MASTER

GAS-STEAM TURBINE
COMBINED CYCLE POWER PLANTS

By

Jeffrey E. Christian

Prepared by: Prepared for:

Oak Ridge National Laboratory

d. !-
'--
u:.··'"'-A
•., gonne
. National Laboratory
Operated by Union Carbide Corporation under Contract W-31-109-Eng-38
for the U. S. Department of Energy with the U. S. Department of Energy
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This report was prepared as an account of work sponsored
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 ANL/CES/TE 78-4
Special Distribution

GAS-STEAM TURBINE COMBINED CYCLE POWER PLANTS

by

Jeffrey E. Christian
Oak Ridge National Laboratory

,-------NOTICE-------,
This report was prepared as an account ~f work
sponsored by the United Stole& Govcomment. Ntlthtr the
United States nor the United States Department ~f
Energy nor any of their employees, nor any of theu
contradtors, subcontractors, or their employees, makes
any warranty, express or implied, or assumes any legal
liability or responsibility for the accuracy, completeness
or usefulness of any information, apparatus, product or
process disclosed, or represents that its use would not
infringe privately owned rights.

Project Manager
Thomas J. Marciniak
Energy and Environmental Systems Division
Argonne National Laboratory

October 1978

Prepared for
ARGONNE NATIONAL LABORATORY
9700 South Cass Avenue
Argonne; Illinois 60439

by
OAK RIDGE NATIONAL LABORATORY
Oak Ridge, Tennessee 37830
Operated by
Union Carbide Corporation
for the
U. S. Department of Energy
 •

The four E's of the cover logo embody the goals of

the Community Systems Program of the Department
of Energy, DOE, namely:

• to conserve Energy;
• to preserve the Environment; and
• to achieve Economy
• in the design and operation of human settle-
ments (Ekistics).
 CONTENTS

FOREWORD. v
ABSTRACT. vii
SUMMARY .. I.B.iii.1
1 INTRODUCTION •. 1
1.1 SCOPE .... 1
1.2 DESCRIPTION .. 2
1. 2.1 Gas Turbine ....•• 2
1. 2. 2 Heat Recovery Boiler. 3
1.2. 3 Steam Turbine ...•..... 4
1.3 AVAILABLE SIZE RANGES AND EXISTING INSTALLATIONS. 4
1.4 SPACE REQUIREMENTS .. 6
1.5 INSTALLATION TIME. 7
2 STANDARD PRACTICE .... 8
2.1 STANDARD RATING. 8
2.2 DERATING FACTORS ..• 8
2.2.1 Ambient Air Temperature. 8
2.2.2 Elevation .....•••....... 9
3 MATERIAL AND ENERGY BALANCE .. 11
3.1 FULL LOAD CONVERSION EFFICIENCY. 11
3.2 PART LOAD CONVERSION EFFICIENCY. 15
3.3 SUPPLEMENTARY FIRED. 16
3.4 FUEL ..•......•....... 18
3.5 WASTE HEAT RECOVERY ... 18
4 ENVIRONMENTAL EFFECTS ..•. 21
4.1 AIR POLLUTION. 21
4.2 NOISE ........ . 22
5 OPERATING REQUIREMENTS. . ........ . 23
5.1 CAPACITY CONTROL ... 23
5.1.1 Unfired Combined-Cycle Heat Recovery Boiler. 23
5.1 .2 Supplementary-Fired Heat Recovery Combined Cycle •. 23
5.1.3 Multiple Unit Inst~llation •• , 25
5 .1.4 Integration Into ICES .. 26
5.2 SAFETY REQUIREMENTS •..•...•... 28
6 MAINTENANCE AND RELIABILITY. 29
6.1 MAINTENANCE REQUIREMENTS •• 29
6.2 ECONOMIC LIFE. 29
6.3 RELIABILITY ..• 30
7 COST CONSIDERATIONS. 31
7.1 CAP! TAL COST ...
7.2 MAINTENANCE COST.
.... ' " 31
33

ICiiS TECHNOLOGY EVAUJATION

1
 'Page

8 STATUS OF DEVELOPMENT AND POTENTIAL FOR IMPROVEMENT................ 34

8 .1 GAS TURBINE DEVELOPMENT WORK. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 34
8. 2 USE OF COAL. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 35
8.3 ADVANCED COMBINED CYCLE....................................... 36
8.4 RESEARCH AND DEVELOPMENT NEEDS. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 36
REFERENCES. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 37

