO switch is made OFF during idle period.

Operating the ransformer beyond 1364kVA is due to mismanagement of Block Supply given to rural areas for

3-phase pump sets. It is proposed that whenever 3-phase supply is given to 11kV kishanpura feeder than other

two feeders should not be operated in three phase block. For 31% time, the loadings are beyond the ideal

loading condition resulting into excess copper losses of 30,000 kWh/ annum. The total saving possible is

33,000kWh/ annum which can result into 66 tons of CO2 per annum.











Case Study # 6

Power Transformer #4 is 1.5MVA for 11kV Leela Sevadi & Ganaheda (24 Hrs. supply) feeder

Capacity of Power Transformer #4 is 1.5MVA. Two nos. 11kV 24 hours supply feeders namely Leela Sevadi

and Ganahera (U) feeders emanates from this transformer. The no-load loss is 1.9kW and Copper loss is 10kW

at unity power factor. The maximum efficiency of the transformer is achieved at the load where no load loss and

copper loss are equal i.e. Loading for maximum efficiency of the transformer = (No load loss/Copper loss)1/2

For this transformer, the maximum efficiency is achieved at (1.9/10)1/2= 43.59% loading i.e. 654kVA. The

loading pattern of this power transformer for Study period 25-July-10 to 23-09-10 (1490 hours) is as follows

It is evident from the loading pattern of the transformer that all the time, the transformer is underloaded and the

maximum loading on the transformer is 20% and mainly the % loading is 10 to 15%. This load can be shifted to

transformer # 1 of 3.15MVA which is also under loaded. The possible saving is due to saving of no-load losses

of this transformer and improving of efficiency of Transformer # 1. The total saving expected is

6650kWh/annum which can result into 33 tons of CO2 per annum.. This will also save the capital amount of

1.5MVA

Transformer.





Energy Savings Opportunities on Transformers in Thermal Power Plant-

Case Study

Devendra Shringi [email protected]

Abstract

A Study on Transformers to find out the losses due to loading on transformers.

Out of 69 L.T. transformers based on loading record of few Months, 30 nos. heavily loaded transformers were

selected for study .And calculation has been done for Transformers Losses and the results are as follows:-

Total Losses in Transformers of one unit of 210 MW are = 687KW or 0.33% of 210MW

Contribution of Power Transformers in Losses per unit 210 MW = 659 KW

Contribution of Service (L.T.) Transformers in Losses per 210 Mw = 29 KW

Total Transformer Losses in Plant of 1240 MW = 4040 KW

Annual Amount Loss due to Transformer Losses which could have been sent out = Rs.6.7 crores /year

Overall Auxiliary Consumption of 1240 MW is 9.72 % and Excluding Power Transformer losses it is 9.39 %.

(A) Savings for 1240 MW due to reduced Station Transformer Losses by P.F. Improvement = RS. 4.20 Lac/year

(B) Savings for 1240 MW due to reduced Distribution Losses by P.F. Improvement = Rs.5.9 crores /year

By Station Transformers Loading Adjustment one no. of Station Transformer can be put-off that will reduce the

Total Losses of 44.50KW plus Service Transformers of EPT, WT, and DMT can also be put-off which will also

reduce 16KW Losses. And by selecting G.T. of 350 MVA its Loading will reduce to 60% .Thus Total Losses

reduction will be up to 136 KW.

(C) Overall by Optimization strategy Annual saving @Rs.2.13/-will is (2.13*325*24*136) Rs.23 lacs.



Expected Total yearly saving on Improving Power Factor and Transformer optimisation for 1240 Mw Power

Plant (A+B+C) = Rs.6.17 crore

Expected Total Saving by improving power factor for 1240 mw Power Plant = RS. 5.95 crores

Expected Total Investment including the installation = Rs. 1.19 crores

Simple Pay back Period = 65 days

Expected Total saving by improving power factor from .83 to .99 and loading optimization on transformers by

distribution companies on 1240 Mw = Rs. 13 crores/year

Key Words: Overall Transformer Losses, Reduction in Transformer Losses by Optimisation, Savings by

improving power factor

1.0 Introduction

1.1 General Plant details

Kota Thermal Power Station is first major coal power station of Rajasthan. Its present installed capacity is 1240

MW. It is located on the left bank of Chambal River at Kota. KTPS has established a record of excellence and

has earned meritorious productivity awards from the Ministry of Power, Govt. of India during

1984,1987,1989,1991 and every year since 1992-93 onwards. In 2008-09 its Gross Generation was 8874 MU at

94.76% PLF with Auxiliary Power consumption 9.37% and Sp. Oil consumption 0.43 ml/kWh.

1.2 Transformers

Types of Transformers:-

Transformers are classified as two categories: power transformers and distribution transformers.

Power transformers are used for transmission of power at high voltage i.e. 400 kV, 200 kV, 110 kV, 66 kV, 33

kV deployed for step-up and step down the power as per requirement.

Distribution transformers are used for distribution of power at low voltage as a means of end user connectivity

i.e. 11 kV, 6.6 kV, 3.3 kV, 440 V, 230 V.



2.0 Methods and Materials

2.1 Transformer losses and Efficiency

The efficiency varies anywhere between 96 to 99 percent. The efficiency of the transformers not only depends

on the design, but also, on the effective operating load.

Transformer losses consist of two parts: No-load loss and On-Load loss

1. No-load loss (also called core loss) is the power consumed to sustain the magnetic field in the transformer’s

steel core. Core loss occurs whenever the transformer is energized; core loss does not vary with load. Core

losses are caused by two factors: hysteresis and eddy current losses. Hysteresis losses occur due to the energy

loss by reversing the magnetic field in the core as the magnetizing AC rises and falls and reverses directions.

2. On-Load loss (also called copper loss) is associated with full-load current flow in the transformer windings.

Cooper loss is power loss in the primary and secondary windings of a transformer due to the resistance of the

windings. Cooper loss varies with the square of the load current. (P = I2R)

For a given transformer, the manufacturer, supply values for no-load loss, PNO-LOAD, and On-load loss, PLOAD.

The total transformer loss, PTOTAL, at any load level can then be calculated from:

PTOTAL = PNO-LOAD + (% Load/100)2 x PLOAD , Where transformer loading is known, the actual transformers loss

at given load can be computed as: No load loss + kVA Load 2 X (full load loss)

Rated kVA

Transformer Efficiency at Unity Power factor = {1-(Total Losses/%Loading*Rated KVA)*100

3.0 Observations and Measurements

3.1 Transformer Losses Calculation

A Study was done on transformers to find out the losses due to loading on transformers. Out of 69 transformers

based on loading record of few Months, 30 heavily loaded transformers were selected for study.



UNTI 7 LOAD CALCULATIONS AT 7.15PM

S.No SERVICES Load

KVA

RATED

KVA

%age

Loading

NO-LOAD

LOSS KW

LOAD

LOSS

TOTAL

LOSS* KW

Transform

er Eff.

1 AHT7A 296 1600 18.50 1.60 13.50 2.06 99.30

2 CTT7A 547 2000 27.35 1.90 15.00 3.02 99.45

3 CTT7B 649 2000 32.45 1.90 15.00 3.48 99.46

4 EPT7A 65 2500 2.60 2.20 20.00 2.21 96.59

5 EPT7B 160 2500 6.40 2.20 20.00 2.28 98.57

6 UST7B 333 2000 16.65 1.90 15.00 2.32 99.30

7 UST7A 353 2000 17.65 1.90 15.00 2.37 99.33

8 SSIVA/IVB 11564 50000 23.13 34.60 185.00 44.50 99.62

9 SST 5A 490 2500 19.60 2.20 20.00 2.97 99.39

10 SST 5B 319 2500 12.76 2.20 20.00 2.53 99.21

11 UAT7A 3904 15000 26.03 8.17 50.34 11.58 99.70

12 UAT7B 8228 15000 54.85 8.17 50.34 23.32 99.72

13 G.T.7 219640 250000 87.86 119.34 599.10 581.77 99.74

SUB-TOTAL 246548 684.39

CHP 338 2.42

TOTAL LOSSES 686.81



UNIT 7 LOAD CALCULATIONS

S.

No

1

SERVICES

2

Load

KVA AT

2.30PM

3

Load

KVA AT

7.15PM

4

Load KW

AT

7.15PM

5

RATED

KVA

6

%

Loadi

ng

7=3/6

No-Load

LOSS

KW

8

LOAD

LOSS

9

TOTAL

LOSSES

KW

10

1 SSIVA/IVB 9136.00 11564.00 9621.25 50000.00 18.27 34.60 185.00 40.78

2 UAT7A 7884.00 3904.00 3162.24 15000.00 52.56 8.17 50.34 22.08

3 UAT7B 6630.00 8228.00 6664.68 15000.00 44.20 8.17 50.34 18.00

4 GEN.TRANS. 218000.0 219640.00 210000.00 250000.00 87.20 119.34 599.10 574.89

SUB-TOTAL 23650.0 23696.00 19448.17 TOTAL

LOSS

655.74

CHP 338.00 338.00 287.30

TOTAL 23988.0 24034.00 19735.47



STATION TRANSFORMERS

S. No. Unit No. Unit Cap. Unit Transf. Cap. Input/Output Volt. Make

1 Unit #1 110 MW 50 MVA 220/7/7 KV Crompton Bombay

2 Unit #2 110 MW 50 MVA 220/7/7 KV Crompton Bombay

3 Unit #3 210 MW 50 MVA 220/7/7 KV BHEL Bhopal

4 Unit #4 210 MW 50 MVA 220/7/7 KV TELK Kerala



UNIT AUXILIARY TRANSFORMERS

S. No. Unit No. Unit Cap. Unit Transform Cap. Input/Output Voltage Make

1 Unit #1 110 MW 15 MVA 11/7 KV BHEL Jhansi

2 Unit #2 110 MW 15 MVA 15.75/7 KV BHEL Jhansi

3 Unit #3 210 MW 2*15 MVA 15.75/7 KV BHEL Jhansi


5 Unit #5 210 MW 2*15 MVA 15.75/7 KV Bharat Bijlee Mumbai



GENERATOR TRANSFORMERS

S. No. Unit No. Unit Cap. Unit Transform Cap. Input/Output Voltage Make

1 Unit #1 110 MW 125 MVA 11KV/240 KV BHEL Jhansi

2 Unit #2 110 MW 125 MVA 15.75KV/240 KV BHEL Jhansi





5 Unit #5 210 MW 250 MVA 15.75KV/240 KV Bharat Bijlee Mumbai



TABLE OF SELECTED TRANSFORMERS FOR ANALYSIS

S.

No

SERVICES AV.

LOAD

AMP.

Load

KVA

RATED

KVA

%age

Loading

NO-LOAD

LOSS KW

LOAD

LOSS

TOTAL

LOSS*

KW

Transfo

rmer

Eff.

1 SST- 1A 60.00 686.00 1600.00 42.88 1.60 13.50 4.08 99.41

2 SST- 1B 65.00 743.00 1600.00 46.44 1.60 13.50 4.51 99.39

3 BCW-1 45.00 514.00 1600.00 32.13 1.60 13.50 2.99 99.42

4 SST II A 55.00 629.00 2000.00 31.45 1.90 15.00 3.38 99.46

5 Compressor IIA 35.00 400.00 1600.00 25.00 1.60 13.50 2.44 99.39

6 EPT3C 50.00 572.00 1600.00 35.75 1.60 13.50 3.33 99.42

7 EPT3A 25.00 286.00 1600.00 17.88 1.60 13.50 2.03 99.29

8 EPT4C 25.00 286.00 1600.00 17.88 1.60 13.50 2.03 99.29

9 Compressor IIA 20.00 229.00 1600.00 14.31 1.60 13.50 1.88 99.18

10 SST II B 55.00 629.00 2000.00 31.45 1.90 15.00 3.38 99.46

11 AHT II B 40.00 457.00 1600.00 28.56 1.60 13.50 2.70 99.41

12 UST5A 25.00 286.00 1600.00 17.88 1.60 13.50 2.03 99.29

13 SSTIIIB 25.00 286.00 2000.00 14.30 1.90 15.00 2.21 99.23

14 Const. Supply 20.00 229.00 1600.00 14.31 1.60 13.50 1.88 99.18

15 SST4A 25.00 286.00 2000.00 14.30 1.90 15.00 2.21 99.23

16 SST4B 30.00 343.00 2000.00 17.15 1.90 15.00 2.34 99.32



17 EPT 6B 45.00 514.00 1600.00 32.13 1.60 13.50 2.99 99.42

18 CT-6A 40.00 457.00 1600.00 28.56 1.60 13.50 2.70 99.41

19 CHP-IIA 20.00 229.00 2000.00 11.45 1.90 15.00 2.10 99.08

20 CHP-IIIA 40.00 457.00 2000.00 22.85 1.90 15.00 2.68 99.41

21 WT-IIA 40.00 457.00 2000.00 22.85 1.90 15.00 2.68 99.41

22 AHT7A 21.00 247.00 1600.00 15.44 1.60 13.50 1.92 99.22

23 CTT7A 47.00 547.00 2000.00 27.35 1.90 15.00 3.02 99.45

24 CTT7B 56.00 649.00 2000.00 32.45 1.90 15.00 3.48 99.46

25 EPT7A 6.00 73.00 2500.00 2.92 2.20 20.00 2.22 96.96

26 EPT7B 9.00 108.00 2500.00 4.32 2.20 20.00 2.24 97.93

27 UST7B 56.00 650.00 2000.00 32.50 1.90 15.00 3.48 99.46

28 UST7A 53.00 602.00 2000.00 30.10 1.90 15.00 3.26 99.46

29 SST 5A 39.00 455.00 2500.00 18.20 2.20 20.00 2.86 99.37

30 SST 5B 38.00 427.00 2500.00 17.08 2.20 20.00 2.78 99.35

TOTAL

LOSSES

81.85

4.0 Results and Discussions

4.1 Power Factor Calculations

KVAr required = P(Kw)(tan 01 – tan 02)

