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Raghupatruni 1 Design and Selection of Exhaust Heat Recovery Application
Experimental Study of Heat Recovery
from Diesel Exhaust at UAF
Prasada Rao Raghupatruni, Chuen–Sen Lin, Dennis Witmer
Ed Bargar, Jack Schmid, Thomas Johnson
University of Alaska Fairbanks
Raghupatruni 2 Design and Selection of Exhaust Heat Recovery Application
Overview
Introduction
Objectives
Background
Heat recovery system design consideration
Exhaust heat recovery system
Hardware and instrumentation
Experimental procedure
Results
Conclusions
Acknowledgements
Raghupatruni 3 Design and Selection of Exhaust Heat Recovery Application
Introduction
Alaskan villages consums about 374,000 MWh electric energy (about 40% of the total fuel energy) annually from diesel generators.
There are unused energy from the engine. Example: 30% of the total fuel energy (about 285,000 MWh) dissipates into the atmosphere from exhaust as heat.
1 gallon diesel contains about 130,000 Btu (0.0381 MWh) of energy
To recover the engine heat for useful applications may save lots of energy or fuel.
Rising cost of diesel fuel may become the driving force for heat recovery
Soot, corrosivity and cost are the major obstacles to heat recovery
Cleaner fuels and cleaner engines might help reduce the obstacles
Exhaust 30%
Power 38%
Liquid jacket
water 18%
Friction
Radiation
7%
Air After
Cooler
7%
Raghupatruni 4 Design and Selection of Exhaust Heat Recovery Application
Objectives
Select the most beneficial application to recover heat from diesel engine exhaust
Design a heat recovery system – economic, reliable, efficient
Conduct feasibility, performance and economic analysis
Raghupatruni 5 Design and Selection of Exhaust Heat Recovery Application
Sulfur naturally present in crude oil
Sulfur in conventional diesel = 350ppm
SO2 : Dissolve in free moisture to form sulfrous acid H2SO3
1 to 2% of SO2 is further oxidized into SO3
SO3 : Combined water vapor to form sulfric H2SO4
Acid dew point (Depends on amount of excess air in combustion, moisture
content, amount of sulfur in fuel)
2010 diesel with 15ppm sulfur content (ULSD) (Acid dew point dropped)
EPA tier 4 standards to off road engines by 2011
This may make heat recovery from diesel engines exhaust easier as there is less
acid and PM in the exhaust
Background about obstacles
Raghupatruni 6 Design and Selection of Exhaust Heat Recovery Application
Soot formation
Major pollutants – NOx and (particulate matter) PM
PM results from un burnt HC and effects health and visibility
The composition of particulate matter by mass are:
Metal – 1.2%, Hydrogen – 2.6%, Nitrogen – 0.5%, Oxygen – 4.9%
Sulfur – 2.5%, Carbon – 88%
Accumulation of PM is referred to as soot
Background about obstacles
Raghupatruni 7 Design and Selection of Exhaust Heat Recovery Application
Experimental Gas-side Pressure Drop and Fouling Resistance for a Fined Tube Bundle in a Diesel Engine Exhaust
*W. J. Marner, “Compact Heat Exchanger”
Some important parameters: temperature and velocity
Raghupatruni 8 Design and Selection of Exhaust Heat Recovery Application
Heat recovery system design consideration
Selection of recovery application
Space and community water loop heating
Desalination
Heat for refrigeration and air conditioning
Heat to power conversion
Thermal electric conversion
Experimental site
Detroit Diesel engine-generator set located at Energy Center, UAF Excellent laboratory site for potential heat recovery application
• Adjust and control engine loads
• Data acquisition system
Raghupatruni 9 Design and Selection of Exhaust Heat Recovery Application
Heat recovery system design consideration
Design requirements
Apply existing technology
Optimize overall efficiency for varying engine load (25 to 100%)
Minimize corrosion to exhaust system and heat recovery system
Meet back pressure requirement (13.8 kPa or 2 psi)
Meet dimension constraints (very limited space)
Be able to emulate different heating applications of Alaskan villages
Be able to measure system and component performance
Be easy to maintain and do not increase maintenance frequency
Work under a wide range of ambient temperatures (-40oC to 33oC)
Be reliable
Raghupatruni 10 Design and Selection of Exhaust Heat Recovery Application
Heat recovery system design consideration
Heat exchanger selected for full load
Unit heater dump load and temperature control for load simulation
Pressure drop and pump selection
Data acquisition system• Mass flow and delta T
of both exhaust and coolant loops
• Pressures• Fuel flow rates• Engine and heating
loads
Gas/liquid Inlet
temperature
Outlet
temperature
Exhaust 540 0C
(1004 0F)
177 0C
(350 0F)
Coolant 77 0C
(170 0F)
88 0C
(190 0F)
Heat recovery system design
Raghupatruni 11 Design and Selection of Exhaust Heat Recovery Application
Pipeline was designed to fit the ISO container design
Physical dimensions of heat exchanger was 51”x 18” x 23”
The heat exchanger was installed on top of the ISO container
• Convenience
• Hot gases prefer to rise
The size of the unit heater and the improved efficiency of the use of cold ambient air required it to be installed outside ISO container
Pipe and control section was installed inside the ISO container.