ICES TECHNOLOGY EVALUATION

ii
 LIST OF FIGURES

Number Title
DS-1 Schematic of Gas-Steam Turbine Combined-Cycle Variables ...... I.B.iii.1
DS-2 Heat Balance-- Representative Unfired Combined Cycles •.•••.• I.B.iii.5
1.1 Schematic of Gas-Steam Turbine Combined-Cycle Variables...... 1
1. 2 Gas Turbine/Steam Turbine Combined-Cy'c le Components ..•••• ~... 2
1.3 Heat Recovery Feedwater Heating Steam Cycle.................. 3
1.4 Equipment Dimensions for a 25-MW Combined-Cycle Power System. 6
2.1 Net Electric Power Output and Heat Rate
as a Function of Ambient Air Temperature •• ~.................. 8
2.2 Net Electric Power Output as a Function
of Elevation at Sea Level ..•....• :........................... 9
3.1 Full-Load Electrical Conversion Efficiency
as a Function of Inlet Temperature, °F.. ... . .. .•. . •. ... ••• •.. 11
3.2 Conversion Efficiency Vs Unfired Combined-Cycle Rated
Capacity..................................................... 13
3.3 Electric Power Conversion Efficiency as a Function
of the Gas Turbine/Steam Turbine Contribution to
Total Combined-Cycle Output .•.••...... _....................... 14
3.4 Part-Load Conversion Efficiency for
Unfired Combined-Cycle System................................ 15
3.5 Unfired Vs Supplementary Fired Boiler
Part-Load Conversion Efficiency.............................. 17
3.6 Heat Balance -- Repre-sentative Unfired Combined Cycles....... 18
5.1 125-MW Combined-Cycle Plant Turndown Capability.............. 25
7.1 Representative Total Installed Cost for Gas-Steam
Turbine Combined Cycle (1976 Dollars)........................ 31
7.2 Total Tnstalled Costs for Gas-Steam Turbine
Combined Cycle in $/kW (1976 Dollars)........................ 32
8.1 Target Thermal Efficiencies.................................. 34

ICES TECHNOLOGY EVALUATION

1.1.1.
 LIST OF TABLES

Number Title
DS-1 Combined-Cycle Units Manufacturers, and Unit Sizes ........ I.B.iii.1
1.1 Combined-Cycle Units Manufacturers, and Unit Sizes ....... . 4
1.2 Combined-Cycle Installations................................. 5
3.1 Representative Gas-Steam Turbine: Combined-Cycle
Application Data ...•.........•....•..............•....•. ~.... 12
3. 2 Steam Turbine Contribution at Part Load...................... 16
7.1 Maintenance Cost Correction Factors as
a Function of Fuel Type...................................... 33
8.1 Theoret ica1 Thermal Effie iencies of Power Cycles .......... ~.. 35

ICES TECHNOLOGY EVALUATION

l.V
 FOREWORD
The Community Systems Program of the Division of Buildings and Commu-
nity Systems, Office of Energy Conservation, of the United States Department
of Energy (DOE), is concerned with conserving energy and scarce fuels through
new methods of satisfying the energy needs of American Communities. These
programs are designed to develop innovative ways of combining current, emerg-
ing, and advanced technologies into Integrated Community Energy Systems (ICES)'
that could furnish any, or all, of the energy-using services of a community.
The key goals of the Community System Program then, are to identify, evaluate,
develop, demonstrate, and deploy ene!'gy systems and community designs that
will optimally meet the needs of various communities.

The overall Community Systems effort is divided into three main areas:
(a) Integrated Systems, (b) Community Planning & Design, and (c) Implementa-
tion Mechanisms. The Integrated Systems work is intended to develop the tech-
nology component and subsystem data base, system analysis methodology, and
evaluations of various system conceptual designs which will" help those inter-
ested in applying integrated systems to communities. Also included in this
program is an active participation in demonstrations of ICES. The Community
Planning & Design effort is designed to develop concepts, tools, and method-
ologies that relate urban form and energy utilization. This may then be used
to optimize the design and operation of community energy systems. Implementa-
tion Mechanisms activities· will provide data and develop strategies to accel-
erate the acceptance and implementation of community energy systems and
energy-conserving community designs.

This report, prepared by Oak Ridge Nat iona,l Laboratory, 1.s part of a
series of Technology Evaluations of the performance and costs of components
and subsystems which may be included i.n community energy systems and is part
of the Integrated Systems effort. The reports are intended to provide suf-
ficient data on current, emerging and advanced technologies so that they may
be used by consulting engineers, architect/engineers, planners, developers,
and others in the development of conceptual designs for community energy sys-
tems. Furthermun::, suffic icnt detail is provi i!P.d so that: calculational models
of each component may be devised for use in computer codes for the design of
Integrated Systems. Another task of the Technology Evaluation activity is to

ICES TECHNOLOGY EVALUATION

v
devise calculational models which will provide part-load performance and
costs of components suitable for use as subroutines in the computer codes
being developed to analyze community energy systems. These will be published
as supplements to the main Technology Evaluation reports.

It should be noted that an extensive data base already exists in tech-

nology evaluation studies completed by Oak .Ridge National Laboratory (O&.'fi.)
for the Modular Integrated Utility System (MIUS) Program sponsored by the
Department of Housing and Urban Development (HUD). These studies, however,
were limited in that they were: (a) designed to characterize mainly off-the-
shelf technologies up to 1973, (b) size limited to meet community limitations,
(c) not designed to augment the development of computer subroutines, (d) in-
tended for use as general information for city officials a~d keyed to rP~i~Pn­

tial communities, and (e) designed specifically for BUD-MIUS needs. The pre-
sent documents are founded on the O~'fi. data base but are more technically ori-
ented and are designed to be upgraded periodically to reflect changes in cur-
rent, emerging, and advanced technologies. Furthermore, they will address the
complete range of component sizes and their application to residential, com-
mercial, light industrial, and institutional communities. The overall intent
.of these documents, however, is not to be a complete documentation of a given
technology but will provide sufficient data for conceptual design application
by a technically knowledgeable individual.

Data presentation is essentially in two forms. The t:1a~n report in-

eludes a detailed description of the part-load performance, capital, operating
and maintenance costs, availability, sizes, environmental effects, material
and energy balances, and reliability of each component along with appropriate
reference material for further study. Also included are concise data sheets
which may be ret:~oved for filing in a notebook which will be supplied to inter-
ested individuals and organizations. The data sheets are colored and are
perforated for ease of removal. Thus, the data sheets can be upgraded period-
ically while the report itself will be updated much less frequently.