COS o1 = 0.83 COS o2 = 0.99 KVAr rating = 10462 kvar



BEFORE CAPACITOR BANK

Auxiliary Load = 19740 KW; Power Factor = 0.83; KVA LOAD = 24034

KVAr = SQRT(240342 – 197402) = 13710 KVAr

AFTER INSTALLING CAPACITOR BANK

Auxiliary Load = 19740 KW; Power Factor = 0.99;

KVAr = 13710 KVAr – 10462 KVAr (Proposed Bank) = 3248 KVAr

KVA Load = SQRT (197402 + 32482 ) = 20005

Reduction in KVA Load = 24034 – 20005 = 4029 KVA

Loading on STATION TANSFORMER after proposed reduction = 9136 -4029 = 5107 KVA

% Loading of STATION TRANSFORMER = (5107/50000)*100 = 10.21%

Losses of STATION TRANFORMER after Power Factor correction = 34.6 + (5107/50000)2 * 185 = 36.52 KW

Reduction in STATION TRANSFORMER Losses after Power factor correction = 40.78 – 36.52 = 4.26 KW

Saving Potential = 4.26 * 24 * 325 * 2.13 = Rs. 71000.00 /year/210MW

(A)Saving Potential for 1240 MW = RS. 4.20 Lacs/year

Reduced current = 4029/6.6*1.732 = 352 Amp.

Reduction in Distribution losses = 352*352*R WATTS

Distribution Losses before Power Factor correction= (24034/1.732*6.6)2*R

% Reduction in Distribution Losses = (352*352*R / (24034/1.732*6.6)2*R)*100 = 2.8%

Saving Potential = .028 * 19740 * 24*325 *2.13 = Rs. 1 crore/year/210MW

(B)Saving Potential for 1240 MW = (1/210)*1240=Rs.5.9 crores /year

Total Annual Savings for 1240 MW Generation (A+B) = Rs 5.942 crores

Expected Annual Saving by Distribution Company @Rs.4.5/unit will be Rs. 1.94 crores/210mw



Expected Annual Saving by Distribution Company for 1240 Mw power plant is Rs. 11.46 crores.

Expected Total year saving by Improving the Power Factor for 1240 Mw Power Plant (A+B) = Rs.5.94 crore

Expected Total Investment including the Capacitor Bank installation = Rs. 1.19 crores

Simple Pay back Period = 70 days

4.2 Transformers Losses Calculations and the results are as follows:-

Total Losses in Transformers of one unit of 210 MW are = 687KW or 0.33% of 210MW

Contribution of Power Transformers in Losses per unit 210 MW = 659 KW

Contribution of Service (L.T.) Transformers in Losses per 210 Mw = 29 KW

Total Transformer Losses in Plant of 1240 MW = 4040 KW

Annual Amount Loss due to Transformer Losses which could have been sent out = Rs.6.7 crores /year

Transformer Losses contributes to share in Auxiliary power Consumption = 3.5 %

Overall Availability of Plant has been considered 325 days in a year

Overall Auxiliary Consumption of 1240 MW is 9.72 % and Excluding Power Transformer losses it is 9.39 %.

By Station Transformers Loading Adjustment one no. of Station Transformer can be put-off that will reduce the

Total Losses of 44.50KW plus Service Transformers of EPT, WT, and DMT can also be put-off which will also

reduce 16KW Losses. Thus Total Losses reduction will be up to 60 KW.

By selecting G.T. of 350 MVA its Loading will reduce to 60% and 76KW Transformer Losses will also reduce.

(C)Overall by Optimization strategy Annual saving @Rs.2.13/-will be (2.13*325*24*136)Rs.23 lacs.

Expected Total yearly Saving on Improving Power Factor and Transformer optimisation for 1240 Mw Power

Plant(A+B+C) = Rs.6.17 crore

Expected Annual Saving by Distribution Company on Improving Power Factor and Transformer optimisation

for 1240 Mw power plant is Rs. 13 crores

5.0 Conclusion

5.1 Recommendations



1) Equal loading shall be done on Service Transformers shall be done to avoid under loading and overloading

2) The transformers at minimum loading shall be replaced from high rated capacity to low required capacity or

shall be switched off by transferring that load on other transformer to avoid losses and maintenance cost.

3) Routine and Preventive maintenance of transformers shall be carried out to avoid tripping.

4) By load analysis - Total losses can be reduced which will reduce the Overall Auxiliary Consumption of

KTPS, and more power will be available to fulfil the gap between demand and supply.

5) Two transformers operating in parallel, should be technically identical in all aspects and more important both

should have the same impedance level .This will minimize the circulating current between transformers.

6)Where the load is fluctuating in nature, it is preferable to have more than one transformer running in parallel,

so that the load can be operated close to the maximum efficiency range by this operation.



6.0 References

• The following books, Literature and websites were referred in preparing this report:-

• Technical Specification Sheets of Transformers

• Tests Reports of Transformers

• Website of RRVUNL

• Guide Books for National Certification Examination on Energy Audit and Energy Management



Experimental Investigation & Analysis to Reduce Boiler Tube Failure in

Thermal Power Plant.

Amol M. Andhare

Assistant Professor in Industrial Engg.,SRKNEC, Nagpur

Bhushan V. Lande,

Lecturer in Mechanical Engg. , PCE, Nagpur

Abstract

Boiler tube failures continue to be the leading cause of forced outages in fossil-fired boilers. To get boiler back

on line and reduce or eliminate future forced outages due to tube failure, it is extremely important to determine

and correct the root cause. Experience shows that a comprehensive assessment is the most effective method of

determining the root cause of a failure. In the modern World, requirement of power has become necessity for

day to day activity. Today’s power generation in the Country is dominated by thermal power plants to the extent

of 65%. Boiler tube failures are conditions that utilities have been battling since the day boilers were invented.

They amount to millions of dollars of lost generation and anything done in this field to aid root cause and

solution determination would be of great benefit to the utility industry. Hence availability of boiler is very much

essential for thermal power generating stations. One of the main reasons for boiler forced outages is boiler tube

leakage. The plan was to carry out the experimental investigation and analysis of the boiler tube failure, and

then run experiments with different power plants and failure techniques until it was considered “effective”.

Improvements between the tubes failure could be measured and recommendations made to the management.

This paper covers the major reason of tube Leakages and recommended remedies to avoid the same.

Index term: leak detection; boiler tube failure root cause analysis system; solution determination; failure

mechanism; physical failure appearance; Knowledge-based cause and effect diagrams; Koradi Thermal Power

Station, Nagpur, Maharashtra, India.

Keywords: Boiler failures; Economizer tube; Corrosion; Failure analysis; Metallurgical examination, Boiler

tube leakage, experimental investigation & analysis, power generation unit.

Problem Identification

In Present Work, data of boiler tube Failure at Koradi thermal power station Collected for last ten years which is

given below. From above data of boiler tube failure shows that maximum tube failure occurs in economizer and

reheater, in reheater section most of the boiler tube failure occurs due to short term overheating and long term

overheating. An accurate analysis of the deposits indicates the source of the problem and the steps needed for

correction. Metallographic analyses are useful, at times, in confirming whether a short- or long-term exposure to

overheating conditions existed prior to failure. Such analyses are helpful also when metal quality or



manufacturing defects are suspected, although these factors are significant only in isolated instances. If the

problem is remains as it is then boiler performance will affect and result in following factors.

Improper availability

Increased forced outage costs.

More cost to repair

Minimum component life

Repeated root cause analysis

In determinant commonalities across the boiler fleet

Repeated Plan for future outages

Please refer table below for the data collection of boiler tube failure. Tube Failure instances from 1994-1995 to

2008-2009

UNIT

NO. ECO

WATER

WALL CAGE PRISH/H

PLATEN

S/H

SEC

S/H R/H TOTAL

1 31 3 6 9 NIL 7 20 76

2 22 2 6 16 NIL 7 21 74

3 14 10 7 7 1 13 10 62

4 16 8 2 3 9 12 12 62

5 16 15 3 5 NIL 4 9 52

6 4 22 4 1 NIL 3 17 51



7 18 16 3 4 NIL 0 12 53

Table 1 Tube Failure instances from 1994-1995 to 2008-2009.

Introduction

The failure of industrial boilers has been a prominent feature in fossil fuel fired power plants. The contribution

of one or several factors appears to be responsible for failures, culminating in the partial or complete shutdown

of the plant. The use of high sulfur or/and vanadium-containing fuel, exceeding the design limit of temperature

and pressure during operation, and poor maintenance are some of the factors which have a detrimental effect on

the performance of materials of construction. A survey of the literature pertaining to the performance of steam

boilers during the last 30 years shows that abundant cases have been referred to concerned with the failure of

boilers due to fuel ash corrosion, overheating, hydrogen attack, carburization and decarburization, corrosion

fatigue cracking, stress corrosion cracking, caustic embrittlement, erosion, etc. Corrosion problems in boiler

tubes arisen due to overheating are quite common. This mode of failure is predominantly found in superheaters,

reheaters and water wall tubes, and in the result of operating conditions in which tube metal temperature

exceeds the design limits for periods ranging from days to years. The phenomenon of overheating is manifested

by the presence of significant deposits, which impart a reduction in water flow and excessive fire-side heat

input. Due to this rise in temperature, steel loses its strength, causing rupture or bulging of the tube due to

internal pressure. In a recent investigation. The failures have been attributed to accelerated corrosion, hydrogen

attack and overheating. In another study, corrosion of stainless superheater tubes occurred due to carburization

resulting in intergranular wastage of steel near the exposed surface. The causes of the majority of failures are

attributed to the upset in water quality and/or steam purity. The mechanisms of failures due to short term

overheating & long term overheating. This paper presents the results of two separate investigations carried out

to determine the causes of failure of boiler tubes of Koradi thermal Power station and Desalination Plants. The

main aim of this paper to investigation and acquaint the operation and maintenance personnel with the different

corrosion modes involved in failures of boiler tubes due to short term overheating & long term overheating, and

to suggest some measures for preventing the recurrence of such failures.

The objectives of today for any power plants are to increase the availability, efficiency and reliability of power

generating systems. Boilers are considered heart of steam and power generation systems. Unpredictable failures

in boilers can bring down operation of power and steam generation to a halt for many days based on the severity

of failure / damage.

Proper operation and maintenance of boilers can ensure prolonged and safe operations of the power / steam

generation systems. However, during downtime of these equipment, inspection and repair at the fastest possible

time play a major role in bringing back the power and generation systems. Inspection and repair time are very

crucial as the failure down time of boilers directly affect other dependent plants in terms of supply of electric

power and utility steam.



Koradi Thermal Power Station is the plant operated by Maharashtra State Power Generation Co. Ltd. Koradi

Thermal Power Plant is 8 Km away from Nagpur. Total capacity of plant is 1110 MW. Plants consist of 7 units,

4 units of 120 MW & 3 units of 210 MW. The Boilers are used in power plant supplied by ABL & BHEL. The

boiler used as front fired & corner fired. The material used for boiler tube is SA 210 T1 & SA213 C22 as per the

unit capacity. In Koradi Thermal Power Plant boiler tube failure is the main reason for boiler forced outages. In

this paper an attempt is being made to present failure analysis of boiler, corrective methods followed and

inspection and repair execution to bring the boilers back to operation at the shortest possible time.

Brief Description of Failure

The boiler had tripped on high furnace pressure caused due to water leak from the riser furnace water wall tube.

On opening the boiler furnace chamber, the chamber was found filled with water. Furnace water wall tube

facing the fire side of the chamber was found leaking. Two of the tubes were found ruptured opened up and two

tubes were found with pinhole leak. The location of the rupture / pin holes is as shown in the layout of the

furnace chamber.

Graph 1 Tube Failures (Causewise)

Graph 2 Tube Failures (Areawise)



Types Of Boiler Tubes Failure

State of the art materials evaluation techniques support reliability engineering efforts to maintain and improve

overall plant performance. Materials failure analysis is a specialized, but important, part of the systems

approach to plant reliability. Frequently, materials failure types is the first step on the path of determining the

root cause failure mechanisms.

1 Stress Rupture

The term “overheating” failure often misused but generally means the failure resulting from operation of a tube

higher than expected in design selection of the tube steel for a period of time sufficient to cause a stress rupture

failure. Time and temperature is an important factor and these types of failure are often called “short term and

long term overheating” failures.

1.1 Short Term Overheating

A short term overheating is one in which a signal indicates exposes the tube steel to an extensively high

temperature (hundred of degree above) to the point where the deformation of the yielding occurs.

Figure 1 Failure due to Short term overheating.

