calicut university energy auditing module 3

8/20/2019 calicut university energy auditing module 3

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ENERGY ECONOMICS

In the process of energy management, at some stage, investment would be required for reducing

the energy consumption of a process or utility, investment would be required for modifications /

retrofitting and for incorporating new technology. It is essential to identify the benefits of the

proposed measure with reference to not only energy savings but also other associated benefits

such as increased productivity, improved product quality etc.

The cost involved in the proposed measure should be captured in totality viz.

1. Direct proect cost

!. "dditional operations and maintenance cost

#. Training of personnel on new technology etc.

To persuade your organization to commit itself to a program of investment in energy efficiency,

you need to demonstrate$

% The size of the energy problem it currently faces

% The technical and good house&eeping measure available to reduce waste

% The predicted return on any investment

% The real returns achieved on particular measures over time. The need for investments in

energy conservation can arise under following circumstances

% 'or new equipment, process improvements etc.

% To provide staff training% To implement or upgrade the energy information system

% "nd other priorities

(nergy manager has to identify how cost savings arising from energy management could be

redeployed within his organization to the ma)imum effect. To do this, he has to wor& out how

benefits of increased energy efficiency can be best sold as,

% *educing operating /production costs

% Increasing employee comfort and well+being

% Improving cost+effectiveness and/or profits

% rotecting under+funded core activities

% (nhancing the quality of service or customer care delivered

% rotecting the environment


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FINANCIAL ANALYSIS

In most respects, investment in energy efficiency is no different from any other area of financial

management. -o when your organization first decides to invest in increasing its energy efficiency

it should apply e)actly the same criteria to reducing its energy consumption as it applies to all its

other investments. It should not require a faster or slower rate of return on investment in energy

efficiency than it demands elsewhere.

The basic criteria for financial investment appraisal include$

-imple aybac& a measure of how long it will be before the investment ma&es money, and

how long the financing term needs to be

*eturn on Investment 0*I2 and Internal *ate of *eturn 0I**2 measure that allow

comparison with other investment options

3et resent 4alue 0342 and 5ash 'low measures that allow financial planning of the proect

and provide the company with all the information needed to incorporate energy efficiency

proects into the corporate financial system.

Simple Pay Back Period:


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Advana!e"

" widely used investment criterion, the paybac& period seems to offer the following advantages$

It is simple, both in concept and application. bviously a shorter paybac& generally indicates a

more attractive investment. It does not use tedious calculations.

It favours proects, which generate substantial cash inflows in earlier years, and discriminates

against proects, which bring substantial cash inflows in later years but not in earlier years.

Limiaion"

It fails to consider the time value of money. 5ash inflows, in the paybac& calculation, are

simply added without suitable discounting. This violates the most basic principle of financial

analysis, which stipulates that cash flows occurring at different points of time can be added or

subtracted only after suitable compounding/discounting.


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It ignores cash flows beyond the paybac& period. This leads to discrimination against proects

that generate substantial cash inflows in later years.

It is a measure of a proect6s capital recovery, not profitability.

#ime $al%e o& Money

" proect usually entails an investment for the initial cost of installation, called the capital cost,

and a series of annual costs and/or cost savings 0i.e. operating, energy, maintenance etc.2

throughout the life of the proect. To assess proect feasibility, all these present and future cash

flows must be equated to a common basis. The problem with equating cash flows which occur at

different times is that the val%e o& money c'an!e" (i' ime. The method by which these

various cash flows are related is called the pre"en val%e concep

If money can be deposited in the ban& at 178 interest, then a *s.177 deposit will be worth

*s.117 in one year9s time. Thus the *s.117 in one year is a future value equivalent to the *s.177

present value. In the same manner, *s.177 received one year from now is only worth *s.:7.:1 in

today9s money 0i.e. *s.:7.:1 plus 178 interest equals *s.1772.

The relationship between present and future value is determined as follows$

'uture 4alue 0'42 ; 34 01 < i2n or 34 ; '4 / 01


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The decision rule associated with the net present value criterion is$ >"ccept the proect if the net

present value is positive, and reect the proect if the net present value is negative.?

The net present value criterion has considerable merits.

It ta&es into account the time value of money.