The temperature inside the ISO container was maintained above freezing
Hardware and instrumentation
Raghupatruni 12 Design and Selection of Exhaust Heat Recovery Application
Heat recovery system
1
2
3
45
Heat source section
Heat exchanger (1) and Related components
Heat sink section
Unit heater (2), 3-way valve (3) by pass line, and related components
Pipe and control section
Pump (4), flow meter (5), and related components
Raghupatruni 13 Design and Selection of Exhaust Heat Recovery Application
Heat Exchanger
Quotation 1 Quotation 2
Shell side Gas Liquid
Tube side Liquid Gas
Gas pressure drop
0.31 psi 2 psi
Maintenance Removable core, 1” gap
and straight tubesU-tube for gas
Heat transfer area
87 ft2 30 ft2
Size 51”x28”x28” (with detailed
drawings)
Shell Φ6.625”, Tube:72”
(No details)
Weight 725 lbs 350 lbs
Material of construction
Tube- SS fin tubeShell- SS inner wall
Tube: Plain SS 316Shell: CS
Insulation Integrated insulation No insulation included
Cost ($) 9,800 7,979
Raghupatruni 14 Design and Selection of Exhaust Heat Recovery Application
Hardware and Instrumentation
Inlet
Outlet
Drain
Bronze ball
valve
Pressure
gauge
Air ventRelease
valve
Temperature
sensor
Bronze ball
valve
Raghupatruni 15 Design and Selection of Exhaust Heat Recovery Application
Space allocation
Hardware and Instrumentation
Raghupatruni 16 Design and Selection of Exhaust Heat Recovery Application
Hardware and Instrumentation
Circuit
setter
Strainer
From
unit
heater
To unit
heater
Expansion
tank
Circuit
setter
Strainer
From
unit
heater
To unit
heater
Expansion
tank
Raghupatruni 17 Design and Selection of Exhaust Heat Recovery Application
Hardware and Instrumentation
Unit heater
To Unit Heater
From Unit Heater
3 way valve
Temperature
thermocouple Insulation
3 way valve
Temperature
thermocouple Insulation
By pass line
Raghupatruni 18 Design and Selection of Exhaust Heat Recovery Application
Hardware and Instrumentation (UAF)C o m p o n e n t Q t y U n i t P r ic e T o t a l P r ic e
T r i s ta n d p ip e v i s e 1 $ 3 1 9 .0 0 $ 3 1 9 .0 0
B o x b e a m 3 " X 3 " X 1 /8 " 2 0 f o o t b a r 1 $ 7 5 .5 7 $ 7 5 .5 7
F la t s to c k 3 " X 3 /1 6 " 2 0 f o o t b a r 1 $ 2 4 .3 1 $ 2 4 .3 1
A n g le b a r 2 - 1 /2 " X 2 - 1 /2 " X 3 /1 6 " 2 0 f o o t b a r 1 $ 3 3 .2 2 $ 3 3 .2 2
F la t s to c k 1 - 1 /2 " X 1 /8 " 2 0 f o o t b a r 1 $ 9 .5 0 $ 9 .5 0
F la t s to c k 1 " X 1 /8 " 2 0 f o o t b a r 1 $ 6 .5 7 $ 6 .5 7
B o x b e a m 1 - 1 /2 " X 3 " X 1 /8 " 2 0 f o o t b a r 2 $ 5 6 .5 4 $ 1 1 3 .0 8
B o x b e a m 1 - 1 /4 " X 1 - 1 /4 " X 1 /8 " 2 0 f o o t b a r 2 $ 3 2 .0 2 $ 6 4 .0 4
B o x b e a m 2 " X 2 " X 1 /4 " 2 0 fo o t b a r 1 $ 8 7 .2 3 $ 8 7 .2 3