1.2 Long Term Overheating

Long term overheating Failures results from a relatively continuous extended period of slight overheating, a

slowly increasing level of temp or stress. Accumulation from several periods of excessive overheating. Metal

degradation and permanent deformation will occur with time depending on the actual temperature & stress

levels. Figure 2 shows the pin holes on failure boiler tube, this feature just similar to failure occur in long term

overheating.

Figure 2 Failure due to long term overheating



2 Dissimilar metal Weld

Dissimilar metal weld (DMW) failures between carbon steels and stainless steels occur in many industrial

applications. These failures are generally attributed to the very sharp changes in composition and corresponding

properties which occur along the fusion line of the weld and the formation of locally high stresses associated

with a thermal expansion mismatch between the carbon steel and stainless steel.

Similarly the other types of boiler tube failure are

3 Water side corrosion:-

Caustic gouging

Hydrogen damage

Acid Phosphate Corrosion

Pitting Corrosion

Graphitization

Stress Corrosion Cracking

4 Fire side corrosion

Coal Ash

Oil Ash

Furnace wall Corrosion

Exfoliation

5 Erostion

Fly Ash erosion

Soot blower erosion

Coal particle erosion

Falling slag damage



6 Fatigue

Thermal Fatigue

Corrosion Fatigue

Rubbing of tubes

7 Lack of quantity control

Chemical cleaning damage Maintenance damage Material Flaes & Welding Flaws

Selection Of Factor And Observation

The below mention table is the total no of observation of boiler tube failure. Tube Failure instances from 1994-

1995 to 2008-2009. Refer table 1 for detail observations.

Eco

Water

Wall Cage Prish/H

Platen

S/H

Sec

S/H R/H

121 76 31 45 10 46 101

Table 2 Total no of boiler tube failure.

Graph 3 Total no of boiler tube failure (1994-95 to 2008-09)



Methodology

Boiler tube failures continue to be the number one cause of forced outages at power generating stations. Great

strides are taken to identify where tubes are wearing so that preventative actions can be taken to avoid failures

during peak operation, but failures still continue to occur. To operate at peak capacity, a plant needs to find

ways to avoid tube failures, as well as to recover from them quickly when they caused forced outages. Fossil

fired boilers of all sizes continue to experience boiler tube failures and if the boiler tube root cause and scope of

damage is not identified repairs will be incomplete and worse a dangerous condition may exist. AIS

Metallurgical Testing has a decade of experience with boiler tube failures including steam drums and water

drums (mud drums) as well as boiler headers and economizer tubes. After identifying failure on tube sample,

testing of failure tube sample was carried out in Metallurgy department of VNIT NAGPUR.

Experimental investigation & analysis were carried out as per Indian Boiler Regulation act 1950.

Testing Of Boiler Tubes

A tube testing system consists of two subassemblies, the probe and the applicator. The probe uses a stack of

Belleville style washers that when compressed allow the locking fingers to relax and the probe to be inserted

into the tube. Once the probe is placed in the correct location using the applicator, the Belleville style washers

are allowed to expand, locking in the fingers and engaging the urethane seals. As the water fills the tube, the air

is pushed through a bleed hole in the mandrel of the probe. The bleed hole leads to a chamber in the top of the

probe that contains a plastic ball. The ball floats on water and as the chamber fills, the ball seals off the leak path

and the tube can then be pressurized and the test performed. Once the test is complete, the water is drained and

using the applicator, the probe is removed from the tube.

Types Of Boiler Tube Testing

1Metallographic Test: - One of the failed tube ends supplied to CTL was sectioned longitudinally through the

groove and crack for metallographic examination. The presence of thick black oxide on the groove and parts of

the crack surface, as well as lack of deformation in the microstructure, confirmed that corrosion was the cause of

the grooving. Deformation of the microstructure at the crack surfaces indicated that the final failure was by

ductile tearing. The microstructure itself consisted of pearlite in an equiaxed ferrite matrix, typical of low carbon

steel, refer fig 3 & 4 below.



Figure 3 Polished metallographic longitudinal cross-section showing oxide-filled groove and crack. Light-

colored material indicated by white arrows is oxide. Yellow arrow indicates crevice attack on part of tube rolled

into tube sheet. (18X Original Magnification)

Figure 4 Microstructure of failed tube showing pearlite in equiaxed ferrite matrix. (2% nital etch) (125X

Original Magnification)

2 Flattening test: - This is usually applied to the boiler tube and involves flattening a sample of tube between

two parallel faces without the tube showing flaws or cracks. The length of the test piece and degree to which it

is to be flattened (i.e. the distance between the parallel faces) are specified. A section of the tube not less than 40

mm length shall be flattened cold between parallel plates. No cracks or breaks in the metal shall occur until the

distance between the plates is less than the given by the following formula. Evidence of lamination or burnt

material or incomplete penetration of the weld shall not develop during the testing.

(1 + e) t

H = ----------------

e + (t /D)

Where t = Specified thickness of tube (in mm)

D = Specified outside diameter of tube (in mm)

e = Flattening test constant as given below:

0.10 for tube grade WC 1

0.07 for tube grades WC2 & WC3.

(ii) The weld shall be placed 90 degree from the line of direction of the applied force.

(iii) Superficial rupture as a result of minor surface imperfections shall not be cause for rejection.

adopted shall be specified.



3 Corrosion test: Various corrosion mechanisms contribute to boiler tube failure. Stress corrosion may result in

either intercrystalline or transgranular cracking of carbon steel. It is caused by a combination of metal stress and

the presence of a corrosive. A metallurgical examination of the failed area is required to confirm the specific

type of cracking. Once this is determined, proper corrective action can be taken.

3.1 Caustic Embrittlement: - Caustic embrittlement, a specific form of stress corrosion, results in the

intercrystalline cracking of steel. Intercrystalline cracking results only when all of the following are present:

specific conditions of stress, a mechanism for concentration such as leakage, and free NaOH in the boiler water.

Therefore, boiler tubes usually fail from caustic embrittlement at points where tubes are rolled into sheets,

drums, or headers.

The possibility of embrittlement may not be ignored even when the boiler is of an all-welded design. Cracked

welds or tube-end leakage can provide the mechanism by which drum metal may be adversely affected. When

free caustic is present, embrittlement is possible.

The device, illustrated in Figure 5, was developed by the United States Bureau of Mines. If boiler water

possesses embrittling characteristics, steps must be taken to protect the boiler from embrittlement-related failure.

Figure 5 Embrittlement related failure protecting device

Sodium nitrate is the standard treatment for inhibiting embrittlement in boilers operating at low pressures. The

ratios of sodium nitrate to sodium hydroxide in the boiler water recommended by the Bureau of Mines depend

on the boiler operating pressure. These ratios are as follows:

Pressure,psi NaNO3 /NaOH Ratio

Up to 250 0.20



Up to 400 0.25

Up to 1000 0.40-0.50

The formula for calculating the sodium nitrate/sodium hydroxide ratio in the boiler water is:

NaNO3 ppm nitrate (as NO3 -)

=

NaOH ppm M alkalinity - ppm phosphate

(As CaCO3) (As PO4 3- )

At pressures above 900 psig, coordinated phosphate/pH control is the usual internal treatment. When properly

administered, this treatment method precludes the development of high concentrations of caustic, eliminating

the potential for caustic embrittlement.

3.2 Fatigue & Corrosion Fatigue: - Transgranular cracking primarily due to cyclic stress is the most common

form of cracking encountered in industrial boilers. In order to determine the cause of a transgranular failure, it is

necessary to study both the design and the operating conditions of the boiler. Straight tube, shell-and-tube waste

heat boilers frequently develop tube and tube sheet failures due to the imposition of unequal stresses.

3.3 Stress-Induced Corrosion: - Certain portions of the boiler can be very susceptible to corrosion as a result

of stress from mechanical forces applied during the manufacturing and fabrication processes. Damage is

commonly visible in stressed components, such as rolled tube ends, threaded bolts, and cyclone separators.

However, corrosion can also occur at weld attachments throughout the boiler (see Figure 6) and can remain

undetected until failure occurs. Regular inspection for evidence of corrosion, particularly in the windbox area of

Kraft recovery boilers, is recommended because of the potential for an explosion caused by a tube leak.

Figure 6 Stress induced corrosion at weld attachment



3.4 Caustic Attack:- Caustic attack (or caustic corrosion), as differentiated from caustic embrittlement, is

encountered in boilers with dematerialized water and most often occurs in phosphate-treated boilers where tube

deposits form, particularly at high heat input or poor circulation areas. Deposits of a porous nature allow boiler

water to permeate the deposits, causing a continuous buildup of boiler water solids between the metal and the

deposits.

Because caustic soda does not crystallize under such circumstances, caustic concentration in the trapped liquid

can reach 10,000 ppm or more. Complex caustic-ferritic compounds are formed when the caustic dissolves the

protective film of magnetic oxide. Water in contact with iron attempts to restore the protective film of magnetite

(Fe3O4). As long as the high caustic concentrations remain, this destructive process causes a continuous loss of

metal. The thinning caused by caustic attack assumes irregular patterns and is often referred to as caustic

gouging (see Figure 7). When deposits are removed from the tube surface during examination, the characteristic

gouges are very evident, along with the white salts deposit which usually outlines the edges of the original

deposition area.

Figure 7 Caustic Attack Causing the failure of caustic gouging

The whitish deposit is sodium carbonate, the residue of caustic soda reacting with carbon dioxide in the air.

3.5 Acidic Attack: - This results in a visually irregular surface appearance, as shown in Figure 8. Smooth

surfaces appear at areas of flow where the attack has been intensified. In severe occurrences, other components,

such as baffling, nuts and bolts, and other stressed areas, may be badly damaged or destroyed, leaving no doubt

as to the source of the problem.

Figure 8 Acidic Attack Causing the failure



3.6 Corrosion Due to Copper: - Pitting of boiler drums and tube banks has been encountered due to metallic

copper deposits, formed during acid cleaning procedures which do not completely compensate for the amount of

copper oxides in the original deposits. Dissolved copper may be plated out on freshly cleaned steel surfaces,

eventually establishing anodic corrosion areas and forming pits very similar in form and appearance to those

caused by oxygen. Copper deposits and temperatures over 1600°F can cause liquid metal embrittlement. Weld

repair of a tube containing copper deposits leads to the failure shown in Figure 9.

Figure 9 Failure due to metallic copper deposits

3.7 Hydrogen Attack: - Since around 1960, hydrogen attack, or embrittlement, has been encountered with

increasing frequency in high-pressure, high-purity systems. It is not encountered in the average industrial plant

because the problem usually occurs only in units operating at pressures of 1500 psig or higher. When

contaminants lower the boiler water pH sufficiently, the acid attack of the steel generates hydrogen. If this

occurs under hard, adherent, nonporous tube deposits, the hydrogen pressure within the deposit can build up to

the point at which the hydrogen penetrates the steel tubing. Ruptures are violent and sudden, and can be

disastrous (see Figure 10)

Figure 10 Hydrogen Attack Causing the Ruptures

4 Tensile Testing. Two 12-inch sections were processed through a typical infiltration brazing furnace cycle

without the application of cladding material. One sample was subsequently normalized at 1,675º F and rapidly

cooled (specific rates are proprietary). A third 12-inch control sample was cut and left in its original state. All

three 12-inch tube sections were then sent to an independent laboratory for ASTM E8 tensile testing. Three

samples from each of the three 12-inch sections, for a total of nine samples, were tensile tested.



5 Proximate Analysis Test: - Proximate Analysis test is carried out to determine the percentage of fixed

carbon, moisture, ash, and volatile matter is coal

Result & Discussion

1 Metallographic Test Result - Microstructure of failure tube sample shown that alternate regions of pearlier

(dark) & ferrite (bright), it is a rolled structure.

Discussion - After carried out careful observation of microstructure as shown in figure 12, there is no

transformation of ferrite to Austenite. In above test the microstructure shows that there is alternate region

pearlite & ferrite shows given structure is rolled structure and there is no effect on increasing temperature of

steam in reheater on tube.

Lab Test Report –

The Metallurgical tests were conducted in the laboratory of metallurgy in VNIT, Nagpur and the following test

reports were taken accordingly as per experiment conducted. See figure 13 for the test report of microstructure

at away from the fracture when Normal ferrite & pearlite and figure 14 for the test report of microstructure at

fracture for Martensite / bainite & no free ferrite.

Fig.ure No 11 Microstructure at 100X

(The above Microstructure shows Alternate Region of Normal ferrite & pearlite.)

Figure. No 12 Microstructure at away from fracture (Normal ferrite & pearlite)

Figure. No 13 Microstructure at fracture (Martensite / bainite & no free ferrite)



2 Flattening Test Result:

A section of tube of length equal to 1.5 times the outside diameter, but not less than 50 mm, shall stand being

flared with a tool having 60 or 45 degree included angle until the tube at the mouth of the flare has expanded to

the percentage given below without cracking.

Tube

Grade

% expansion in outside diameter D for

a d/D

0.6 and

under

Over 0.6 to 0.8

including

Over

0.8

WC1 12 15 19

WC1 12 15 19

WC3 10 12 17

d = inside diameter of tube.

Table 3 flattering test results.

Discussion:-The flatting test is performed as IBR act 1950. In this test calculate distance H = 32.84 mm

indicates no cracks present on given tube. This indicates the given material of tube is ductile material and failure

of the tube is not occur do to short term overheating.