It considers the cash flow stream in its proect life

Inernal Rae o& Re%rn )IRR*:

The internal rate of return 0I**2 method e)presses each investment alternative in terms of a rate

of return 0a compound interest rate2. The e)pected rate of return is the interest rate for which


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total discounted benefits become ust equal to total discounted costs 034;72. The criterion for

selection among alternatives is to choose the investment with the highest rate of return.

In the internal rate of return calculation, we set the net present value equal to zero and determine

the discount rate 0internal rate of return2, which satisfies this condition

Advana!e"

" popular discounted cash flow method, the internal rate of return criterion has several

advantages$

It ta&es into account the time value of money.

It considers the cash flow stream in its entirety.

It ma&es sense to businessmen who prefer to thin& in terms of rate of return and find an

absolute quantity, li&e net present value, somewhat difficult to wor& with.

Ca"' Flo("

@enerally there are two &inds of cash flowA

5ash Inflow$ the initial investment as one or more installments, and

5ash outflow$ the savings arising from the investment.

There are usually other cash flows related to a proect. These include the following$+

5apital costs are the costs associated with the design, planning, installation and commissioning

of the proectA these are usually one+time costs.

"nnual cash flows, such as annual savings accruing from a proect, occur each year over the life

of the proectA these include ta)es, insurance, equipment leases, energy costs, servicing,

maintenance, operating labour, and so on. Increases in any of these costs represent negative cash

flows, whereas decreases in the cost represent positive cash flows.


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Sen"iiviy or Ri"k Analy"i"

5ash flows are based on assumptions that have an element of uncertainty. The present day cash

flows, such as capital cost, energy cost savings, maintenance costs, etc can usually be estimated

fairly accurately. 5ash flows in future years normally contain inflation components which are

often Bguess+etimatesB at best. The proect life itself is an estimate that can vary

significantly.

-ensitivity analysis is an assessment of ris&. Cecause of the uncertainty in assigning values to the

analysis, it is recommended that a sensitivity analysis be carried out + particularly on proects

where the feasibility is marginal.


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Facor" 'a need o +e con"idered in calc%lain! ann%al ca"' &lo(" are$+

Ta)es, using the marginal ta) rate applied to positive 0i.e. increasing ta)es2 or negative 0i.e.

decreasing ta)es2 cash flows.

"sset depreciation, the depreciation of plant assets over their lifeA depreciation is a >paper

e)pense allocation? rather than a real cash flow, and therefore is not included directly in the life

cycle cost. owever, depreciation is >real e)pense? in terms of ta) calculations, and therefore

does have an impact on the ta) calculation noted above. 'or e)ample, if a *s.17,77,777 asset is

depreciated at !78 and the marginal ta) rate is E78, the depreciation would be *s.!77,777 and

the ta) cash flow would be *s.F7,777 and it is this latter amount that would show up in the

costing calculation.

Intermittent cash flows occur sporadically rather than annually during the life of the proect,

relining a boiler once every five years would be an e)ample.

Ener!y Con"ervaion and i" Imporance

5oal and other fossil fuels, which have ta&en three million years to form, are li&ely to deplete

soon.

Today, FG8 of primary energy comes from non+renewable, and fossil sources0coal, oil, etc.2.

These reserves are continually diminishing with increasing consumption and will not e)ist for

future generations.


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The word energy conservation means, >reduction in growth of energy consumption? as a result

of several processes or developments, such as productivity increase or technological progress.

(nergy efficiency is achieved when energy intensity in a specific product, process or area of

production or consumption is reduced without affecting output, consumption or comfort levels.

romotion of energy efficiency will contribute to energy conservation and is therefore an integral

part of energy conservation promotional policies.

(nergy conservation and energy efficiency are both ways to reduce consumption of energy,

bringing the cost of electric bills down, and ma&ing less impact on the environment since lower

energy use means fewer greenhouse gas emissions and conservation of non+renewable resources.

(nergy conservation is a behavior change that results in not using energy at a time when

one might normally. 'or e)ample, riding a bi&e instead of driving a car, unplugging computers

and other electronics at night or when not in use, or turning of the lights when you leave a room.

(nergy efficiency is an improvement in technology that ma&es an e)isting use of energy

more efficient, i.e. allows us to do more with less. ()amples of energy efficiency include

replacing incandescent light bulbs with compact florescent 05'Hs2 or H(Ds, adding e)tra

insulating to a house, or using (nergy -tar appliances that have power+saving measures

installed.


