NBSIR 77-1207

PERFORMANCE OF THE ENGINE-GENERATOR USED IN THE

JERSEY CITY TOTAL ENERGY PLANT

John B. Coble

Mark E. Kuklewicz

John H. Hebrank

Center for Building Technology

Institute for Applied Technology

National Bureau of Standards

Washington, D. C. 20234

October 1976

Final Report

Prepared for Division of Energy, Building Technology and Standards

Office of Policy Development and Research

Department of Housing and Urban Development

Washington, D. C. 20410

X*’

#r

e0 / V .

' \

0«

U.S. DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary

Dr. Betsy Ancker-Johnson, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Acting Director

ABSTRACT

Each of five 600-kilowatt (kw) diesel engine-generators which were to

be installed in a total energy plant was performance tested under NBS

direction at the engine-generator vendor's plant. These tests provided

a basis for acceptance of the engine-generators and for comparison

with installed performance.

This testing was performed as a part of a comprehensive study to assess engineering, economic, and environmental aspects of a total energy plant

which supplies all electrical power, hot water, and chilled water to an apartment complex in Jersey City, New Jersey. Under sponsorship of

the Department of Housing and Urban Development (HUD), the National

Bureau of Standards (NBS) has instrumented the total energy site for

engineering data and is collecting economic and environmental data.

The engines were tested at seven power levels ranging from 0 to 110%

rated electrical load. In the tests, fuel consumption, electrical

output, and jacket-water heat recovery were measured, as well as many

other parameters. Results are reported for fuel consumption, electrical

efficiency, and electrical -pi us-thermal efficiency, and comparisons are made with measured data from the total energy plant.

Key words: Diesel engine performance; engine-generator performance;

engine-generator efficiency; heat recovery; total energy

systems

.

l
TABLE OF CONTENTS

Abstract i

1. Introduction 1

2. Units Tested 5

3. Test Procedures and Test Conditions 5

4. Test Results 7

4.1 Energy Input and Output 7

4.2 Electrical Efficiency 7

4.3 Electrical Plus Thermal Efficiency 14

5. Conclusions 16

Acknowledgments 17
Performance of the Engine-Generators Used in the

Jersey City Total Energy Plant

by

John B. Coble, Mark E. Kuklewicz and John H. Hebrank

1. Introduction

An apartment complex in Jersey City, N.J. sponsored by the

Department of Housing and Urban Development (HUD), is being evaluated

as a total energy demonstration project by the National Bureau of

Standards (NBS). The complex covers 2.4 hectares (6 acres) of land

and consists of 485 dwelling units in four medium-and high-rise

buildings, an elementary school, a 4600-square meter (50,000 square foot)

office building, a community swimming pool, and a central equipment

building. All of the electrical power, hot and chilled water for

space heating, cooling and domestic hot water required by the site are provided by a central plant.

Electrical power is generated by five 600 kW diesel engine-generators.

Thermal energy for space heating and domestic hot water production is

recovered from the jackets of the engines and from heat exchangers on their exhausts. Supplementary thermal energy is supplied by two 4.0 MW

(13.6 • 10

6

Btu per hour) hot-water boilers. During the air-conditioning

season, the recovered thermal energy is used in two 1.9 MW (6.6 • 10

Btu per hour) absorption refrigeration machines to produce chilled water.

The electrical power, hot water and chilled water are distributed from

the central equipment building to the site buildings through underground

conduits

1
At the Jersey City Site, heat is recovered from the engine-generators and

utilized by a primary hot water loop. As shown in Figure 1, the

primary loop hot water which ranges in temperature from 82° to 99°C

(180° to 210°F) passes through the engines, boilers, chillers, a site

heat exchanger, dry cooler, and an emergency heat exchanger. The

primary loop supplies 5000 kilograms (11000 pounds) of water per minute

to the engine jackets and mufflers. From the engines, this water

passes through two 25 HP circulation pumps and then through the boilers

where additional heat can be added if necessary. In summer the primary

water is routed through two 546 ton absorption chillers which provide

chilled water at 7°C (45°F) for the site. The primary hot water also

passes through heat exchangers transferring heat to the site secondary

hot-water loop. A four-pipe network circulates the chilled water and

the secondary hot-water to the site buildings. In the rare event that

both heating and cooling demands are extremely low, dry coolers release

excess primary heat to the atmosphere to prevent the engines from overheating. An emergency heat exchanger using raw city water backs up

the dry coolers.