3 Corrosion Test Result:

Corrosion product is to found loose, brown in color.

Pitting is not found on both the surfaces.

Oxide film is not found on both the surfaces



Discussion

The third result of corrosion test is directly related failure of tube is due to hydrogen damage in hydrogen

damage failure damages occur due to heavy scales deposit on water/ steam side of boiler tube concentrate

sodium hydroxide will remove the protective magnetic film. In hydrogen damage when the protective oxide

layer destroyed from inner side and outer side of tube the reaction of iron with concentrate sodium hydroxide

form sodium ferrite and atomic hydrogen.

Fe + 2 NaoH - Na2Feo2 + 2 H

When hydrogen trapped between steel a scale, hydrogen react with iron carbide formed methane. Methane

Formation weakens the steel. It is necessary to avoid excessive water deposition & control Ph value the feed

water. The given tube fail is due to hydrogen damage because of protective oxide layer from inner side and

outer side is reduces.

4 Tensile Test Results: - Tensile test results of Tensile Testing and calculated Yield Strength are tabulated

below. Results shown in the center section of the table indicate that subjecting the tubes to a typical brazing

cycle reduced the tensile strength of the material to its minimum allowable level of 60 ksi, and reduced the

material yield strength to below its minimum allowable level of 37 ksi.

Tensile Test Result

Tensile Yield Elongation

Strength

(ksi)

Strength

(ksi) (%)

Control sample

1 68 46.7 34.6

Control sample

2 69 46.5 35.2

Control sample 67 46.2 35



3

Average 68 46.5 34.9

Braze Cycle

Sample 1 59.5 33.4 33.5

Braze Cycle

Sample 2 60.5 33.1 32.9

Braze Cycle

Sample 3 60 32.8 31.6

Average 60 33.1 34.9

Brazed and

Normalized

Sample 1

59.5 36.1 36.3

Brazed and

Normalized

Sample 2

60.5 37.7 38

Brazed and

Normalized

Sample 3

60 37.1 37.8

Average 60 37 34.9

Table 4 Tensile test result.

The normalization heat treatment process, as shown in the bottom section of the table, increased the material

yield strength to the minimum allowable level of 37 ksi



Graph 4 Tensile test result

5 Proximate Analysis Test Result:-

Proximate Analysis Test Result

Moisture content in coal 5.82%

Ash content in coal 40.25%

Fixed carbon in coal 30.44%

Volatile matter in coal 23.49%

C.V. of Coal 3840Kcal

Chemical Composition (W / T %)

% C % SI % MN % S % P

0.19 0.26 0.48 0.014 0.016

Discussion:-The above value of moisture Ash, fixed carbon, and volatile matter in coal indicate the quality of

coal is used in power plant is not inferior and there is no effect of coal quality on tube failure.



Conclusions

After carrying out failure analysis of boiler tube, it is found that major failure occurred in reheater, super heater

and economiser tube. In reheater due to high temperature of steam, tube failure occurred. The reason for such

failure is short term overheating and long term overheating. To avoid the failure of boiler tube due to short term

overheating, the flow starvation due to low drum level is suggested. Also it is necessary to flush the boiler 2-3

times before hydraulic test. Another reason for tube failure is corrosion. To avoid the failure of boiler tube due

to corrosion, it is suggested to maintain water chemistry, not to run the boiler in condenser leakage condition

and also maintain PH value is 9.3.

Presence of sulfur in the oil ash deposited on the fireside surfaces of the tube appears to be the main cause of the

failure of the boiler tubes at Al-Khobar Power Plant.

References:

• Reid, W. T. External Corrosion and Deposits - Boilers and Gas Turbines. New York :Elsvier 1971.

• Stringer, J. “High Temperature Problems in the Electric Power Industry and their Solutions”, in High

Temperature Corrosion. Ed., R. A. Rapp. Houston : National Association of Corrosion Engineers,

1983, p. 389.

• French, D. N. “Liquid Ash Corrosion Problems in Fossil Fuel Boilers”, Porc, Electrochem Soc.,

(1983), 83-85, p. 68.

• “Corrosion in Fossil Fuel Power Plants”, in Metal Handbook, Vol. 13 ed. B. C. Syratt, Metals, Park,

Ohio : American Society for Metals, 1987, p. 985.

• Porta R. D. and H. M. Herro, “The Nalco Guide to Boiler Failure Analysis. New York : McGrawll Hill,

1991.

• Dooley, R B. “Boiler Tube Failures - A Perspective and Vision”, Proceedings International Conference

on Boiler Tube Failures in Fossil Plants, Palo Alto, California : EPRI, 1992.

• Calannino J., “Prevent Boiler Tube

• Calannino, J. “Prevent Boiler Tube Failures Part II : Waterside Mechanisms”, Chemical Engg.

Progress, November 1993, p. 73.



• Hendrix, D. E., “Hydrogen Attack on waterwall Tubes in High Pressure Boilers”, Materials

performance, (1995), 32(8), p. 46.

• Public Works Technical Bulletin 420-49-21, “Boiler Water Treatment – Lessons Learned”, Nov. 1999.

• 11. R. K. Dayal and N. Parvathavarthini, “Hydrogen embrittlement in power plant steels”, pp 431-451,

Sadhana, Vol. 28, Aug. 2003.

• 12. Glenn N. Showers, PE, “ The importance of Burner Management Control”, pp 39-41, HPAC, Dec.

1997.

• 13. S. Tuurna, O. Cronwall, L. Heikinheimo, M. Hanninen, H. Talja, O. Tiihonen, "State of Art Report

Lifetime Analyis of Boiler Tubes”, VTT Technical Research, Oct. 2003.

• M. N. Hovinga, G. J. Nakoneczny, “Standard Recommendations for Pressure Part Inspection during a

Boiler Life Extension Programme”, International Conference on Life Management and Life Extension

of Power Plant, May 2000.

• Darryl Rosario, Peter Riccardella and Thomas Sherlock, “A Risk Management Approach for Boiler

Waterwall Tube Failure”, EPRI Maintenance Conference, June 1999.



Designing 5 MW Grid connected solar power plant with software

simulation

DR.R.N. Singh and Kumar Pawar

[email protected], [email protected]

Abstract

The present report is based on the designing of 5 MW Grid Connected Solar PV Power Plant to be

installed in Rajgarh District of Madhya Pradesh. The report covers the various aspect of designing of grid

connected solar PV Power Plant including collection of meteorological data, selection of module and inverter,

designing of mounting structures, shadow analysis, and The PV designing software PVSYST is also used for the

designing and simulation of this Power Plant.

Keywords:

Handbook of solar radiation by Anna Mani.

Solar energy and surface metrology (NASA).

1. Introduction

Tata International Limited was established in 1962 as Commercial and Industrial Exports Ltd (CIEL) to promote

exports of Tata Group products and services as well as those of other reputed Indian manufacturers. The

company was renamed as Tata Exports in 1968 and has evolved to become an International Business Company.

The company assumed the name Tata International Limited (TIL) in March 1998 to reinforce its evolution from

an exporter to an internation0al business company. TIL is one of largest export houses in India with the status of

Five Star Export House. The company has five Global Business Units namely Leather & Leather Products

(L&LP), Steel, Minerals, Engineering and Bulk Commodities & Chemicals.

The L&LP business started in 1975 with the establishment of integrated Leather Complex at Dewas;

manufacturing Finished Leather, Leather Garments and Footwear. The business has since consistently grown

and has taken a global shape with a subsidiary in Hongkong; front offices in Shanghai, Dong Guan, London;

supply chain bases in Bangladesh, China and across India (primarily Chennai); and global sourcing of raw

materials & other inputs. L&LP Dewas & Chennai operations are ISO-9001 certified and the own

manufacturing set-up at Dewas ISO 14001 certified tannery, largest in India.

L&LP operates its business through three business lines – Finished Leather, Leather Garments & Articles and

Footwear. The three businesses are lead by respective Global Business Heads. L&LP is largest exporter of

leather & leather products from India since 1982, with 3.8% share. L&LP has consolidated its leadership in the

industry as world’s largest producer of Goat & Sheep leathers, being among top 10 producers.



Of Finished Leather worldwide and has already strategic plans in place for an exponential growth of

around 20% per annum in next 3 years.

The Leather Garment and Footwear Business exports products to the leading brands of the world. The Articles

business is integrated with the Leather Garments Business and includes wide range of products from Luggage &

Portfolios to Wallets & Purses. Our association with best international designers and design studio in Italy and

Spain enable us to produce value added and customized products in vogue with the latest International trends.

The Company is committed to good corporate citizenship by being proactive, integral and responsible member

of communities and environment in which it operates. The company’s Environmental Policy demonstrates its

commitment to the environment.

The principal potential impact of the L&LP operations on society is from its Dewas manufacturing facility.

L&LP has been certified with ISO 14001 at Dewas which ensures that systems and processes are implemented

for improved environment management. It won the Rajiv Gandhi National award for environment protection in

the year 2002 and MP State Award for Environment Conservation In 2004.

2. Methods and Materials

2.1 Data collection methods and using material:

As Handbook of solar radiation was not available so Data has been taken from NASA (Surface meteorology and

solar energy). Following data has been collected from NASA for the assessment of solar energy potential in

Rajgarh.

Average solar radiation on horizontal surface in Rajgarh.

Average solar radiation on tilted surfaces in Rajgarh.

Average maximum and minimum solar radiation in Rajgarh.

Average ambient air temperature in Rajgarh.

Average sunshine hours in Rajgarh.

Average wind speed.

All the analysis has been done with the help of this data.

2.2 Selection of PV Modules



After the collection of Meteorological data different PV modules were compared according to their efficiencies

and types. PV modules based on thin film technology are not considered as their efficiency is less and there is

probability of breakage. Around 5 % of breakage has been reported as per different case studies. Only Mono

crystalline and polycrystalline PV modules have been considered for the project. Both monocrystalline and

polycrystalline modules were compared on the basis of their efficiencies and cost. A Chinese company has been

considered to supply the modules. Only modules with rated power greater than 200W have been considered for

the project.

2.3 Selection of inverters

Different inverters of rating 500 kW are compared from different companies as per the information given by the

vendors. As inverter is to be connected to grid, only grid connected inverters are considered for the project.

Inverters are compared on the basis of following parameters.

Efficiency

Total harmonic distortion.

IP protection rating.

MPPT voltage rating.

Software for control and monitoring.

Technology used in the inverter.

Isolation protection.

Standby losses.

Maximum DC input current and DC voltage.

2.4 PVSYST software simulation

The calculations done in the software are based on following inputs.

Planned capacity.

Location.

Type of system.

Type of module and type of mechanism required for mounting of PV array.



Inverter capacity.

For shadow analysis we have to give the distance between the rows. Although this distance can also be

optimized.

After giving these inputs all the necessary calculations regarding number of modules to be connected in series

and number of strings to be paralleled are done by software and based on these necessary calculations for the

energy output of the system are done by software.

3. Observations and Measurements

Table 3.1 Monthly Average Maximum Global solar Radiation on tilted surfaces:

S.No Month

Solar Radiation (kWh/m2/day)

Tilt angle =250 Tilt angle =400

1 Jan 6.44 6.97

2 Feb 6.74 7.02

3 Mar 7.32 7.23

4 Apr 7.27 6.24

5 May 6.71 5.89

6 Jun 6.27 5.86

7 Jul 5 4.44

8 Aug 5.3 4.91



9 Sep 5.6 5.38

10 Oct 6.66 6.81

11 Nov 6.42 6.91

12 Dec 6.25 6.85

13 Avg 5.85 6.32

Table – 3.2 Specification of PV array for 5 MW

S.No Parameter Specification Unit

1 Module’s rated power 260 W

2 Modules in a string 18 Nos

3 String power rating 4.691 kW

4 Strings in an array 108 Nos

5 Total arrays 10 Nos

6 Array power rating 507 kW

7 Total number of modules

required 19440 Nos



Table – 3.3 Area requirements with the help of shadow analysis for PV arrays corresponding to tilt angle 250

and 400

Tilt angle 25 o 40 o

Area required for one string (Sq m) 54.04 73.86

Area required for 216 strings (1.008 MW) (Sq m) 11673 15953

Area required for 1080 strings (5.04 MW) (Sq m) 58363 79768

Area required for 5 MW (Acre) 14 19

4. Result and Discussion

Fig 4.1 Block diagram for 5 MW solar PV power plant PVSYST software simulations

Table-4.1Calculations of power decrement with rise in temperature

Onth Wp (Tavg)amb (NOCT)rated

(°C)

solar

insolation

(kWh/m2

Monthly

Avg Day

light

(Gavg)

(W/m2) (Tcell)avg

η

Power at

cell temp



day) hours W/0C (W)

Jan 260 21.6 45 5.56 10.9 510 34.35 -0.5% 247.842

Feb 260 23.65 45 6.24 11.4 547 37.33 -0.5% 243.965

Mar 260 28.4 45 6.59 12 549 42.12 -0.5% 237.732

Apr 260 31.5 45 6.49 12.6 545 44.37 -0.5% 234.804

May 260 31.95 45 6.18 13.2 468 43.65 -0.5% 235.749

Jun 260 29.10 45 5.52 13.5 408 39.32 -0.5% 241.381

Jul 260 26.55 45 4.03 13.3 303 34.12 -0.5% 248.137

Aug 260 26.10 45 3.12 12.9 288 33.30 -0.5% 249.197

Sep 260 27.15 45 4.83 12.3 392 36.96 -0.5% 244.442

Oct 260 27.45 45 5.83 11.6 502 40.01 -0.5% 240.480

Nov 260 25.35 45 5.82 11 529 38.57 -0.5% 242.344

Dec 260 22.40 45 5.36 10.8 496 34.80 -0.5% 247.250

Avg 280 26.31 45 5.51 12.13 459 38.24 -0.5% 242.788

Table 4.2 PVSYST software simulation





5. Conclusions

After theoretical calculations the simulation of Grid connected 5 MW solar PV Power Plant was done with the

help of PVSYST software. The module, inverter and all the meteorological data is taken from the software

database and also the weather data files are imported from NASA database. The different tables and reports

generated according to the inputs given in the software are given on the upcoming pages.