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5onservation certainly reduces energy use, but it9s not always the best solution because it

may impact comfort or safety as well. (fficiency, on the other hand, maintains the same level of

output 0e.g. light level, temperature2 but uses less energy to achieve it. " combination of both

energy conservation and energy efficiency measures yields an ideal solution.

.

(nergy efficiency had even more importance because of being the most cost+effective and

reliable means of mitigating the global climatic change. *ecognition of that potential has led to

high e)pectations for the control of future 5! emissions through even more energy efficiency

improvements than have occurred in the past.

,G Sy"em

Diesel engine is the prime mover, which drives an alternator to produce electrical energy. In the

diesel engine, air is drawn into the cylinder and is compressed to a high ratio 01E$1 to !G$12.

During this compression, the air is heated to a temperature of J77 :7775. " metered quantity of

diesel fuel is then inected into the cylinder, which ignites spontaneously because of the high

temperature. ence, the diesel engine is also &nown as compression ignition 05I2 engine.

Selecion Con"ideraion"

The two most important factors to ma&e a decision on the type of engine, which is most suitable

for a specific application, are$ power and speed of the engine.

The power requirement is determined by the ma)imum load. The engine power rating should be

17+!7 8 more than the power demand by the end use. This prevents overloading the machine by


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absorbing e)tra load during starting of motors or switching of some types of lighting systems or

when wear and tear on the equipment pushes up its power consumption.

Diesel engines typically running at lower speeds 01#77 + #777 *K2. There will be an optimum

speed at which fuel efficiency will be greatest. (ngines should be run as closely as possible to

their rated speed to avoid poor efficiency and to prevent buildup of engine deposits due to

incomplete combustion + which will lead to higher maintenance and running costs.

'or a generator, it is important to get a good speed match with diesel engine. If a good match can

be obtained, direct coupling of engine and generator is possibleA if not, then some form of

gearing will be necessary + a gearbo) or belt system, which will add to the cost and reduce the

efficiency.

Kost frequently used diesel engine sizes are between the range E to 1G K=. 'or continuous

operation, low speed diesel engine is more cost+effective than high speed diesel engine.

The various other factors that have to be considered, are cooling system, abnormal

environmental conditions 0dust, dirt, etc.2, fuel quality, speed governing 0fi)ed or variable speed2,

poor maintenance, control system, starting equipment, drive type, ambient temperature, altitude,

humidity, etc.

Advana!e" o& adopin! ,ie"el Po(er Plan" are:

How installation cost

-hort delivery periods and installation period

igher efficiency 0as high as E# +EG 82

Kore efficient plant performance under part loads

-uitable for different type of fuels such as low sulphur heavy stoc& and heavy fuel oil in case of

large capacities.

Kinimum cooling water requirements,

"dopted with air cooled heat e)changer in areas where water is not available

-hort start up time

Ener!y Savin! Mea"%re" &or ,G Se"

a2 (nsure steady load conditions on the D@ set, and provide cold, dust free air at inta&e 0use of

air washers for large sets, in case of dry, hot weather, can be considered2.

b2 Improve air filtration.


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c2 (nsure fuel oil storage, handling and preparation as per manufacturers6 guidelines/oil company

data.

d2 5onsider fuel oil additives in case they benefit fuel oil properties for D@ set usage.

e2 5alibrate fuel inection pumps frequently.

f2 (nsure compliance with maintenance chec&list.

g2 (nsure steady load conditions, avoiding fluctuations, imbalance in phases, harmonic loads.

h2 In case of a base load operation, consider waste heat recovery system adoption for steam

generation or refrigeration chiller unit incorporation. (ven the Lac&et 5ooling =ater is amenable

for heat recovery, vapour absorption system adoption.

i2 In terms of fuel cost economy, consider partial use of biomass gas for generation. (nsure tar

removal from the gas for improving availability of the engine in the long run.

2 5onsider parallel operation among the D@ sets for improved loading and fuel economy

thereof.

&2 5arryout regular field trials to monitor D@ set performance, and maintenance planning as per

requirements.

FANS - BLO.ERS

'ans and blowers provide air for ventilation and industrial process requirements. 'ans generate a

pressure to move air 0or gases2 against a resistance caused by ducts, dampers, or other

components in a fan system. The fan rotor receives energy from a rotating shaft and transmits it

to the air.