Each document was reviewed by several individuals from industry, re-

search and development, utility, and consulting engineering organizations and
the resulting reports will, hopefully, be of use to those individuals involved
in community energy systems.

ICES TECHNOLOGY EVALUATION

V1
 ABSTRACT

The purpose of this technology evaluation 1s to provide performance

and cost characteristics of the combined gas and steam turbine, cycle sys-
tem applied to an Integrated Community Energy System (ICES). To.date~ most
of the applications of combined cycles have been for electric power genera-
tion only. The basic gas-steam turbine combined cycle consists of: (1) a
gas turbine-generator set, (2) a waste-heat recovery boiler in the gas tur-
bine exhaust stream designed to produce steam, and (3) a steam turbine act-
ing as a bottoming cycle. Because modification of the standard steam por-
tion of the combined cycle would be necessary to recov~r waste heat at a
useful temperature (> 2l2°F), some sacrifice in the potential conversion
efficiency is necessary at this temperature.

The total energy efficiency [(electric power + recovered waste heat)

input fuel energy] varies from about 65-73% at full load to 34-49% at 20%
rated electric power output. Two maJor factors that must be considered when
installing a gas-steam turbine combined cycle are: (1) the reliability of.
the gas turbine portion of the cycle, and (2) the availability of liquid and
gas fuels or the feasibility of hooking up with a coal gasification/liquefac-
tion process.

ICES TECHNOLOGY EVALUATION

vii
 TECHNOLOGY EVALUATION
SUMMARY SHEET
OF
GAS-STEAM COMBINED CYCLE POWER PLANTS
By: Jeffrey E. Christian, ORNL October, 197

1 INTRODUCTION

This technology evaluation 1s intended to provide the pertinent per-

formance, environmental impacts, and cost ,considerations necessary to eval-
uate the incorporation of a gas-steam turbine combined cycle into an Inte-
grated Community Energy System (ICES). Figure DS-1 shows a schematic of
the major variables that describe the energy and material inputs, outputs,
environmental variables, and the system performance characteristics neces-
sary to simulate the combined cycle.

CONTROL· VARIABLES

AMBIENT
TEMPERATURE
ELECTRIC TYPE OF
AND CAPACITY
THERMAL LOADS CONTROL

! l OUTPUTS

WASTE HEAT
RECOVERY FOR
COI.111.UNITY USE
INPUTS
t--- EL ECTRIC POWER
FUEL (MW)
4
Btu /SHP·h '"'--- COMBINED CYCLE GAS TURBINE /STEAM TURBINE EXHAUST HEAT

- A I R EMISSIONS

NOISE

nu!SION GAS TtBINE

CONTROL ALTILDE EXHAUST
EQUIPMENT DESIGN TEMPERATURE
ELECTRIC
UNIT FUEL AND
CAPACITY TYPE THERMAL LOADS
*SHP: SHAFT HORSEPOWER
DESIGN I'ARAMETERS

..
i
I
Fig. DS-1' Schematic of Gas-Steam Turbine Combined-C cle Variables
ICES TECHNOLOGY EVALUATION
'I
I.B.iii.1
 The gas-steam turbine, combined cycle consists of three basic campo-
nents;

(1) gas-turbine generator set,

(2) waste-heat recovery boiler, and
(3) a steam turbine-generator set.
I
The gas turbine's exhaust gas is passed through the waste-heat recovery boil- I
.I
er where steam is produced either with or without supplemental fuel combus- !

tion. Steam from the waste-heat recovery boiler then is sent to a steam tur-
. bine, which generates electricity and has either extrac.tion ports or exhaust
steam recovery capabilities for satisfying process hP.at requirements,

1.1 SIZE RANGES

The smallest conventionally available, packaged, combined-cycle sys-

tem offered by manufacturers contacted has a base-loaded capacity of around
22 MWe; however, smaller combined-cycle units are available, and some, as
small as 5 MW, have been installed. At least one turbine manufacturer 1s
developing smaller combined-cycle units in the size range from 1.4 to 7 MW.
Table DS-1 lists various manufacturers of combined-cycle units, and avail-
able size ranges.

Table DS-1 Combined-Cycle Units Manufacturers

·and Unit Sizes

Manufacturer Size Range (MW)

u.s.
Curtiss-Wright Corp 22-125
Ceneral Electric 25-100
T-...trbo Powor & Marine Gystem 125
Turbodyne 96
Westinghouse 25-260

European
Brown-Boveri 20-200
Stal Laval 120,240

..
I
I

ICES TECHNOLOGY EVALUATION

I.B.iii.2
..
~ J
I

1.2 SPACE REQUIREMENTS

Examination of 25 and 100 MW combined-cycle plant layouts indicates

a floor spacerequirement of about 0.24 ft 2 /kW.

1.3 INSTALLATION TIME

Although typical installation times for currently manufactured com-

bined-cycle plants are about two to three years, smaller packaged combined-
cycle plants (1-7 MW) could be installed in considerably less time. Ho~

ever, allowance for the acquisition of special permits for local, state,
and federal regulatory agencies may add as many as two years to the instal-
lation time.

2 STANDARD PRACTICE

Nominal performance refers to that at the International Standards

Organization (ISO) standard day, i.e., 59°F and SO% relative humidity at
sea level. Standard fuel consists of liquid distillate with a "lower heat-
ing value (LHV) of 18,400 Btu/lb.