System can be sized as per the requirement.

Orientation and tilt angle can be optimized for maximum power production.

Shadow analysis can be done in the software.

Different losses can be calculated with the help of software.

Calculations for normalized performance coefficients Calculations for inverter losses.

Solar pumping systems and stand alone systems can also be designed and simulated with this software

Cost analysis can also be done with the help of software.



References

• Solar Energy- Principle of thermal collection and storage by S P Sukhatme and J K Nayak, Thired

Edition, Tata-McGraw-Hill Publication company ltd, Delhi.

• Planning and Installing Photovoltaic System by- A guide for installers, Architect’s and Engineer’s

• www.susdesign.com

• www.solarphotovoltaic.net

• www.wikipedia.org

• www.indiasolar.com/

• www.pvresources.com/en/inverter.php

• www.solardirect.com/pv/inverters/inverters.htm

• www.automation.siemens.com/mcms/solar-inverter.aspx

• PVSYST Software- Simulation and Shading analysis.

Adaptation of New Technology on “Carbon Capture, Sequestration and conversion of fly ash into artificial

zeolites

SP Singh

Ex. Member (UPSEB)

Council Member, Institution of Engineers (I)

Reference:

• International Conference on Green Power Generation–Vision 2020 organized by The Institutions of

Engineers (India), Anpara Local Centre at HINDALCO (Renusagar Power Division) Renusagar, Distt.

Sonbhadra (UP) on 10th to 12th December 2010.



Carbon Capture & Sequestration

Government of India has declared its policy on CO2 abatement by the announcement and adoption of the

‘National Action Plan on Climate Change’. It has also made voluntary commitment at the Copenhagen Summit

that the Country shall decrease its Carbon Intensity by 20% by 2020 and 50% by 2050. The path chosen makes

it imperative that the CO2 which forms 95% of the GHG emissions be reduced. The bulk of CO2 is emitted by

the Thermal Plants in the Power Sector. For EPA regulations to be implemented there have to be a road map as

to how this can be done without major impact on the cost or efficiency. RGTU Bhopal has taken lead in

establishing India’s first CO2 Capture & Sequestration Plant.

The thermal plants in India have a thermal efficiency of 35% and an emission ratio of 0.90Kg/kWh of CO2

emissions as published by CEA. The reduction of 20% intensity would translate to a decrease of 0.20Kg/kWh of

CO2 emissions to 0.70Kg/kWh CO2 emissions by 2020. This decrease is possible by a combination of

abatement and recycling measures. However, the CO2 reduction by an Amine system of 30% CO2 capture

would mean a decrease of Thermal Efficiency by 2%. This, can be demonstrated only after establishment of full

scale CO2 Capture and Sequestration plant on an actual coal fired Unit and carrying out System Optimization

studies.

It is the need for the future looking to environment & climate change issues, and decided to have round table on

the above said issues to discuss in detail.

The round table was held and following issues were discussed:

Adaptation Technology on Existing Plant / Green Field Units

Technology Transfer v/s Departments within the country

Funding aspect from GOI.

The round table unanimously concluded that “Carbon Capture & Sequestration” should be installed in one of

the plant in the existing power belt of Singrauli region. Following Plants were suggested-

Anpara Thermal Power Station 3 X 210 MW & 2 X 500 MW

Renusagar Power 60 MW unit-1.

STPS NTPC Shaktinagar



RGTU will be Principal consultant to this project and Institution of Engineers (I) will coordinate the entire

activity.

Another new technology discussed by the I E (I) forum is the “Conversion of Fly Ash into Artificial Zeolites”

had to be installed in one of the above plants in the existing power belt of Singrauli region.



An Electronic Sensor Based Photo Voltaic Tracking System

Mr. Priyadarshi

[email protected]

Abstract

This paper presents a cost effective way of tracking of Solar PhotoVoltaic panel using electronic sensors.

Solar PhotoVoltaic Panels are used to harness Solar Energy. The main objective of this work is to utilize the

maximum of solar radiation by minimizing the angle between solar incident ray and the normal to the tilted

surface i.e. to minimize angle of Incidence.

Introduction

Electricity generation is the process of creating electricity from other forms of energy. Solar power is the

conversion of sunlight into electricity, directly using photovoltaics (PV). The photoelectric effect refers to the

emission, or ejection, of electrons from the surface of, generally, a metal in response to incident light.

A photo voltaic panel is a series combination of PN junction. When sun radiation full of photons falls on PN

Junction, results in diffusion which starts power generation. PV converts light into electric current using the

photoelectric effect.

Photovoltaic power generation employs solar panels comprising a number of cells containing a photovoltaic

material. Materials presently used for photovoltaics include monocrystalline silicon, polycrystalline silicon,

amorphous silicon, cadmium telluride, and copper indium selenide/sulfide.

Sun path refers to the apparent significant seasonal-and-hourly positional changes of the sun (and length of

daylight) as the Earth rotates, and orbits around the sun.

With respect to earth sun moves in two paths –

East To West

North To South and vice versa

Due to the rotation of earth on its own axis east to west movement of sun is possible. At every place on earth

sun rises in east and sets to west. Due to this action the solar azimuth angle and air mass ratio continuously

changes. As a result the resultant radiation continuously changes.



As we know the earth is tilted at 23.5° on its pole-to-pole axis. Due to this there is seasonal variation found

where sun travels back and forth from north to south. The sun comes overhead at the places which are in

between Tropic of cancer and Tropic of Capricorn. Due to this variation there is a slight change in radiation

coming on earth.

Solar PV Tracking

There are various tracking systems as- Concentrated Photovoltaic (CPV) Module Trackers, Single Axis

Trackers, Horizontal Single Axis Tracker (HSAT), Vertical Single Axis Tracker (VSAT), Tilted Single Axis

Tracker (TSAT), Polar Aligned Single Axis Trackers (PASAT), Dual Axis Trackers , Tip – Tilt Dual Axis

Tracker (TTDAT), Azimuth-Altitude Dual Axis Tracker (AADAT), Active tracker, Passive tracker,

Chronological tracker.

Suggested Single Axis Tracking

The major sections of this tracking are listed below and will be explained in detail.

Sensor

Ball Bearing

PV panel

Electronic Ckt.

DC Motor

LDR SENSORS

Panel

Ball Bearing

E- Ckt



Observations and Measurements

By Implementing The methodology I found drastic change in efficiency of PV module. The measurements are

listed below-

S.No.

Without

tracking(KWh/m2/Day)

(From Nasa)

With Tracking(KWh/m2/Day)

1. 6.18 7.4

2. 6.68 7.8

3. 6.72 7.9

4. 5.62 6.6

Results and Discussion

We can see after tracking the panel we are collecting more and more solar radiation. The efficiency increase

varies from 18 -20 %.

If we increase the resolution and go for dual axis tracking the efficiency can be increased up to 30-35%.

The same concept of tracking can be easily extended for dual axis tracking.

Conclusions

The system developed is found to be very easy to implement. The maintenance is very less. System complexity

is very less.

The concept can be extended to Concentrator tracking with further R& D.



Technical paper on Energy Saving Aspect in Boiler Feed Pump in Thermal

power plant

Santosh M. Mestry and Paresh Kumar Parhi

[email protected], [email protected]

Profile

Power Plant Name Dahanu thermal Power Station

Location Dahanu, Distt- Thane, Maharashtra

Power Plant Capacity 2*250 Mw

Introduction

In a thermal power plant, steam is produced and used to spin a turbine that operates a generator. Shown here is

a diagram of a conventional thermal power plant, which uses coal, oil, or natural gas as fuel to boil water to

produce the steam. The electricity generated at the plant is sent to consumers through high-voltage power lines.



Introduction on BFP of Thermal Power Plant

There are two 100% capacity Boiler Feed Pumps per unit. Boiler feed pump set consists of a booster stage

pump, directly driven from one end of the shaft of an electric motor, a pressure stage pump driven from the

opposite end of the motor shaft through a variable speed drive ( Hydraulic Coupling ) unit.

Each pump set is supplied with suction strainer, NRV on the pressure stage pump discharge and modulating

minimum flow re-circulation system. Recirculation line is provided before discharge valve with a pneumatic

control valve, which maintains a minimum flow of 240 T/hr. Each pump is of three stage horizontal cartridge

type.

Boiler feed pump is the major power consumer among all power consuming equipment in the power plant. HT

motor consumes almost 95% power in thermal power plant. Out of which BFP is a major contributor of

auxiliary power consumption. It is illustrated in following chart.

There are 3-case study explained on Energy Saving Aspect in Boiler Feed Pump

Replacement of pump cartridge

Drum Level Controlled by BFP SCOOP operation in 3-Element mode instead of DP mode

Replacement Of Recirculation Valve Of Boiler Feed Pump

Case Study-1: Replacement of pump cartridge

Background

One of the major auxiliaries of DTPS is Boiler Feed Pump (9000 KW). The purpose of Boiler Feed Pump is to

pump feed water to boiler drum, provide spray water to HPBP, APRDS, De-super heater station. One BFP

caters to entire requirement of the process. The second pump remains as an auto stand by equipment.

AUX. POWER CONSUMPTION PATTERN

HT MOTOR LOAD 94%

LT MOTOR LOAD

5%

MISC.1%

2.78

0.22

1.381.41

0.26

0.74

0.35

0.29

0.26

2.37

BFPsFD FANSIDFANSPAFANSCEPMILLSCHPAHPComp.airOthers



Observation

The Boiler Feed Pump at DTPS is of multistage (three stage) type. It was observed that the BFP-2B is taking

much higher current than other BFPs. From performance curve of the pump also it was clear that it is consuming

much higher power corresponding to the flow.

Technical & Financial analysis

Three root causes shortlisted from technical analysis.

Wear & tear of pump internals due to ageing

Possible damage to internal gasket

Short-circuiting of suction and discharge chambers

It was concluded that loss is taking place due to interstage leakage or recirculation.

Hence decision was taken to replace the cartridge of pump.



Impact of Implementation

After replacing the cartridge the current drawn reduced by 70 Amp.

Power saved per day = √3*V*I*PF* 24

= 1.73*6.6Kv*70amps*0.85 * 24=16304 KWH

Power saved per year=5950960 KWH

Saving of cost= 5950960*3.5= Rs2,08,28,360

Simple Pay Back Period: 70 days with 40 Lakh Rs. Investment

Case Study -2 :

Drum Level Controlled by BFP SCOOP operation in 3-Element mode instead of DP mode.

Background

Boiler drum level control is done by BFP scoop & feed water regulating station (FRS) control valve in two

ways,

DP mode

Three element mode

In DP mode BFP scoop maintain the DP across the FRS as per set point & control valve regulate feed water

flow as per three element errors to maintain drum level as per set point. Whereas in three element mode, scoop

maintain the drum level as per three element error keeping FRS control valve wide open.



Observation:

In most of units having MD BFP only, drum level control is accomplished through DP mode because it believed

that is robust control. But it results in appreciable energy loss due to throttling of FRS valve. DP set point for

scoop is observed between the range of 7-10 kg/cm2;

hence same is the pressure drop across FRS valve. Reason of high DP set point to increase differential pressure

to improves the control. Disadvantage of DP mode is increased pressure loss & Energy loss.

Technical & Financial Analysis:

Energy Saving potential in throttled FRS valve is given below which clearly indicates pump power loss can be

optimized by minimizing pressure drop across the valve.

DP optimization in “DP” mode gives no substantial energy saving due to action of FRS valve. Further pressure

drop reduction is only possible in three element mode scoop operation where FRS valve is kept fully open

Pump power (100- efficiency) Pump losses % = ------------------------------------

Generated Load

In 250 MW capacity unit having overall efficiency of 38 %

and for pump power = 7 MW, DP =7.5 kg/cm2,

Total pr. Developed by pump = 180 kg/cm2,

Pressure drop across the valve x Pump Power

Energy Saving Potential = -------------------------------------------------------------

Total Pressure rise across the Pump



Energy saving potential & Calculated pump loss is given below which are unusually high figure.

Energy saving potential =29 %

Calculated pump loss = 1.736 % of Boiler Heat I/P

As flow control by throttling in case of high power pump like BFP is inefficient, flow control by speed

regulation by means of BFP scoop is adopted.

Effect on System Curve with Throttling HEAD

Pump



FLOW

In the above system, pump system curve get shifted to lower efficiency region as throttling increases. Point A is

the best efficiency point (BEP) where valve is full open at the pump’s best efficiency point (BEP). But, in actual

operation, amount of flow in valve full open condition is not necessary hence we throttle the valve. To point B

to get desired flow.