,i&&erence +e(een Fan"/ Blo(er" and Compre""or"

'ans, blowers and compressors are differentiated by the method used to move the air, and by the

system pressure they must operate against.


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Fan La("

Ener!y Savin!" Oppor%niie"

1. Kinimise e)cess air level in combustion system.

!. Kinimise air lea&ages in flue gas path as well as air+conditioning paths.

(nergy can be saved by,

1. 5hange of impeller by a high efficiency impeller along with cone.


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!. 5hange of fan assembly as a whole, by a higher efficiency fan

#. Impeller derating 0by a smaller dia impeller2

E. 5hange of metallic / @lass reinforced lastic 0@*2 impeller by the more energy efficient

hollow '* impeller with aerofoil design, in case of a)ial flow fans, where significant savings

have been reported

G. 'an speed reduction by pulley diameter modifications for derating

M. ption of two speed motors or variable speed drives for variable duty conditions

J. ption of energy efficient flat belts, or, cogged raw edged 4 belts, in place of conventional 4

belt systems, for reducing transmission losses.

F. "dopting inlet guide vanes in place of discharge damper control

:. Kinimizing system resistance and pressure drops by improvements in duct system

Facor" 'a Co%ld A&&ec Per&ormance

Hea&age, re+circulation or other defects in the systemA

Inaccurate estimation of flow resistanceA

(rroneous application of the standardized test dataA

()cessive loss in a system component located too close to the fan outletA

Disturbance of the fan performance due to a bend or other system component

located too close to the fan inletA

(rror in site measurement

AIR CON,I#ONING SYS#EM

The eating, 4entilation and "ir 5onditioning 04"52 and refrigeration system transfers the heat energy

from or to the products, or building environment. (nergy in form of electricity or heat is used to power

mechanical equipment designed to transfer heat from a colder, low+energy level to a warmer, high+energy

level.

*efrigeration deals with the transfer of heat from a low temperature level at the heat source to a high

temperature level at the heat sin& by using a low boiling refrigerant.

Two principle types of refrigeration plants found in industrial use are$ 4apour 5ompression *efrigeration

045*2 and 4apour "bsorption *efrigeration 04"*2. 45* uses mechanical energy as the driving force for

refrigeration, while 4"* uses thermal energy as the driving force for refrigeration.


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$apo%r Compre""ion Re&ri!eraion

How pressure liquid refrigerant in the evaporator absorbs heat from its surroundings, usually air, water or

some other process liquid. During this process it changes its state from a liquid to a gas, and at the

evaporator e)it is slightly superheated

The superheated vapour enters the compressor where its pressure is raised. There will also be a big

increase in temperature, because a proportion of the energy put into the compression process is transferred

to the refrigerant.

The high pressure superheated gas passes from the compressor into the condenser which de+superheats

the gas before it is then turned bac& into liquid. The cooling is usually achieved by using air or water. "

further reduction in temperature happens in the pipe wor& and liquid receiver so that the refrigerant liquid

is sub+cooled as it enters the e)pansion device.

Ener!y Savin! Oppor%niie"

Cold In"%laion

Insulate all cold lines / vessels using economic insulation thic&ness to minimize heat gainsA and choose

appropriate 0correct2 insulation.

B%ildin! Envelop

ptimise air conditioning volumes by measures such as use of false ceiling and segregation of critical

areas for air conditioning by air curtains.

B%ildin! 0ea Load" Minimi"aion

Kinimise the air conditioning loads by measures such as roof cooling, roof painting, efficient lighting,

pre+cooling of fresh air by air+ to+air heat e)changers, variable volume air system, optimal thermo+static

setting of temperature of air conditioned spaces, sun film applications, etc.

Proce"" 0ea Load" Minimi"aion

Kinimize process heat loads in terms of T* capacity as well as refrigeration level, i.e., temperature

required, by way of$ i2 'low optimization ii2 eat transfer area increase to accept higher temperature

coolant iii2 "voiding wastages li&e heat gains, loss of chilled water, idle flows. iv2 'requent cleaning / de+

scaling of all heat e)changers

A 'e Re&ri!eraion A1C Plan Area

i2 (nsure regular maintenance of all "/5 plant components as per manufacturer guidelines.

ii2 (nsure adequate quantity of chilled water and cooling water flows, avoid bypass flows by closing

valves of idle equipment.

iii2 Kinimize part load operations by matching loads and plant capacity on lineA adopt variable speed

drives for varying process load


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iv2 Ka&e efforts to continuously optimize condenser and evaporator parameters for minimizing specific

energy consumption and ma)imizing capacity.

v2 "dopt 4"* system where economics permit as a non+5'5 solution.