2. 1 EFFECT OF AMBIENT AIR TEMPERATURE

Ambient air temperature affects both the heat rate and the continu-
ous base-loaded electric power generating capacity. This relationship can
be estimated by Eqs. DS-1 and DS-2.

HR 116 - 0.2 (TA) - 0.00118 (TA)2 (Eq. DS-1)

EP = 103.3 - 0.056 (TA) (Eq. DS-2)

where:

HR = % of nominal heat rate

TA = ambient temperature CF), (0 -< TA -< 100)

EP = % of nominal electric output

.. I
I
I
ICES TECHNOLOGY EVALUATION

I.B.iii.3
 ..
I -.
I

2.2 EFFECT OF ELEVATION

The heat rate is not significantly affected by changes 1n the Baromet-

r1c pressure; however, the electric power generating capacity of a combined-
cycle plant is affected by elevation as indicated by Eq. DS-3.

EP = 100 - 0.0033 (ELEV) (Eq. DS-3)

where:

ELEV = elevation above sea level (ft) (O < ELEV < 6000)

3 MATERIAL AND ENERGY BALANCE

3. 1 FULL LOAD

The electricaL po~er generating conversion efficiency, defined as the

output electrt~ energy, divided by the total input fuel energy, varies as a
function of the combined-cycle unit size as indicated by Eq. DS'-4.
I
2 3 I\
ns = 25.58 + 0.928(MW) - 0.0165(MW) + 0.00009l(MW) (Eq. DS-4) I
I

where:

ns = conversion efficiency (%)

MW = nominal rated electric power generating capacity
(3 < MW < 120)

Equation DS-4 is based on a number of unfired combined-cycle power

plants with the steam portion contributing about SO% of the electrical power
output of the gas turbine output. Supplemental firing of the exhaust heat
recovery boiler increases the steam turbine output; however, the additional
capacity is added at an efficiency of only 20-25%.

3.?. PART LOAD

The part-load conversion efficiency curve of a combined-cycle system

var1es considerably with design. Two representative part-load efficiency

ICES TECHNOLOGY EVALUATION

I.B.iii.4
.. I
 I
I
I
I
I
I
- I
i

·'-
curves for two different combined-cycle designs can be estimated by Eq. DS-5
and DS-6, which indicate that efficiency decreases as load decreases. Equa-
tion DS-5 estimates part-load efficiency for an unfired combined-cycle sys-
.tem (without supplemental heat); Eq. DS-6 estimates the percent of nominal
efficiency at part loads for a combined-cycle system with a supplementary·
fired, waste-heat recovery boiler.
N = 22.4 + 1.125 (L)- 0.0035 (L) 2 (Eq. DS-5)

N = 203- 10.73 (L) + 0.2664 (L) 2

- 0.002478 (L) 3
+ 0.00000776(L)~
(Eq. DS-6)
where:
N = % of nominal conversion efficiency of the combined cycle plant
at full load.
L = % of base load (20 < L < 100)

3.3 WASTE HEAT RECOVERY

The waste heat recovered 1s supplied from the steam cycle portion of
the combined cycle. To recover waste heat at useful temperatures (>2l2°F),
some reduction 1n conversion efficiency of a standard steam turbine usually
1s necessary. An estimate of the breakdown of major energy outputs is shown
1n Fig. DS-2.
100 . - - - - - - - - - - - - - . . . , . . - - - - - - - ,

80 n11 = 33.8• 0.841(L)- 0.00446(L) 2

>- ==~=:.JL-............LJ
......"'a:z n11 = 23.15• 0.931(L)- 0.005(L)
2

........ 60
...
:::>

...
0
2
40 n, : ·0.214 • 0.56821 (L)· 0.00205(L)
...~a:
u
...
Q.
2
20 n, = -0.3 • 0.42384(L)- 0.00167(l)

0 20 40 60 80 100
PERCENT OF RAllO t:LECTIIICAL LOAD ( LI

Fig. DS-2 Heat Balance - Representative Unfired Combined Cycles

Equation DS-7 could be used to estimate the conversion efficiency

(ns) of a representative combined cycle, and Eq. DS-8 to estimate the total
energy efficiency.

ICES TECHNOLOGY EVALUATION

I.B.iii.5
 ns
nte
= -0.214 + 0.5682l(L) -·0.00205(L)
33.8 + 0.84l(L)- 0.00446(L) 2
2
(Eq. DS-7)
(Eq. DS-8)
_._
I
I
I
~

where:

(iO< L < 100)

The total energy efficiency (nte) is equal to the sum of electric power
and recovered waste heat energy outputs divided by the total fuel energy
input. A more indepth procedure for estimating heat recovery from a steam
eye le can be found in Ref. 5.

4 ENVIRONMENTAL EFFECTS

The air pollution emissions from an unfired, combined-cycle power

plant are similar to those of a gas turbine install.'ltinn; however, the
emission quantities are 20-30% less per kW generated than from a pure gas
turbine plant.

5 OPERATING REQUIREMENTS

5.1 UNFIRED WASTE-HEAT RECOVERY BOILER

The steam turbine capacity generally floats on the amount of steam

generated by the electric loads on the gas turbine, and the gas turbine usu-
ally operates as a simple-eye le generating unit up to about 40% of the total
rated plant output.