The reduction in flow rate has to be effected by a throttle valve. In other words, we are introducing an artificial

resistance in the system. Due to this additional resistance, the frictional part of the system curve increases and

thus the new system curve will shift to the left -this is shown as the red curve. So the pump has to overcome

additional pressure in order to deliver the reduced flow. Now, the new system curve will intersect the pump

curve at point B. At point B, pump head is increased the red double arrow line shows the additional pressure

drop due to throttling. You may note that the best efficiency point has shifted from 82% to 77% efficiency. So

what we want is to actually operate at point C which is on the original system curve for the same required flow.

The head required at this point is reduced. What we now need is a new pump which will operate with its best

efficiency point at C. But there are other simpler options rather than replacing the pump.

The speed of the pump can be reduced or the existing impeller can be trimmed (or new lower size impeller). The

blue pump curve represents either of these options. It is not feasible to replace pump or trimming of impeller,

best solution is to reduce the speed. Hence flow control by speed control method is more efficient.

DP control mode & three element mode schematic is given below.

Scoop operation in DP mode

Scoop operation in three element mode



Changeover philosophy from DP mode to three element mode. (SCOOP Operation- DP mode & Auto. FRS

valve- Auto)

Take SCOOP and FRS control Valve in MAN.

Select three element mode of scoop operation.

Put scoop in AUTO. Observe scoop operation.

Gradually open the FRS valve fully.

Changeover philosophy from Three element mode to DP mode. (SCOOP Operation- Three element mode &

Auto. FRS valve- Manual)

Set the required DP set point

Gradually close the FRS valve so that DP across valve matches the DP set point

Take SCOOP in MAN. Select DP mode from three element mode.

Put SCOOP & FRS valve in AUTO. Observe the response.

DP mode is suitable in case of emergency & fluctuating load condition whereas three element mode is suitable

in steady load condition.

Impact of Implementation:

AMP. Gain/Hr KW saving/Hr GHG reduction KG/Hr

1 BFP-1A 10 97 83

2 BFP-1B 2.6 25 21

3 BFP-2A 4.2 40 35

4 BFP-2B 14.2 137 118



In DTPS, BFP scoop operation successfully tested in three element mode for each BFP.

Pressure drop across FRS valve is observed to be @ 3.5 kg/cm2 in valve full open condition.

Ampere saving achieve is given above Table.

Difference in energy saving may be due to change in vacuum, operating drum pressure & metering error.

BFP hydraulic coupling’s response time and subsequent change in drum level shows that drum level control

directly through BFP scoop operation in three element mode variation is quite feasible especially under steady

operating condition.

Simple Pay Back Period: Immediate with Nil investment

Case Study - 3 :

Replacement Of Recirculation Valve Of Boiler Feed Pump

Background

Boiler Feed pump is supplied with suction strainer, NRV on the pump discharge and modulating minimum flow

re-circulation system. Recirculation line is provided before discharge valve with a pneumatic control valve,

which maintains a minimum flow of 240 T/hr. This valve avoids dry run and overheating of pump.

Observation

It was observed that after certain running hours the suction flow of a loaded pump was much higher than the

discharge feed water flow.

Technical & Financial analysis

When recirculation valve of the BFP was further closed, the difference got reduced. Hence the manual isolating

valve was closed and it resulted in drastic reduction of suction flow .

Now the suction flow was matching with the discharge feed water flow. Hence it was suspected that some flow

is passing through valve seat.

After due maintenance of the existing valve not much improvement was observed. Hence it was decided to

replace the existing valve with an advanced class of drag technology valve.



Impact of Implementation:

After replacement of valve the current drawn by the motor of pump reduced by 60 amp.

Power saved due to the reduction current drawn by motor = 6.6*60*1.73*0.85

Power saved= 582 KWH/HR

Saving in cost/hr = 582*3.5= Rs 2037

Saving/year =2037*24*365=1,78,44,120

Investment = Rs 2500000

Simple Payback period = 2500000 / 2037 = 51days

Same valve replaced in all the 4 BFP with an investment of 1 crore which resulted in saving of Rs 7,13,76,480.

Conclusion

Thermal power plants contribute 70% of India’s power generation installed capacity. It is not possible to meet

the growing demand due to long gestation period of power plant. Only solution is to reduce auxiliary power

consumption by energy conservation & energy efficiency practices.

There is tremendous scope in power sector for reducing auxiliary power consumption (APC). In India, It is

estimated that; reduction in APC by 1%, equvivalant of generation of 5000 Mu of energy per annum. Saved

energy can be sold out. to minimize the gap between supply & demand.

This changed scenario impacted the bottom line of power generation utilities.

Hence the ways to retains one’s competitive edge in the fiercely competitive industry.



Heat Recovery Hot Water Heater Desuperheater in Refrigeration System

Vrajalal Kanetkar

[email protected] • www.refreconmagic.com

Process Industries / hospitality Industries requiring hot water

Hospitality Industry

Hospitals

Chemical and Pharmaceutical Industries

Economiser for Boiler water Pre-heater

Dairies and milk processing plants

Engineering Industries

Compressor Heat Recovery for Air Compressor

Waste heat recovery to make hot water from air conditioning compressor (use of our Desuperheater ) is one the

major tools available for Hospitality industry in general. Hospitality, Pharmaceutical, Dairies, and Process

Industries have also adopt this in recent past. Techno-commercial advantages of this heat recovery are incredible

and this is why international institutes like ASHRAE, CADDET, AEE, DOE in USA and now number of Indian

users are strongly supporting this concept.

Dairies and Hotels are bulk consumers of hot water at 500 to 700C. Invariably this hot water is generated using

prime energy either fuels or using electricity. In recent past good number of users meet their requirement

through solar hot water heaters. .

Using high-grade waste heat to generate hot water for boiler was a common practice adopted by users as well as

manufacturers for decades. There are number of good manufacturers to supply this system for industrial

application.

We are discussing here commercial success of low-grade heat in reciprocating or screw compressors to generate

hot water. At REFRECON we have now more than 100 successful installations saving crores of rupees for our

customers (Aggregate savings withal installations put together.)



Users or refrigeration systems and air compressors are at great advantage to offset their hot water heating cost

by implementing heat recovery. Users of REFRECON system have reduced 50 to 70% of hot water heating cost

along with number of other benefits. Successful heat recovery normally has several cascaded hidden benefits.

Refrecon has several success stories of recovery of this low-grade heat.

Adiabatic compression process generates high temperatures depending upon type of compressors used.

Reciprocating compressors have higher temperature after compression where as screws normally have lower

delivery gas temperature. But both have potential to deliver usable hot water for process need.

Dairies and Star Hotels are potentially large consumers of refrigeration and hot water. Cascading heat recovery

with cooling effect has great advantage for the system efficiency improvement along with reduction of energy

cost by adopting this heat recovery. Retrofitting old systems or installing new systems with hot water

desuperheater gives great advantage of operating cost reduction as well as stable and efficient operation of

refrigeration system.

Superheat in refrigeration is necessity for stable and safe process operation. Same superheat is also cause to

reduce operation efficiency of compression. Heat Recovery Hot Water Heater - Desuperheater installation with

refrigeration is boost to dairy and hotel industry in general saving operating energy cost and avoiding pollution

due to fuel use. This also has added advantage of eco-friendly image building when globally every one talks of

green gas emission reduction.

All compressors deliver hot gas/air at outlet and this gas is either condensed or cooled after compression

rejecting heat to atmosphere. Converting this hot gas into hot water substantially reduces heating cost to

generate hot water.

Enclosed schematic technically explains mode of connecting this heat recovery system. Material of Construction

(MOC) will depend upon the type of gas/air handled by compressor. While SS is most safe for water some times

comer also can be deployed to optimise cost of manufacturing. Some built in safeties are essential to ensure

We will discuss two specific applications in this paper.

Dairy and milk Processing

Hotels, hospitals or hospitality industry

1. Dairy and milk Processing

Refrigeration and boiler constitute more than 75 % of operating energy cost of dairy. As much as dependability

of these systems is important, operating plant efficiency and consistency in performance is also required to limit

processing cost of milk. Built-in improvement in operating efficiency constitutes major saving opportunities in

dairy utility system. Installation of desuperheater for recovery of waste heat is major step in this direction.



REFRECON has several successful desuperheater installations in operation since past eight years. The

technology is successfully implemented for various systems using ammonia and R 22 refrigerants.

Dairy cooling requirement

1. Pasteurisation 2. Cold storage 3. Milk chilling

Hot water requirement

a. Boiler feed water b. Crate / Can washing

c. Tanker washing d. CIP

Conventional mode of hot water generation

a. Use of direct fuel fired hot water heaters

b. Direct steam injection

c. Condensate recovery after steam use in plant

Desuperheater mode of “ FREE “ hot water generation in Dairy

With cold storage and IBT in operation in dairy, chilling plants and refrigeration compressors operate almost 24

hours per day. IBT takes care for fluctuating cooling demand by generating appropriate ice thickness on

ammonia coils to chill the milk protecting product quality.

Adiabatic compression in ammonia compressor results in high discharge gas temperatures at compressor outlet.

(1200 C and above) This gas is cooled and condensed in condenser and stored in receiver at 12 to 16 - kg/cm2

pressure and atmospheric temperature. Condensing temperature (varying between 300to450 C) vary depending

upon type of condenser cooling and atmospheric conditions.

Desuperheater installed in ammonia circuit between compressor discharge and condenser, removes high

temperature gas heat and passes entire gas to condenser to condense similar to normal refrigeration cycle. Gas

heat removed in desuperheater heats circulating water up to 550 – 700 C. This recovered heat in the form of hot

water is available free of cost for various requirement in dairy. Refrigeration plant operates almost 24 hours per

day generating hot water at specific rate. This hot water is stored in adequately sized hot water tank to meet

demand of hot water in plant as and when required.



ADS series of REFRECON desuperheater is specifically designed for ammonia compressors. MOC and process

parameters are appropriately matched for life long consistency in performance. The fully welded construction of

desuperheater has complete safeties required for installation and infinite life of operation. The desuperheater is

capable to withstand 40 bar pressure and is tested for bubble-tight leak-proof performance at 25 bar pressure in

the manufacturing process. The perfected design results in flaw less commissioning during field installation.

The performance consistency has been proven with number of installations. Though available heat potential for

reciprocating compressors is large REFRECON has successfully installed desuperheaters on ammonia screw

compressors (180 TR and 250 TR) and proved its commercial viability.

2. Hotels and Hospitality Industry

Air conditioning has been primary need of hospitality industry. At the same time fuel fired (Diesel or Furnace

oil) boilers are used to generate hot water for domestic use, cleaning, or kitchen. Air conditioning rejects heat to

atmosphere through air-cooled or water-cooled condensers. Heat rejection and fresh hot water generation is

done across the wall at facility basement and seldom noticed for complimenting each other. While this energy is

of low-grade, it still represents waste energy. Combining these two, (waste heat and fresh heat generation) make

cleaver sense of energy conservation and saves substantial money.

In the tropical country like India, cooling is a non-compromising need. Interruptions in air conditioning or loss

of efficiency of cooling are normally not acceptable, as it directly reflects quality and cost of facility service.

Under this circumstance facility owners need comfort from O & M staff as well as consultants to implement the

change in the system.

Heat recovery is a secondary activity. Generally it has standby operating system to provide required hot water.

Any change made in the total comfort system must ensure no alteration in the performance of refrigeration

cycle. In fact present experience is that cooling capacity of existing system has improved to a small extent.

Economics of Heat Recovery Desuperheater

The economics of this heat recovery is attractive. It is important to ensure recovered hot water displaces prime

energy used by facility. The economics can be adversely affected due to poor operating hours of compressor.

The system evaluation and total integration with facility hot water system is essential step to ensure favorable

economics of project. Though there are other advantages of heat recovery system, over empathising of these

benefits can create serious situation. While system is conceptualised use of hot water should be properly

estimated so that recovered heat is not wasted. Providing metering of hot water flow and recording the operating

temperature will help to monitor and compare post implementation performance of system.

Following general norms may be useful for estimating hot water need by process

1 liter of fuel oil delivers 270 liters of hot water at 550C



1 kWh of electricity delivers 28 liters of hot water at 550C

Hotel uses 200 to 300 liters hot water per occupied room

Dairy needs 0.5 to 0.75 liter hot water at 600C for general sanitation per liter of milk processed.

There are hundreds of success stories of heat recovery desuperheater. Every year Beuro of Energy Efficiency

(BEE) under Ministry of Power gives energy conservation awards for outstanding efficiency improvement

performance in India. Since 2006 award winners in dairy sector successively have been honored who have been

users of REFRECON desuperheater and it is proud moment for us to say that each of these award winners have

praised for REFRECON desuperheaters in their presentation to BEE as well as expressed same opinion on their

website. Needles to say we are proud of our customers for this action.



Cold storage design and operational parameters influencing energy

consumption in composite climate of Indore

R.K. Singh, S.P. Singh, R.L. Sawhney

[email protected]

Abstract

With high economic growth rates India is a significant consumer of energy resources. Like the other sectors,

cold storages are also the significant consumers of electrical energy. In this paper, few energy influencing

parameters of cold storages were discussed. The study is based on the survey results of the actual potato cold

storages and it is able to explain the energy consumption patterns and energy consumption levels of cold

storages. The trend analysis and regression methods were used in the study to explain the influence of the

parameters on specific energy consumption. The results show that the capacity utilization factor, aspect ratio and

overall heat transfer coefficients of cold storages significantly affect the energy consumption of the cold

storages.