The five 600 kW diesel engine-generators used in the total energy plant were selected to match the combined plant and site electrical demand

and provide the necessary standby capacity. At the lowest demand

(^600 kW), two engine-generators can meet the demand without operating

below a 50% load factor. At the highest demands (^1 400 kW), three

units can meet the demand without operating above 80% of their rated

full load. This design promotes engine longevity, maintains high

average efficiency, and allows the maximum electrical load to be met

while one spare engine is being maintained and the other spare engine

is on standby. Figure 2 shows one of the five engines as it has been

installed.

2
ELECTRIC

POWER

TO

PLANT

AND

SITE

Ul2 *

r Z<1. 1 CO

0

0

3

Figure

1.

Schematic

of

Primary

Hot-Water

Loop

Which

Recovers

Heat

From

Engines

and

Boilers

for

Site

Hot

Water

and

Chilled

Water

Production
4

Figure

2.

Photograph

of

One

Engine-Generator

as

Installed

at

the

Jersey

City

Total

Energy

Site
The tests of the engine-generators were conducted at the vendor's

facilities according to the purchase specification under the

direction of the National Bureau of Standards (NBS). The purchase

specification was based upon a performance specification for the

Jersey City total energy plant. These acceptance tests covered

electrical and thermal efficiency, speed control, operating temperatures,

and several other factors.

2. Units Tested

The V-12 diesel engines were of the 4-cycle type designed to

operate at 1200 RPM, and were equipped with turbochargers and aftercoolers. The electrical generators were designed to deliver 600 kW

at 480 volts, three-phase, and 60 hertz. The units were tested

simulating anticipated plant conditions. Fuel temperature, intake air

temperature, cooling water temperatures and flow rates, and load power

factor values were adjusted in accordance with site design. One

exception was that cooling water was circulated by unit-driven mechanical

pumps for the tests; at the site, cooling water is pumped by external

electrical pumps. Also, heat was not recovered from the engines' exhaust

gases during the factory tests.

3. Test Procedures and Test Conditions

Fuel consumption and jacket water heat recovery were measured for

all five units at constant electrical loads of 0, 20, 40, 60, 80, 100

and 110% full load. During each load test, the pertinent electrical,

mechanical and thermal variables were recorded.

Tests were conducted and data were recorded by vendor personnel and

contractors under NBS supervision. Test results were analyzed by NBS

staff.

*National Bureau of Standards Interagency Report NBSIR 10313-A Performance

Specification for a Total Energy Plant at the Jersey City Breakthrough

I Site - (Dec. 1970)

.

5
Each unit was set up in an individual test cell. Electrical loads were applied from a load bank having a constant power factor of 0.8.

The frequency of the delivered power was maintained at 60 hertz and

the voltage was maintained between 472 and 480 volts.

The water flow rate through the engine jacket was maintained constant

for all tests at 1136 liters (300 gallons) per minute. The water flow

rate through the oil cooler and aftercooler was maintained constant

at 379 liters (100 gallons) per minute. The water passed through the

oil cooler first and then through the aftercooler. Below 100% full

load, jacket water inlet temperatures were kept below 109°C (228°F).

At 100 and 110% load, jacket inlet temperatures were kept below 93°C

(200°F) .

.

Number 2 fuel oil was burned in each engine throughout the tests. The

higher heating value for this fuel averages 45.36 MJ per kg (19500 BTU

per pound)

.

Units were tested under steady-state conditions and data were recorded

only after all parameters stabilized. Each unit was operated initially

at 110% full load for two hours followed in order by one-hour tests

at 100%, 80%, 60%, 40% and 20% load conditions and finally at no load

conditions for one-half hour. During the tests, data were recorded

every 15 minutes so that four sets of data points were taken for each

unit at each test load (except at 110% and 0% loads).

6
4. Test Results

The average values and the range of values for each of the loadindependent variables observed on the five units during the tests are summarized in Table 1. The corresponding average values of loaddependent variables are shown separately in English and SI units in

the two parts of Table 2. From this data, energy input-output rates,

engine-generator electrical efficiency, and electrical -pi us-thermal

efficiency have been computed.

4.1 Energy Input and Output

The energy-equivalent of the engine fuel consumption, the electrical

output, and the jacket heat recovery at the 6 power levels are expressed

as kilowatts in Figure 3. These results are summarized in Table 3.

4.2 Electrical Efficiency

Electrical efficiency is equal to the total electrical load divided

by the rate of fuel consumption times the fuel's higher heating value.