5.2 SUPPLEMENTARY-FIRED HEAT RECOVERY BOILERS

· Supplemental firing provides enhanced part-load efficiency but re-

quires more controls to operate. It generally adds an additional 24-30%
capacity to the combined-cycle electrical output.

5.3 INTEGRATION INTO AN INTEGRATED COMMUNITY ENERGY SYSTEM (ICES)

Steam for district heating and absorption air-conditioning can be

supplied directly from the waste-heat boiler, from a suitable extraction
point on the steam turbine, or from exhaust of a back-pressure steam tur-
bine.

A combined-cycle system employed in an ICES will show enhanced per-

formance if it is coupled to the local electric power grid.

ICES TECHNOLOGY EVALUATION

I.B.iii.6
.-.
- i
I
5.4 SAFETY REQUIREMENTS

The following four organizations have compiled standards applicable

to combined-cycle installations.

American Society of Mechanical Engineers

Gas Turbine Power Plants (R 1973)
PTC 22-1966
American National Standards Institute
Gas Turbine Procurement Standards
(1978)
Internationsl Standards Organization
Gas Turbine -Procurement 'ISO/DIS 3977
National Fire Protection Association
(NEPA No. 37-1975)

6 MAINTENANCE AND RELIABILITY

The econom1c life of a combined-cycle plant is estimated at 15-25

years, and the availability is estimated at 77%, assuming one gas turbine,
one waste-heat recovery boiler, and one steam turbine. A 10% loss in avail-
ability is caused by preventative maintenance.

7 COST CONSIDERATIONS

7.1 CAPITAL COSTS

The total installed cost (1976 dollars) for a gas-steam turbine com-
bined cycle without waste heat recovery can be estimated by Eq. DS-9.

total install.P.d = 21 (l-IW_ )· 93

(Eq. DS-9)
cost (10 6 $) 10

where:

MW = base-loaded electric output (3 ~ MW ~ 120)

If the system is to have a supplementary-fired heat recovery boiler,

add about 7% to the cost estimate generated from Eq. DS-9. Add another $2
per kW for noise attenuation. Air pollution control equipment, if needed,
will also increase the cost. These costs do not include heat rejection or
waste-heat recovery equipment.

ICES TECHNOLOGY EVA·LUATION

I.B.iii.7
 .-.
I -
I
7.2 MAINTENANCE

Estimates vary between 1.1 to 4.3 mils per kWh for natural gas. Costs
increase 30% for distillate oil and double for crude oil. If residual oil
is used, the maintenance costs are expected to be 3.3 times the maintenance
cost of a combined-cycle, natural gas plant.

8 STATUS OF DEVELOPMENT AND POTENTIAL FOR IMPROVEMENT

At least one company currently is developing small, prepackaged, com-

bined-cycle units in t-he 1.5 to 7.2 MW size range. P.reseutly, the steam tur-
bine is being designed as a full conden~ing steam t-urbi_n,. with t\-10 pressure
level inlet ports. A modification of the steam cycle to an induction/extrac-
tion turbine would be most applicable for IC.ES communiti!ile:. An indueti(')n/
extraction turbine has the capability of either exhausting or admitting a
supplemental flow of steam through an intermediate port in the casing, there-
by acting to maintain thermal energy and/or process heat ba_lance. The induc-
tion capabilities allow the steam turbine to utilize both high-pressure steam
and low-pressure steam from the waste-heat recovery boiler or other thermal
energy sources such as solar energy.

ICES TECHNOLOGY EVALUATION

I.B.iii.8
 TECHNOLOGY EVALUATION OF
GAS-STEAM TURBINE COMBINED CYCLE POWER PLANTS

Prepared by J .E.. Christian, ORNL

Date October, 1978

1 INTRODUCTION

1.1 SCOPE

The purpose and scope of this technology evaluation lS to provide per-

formance, environmental impact, and cost data necessary to evaluate the in-
corporation of a gas-steam turbine combined cycle into an Integrated Communi-
ty Energy System (ICES).

Figure 1.1 shows a schematic of the variables useful in depicting

the combined cycle full- and part-load performance. The most important re-
lationships among the control, input and output variables, and design param-
eters are presented in the Material and Energy Balance section.

CONTROL VARIABLES

AMBIENT
TEMPERATURE
ELECTRIC TYPE OF
AND CAPACITY
THERMAL LOAD~ CONTROL

l OUTPUTS

WASTE HEAT
RECOVERY FOR
COMMUPHTY USE

INPUTS - EL ECTRIC POWER

(MWJ
FUEL· *
Btu /SHP-h ~ CYCLE GAS TUR~INE /STEAM TURBINE EXHAUST HEAT
COMBINED

--AIR EMISSIONS

NOISE

nJsloN GAS TtBINE

CONTROL . ALTtDE EXHAUST
EQUIPMENT DI!SIGN TEMPERATURE
ELECTRIC
UNIT FUEL AND
CAPACITY . TYPE THERMAL LOADS
*SHP; SHAFT HORSEPOWER
DESIGN PARAMETERS

Fig. 1.1 Schematic of Gas-Steam Tu.rbine Combined-C cle Variables

ICES TECHNOU)GY EVALUATION

1
1.2 DESCRIPTION

The combined cycle covered here comprises three major components:

(1) the gas turbine generator, (2) the heat recovery boiler, and (3) a
steam turbine, as shown in Fig. 1.2. The following paragraphs describe
the operation of the system.