Key words: Cold storage, Energy consumption, Energy efficient building

Introduction

With high economic growth rates and over 15 percent of the world’s population, India is a significant consumer

of energy resources. In 2009, India was the fourth largest oil consumer in the world, after the United States,

China, and Japan. Despite the global financial crisis, India’s energy consumption has risen remarkably in the

past few decades. As the energy demand increases, energy conservation has been included on the agenda of the

developing countries like India [1]. Like the other sectors, cold storages are also the significant consumers of

electrical energy and will increase in future. Potato is a most eatable vegetable and used throughout the year in

human diet. The perishable nature of potato forces to keep it in a controlled environment. India is one of the

countries where potato is grown in large quantities. Being a second largest producer of potato, India produces

about 30 million tons of potato every year. The huge quantity of potato has gone wastage every year due to lack

of sufficient storage facility in the country [2]. Therefore, it is urgent need to develop the sufficient storage

facility for reducing wastage and emergences the opportunity to the producers for selling out their potato

commodity at good value.

Energy saving potential in Indian potato cold storages was reported earlier [3]; however, there is no clear cut

indication of energy consumption pattern of cold storage. In this situation, it becomes very significant to identify

and figure out the parameters those influence energy consumption of potato cold storages to further

development of new energy efficient cold storages, so as to put forward the corresponding energy saving

measures.



In this study, the impact of aspect ratio and effective overall heat transfer coefficient on the energy consumption

of potato cold storages were discussed using the trend analysis. Also, the variation in energy consumption with

capacity utilization factor was analyzed. Results arising from this study provide important reference materials

for the cold storage designers, architects, consultants, owners and operators in assessing electricity energy

consumption patterns and selecting a more accurate approach to estimate future energy demand. However, study

is limited for a small cluster of the composite climate in the country and results may influence in other part of

the same climate or in other climatic conditions. Therefore, similar study for other parts of the country would be

more significant for better results.

Study region

The surveyed cold storages are located in Indore region, which is a big chunk of cold storages. Indore is located

in the mid western part of India South of the Tropic of Cancer (latitude 22.71N, longitude of 75.91E). About 52

cold storages are functioning for preserving perishable items like potato and help greatly to regulate the demand

and consumption of these items throughout the year. The climate of Indore is composite having three distinct

seasons summer, monsoon and winter.

Data collection and analysis

This study intends to determine the energy consumption pattern of potato cold storages through field survey and

experimental procedures. A survey of 10 potato cold storages out of 52 in Indore and nearby area was

conducted. The survey was targeted to obtain data about construction pattern of buildings; design features of

building i.e. aspect ratio and orientation; types of refrigeration are being used and the intensities of their uses;

electrical energy consumption and storage pattern of cold storages.

The questionnaire was prepared and issued to the responsible person of the respective cold storages. Besides, the

questionnaire; also interviewed the owners, managers and operators during the data collection. Each interview

was performed for group of people. The obtained data was consisted the monthly electricity bills, building

construction pattern, storage pattern, refrigeration units and indoor environmental conditions. Out of the 10

surveyed cold storages in the sample, 7 were in private sector and 3 in Co-operative sector. The questionnaire

survey was used for surveying the cold storages situated in Indore and nearer area. This was considered a

reliable and efficient method because the author should had sufficient easy to justify the given information and

could visit frequently the considered cold storages and enable them to respond correctly to the questions in the

questionnaire. To improve the accuracy and completeness of the energy consumption information, the monthly

electricity bills were collected directly from the Madhya Pradesh State Electricity Board (MPSEB), Indore

region. MPSEB is responsible for supplying electricity to the cold storages in the region. Site visits had also

been made to all cold storages to justify the information provided in the questionnaire and measurements of

indoor environmental parameters like storage temperature.



Data of energy consumption and storage pattern for 10 cold storages were collected for four consecutive years

(2001-2004). The Specific energy consumptions (SEC) for four consecutive years (2001-2004) are given in

Table 1. The respective storage patterns of cold storages are shown in Figure 1.

Table 1. Annual Specific Energy Consumption (SEC) of Potato cold storages

Cold

Storage

Annual Specific Energy consumption(kWh/ton)

Y-2004 Y-2003 Y-2002 Y-2001

A 10.07 10.86 10.77 10.49

B 10.01 9.92 12.33 13.69

C 9.00 9.90 12.79 13.00

D 14.63 14.96 13.67 21.47

E 12.79 13.38 11.30 12.58

F 9.47 9.92 10.17 9.66

G 9.70 10.84 10.38 10.61

H 15.56 16.82 9.64 10.80

I 11.35 12.05 26.08 13.81

J 12.15 8.90 11.93 12.38



Figure 1. Annual potato storage patterns for years 2001-2004

Buildings of cold storages still remain the second largest consumer of energy and will be singled out for the

present study as a target for energy conservation. In general, the factors that affect cooling energy consumption

in a cold storages building include thermal conduction gains through building envelop and infiltration. The

amount of thermal conduction gain mainly depends on aspect ratio; envelop orientation, exterior colour,

construction materials as well as shape of buildings [4-7]. The survey was done for all described parameters of

building envelop of cold storages. The buildings were insulated and rectangular in size with sloping roofs. A

false flat ceiling were constructed and sloping roof works as shading device, which restricts the direct solar

radiation from the roof. Building envelope for all cold storages were constructed in similar manner and bricks,

and RCC used as construction materials. The walls and roof consists of a number of layers with different

thicknesses and construction materials. The arrangement patterns of layers used in construction of buildings of

surveyed cold storages are given in Table 2.

Table 2. Construction pattern of false ceiling and walls

Construction layers

False

ceiling Wood Tarcol Sheet Thermocole Plaster Wood

Walls Plaster Brick Plaster Thermocole Iron net Plaster



Refrigeration units require to controls the indoor storage environment at required temperature level and maintain

the quality and flavour of stored produce. Surveyed storages were maintaining at 20C and 80-95% humidity

using the conventional vapour compressor refrigeration systems. The major components of a vapor-compression

refrigeration system include a reciprocating compressor, a condenser, receiver, expansion valve and an

evaporator. The compressors room of a cold storage’s refrigeration unit is shown in Figure 3.

Figure 3. Compressor’s room of a refrigeration unit in a cold storage

Two types, i) bunker type and ii) fan coil units (FCUs), of air-handling units (AHUs) were used in the cold

storage for inside air circulation (Figure 4). About 80 percent cold storages were using bunker type air handling

units and other 20% fan coil unit type. The air handling units were kept in the top of the cold storages chambers

and cool the inside air by re-circulating the indoor air continuously. The indoor air removes completely in the

morning hours every day and fills fresh air into the chambers accordingly.

Figure 4. Air handling unit a) Banker type b) Fan coil unit



Results and discussions

We know that factors affecting energy consumption are interactive. Trend analysis can be used for data analysis

to investigate the relationships between variables and ascertain the causal effect of others factors on energy

consumption of cold storage.

The parameters, which may influence the energy consumption, were capacity utilization factor (CUF), overall

heat transfer coefficient (Ueff), aspect ratios of buildings, capacities of refrigeration units and air handling units.

The trend analysis is particularly helpful for identifying the general behavior of the interpreter and also

examines changes in its behavior across the whole spectrum of its numerical values. The capacity utilization

factor is determined by dividing the used capacity by total capacity of the cold storage. The capacity utilization

factor can be expressed as follows:

ns)storage(to cold ofcapacity Fullns)storage(to cold ofcapacity Usedfactorn utilizatioCapacity =

The specific energy consumption is the only suitable and sufficient parameter to explain the energy consumption

pattern of cold storages. It can be seen from Table 1, the specific energy consumption is varying between 9-25

kWh/ton/year that clearly indicates the sufficient potential for reducing it. The variation in specific energy

consumption defiantly influenced by various buildings as well as refrigeration parameters. The trend analysis

focuses on the impact of individual predictors on SEC acting alone.

Effect of capacity utilization

From the surveyed data, it was observed that the capacities of the cold storages were not utilized at its full

capacity at all time. The capacity utilization mainly depends on the crop yield in that respective year and market

demand. The capacity utilization influences the specific energy consumption significantly. Fig. 5 shows the

relationship between the average specific energy consumption as a function of capacity utilization factors of the

cold storages with corresponding regression line.

y = -14.163x + 17.907R2 = 0.6267

5

7

9

11

13

15

17

0.2 0.3 0.4 0.5 0.6 0.7

Capacity utilization factor(ton/ton)

Spe

cific

ene

rgy

cons

umpt

ion(

kWh/

ton)

Figure 5. SEC vs. capacity utilization



The average negative slope of the SEC with changes in CUF was 14.163 kWh/ton that mean the increase in

CUF by 0.1 decreases the energy consumption by 1.46 kWh/ton. Beyond a CUF of 0.35, the change in SEC is

marginal and before 0.35 value of CUF, the SEC increases significantly. This indicates that the specific energy

consumption is affected a little for capacity utilization factor above 0.35; however, lower value of capacity

utilization factor is one of the significant causes for higher energy consumption. It is recommended to the

owners and operators, to operate the cold storages for higher value of CUF or they should use the partial volume

of the cold storages for efficient operation.

Effect of aspect ratio of building

The shape of the building envelope plays a significant role since it determines the surface of the external

envelope [6]. Compactness is expressed by the aspect ratios of building envelope for a specified volume. As

the losses are proportional to the surface of the envelope, the more it is compact, the more the losses of heat will

be less. The aspect ratios of the surveyed cold storages were not found same, however, the shape of the

buildings were similar. The buildings were made rectangular in shape with trusted roof. Figure 6 shows the

effect of aspect ratios of building envelope on specific energy consumption

10

11

12

13

14

15

16

17

0.20 0.21 0.33 0.43 0.59 0.64

W/L

Ave

rage

spe

cific

ene

rgy

cons

umpt

ion(

kWh/

ton/

year

)

0.4 0.37 0.8 0.63 0.91 1

H/L

Figure 6. SEC vs. aspect ratios

The minimization of the external surface area for a specified volume will reduce the heat gain through the

building envelope and ultimately energy consumption. As clear from the Figure 6, the specific energy

consumption of cold storages vary with aspect ratio and found the building having W/L=0.64, H/L=1 values of

aspect ratio is better from the energy efficiency point of view. However, the values of aspect ratios for lower

energy consumption may change with location and climatic conditions. Therefore, further studies for other

climates and locations would strengthen the concept and helpful to setup the guidelines for designing energy

efficient cold storage in future.



Effect of U value

Overall heat transfer coefficient of building envelope is one of the most important thermophysical properties

affect the thermal performance of the building envelope and it is easy to control by minor modification or

adopting energy efficient designs. The values of overall effective heat transfer coefficients were calculated for

each cold storage from the collected data and correlated with respective specific energy consumption as shown

in Figure 7. The expected pattern of energy consumption can be observed from the Fig. 7. Higher the effective

heat transfer coefficients, higher the energy consumption. The optimization of effective overall heat transfer

coefficient values are recommended for composite as well as other climatic conditions for minimizing the

energy consumption of the cold storages.

y = 29.501x + 2.879R2 = 0.252

5

7

9

11

13

15

17

0.2 0.25 0.3 0.35 0.4

Ueff(W/m2-K)

Aver

age

spec

ific e

nerg

y co

nsum

ptio

n(kW

h/to

n)

Figure 7. SEC vs Ueff

Effect of sizes of refrigeration and air handling units

In this section the effect of refrigeration and air handling units on the energy consumption of cold storages were

discussed. The Figures 8 & 9 shows the variation in specific energy consumption with specific refrigeration

capacity and specific capacity of AHUs.

y = 142.85x + 7.6389R2 = 0.0094

02468

1012141618

0.03 0.031 0.032 0.033 0.034 0.035

Specif ic refrigeration capacity(kW/ton)

Aver

age

spec

ific e

nerg

y co

nsum

ptio

n(kW

h/to

n)

Figure 8. SEC vs. Specific refrigeration capacity



y = -0.5681x + 13.662R2 = 0.0007

02468

1012141618

2.35 2.4 2.45 2.5 2.55 2.6 2.65

AHU specif ic capacity(W/ton)

Aver

age

spec

ific e

nerg

y co

nsum

ptio

n(kW

h/to

n)

Figure 9. SEC vs. Specific AHU capacity

The trend indicates the minor increment in the specific energy consumption with increase in specific

refrigeration capacity, on the other hand negative slope in the trend line indicates the specific energy

consumption decreases with increase in specific capacity of AHU. However, the correlation coefficients are not

so strong and needs further study of greater number of samples.

The study is based on a small cluster of composite climate and results may vary for other climates and locations,

therefore, further study for other climatic zones of India would be helpful to set the guidelines for setting up new

energy efficient cold storages.

Conclusion

Based on survey of 10 cold storages in composite climate of Indore, the parametric study was performed for

analyzing the impact on energy consumption. The trend analysis method is used to identify the factors of cold

storages that affect the specific energy consumption of cold storages. The factors, namely capacity utilization

factor, aspect ratio and overall heat transfer coefficients of cold storages are found to be significant parameters.