Because engine-driven mechanical pumps were used to circulate the

water through the jackets, oil coolers, and aftercoolers during these

acceptance tests, a correction must be made for the shaft power required

for these pumps in order to allow a comparison of engine-generator

efficiencies during the acceptance tests with operation at the

Jersey City site. The engines' manufacturer determined that these pumps

required approximately 17 horsepower during the tests. To correct for

the pump power during the tests, the 17 additional horsepower required

by the pumps is assumed to be available for electric conversion. A

92% efficient generator would convert 17 horsepower to 11.7 kW. Thus,

in computing the engine-generator efficiency for these tests 11.7 kW was added to the generator electrical power output.

The corrected electrical efficiency results are graphed in Figure 4

and summarized in Table 3. Electrical efficiency ranged from 31.6%

7
Table 1

Performance of Five Diesel Engine-Generator Units

Average Values of Load-Independent Variables Measured During Tests

Fuel Pressure

Lubrication Oil Pressure

Oil Cooler Inlet Pressure

(water side)

Oil Cooler Outlet Pressure

(water side)

Aftercooler Inlet Pressure

(water side)

Aftercooler Outlet Pressure

(water side)

Generator Output Voltage

Generator Output Frequency

Load Power Factor

Engine Speed

Fuel Temperature

Inlet Air Temperature

Jacket Water Flow

Jacket Water Pressure Drop

Oil Cooler/Aftercooler Water Flow

Oil Cooler/ Aftercooler Water Pressure

Drop

Mean Range*

1 .65 • 10

5 Pa (24 psi) + 8%

3.72 * 10

5 Pa (54 psi) + 15%

4.69 • 10

5

Pa (68 psi) + 7 %

4.65 * 10

5 Pa (67.5 psi) + 7 %

4.55 ' 10

5 Pa (66 psi) + 7 %

4.41 / 10

5 Pa (64 psi) + 7%

479 volts 472 - 480

60 Hz. negligible

0.8 negl igible

1200 rpm 1200 - 1201

31 °C (88°F) 26°C - 35°C

31 °C (88°F) 23°C - 38°C

1 .89 • 10

2 m

2 /s (300 gpm) negl igible

3.45 ‘ 10

4

Pa ( 5 psi) + 6 %

6.31 . 10

-3 m3

/s ( 1Q0 gpm ^ negl igible

2.07 ' 10

4

Pa ( 3 psi

)

CO 1+

*Range includes variations among engines, variation from load changes,

and apparatus drift. Variables which were strongly load dependent

are not listed on this table but are listed in Table 2.

8
Table 2 (English Units)

Performance of Five Diesel Engine-Generator Units

Average Values of Load-Dependent Variables Measured During Tests

to Load 110% 100% 80% 60% 40% 20% 0%

Generator Load (KW) 660 600 475 356 237 118 0

Jacket Inlet Temp. (°F) 197.0 196.6 227.0 220.4 213.04 207.8 215.1

Jacket Outlet Temp. (F°) 210.6 208.4 235.3 226.8 218.1 211 .2 216.1

Oil Cooler Water Inlet Temp.(°F) 130.1 128.9 128.5 127.5 127.0 126.6 126.1

Oil Cooler Water Outlet Temp.*(°F) 136.0 134.4 134.5 133.2 132.0 130.5 129.3

Aftercooler Water Outlet Temp. (°F) 143.5 140.5 138.4 135.5 132.8 131 .0 129.3

Inlet Manifold Temp. (°F) 157 151 144 137 132 129 127

Exhaust Manifold Temp. (°F) 1036 987 888 787 655 506 333

Exhaust Back Pressure (psi) .60 .50 .33 .21 .13 .08 .05

Fuel Consumption Rate (lb/hr) 377.2 340.2 269.6 206.6 145.5 91 .5 12.0

Generator Temp. (°F) 171 151 137 124 113 106 104

Exciter Current (amperes) 3.5 3.1 2.7 2.4 2.0 1 .7 1 .5

*Value is also aftercooler water inlet temperature

9
Table 2

(SI Units)

Performance of Five Diesel Engine-Generator Units

Average Values of Load-Dependent Variables Measured During Tests

% Load 110% 100% 80% 60% 40% 20% 0%

Generator Load (KW) 660 600 475 356 237

t-yj/o 118

\j /o

0

Jacket Inlet Temp. (°C) 91 .7 91 .4 108.3 104.7 100.8 97.7 101 .7 Jacket Outlet Temp. (°C) 99.2 98.0 112.9 108.2 103.4 99.6 102.3