STEAM
TURBINE

Fig. 1.2 Gas Turbine/Steam Turbine Combined-Cycle Components

1.2.1 Gas Turbine

The ambient a1r 1s drawn into the gas turbine and compressed; fuel is
injected into compressed air and ignited. The combustion temperatures gen-
erally are between 1500°F to 1800°F. Rotation of the turbine, caused by the
expanding combustion gases, drives the compressor and an electric generator.
The combustion products, after expansion through the turbine stages, are ex-
hausted into the heat recovery boiler. For additional performance informa-
2
tion on .gas turbines, see the ICES Technology Evaluation on Gas Turbines.

ICES TECHNOLOGY EVALUATION

2
1.2.2 Heat Recovery Boiler

The hot exhaust gases (950°F to 1100°F) from the gas turbine are
directed to a heat recovery boiler which contains finned-tubed heat ex-
changers to reproduce steam. The steam is directed to the steam turbine,
and the cooled exhaust gases (V'350°F) are discharged to the atmosphere. In
most combined cycles, additional fuel is burned in the heat r.ecovery boiler
to supplement the heat in ·the gas turbine exhaust. Efficient combustion is
possible because of the high percentage of oxygen (.1'17%) in the high temper-
ature exhaust from the gas turbine. Supplemental firing generally improves
the thermal efficiency at part-load electrical demand. This 'addition adds
to the complexity of ·controlling the operation of the combined-cycle plant
and thus increases the maintenance cost.

Because no combustion occurs in the unfired heat recovery boiler in

the unit, soot-blowing problems should be minimal. Although the exhaust gas
temperatures rarely are much higher than 1000°F in the unfired units, steam
temperatures can approach within 100°F of the inlet gas temperature. Waste-
heat recovery boilers, as shown in Fig. 1.3, are available for producing two
steam pressure levels. Hot gas from the gas turbine initially flows past
the superheater which then yields the high-pressure steam from the evapor-
ator. Next, the exhaust gas traverses the high-pressure economizer and the
low-pressure economizer and yields low-pressure steam. 3

STEAN TURBINE GENERATOR

L. P. ECONONIZ ER

H. P, ECOHONIZER

EVAPORATOR

F. W. L. P.
PUWI' ECOH.
SUi>ERHEAHR PUNP

HEAo RECOVERY C 0 N DE NSATE PUMP

STEAN GENERATOR

Fig. 1.3 Heat Recovery Feedwater Heating Steam Cycle

ICES TECHNOLOGY EVALUATION

3
 For ICES applications, it might be desirable to place additional
finned tube heat exchangers in the recovery boiler to supply thermal energy.
However, use of the turbine exhaust gas is limited to 325°F ~ 25°F by the
possibility of dew point corrosion in the heat recovery equipment, particu-
larly where sulfur-bearing fuels are involved. For additional performance
information on waste-heat recovery boilers, see the ICES Technology Evalu-
ation Heat Recovery Equipment for Engines.4

1.2.3 Steam Turbine

Steam produced 1n the heat recovery boiler in a typical combined
cycle power plant is expanded in the steam turbine and condensed in the con-
denser as shown in Fig. 1.3. For ICES applications, the conventional com-
bined cycle will be modified slightly to provide for utilization of some
thermal energy from either partially or fully expanded steam. Heat removal
from a full condensing steam turbine provides hot water at relatively low
temperatures (60 to 110°F). Therefore, the modification to the steam tur-
bine portion of the standard combined-cycle plant will amount to extraction
of steam from at least one suitable extraction point on the steam turbine or
by employing a back-pressure steam turbine. A back-pressure steam turbine
operates with an exhaust steam pressure equal to, or greater than, atmos-
pheric pressure and allows for heat utilization from the exhaust steam at
higher, more useful temperatures. For additional performance information
on steam turbines, see the.ICES Technology Evaluation, Steam Turbines. 5

1.3 AVAILABLE SIZE RANGES AND EXISTING INSTALLATIONS

Table 1.1 lists several major manufacturers of combined-cycle units
and typical available sizes that might be applicable to an ICES. Combined-
cycle units conventionally are available in sizes ranging from 22 MW and
Table 1.1 Combined-Cycle Units-- Manufacturers
and Unit Sizes

Company Size Range (MW)

u.s.
Curtiss-Wright Corp. 22-125
General Electric 25-100
Turbo Power & Marine System 125
Turbodyne 96
Westinghouse 2.'5-260

European
Brown Boveri 20-200
Stal Laval 120-240

ICES TECHNOLOGY EVALUATION

4
 extend1ng beyond 100 MW up to about 400 MW. Although smaller combined-cycle
systems have been installed, no manufacturer was found to offer them as stan-
.dard "off the shelf" items at the time of this evaluation.
Table 1.2 lists several actual combined-cycle installations used mainly
for electrical power generation in the United States with combined electrical
power generating capacity of less than 100 MW. 6
Table 1.2 Combined-Cycle Installations 6

Gao Gao Turbine Cambined

Mfr Out put llo. Output Cycle Order Oper-
(MW) (MW) Planto Year ation Puel Cclllmenta