The purpose of this study was to establish a help for architects, engineers, consultants, owners and operators to

take into account the impacts of design and operation choices on energy consumption while designing and

operating the potato cold storages. Also, some recommendations were made for energy efficient operation and

designs of cold storages.



References

• Bureau of Energy Efficiency, Ministry of Power, Government of India (www.bee-india.nic.in)

• www.indiastat.com

• Ramkishore Singh, Singh, S.P., Singh R.N.(2010). Energy saving potential in Indian cold storages.

2ndBharatiya Vigyan Sammelan held on 1-3 December, 2010, DAVV, Indore.

• Kaur, J., Singh, S.P., Sawhney, R.L. and Sodha, M.S. (1991) Optimum Layered Distribution of

masonry and insulation of building component. International Journal of Energy Research, 15, 11-18.

• Kumar, A. Ashutosh, S. and Sodha, M.S. (1989) Optimum distribution of insulation over various

components of air-conditioned building, Building & Environment, 24(2), 169-178.

• Bansal N.K., Shail and Garg S.N. (1997) Calculation of solar radiation intercepted by Nubian Vault

and Dome Shaped Building. International Journal of Energy Research, 21, 723-736.

• Sodha, M. S., Jagjit Kaur and Sawhney, R. L. (1992) Effect of orientation on thermal performance of a

building. International Journal of Energy Research, 16, 709-715



A concept in Energy Efficient Lighting - Electromagnetic Induction Light

CIMS Power Technologies Pvt. Ltd.

Present Scenario:

Economic growth, industrialization and growing population in the developing countries of Asia especially India

demand a huge growth in energy supplies in the region while global environmental problems call for cuts on

fossil fuel use, which keeps Power sector in continuous focus. Today the sustainable world energy policy is

based on end-use-oriented energy strategy technically called Demand Side Management (DSM).

If fusion of proper DSM models and mechanisms with proper technology can be achieved then the shortfall in

the energy production can be compensated to a greater extent by efficient use of energy. This energy-use-

oriented approach leads to an energy efficient future that is much-less capital and resource intensive and more

environmentally benign which is the need of the hour for countries like India. As per an estimate about 17% of

total power generated in INDIA is consumed for lighting alone and use of energy efficient lighting itself can

make a big difference in the total energy scene of the Nation (estimated total generation of the country is

150000MW and if even 15% of lighting load can be saved means 3825MW). At present the scope for energy

saving in lighting sector, especially in community light is up to 50%.

Electromagnetic Induction Light is the most energy efficient light source so far known to mankind for highway

lighting, but we are unable to explore the benefits of this light source. This paper will discuss the barriers

(Technological, commercial and policy intervention) in promoting the Electromagnetic Induction Light in the

country and also attempt to address the likely policy intervention for up scaling the use of Electromagnetic

Induction Light including the need of institutional/research capacity enhancement and public awareness.

Need for adopting energy efficiency measures:

• To reduce the ever increasing energy demand supply gap.

• To follow the concept: “ENERGY SAVED IS ENERGY PRODUCED”

• To utilize the available energy capacity in a more efficient way so that it’s widespread use can be

envisaged catering to a larger section of the society.

• To spend minimum while obtaining the maximum value for compulsory obligations like street lighting

this is, in general, commercially unproductive activity for the Government utilities.

• To look forward to the trends which are environment friendly and in pace with the



• emerging technologies at international level.

What to be expected from an Energy Efficient Lighting Solution?

• Should be substantially energy efficient as compared to the lighting products which are being currently

used.

• Should provide at least the present standard of light quality, if not more.

• Should be able to address the concerns of environmental pollution effectively.

• Should provide good energy saving potential so that it can be commercially viable in the longer run.

Merits and Demerits of conventional lighting solutions:

Merits:

• Initial low cost of procurement, hence less initial investment.

• Easily available in almost all types of fittings and fixtures.

Demerits:

• Very high recurring energy usage costs and low power factor maintenance despite the initial low

procurement cost.

• Very less life ( Only 10000 to 12000 Hours of useful life)

• Poor illumination at the ground level for HPSV, LPSV, Metal Halide and CFL lamps.

• Severe degradation in Lumen Output after first 4000 Hours of operation (Up to 40%).

• Poor Color Rendering Index (CRI) – Well below the national and international standards for HPSV,

LPSV and Metal Halide Lamps.

• Very long start and re strike time (8 to 10 minutes) for HPSV, LPSV and Metal Halide Lamps.

• Generate excess amount of heat.

• Presence of UV radiation and liquid mercury poses environmental threat.

So the demerits of these lamps outweigh their merits in a big way.



Merits and Demerits of LED Lamps:

Merits:

• Long life of LED Lamp (up to 100000 Hours)

• Very good power factor maintenance (> 0.9)

• A wide color range is available.

Demerits:

• Very high initial cost of procurement.

• Very low life of the ballast or driver of the lamp primarily due to excess heat generation and high

current dependence for more light.( Up to 12000 Hours only)

• LED lamps of higher capacity (>18W) are very bulky and in certain cases rendered unfit for pole

mounting.

• LED lamps of capacities higher than 100W are not available easily and are very costly and LED lamps

of lower capacities are not suitable for outdoor street lighting.

• LED Lamps produce enormous glare at the top but provide very low lumen output at the ground level.

So the LED Lamps also prove to be a gloomy replacement option for the conventional lighting products.

With the above mentioned scenario and the analysis of presently available lighting solutions, the stage is now

set to look for such an option that addresses the present concern for energy efficiency, while accommodating the

mentioned merits and at the same time negating the demerits of the available conventional lighting systems as

well as much hyped LED lighting systems.

The first question that arises now is that – “Does such a lighting solution like this exist?”

Our answer is- “YES”

The second question that arises is that – “What is that option?”

The obvious answer is- “ELECTROMAGNETIC INDUCTION LIGHTING”



In the following sections, we would like to highlight the details, advantages and disadvantages of

Electromagnetic Induction Lighting, its applications and its future commercial viability in a power hungry

country /economy like India.

History of Electromagnetic Induction Light

Nikolas Tesla

The dream of lighting inventors has been to produce a lamp with no internal electrodes so as to eliminate these

common failure modes. In an electrodeless lamp the envelope [bulb] is completely sealed and thus there is no

chance of atmospheric contamination due to seal failure and no electrodes to wear out over time. In June of

1891, Nicholas Tesla was granted a US patent to cover a very early form of Induction lamp.

Nikol a s Tesla demonstrated wired and wireless transfer of power to electrodeless fluorescent and incandescent

lamps in his lectures and articles in the 1890s, and subsequently patented a system of light and power

distribution on those principles. Noting the diagrams in Tesla's lectures and patents, a striking similarity of

construction to electrodeless lamps that are available in the market currently is readily apparent. Further, a

statement in 1929 by Tesla, published in The World :

“Surely, my system is more important than the incandescent lamp, which is but one of the known electric

illuminating devices and admittedly not the best. Although greatly improved through chemical and metallurgical

advances and skill of artisans it is still inefficient, and the glaring filament emits hurtful rays responsible for

millions of bald heads and spoiled eyes. In my opinion, it will soon be superseded by the electrodeless vacuum

tube which I brought out thirty-eight years ago, a lamp much more economical and yielding a light of

indescribable beauty and softness.”

How Electromagnetic Induction Light works?

Electromagnetic induction lamps are basically fluorescent lamps with electromagnets wrapped around a part of

the tube, or inserted inside the lamp. In external inductor lamps, high frequency energy, from the electronic



ballast, is sent through wires, which are wrapped in a coil around the ferrite inductor, creating a powerful

magnet.

The induction coil produces a very strong magnetic field which travels through the glass and excites the mercury

atoms in the interior which are provided by a pellet of amalgam (a solid form of mercury). The mercury atoms

emit UV light and, just as in a fluorescent tube, the UV light is up-converted to visible light by the phosphor

coating on the inside of the tube. The system can be considered as a type of transformer where the inductor is

the primary coil while the mercury atoms within the envelope/tube form a single-turn secondary coil.

Applications of Electromagnetic Induction Light

• In hard-to-reach locations that make maintenance costs high, such as street lighting and tunnels, or in

high ceilings where there is continuous operation.

• Cold environments, such as supermarkets, walk-in coolers and freezers.

• Where high-quality lighting is required or highly desirable.

• Where reliability is highly valued.

• Where high lumen output is required.

• In areas that require lamps to reach full illumination immediately.

• In industrial factories, workshops, mines, backyard, sport, high security areas, etc.

They are also ideally suited for such applications where the advantages of fluorescent lighting are sought but a

light source is needed that can start and operate efficiently in extremely cold temperatures.

As a result, induction lighting is a suitable for a wide range of applications, including not only warehouses,

industrial buildings, cafeterias, gymnasiums, etc., but also signage, tunnels, bridges, roadways, outdoor area and

security fixtures, parking garages, public spaces, and freezer and cold storage lighting.



Why Electromagnetic Induction Light?

• The induction lamps are capable of saving a generous 40% over their counterparts and boast a life

expectancy of up to 100,000 hours

• Other advantages of induction lighting are better color rendition, and better control of the bulbs color

range from daylight to soft white. The Kelvin values match the accepted standard.

• Induction Lamps have no stroboscopic effect, no dazzle and no ultraviolet radiation in the spectrum;

therefore it is definitely recognized as a Green illumination, which protects us from diseases such as

myopia, headache, insomnia, tiredness, skin cancer, etc.

Advantages of using Electromagnetic Induction Light

• Moderately high initial cost of procurement as compared to HPSV, LPSV and Metal Halide Lamps and

very less as compared to LED Lamps.

• More lumen output while consuming almost half the wattage rating.

• Excellent power factor (> 0.9)

• Excellent Color Rendering Index (CRI) of 80.

• Very high S/P Factor ( 1.7 to 2.0)

• Instant start and no flicker.

• Very low lumen de rating (10% after 2000 Hours and then stable through out its life)

• Long life (80000 to 100000 Hours)

• No UV radiation, hence environment and health friendly.

• No liquid mercury thus ensuring safe disposal.

• Less heat generation.



A tabular summary of advantages of using Electromagnetic Induction Lamps:

Comparison of Electromagnetic Induction Light with its conventional counterparts:

A new trend in light measurement – “Pupil Lumens” or “Visual Acuity Lumens”

Current codes and standards are based on measurements that do not address the impact of pupil lumens, and

pupil lumens are quite different from traditionally measured lumen output of lamps. Studies on the relevance of

light spectrum and the mechanics of vision are ongoing, and codes and standards will reflect that in the near

future.

Researchers have developed a conversion factor that applies the P/S ratio to lumen output of various light

sources, and then expresses the effective lumens the eye will perceive for vision based on the size of the pupil. It



is called Pupil Lumens or Visual Acuity Lumens and is now being considered as the most important factor in

deciding the energy efficiency and quality of the light in addition to CRI and CCT.

Electromagnetic Induction Lamps score significantly here as they achieve very high P/S ratio of 2.0, whereas

low pressure sodium vapor and high pressure sodium vapor lamps achieve a low P/S ratio of 0.38 and 0.76 only

respectively eventually degrading their effective lumen output resulting in poor visibility. The economics of

using Induction lamps is favorable over life cycle.

Conclusion:

Electromagnetic Induction Light sources pose technical challenges, most of which have been addressed by

vendors now that the technology is nearly a decade old. Early systems faced concerns about electromagnetic

interference from the field generators, but today's products meet FCC 47CFR Part 18 Non-Consumer

certification, and complaints are just about nonexistent.

GOVERNMENTAL INTERVENTION REQUIRED FOR ACHIEVING ENERGY

CONSERVATION

• Unlike many other energy efficient gadgets, Electromagnetic Induction Light fails to attract the

attention of Government policy makers for a Electromagnetic Induction Light promotional scheme on

National level as in the case of Compact Fluorescent Lamp-CFL (National scheme of Bachat Lamp

Yojna is launched to promote use of CFL) In order to promote efficient use of available energy sources

specially in lighting sector followings are the suggestions for Energy efficiency measures under DSM:

• Government should make a Nation Wide Energy Efficiency-Demand Side Management (EE-DSM)

plan to promote use of Electromagnetic Induction Light where ever it is possible.

• Government should make stringent standards for quality Electromagnetic Induction Light gadgets, may

be Energy Star labeling be done on Electromagnetic Induction Light products to ensure the quality of

the gadget.

• For hoardings and signboards use of Electromagnetic Induction Light must be made mandatory.

• A National body that addresses the new research and carries quality testing for Electromagnetic

Induction Lighting gadget is also suggested.

From the details given above it becomes very clear that the option of Electromagnetic Induction lighting is one

of the most energy efficient way and will help in National Demand Side Management program. By keeping in

view the supply demand gap in the energy requirements of our country, Electromagnetic Induction lighting is

the need of the hour and it deserves due promotion and recognition from the government. Use of

Electromagnetic Induction lights is economical and environment friendly. With the help of Government



intervention use of Electromagnetic Induction lights can be made multifold and this will conserve energy which

can be used to bring the new era of lighting to those villages that are still away from even a light source.

Thanks & Regards

For further information and inquiry, please contact:

Date post:	20-Feb-2015
Category:	Documents
Upload:	mspiso2000
View:	153 times
Download:	5 times

07 Technical Session Seven

Documents