F le x ib l e , i n s u l a te d t h e r m o c o u p l e p r o b e s w i t h e x p o s e d 1 5 $ 1 7 .5 0 $ 2 6 2 .5 0
S l ip o n F l a n g e , 1 5 0 p s i , 5 " p i p e d ia , 1 0 " O D , 8 - 1 /2 " b o lt 3 $ 3 8 .0 3 $ 1 1 4 .0 9
G r e a t s tu f f i n s u la t i n g fo a m s e a l a n t 6 $ 8 .4 9 $ 5 0 .9 4
C e n t r i f u g a l P u m p 1 /3 H P 3 0 G P M 1 $ 6 7 2 .0 0 $ 6 7 2 .0 0
E x p a n s io n t a n k 1 $ 3 4 .1 8 $ 3 4 .1 8
H e a t E x c h a n g e r 1 $ 1 0 ,0 1 9 $ 1 0 ,0 1 9 .0 0
F ib e r g l a s s in s u la t io n - b a g 1 $ 6 1 .7 9 $ 6 1 .7 9
S i g n a l C o n d it io n e r 0 - 5 V 1 $ 5 2 4 .0 0 $ 5 2 4 .0 0
T u r b in e f l o w m e te r , 4 - 6 0 l i n e a r r a n g e ( G P M ) 1 $ 1 ,2 8 9 $ 1 ,2 8 9 .0 0
P r e s s u r e g a u g e , d c p o w e r e d , d u a l a la r m s 3 $ 3 7 5 .0 0 $ 1 ,1 2 5 .0 0
T y p e K g r o u n d e d th e r m o c o u p le p r o b e w i t h 1 0 $ 2 5 .9 0 $ 2 5 9 .0 0
T y p e K u n - g r o u n d e d th e r m o c o u p le p r o b e w i t h 2 5 $ 2 6 .8 0 $ 6 7 0 .0 0
T y p e K u n - g r o u n d e d th e r m o c o u p le p r o b e w i t h 1 0 $ 2 7 .6 0 $ 2 7 6 .0 0
T e f lo n in s u la te d t y p e K th e r m o c o u p le w i r e 1 $ 4 0 5 $ 4 0 5 .0 0
M in ia tu r e t y p e K t h e r m o c o u p le c o n n e c to r p a i r 5 0 $ 4 $ 2 0 0 .0 0
T y p e K g r o u n d e d th e r m o c o u p le p r o b e w i t h 1 0 $ 2 4 $ 2 4 0 .0 0
T y p e K g r o u n d e d th e r m o c o u p le p r o b e w i t h 1 0 $ 2 4 $ 2 4 0 .0 0
2 4 g a u g e g a l v a n i z e d m e ta l ( S iz e 6 3 " X 3 9 " ) 1 $ 7 8 .0 0 $ 7 8 .0 0
2 4 g a u g e g a l v a n i z e d m e ta l ( S iz e 6 0 " X 4 0 " ) 2 $ 7 8 .0 0 $ 1 5 6 .0 0
2 4 g a u g e g a l v a n i z e d m e ta l ( S iz e 6 6 " X 4 2 " ) 1 $ 1 0 0 .0 0 $ 1 0 0 .0 0
S i n g le lo o p c o n tr o l l e r w i t h tw o 0 - 1 0 V D C a n a l o g o u tp u t s 1 $ 1 0 0 .4 5 $ 1 0 0 .4 5
1 - 1 /4 i n c h 3 W B R c o n t r o l v a lv e U F x U F w i t h 0 -1 0 V D C 1 $ 2 9 2 .7 7 $ 2 9 2 .7 7
N ic k e l im m e r s io n t e m p e r a tu r e s e n s o r 1 $ 3 5 .0 2 $ 3 5 .0 2
3 0 V A t r a n s fo r m e r f o r R W D c o n tr o l l e r 1 $ 2 1 .6 4 $ 2 1 .6 4
H y d r o n i c u n i t h e a te r , m o d e l S - U n i t h e a te r 1 $ 1 ,6 5 5 $ 1 ,6 5 5 .0 0
P i p e c o m p o n e n ts $ 6 ,3 0 3 .9 0
M is c e l l a n e o u s f r o m w a r e h o u s e $ 4 ,0 0 0 .0 0
T o t a l c o s t $ 2 9 ,9 1 7 . 8 0
Raghupatruni 19 Design and Selection of Exhaust Heat Recovery Application
Hardware and Instrumentation (Field)
Component Qty Unit Price Total Price
Box beam 3"X3"X1/8" 20 foot bar 1 75.57$ 75.57$
Flat stock 3"X3/16" 20 foot bar 1 24.31$ 24.31$
Angle bar 2-1/2"X2-1/2"X3/16" 20 foot bar 1 33.22$ 33.22$