Apache Arizona GE 11 93 ODe 1960 1963 JIG 38.5 Efficiency

City Fairbanko Alaoka GE s ODe 1961 1963 Oil Repo~riag at.em
City Fairbank• Alaoka GE 6 18 ODe 1961 1963 Oil
Chugach) Electric Al·aeka w ODe 1962 1963 Oil
Coa:munity P .s·. New Mexico cE 12 One 1963 1965 JIG
Empire Riverton Kansas w 13 so ODe 1963 1964 Oil
Dow Chemic a 1 Texas w 29 :lbree 1964/65 1966/67 NG
Southland Paper Texas GE 1S 46 1964/66 1966/68 NG
University Texas w 13 One 1965 1967 NG
Wolverine REA Michigan GE 15 23 ODe 1965 1968 Oil
Ottawa Wtr & Light Kansas GE 12 One 1966 1968 JIG
City Wyandotte Michigan w 15 r One 1967 1969 Gao/Oil Repovering oteam turbine

Dow Chemical Texas w 44 Six 1967/69 1969/72 NG

City Clarksdale Mississippi GE 18 26 ODe 1968 1971 NG
Gulf Coaot Aluminum Turbd 53 3 One 1968 1970 JIG
City Hutchinson Minnesota GE 12 One 1970 1972 Oil
(
Dow Chemical Texas w 60 Tvo 1970 1972 NG
GE Lynn, Mass. GE 21 35 One 1970 1972 Gao/Oil
Kansas Power & Light GE 4~ 60 One 1970 1972
City Detroit Michigan w 30 One 1971 1973 Gao/Oil· Repovering oteam· turbine

St. Joe Power 6 Light w 60 60 ODe 1971 1972 Oil Repovering ateam turbine

Central Iowa Co-op 30 30 ODe 1972 1973 Oil Repovering ateam turbine

Southvee~ Pub Serv Texas w 30 30 ODe 1972 1973 NG Repovering Iteam turbine

Ariaofta Publ ia Sonicv 55 S5 ODe 1973 197~ NG

Braintree Maaaachueetta Turbd 60 60 One 1973 1976 Oil
C-W WDod-Ridge New Jersey cw 13 13 ODe 1973 1975 JIG Converted to gasified coal

Pacific Gao 6 Elec. TPM 50 50 One 1973 197S JIG

Salt River Ari&ona GE 55 55 :lbree 1973 1974 JIG

Central Iowa Co-OP w 60 30 ODe 1974 1975 Oit

Dov Chemical Texas GE 67 67 ODe 1974 1976 NG
Rurhank Cali farnia TPM ~0 so One 1975 1976 Gao/Oil Repovering Iteam turbine

Chugach Alaoka Turbd 60 60 ODe 1975 1976 Oil Repovering Iteam turbine

ICES TECHNOLOGY EVALUATION

5
1.4 SPACE REQUIREMENTS

A plant layout is provided to give some idea of the amount of building

area required to install a combined cycle installation. Figure 1.4 shows the
actual dimensions of 25 MW, combined-cycle plant equipment installed in the
city of Clarksdale, Mississippi. The total building floor area required is
about 6000 ft 2 (.24 ft 2 /kW), and the total height of the equipment is about
60 t't 7 •

I rOOT • 0. 3048 METERS

f
59'- 9 .,2·
TO FLOOR LINE

~--···-·

Fig. 1.4 Equipment Dimensions for a 25 MW Combined-Cycle Power System 7

ICES TECHNOLOGY EVALUATION

6
1 •5 INSTALLATION TIME

The installation. t.ime from the· dat.e the equipment 1.s. ordered for .a
gas-steam, combined-cycle unit is. found' t;o range from 2-3 years. Generally
it is poss.ible· to have a two-phase· ins.tallation in which the gas turbine-
generators and: was):e-heat recovery boilers can .be in. service. in approximate~
ly 12 to 18 months. ·The steam system. then· can be instal I.ed' while the gas.
turbines are in operation.

ICES: TECHNOLOGY EVALUATION;

7
 2 STANDARD PRACTICE

2. 1 STANDARD RATING

The standard rating conditions for the combined cycle are the same as
those used for the simple-cycle, gas turbine and are in agreement with the
International Standards Organization (ISO) standard d~y, i.e., S9°F (lS°C)
and SO% relative humidity at sea level ( 1 atm). Ratings also are for stan-
dard fuel conditions consisting of liquid distillate fuel with lower heating
value (LHV) of 18,400 Btu/lb and a density of 7 lb/gal.

2.2 DERATING FACTORS

2.2.1 Ambient Air Temperature

FigurP. 2.1 ::;hows the effect of the ambient temperature 8 on the elec-
trical power output and the estimated heat rate of a representative com-
bine<;\ cycle.

h =11_6- 0.2(°F)- 0.00118 (°F} 2

110 - WHERE=
en
e:: h = % OF NOMINAL HEAT
0
1- _J 105
0<::
~:z
~
100
w 0z
0
z
LL
<[
::!: 0
95
a:: n= 103.3- 0.056(°F)
0~
LLo
e::::~ 90 WHERE:
w n =%OF NOMINAL ELECTRICAL OUTPUT
0...
85

0 20 40 60 80 100
AMBIENT TEMPERATURE (°F)

Fig. 2.1 Net Electric Power Output and Heat Rate

as a Function of Ambient Air Temperature

ICES TECHNOLOGY.EVALUATION

.8
 The heat rate is equal to the amount of heat 1n Btus required to pro-
duce a net output of 1 kWh of electric energy. The heat rate is related to
the conversion efficiency as follows:

3413 Btu
Heat Rate (Eq. 2.1)
Conversion Efficiency kWh

The convers1on efficiency of a combined-cycle system is defined as

the output electric energy divided by the total fuel input energy.
Equation 2.2 can be used to determine the heat rate of a combined-
cycle plant at ambient temperatures from 0 to 100°F.