Oil Cooler Water Inlet Temp. (°C) 54.5 53.8 53.1 52.8 52.6 52.6 52.3

Oil Cooler Water Outlet Temp.*(°C) 57.8 56.9 56.9 56.2 55.6 54.7 54.1

Aftercooler Water Outlet Temp. (°C) 61 .9 60.3 59.1 57.5 56.0 55.0 54.1

Inlet Manifold Temp. (°C) 69 66 62 58 56 54 53

Exhaust Manifold Temp. (°C) 558 531 476 419 346 263 167

Exhaust Back Pressure (Pa) 4.1 '10 3 3 . 4

* 1

0

3

2 .3 *1

0

3

1 .4*1

0

3 8.9 *102 5.5*1

0

2

3 .4 * 1

0

2

Fuel Consumption Rate (kg/hr) 171 .1 154.3 122.3 93.7 66.0 41 .5 5.4

Generator Temp. (°C) 77 66 58 51 45 41 40

Exciter Current (amperes) 3.5 3.1 2.7 2.4 2.0 1 .7 1 .5

10
2500

o

<O

_J

<

o

cr

h“O

LiJ

LjJ

(SliVMOIDi) d3M0d

ll

Figure

3.

Energy

Equivalents

of

Fuel

Input,

Electrical

Output,

and

Electrical

Output

Plus

Jacket

Heat

Recovery
Table 3

Performance of Five Diesel Engine-Generator Units

Efficiency Computations and Results

% Load 110% 100% 80% 60% 40% 20%

Electrical Output (KW) 660 600 475 356 237 118

Electrical Equivalent of Pump (KW) 11 .7 11.7 11 .7 11.7 11.7 11 .7

Total Electrical Output (KW) 671 .7 611.7 486.7 367.7 248.7 129.7

Jacket Water Flow Rate (L/S) 1136 1136 1136 1136 1136 1136

(gpm) 300 300 300 300 300 300

Jacket Water Temp. Rise (°C) 7.56 6.50 4.61 3.56 2.61 1 .89

(°F) 13.6 11.7 8.3 6.4 4.7 3.4

Heat Recovered from Jacket (KW) 598 515 365 282 207 150

(KBtu/hr) 2042 1757 1246 961 706 511

Electrical Plus Thermal Output (KW) 1269.7 1126.7 851 .7 649.7 455.7 279.7

Fuel Consumption (kg/h) 171 .1 154.3 122.3 93.7 66.0 41 .5

Heat Content of Fuel (MJ/Kg) 45.35 45.35 45.35 45.35 45.35 45.35

Power Input (MJ/h) 7759 6998 5546 4249 2993 1882

(KW) 2155 1944 1541 1180 831 523

Electrical Efficiency 31 .2% 31 .5% 31 .6% 31 .2% 29.9% 24.8%

Electrical Plus Thermal Efficiency 58.9% 58.0% 55.3% 55.1% 54.8% 53.5%

12
40

°/

o

+-> fd

s-aic

ai o

O)a

c

n

c

4-o

>>o

c

cu

•r—O

fOa

•r*s- +Jo

a)

to

too

sCJ3

O)s-CO

A0N3I3U J3

13

versus

Generator

Load
at 80% load to 29.9% at 40% load. Individual unit results had a standard deviation of 0.9%. Individual results are not reported

because their standard deviation was in the range of the probable

fuel -consumption measurement accuracy.

4.3 Electrical Plus Thermal Efficiency

Electrical -pi us-thermal efficiency was computed by summing the

total electrical load (including the circulating-pumps electrical -load

equivalent) with the rate of jacket heat recovery and dividing that

quantity by the rate of fuel consumption times the fuel 's higher

heating value using consistent units.

Results are graphed in Figure 5 and summarized in Table 3. Electrical

plus-thermal efficiency ranged from 55.3% at 80% load to 54.8% at

40% load. Figure 5 shows a 3 to 5 percent increase in the electrical

plus-thermal efficiencies at 100% and 110% percent loads in comparison

with the efficiencies at 40% to 80% loads. This increase in efficiency

corresponds to the lower inlet temperature of the jacket water used

during the tests at 100% and 110% loads and appears to be a direct

result of this change in operating conditions.

The jacket inlet and outlet temperature differential was determined by

two separate temperature measurements each having minimum uncertainty

of +.3°C (+. 5°F). Errors in the calculated jacket heat recovery from

5% to 23% may have resulted because of the relatively small (1.9°C to

7.5°C) temperature difference between the jacket's inlet and outlet

water. It should be noted that heat recovered from the units' oil

coolers and aftercoolers is not included in the thermal efficiency

computation, because its temperature is too low for use in the primary

loop at the site.