Flat stock 1-1/2"X1/8" 20 foot bar 1 9.50$ 9.50$
Flat stock 1"X1/8" 20 foot bar 1 6.57$ 6.57$
Box beam 1-1/2"X3"X1/8" 20 foot bar 2 56.54$ 113.08$
Box beam 1-1/4"X1-1/4"X1/8" 20 foot bar 2 32.02$ 64.04$
Box beam 2"X2"X1/4" 20 foot bar 1 87.23$ 87.23$
Slip on Flange, 150 psi, 5" pipe dia, 10" OD, 8-1/2" bolt 2 38.03$ 76.06$
Great stuff insulating foam sealant 6 8.49$ 50.94$
Centrifugal Pump 1/3HP 30GPM 1 $672.00 672.00$
Expansion tank 1 34.18$ 34.18$
Heat Exchanger 1 $10,019 10,019.00$
Fiberglass insulation - bag 1 61.79$ 61.79$
Type K un-grounded thermocouple probe with 6 $26.80 160.80$
teflon insulated type K thermocouple wire 1 $405 405.00$
miniature type K thermocouple connector pair 50 $4 200.00$
Pressure gauge 3 $10 30.00$
24 gauge galvanized metal (Size 66"X42") 1 100.00$ 100.00$
Single loop controller with two 0-10VDC analog outputs 1 100.45$ 100.45$
1-1/4inch 3W BR control valve UFxUF with 0-10VDC 1 292.77$ 292.77$
Nickel immersion temperature sensor 1 35.02$ 35.02$
30VA transformer for RWD controller 1 21.64$ 21.64$
Pipe components $6,303.90
Labor cost 80 75.00$ 6,000.00$
Parts 1 400.00$ 400.00$
Total cost 24,977.07$
Raghupatruni 20 Design and Selection of Exhaust Heat Recovery Application
Experimental Plan
Verify performance of system—as compared to design
• Measure heat flows
Evaluate maintainability
• Soot formation
• Corrosion
Economic analysis
Purpose
Raghupatruni 21 Design and Selection of Exhaust Heat Recovery Application
Experimental Plan
Heat recovery system - operated and monitored for nearly 350 hours
Hour Coolant Purpose
0 to 150 Water Investigation of the performance of system and components (e.g.
leakages, inappropriate calibrations)
Investigation of the effect of the heat recovery system on engine
performance
150 to
250
40%
Propylene
glycol
Investigate performance consistency
250 to
350
40%
Propylene
glycol
Collection of data for performance and economic analysis
Engine load: 25%, 50%, 75%, and 100%
Heat exchanger outlet temperature: 88 oC, 77 oC, 65 oC
Test procedure
This presentation reports the performance results for 100% engine load and 87 oC.
Raghupatruni 22 Design and Selection of Exhaust Heat Recovery Application
Results
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
1.60
0 25 50 75 100
% Load
Flo
w (
Kg/
s)Total fluid flow rate (Kg/s) Flow rate in bypass (Kg/s) Flow rate across Radiator (Kg/s)
Fluid flow distribution across the bypass and unit heater-different loads
Raghupatruni 23 Design and Selection of Exhaust Heat Recovery Application
Results
0
10
20
30
40
50
60
70
0 10 20 30 40 50
Time (hrs)
Heat
ab
so
rb
ed
or h
eat
dessip
ate
d (
KW
)
.
-35
-30
-25
-20
-15
-10
-5
0
Time (hrs)
Tem
peratu
re (
deg
C)
.