Per&ormance #erm" and ,e&iniion"

#on" o& re&ri!eraion )#R*: ne ton of refrigeration is the amount of cooling obtained by

one ton of ice melting in one day$ #7!E &5al/h, 1!,777 Ctu/h or #.G1M thermal &=.

Ne Re&ri!erain! Capaciy2

" quantity defined as the mass flow rate of the evaporator water multiplied by the difference in enthalpy

of water entering and leaving the cooler, e)pressed in &5al/h, tons of *efrigeration.

k.1on rain!$ 5ommonly referred to as efficiency, but actually power input to compressor motor

divided by tons of cooling produced, or &ilowatts per ton 0&=/ton2. Hower &=/ton indicates higher

efficiency.

Coe&&icien o& Per&ormance )COP*$ 5hiller efficiency measured in Ctu output 0cooling2

divided by Ctu input 0electric power2.

Ener!y E&&iciency Raio )EER*$ erformance of smaller chillers and rooftop units is frequently

measured in ((* rather than &=/ton. ((* is calculated by dividing a chiller9scooling capacity 0in Ctu/h2

by its power input 0in watts2 at full+load conditions. The higher the ((*, the more efficient the unit.


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Example


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34514256 3 627

LIG0#ING


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Hamp Types and their 'eatures

Some Good Pracice" in Li!'in!

In"allaion o& ener!y e&&icien &l%ore"cen lamp" in place o& 8Convenional9 &l%ore"cen lamp"2

(nergy efficient lamps are based on the highly sophisticated tri+phosphor fluorescent powder technology.

They offer e)cellent colour rendering properties in addition to the very high luminous efficacy.

In"allaion o& Compac Fl%ore"cen Lamp" )CFL"* in place o& incande"cen lamp"2

5ompact fluorescent lamps are generally considered best for replacement of lower wattage incandescent

lamps. These lamps have efficacy ranging from GG to MG lumens/=att. The average rated lamp life is

17,777 hours, which is 17 times longer than that of a normal incandescent lamps. 5'H9s are highly


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suitable for places such as Hiving rooms, otel lounges, Cars, *estaurants, athways, Cuilding entrances,

5orridors, etc.

In"allaion o& meal 'alide lamp" in place o& merc%ry 1 "odi%m vapo%r lamp"2

Ketal halide lamps provide high color rendering inde) when compared with mercury N sodium vapour

lamps. These lamps offer efficient white light. ence, metal halide is the choice for colour critical

applications where, higher illumination levels are required. These lamps are highly suitable for

applications such as assembly line, inspection areas, painting shops, etc. It is recommended to install

metal halide lamps where colour rendering is more critical.

In"allaion o& 0i!' Pre""%re Sodi%m $apo%r )0PS$* lamp" &or applicaion" ('ere colo%r

renderin! i" no criical2

igh pressure sodium vapour 0-42 lamps offer more efficacy. Cut the colour rendering property of

-4 is very low. ence, it is recommended to install -4 lamps for applications such street lighting,

yard lighting, etc.

Opim%m %"a!e o& dayli!'in!

=henever the orientation of a building permits, day lighting can be used in combination with electric

lighting. This should not introduce glare or a severe imbalance of brightness in visual environment.

In"allaion o& ;e


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To prevent voltage fluctuation the lighting equipment has to be isolated from the power feeders. This will

reduce the voltage related problems, which in turn increases the efficiency of the lighting system.

In"allaion o& 'i!' &re=%ency )0F* elecronic +alla"" in place o& convenional +alla""

3ew high frequency 0!F+#! &z2 electronic ballasts have the following advantages over the traditional

magnetic ballasts$

(nergy savings up to #G8

Hess heat dissipation, which reduces the air conditioning load

Hights instantly

Improved power factor

perates in low voltage load

Hess in weight

Increases the life of lamp


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