14
65°/< o<o<o

cro

LU

UJ

A0N3I0I3J3

uc

dJ

>3

idJ>0

CJ

Cl) o;

+-> 03

O) 3C1 +-> QJ

j*:u

03

•"3

CO

Z3

03Uu

dJ

to

coo

i- o

Ln0) S13CD

•i—

Li_

15

versus

Generator

Load
5. Conclusions

The test results indicated that the five units have very similar

efficiencies, since the standard deviation among the values for the

five engines was only 0.9%. Over the 40% to 80% load range, which

comprises the major part of the operating duty, average electrical

efficiency of the five units ranged from 29.9% to 31.6%, electricalplus-thermal efficiency ranged from 54.8% to 55.3% (exhaust heat was

not recovered)

.

Performance of the engine-generators at the Jersey City total energy

plant has been monitored by an on-site data acquisition system. It

should be noted that several differences exist between the factory

test set-up and the plant installation of the engines. For instance,

at the site, heat is recovered from both the engine jackets and the

exhaust gases. Also, at the site, jacket water heat is lost because

it is circulated through the idle engines.

After 10,000 to 15,000 hours of engine running time, preliminary

results from measured data indicated that the engine-generator gross

electrical efficiency averaged 32.4% during a period of 60% load on three engines. Electrical -plus-thermal efficiency, including exhaust

recovery and idle engine losses, averaged 61.4% during the same period.

A summary of the plant operating performance will be available in a future publication.

16
Acknowledgments

The following organizations and personnel participated in the factory

tests described in this report.

1. Volt Information Sciences, Inc.

Julius Brick

2. National Bureau of Standards, U.S. Department of Commerce.

John Coble

Doug Ballard

Mark Kuklewicz

Pat Reynolds

3. Foley Machinery Co.

Bill Jones

Dave Trevorrow

4. Caterpillar Tractor Co.

Pete Yount

Dick Dexter

Ron Rager

Kayton Heavrin

Ed Schlaffer

Fred Ozment

17
NBS-1 14A (REV. 7-73)

U.S. DECT. OF COMM. bibliographic data

sheet

1. PUBLICATION OR REPORT NO. NBSIR 77-1207

2. Gov’t Accession

No.

4. TITLE AND SUBTITLE

PERFORMANCE OF THE ENGINE-GENERATORS USED IN THE

JERSEY CITY TOTAL ENERGY PLANT

3. Recipient’s Accession No.

5. Publication Date March 1977

6. Performing Organization Code

7. AUTHOR(S)

John B. Coble, Mark E. Kuklewicz and John H. Hebrank

8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No.

11. Contract/Grant No.

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP)

Department of Housing and Urban Development

Washington, D.C. 20410

13. Type of Report & Period Covered

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here.) Each of five 600-kilowatt (kW), diesel engine-generators which were to be installed in

a total energy plant was performance tested under NBS direction at the engine-generator

vendor's plant. These tests provided a basis for acceptance of the engine-generators

and for comparison with installed performance.

This testing was performed as a part of a comprehensive study to assess engineering,

economic, and environmental aspects of a total energy plant which supplies all

electrical power, hot water, and chilled water to an apartment complex in Jersey City,

New Jersey. Under sponsorship of the Department of Housing and Urban Development (HUD)

the National Bureau of Standards (NBS) has instrumented the total energy site for

engineering data and is collecting economic and environmental data.

The engines were tested at seven power levels ranging from 0 to 110% rated electrical

load. In the tests, fuel consumption, electrical output, and jacket-water heat recovery

were measured, as well as many other parameters. Results are reported for fuel con- sumption, electrical efficiency, and electrical-plus-thermal efficiency, and comparison;

are made with measured data from the total energy plant.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by semicolons

)

Diesel engine performance; engine-generator performance; engine-generator

efficiency; heat recovery; total energy systems.

18. AVAILABILITY Unlimited

For Official Distribution. Do Not Release to NTIS

| | Order From Sup. of Doc., U.S. Government Printing Office Washington, D.C. 20402, SD Cat. No. C 1 3

I y ! Order From National Technical Information Service (NTIS)

Springfield, Virginia 22151

19. SECURITY CLASS

(THIS REPORT)

UNCLASSIFIED

20. SECURITY CLASS

(THIS PAGE)

UNCLASSIFIED

21. NO. OF PAGES

21

22. Price

*3-50

USCOMM-DC 29042- P 74