Heat absorption by Propylene (KW) Dissipated heat from unit heater (KW) Total pipe heat loss (KW) Ambient temperature (deg C)
Raghupatruni 24 Design and Selection of Exhaust Heat Recovery Application
Results
0
10
20
30
40
50
60
70
80
0 10 20 30 40 50
Time (hrs)
Hea
t re
leas
e o
r h
eat ab
sorb
ed (
KW
)
Heat release by exhaust (KW) Heat absorption by propylene (KW)
Raghupatruni 25 Design and Selection of Exhaust Heat Recovery Application
Soot Deposition Results
Collected and measured -150 grams of soot
Cleaning: Compressed air and/or a soft brush
Estimated maintenance – Not more than twice a year
No trace of any corrosion spot was observed
Raghupatruni 26 Design and Selection of Exhaust Heat Recovery Application
Economic Results
Initial cost of the recovery system = $30,000 (UAF system)
Installation cost = $6,000 ($75/hr x 8hours x 10 days)
Airfare, lodging, meals = $1,950 ($600 Airfair + $90/day x 15 days)
Total capital cost = $37,950
Maintenance cost:
$2400 per year
$1200 per visit: One day of labor ($75/hr) and flight ticket ($600)
$300 for supplies
Heat recovered per hour = 204,728 Btu
Heating value of fuel = 130,000 Btu/gal
Assuming 100% recovered heat used and 60 kW heat recovery
rate at rated load with 8 hours per day
Raghupatruni 27 Design and Selection of Exhaust Heat Recovery Application
Economic Results
Payback time with fixed capital cost
0
1
2
3
4
5
6
7
8
1.5 2 2.5 3 3.5 4
Fuel price /gal ($)
Pay
bac
k t
ime
(yrs
) .
0% 5% 10% 15%
Raghupatruni 28 Design and Selection of Exhaust Heat Recovery Application
Conclusions
The performance of our exhaust heat exchanger was reliable and consistent.
For the 125 kW diesel generator used in this experiment, the rate of heat recovered from
the exhaust was about 60 kW.
No effects were observed on the engine performance and maintenance frequency due to
the heat recovery system.
According to the soot accumulation data obtained from this experiment, the estimated time
for heat exchanger maintenance is less than two days per year.
Corrosion was not observed to be a problem in the laboratory test of 350 hours.
Based on experimental data obtained from this experiment, the estimated payback time for
a 100% and 8 hours/day use of recovered heat would be about 3 years for a fuel price of
$2.5 per gallon. For 80% use of the recovered heat, the payback time would be 4 years.
Operation cost is largely case dependent. Influential parameters would include diesel fuel
cost, the application of the recovered heat, location of the power plant, etc.
Performance and economic outcomes will be different from one case to another. However,
analysis is recommended before the installation of an exhaust heat recovery system to a
village generator set.
Raghupatruni 29 Design and Selection of Exhaust Heat Recovery Application
Acknowledgements
DOE
ICRC
AVEC
Raghupatruni 30 Design and Selection of Exhaust Heat Recovery Application
Questions ???
Raghupatruni 31 Design and Selection of Exhaust Heat Recovery Application
Vendors
Cain Industries Inc.
Tel: 262-251-0051 Ext-19
800-558-8690
cainind.com
ITT Heat Transfer
175 Standard Parkway
Cheektowaga, NY
716-862-4058
Raghupatruni 32 Design and Selection of Exhaust Heat Recovery Application
Hardware and Instrumentation
y = 1.058x - 0.0931
R2 = 0.9992
1.00
1.05
1.10
1.15
1.20
1.25
1.30
1.35
1.40
1.45
1.50
0.80 0.90 1.00 1.10 1.20 1.30 1.40 1.50 1.60
Load cell (kg/s)
DA
Q (
kg/s
)
Net weight(kg/s) Linear (Net weight(kg/s))
Flow meter calibration curve
Raghupatruni 33 Design and Selection of Exhaust Heat Recovery Application
Tier 3 and Tier 4 General Information (Off-Road)
Tier 3 (grams/kilowatt-hour): Non-Methane Hydrocarbons+NOx (NMHC+NOx): 4.0
Carbon Monoxide (CO): 3.5Particulate Matter (PM): 0.2Approximately: 2008 to 2010
Tier 4 (grams/kilowatt-hour):Non-Methane Hydrocarbons (NMHC): 0.19
Oxides of Nitrogen (NOx): 3.5Carbon Monoxide (CO): 0.4Particulate Matter (PM): 0.02Approximately: 2011
ULSD: 2010Solutions:
Fuel: Synthetic diesel, ultra low sulfur diesel (ULSD)After treatment
Raghupatruni 34 Design and Selection of Exhaust Heat Recovery Application
Raghupatruni 35 Design and Selection of Exhaust Heat Recovery Application