(Eq. 2.2)

where:
h % of nominal heat rate
TA = ambient temperature (oF) (O .S. TA i 100)

Equation 2.3 can be used to determine the electrical power output of

a combined-cycle plant at varying ambient temperatures.

EP = 103.3 - 0.056 (TA) (Eq. 2.3)

where:
EP % of nominal electric output
TA =ambient temperature (°F) (0 .S. TAi 100)

2.2.2 Elevation

Figure 2. 2 shows the effect of elevation on the power output of the

combined cycle which actually has the same effect as the gas turbine oper-
ating as a simple cycle.

...J
100
w <t
u :z
:z
<t a::
(f) -
~ 90 % OF NOMINAL
::o :z 0
a:: I - ELECTRICAL
ou
LL.
a::~
<t LL.
0
80 OUTPUT = 100- 0.0033 (ELEV)
w
0~
a..
70
0 1000 2000 3000 4000 5000 6000
ELEVATION ( FT)
Fig. 2.2 Net Electric Power Output as a·Function of Elevation above Sea Level·

ICES TECHNOLOGY EVALUATION

9
 3 MATERIAL AND ENERGY BALANCE

3.1. FULL-LOAD CONVERSION EFFICIENCY

Figure 3.1 shows the combined-cycle, full-load conversion efficiency
as a function of the turbine inlet temperature for several plants installed
in the 1950-1975 period. 7 , 9 ,1o,11

-~ 45r---------------------------------------------~
c:
. 40 n =-92.95 +0.1352(T; )-0.0000338(T; )
5
2

~
WHERE:
u
z Ti S 1960°F
UJ 35

z
0
en 25
a::
~
z
20 ~------~---------L--------~--------~------~
0
u 1000 1200 1400 1600 1800 2000
TURBINE INLET TEMPERATURE °F

Fig. 3.1 Full-Load Electrical Conversion Efficiency as

a Function of Turbine Inlet Temperature, °F

The gas turbine inlet temperature is one of the key variables that must be
considered to improve the conversion efficiency of the· gas-steam turbine
combined cycle.

The data points shown in Fig. 3.1 were used to develop Eq. 3.1 which
can be used to estimate the conversion efficiency of a combined-cycle plant
with turbine inlet temperatures varying from 1325-1960°F.

n
s
= -92.25 + 0.1352 (T.)- 0.0000338 .(T.)
1 1
2 (Eq. 3.1)

where:

ns = Conversion ef!iciency, %
T.
1
= Turbine inlet temperature, °F

ICES TECHNOLOGY EVALUATION

_.
11·
 Table 3.1 shows data describing the full-load operating conditions of
six representative combined-cycle plants. Three of the systems are based on
actual plants, and three are based on paper studies (identified by footnote
(a) of Table 3.1).

Table 3.1 Representative Gas-Steam Turbine: Combined-Cycle Application Data

Combined-Cycle Installations

Reference 8

Total rated power(c)(MW) 1.4 3 12.8 15.6 26 118

Gas turbine net power
in combined cycle (MW) .83 1.98 9.68 10.4 15 75 .s

Gas turbine fuel mass

2.1 2.16 3.43 15.31
flowrate (lb/sec)
Gas turbine air flow-
rate (lb/ sec)
28 .16. 793.8

Gas turbine exhaust

752 896 992 925 905
temp C F)
Steam cycle net power (MW) .57 1.02 3.12 5.15 11 42.5
Steam flowrate (lb/sec) 3. 77 13.23 14.3 27.75 108.8
Steam inlet pressure (psig) 337 1180 600 42S,(d) 456.7, (d)
91 63.8
Steam inlet temp (°F) 662 806 800 808, 743,
320 329
Steam exhuast pressure
(in. hg)
2 88 3 1.5 1.0

Conversion efficiency (%) 26.2 34.6 31.4 37.0 36.3 42

(a)
Based on paper studies
(b)Employs a back pressure steam turbine
(c)Rated condition of 59°F, sea level, SO% relative humidity
(d)
Accepts steam at two pressures

ICES TECHNOLOGY EVALUATION

12
The capacities vary· from 1.4 MW' to 118 MW and the waste-heat recov,ery' boiler
is· assumed· to be: unfired. The 12 •. 8-MW unit has a conversion efficiency of
31.4%, which is slightly inconsis·tant with the other systems because. the
ste·am turbine' is a back-pressure mode 1 that allo.ws fo.r. heat remova1 from the
S·te·am-turbine· eye le· at more useful temperatures and pressures.. The: back
pr.essure is 4Y.5 paia (273°F) comvared to the conden~ing pressures. of ~~5 to
1.5 ps'ia (80 to l16°F) for fulL l:Ondensing steam turbines..

The full-load' conversion efff.cienc.y• for combined-c.ycle s.yst.ems w;i:th a

full condensing steam turbine is: plotted. against the total rated. capacity. in.
Fig. 3.2.

50·
>-
u
z •
LJ.J 40
U·-
w:~ 30
LJ...-
LJ.J
= 25.58 1' O~ 928 (MW)- 0.0165 tMW} 1' 0. 00009l (MWl3
2
en n5
;z~ 20
Q WHERE:
en
a::
LJ.J 10 3 . 0 < MW
- .-< 120
>
z
0 0
u
0 10 20 30 40 50 60 70 80 90 100 110 120

RATED CAPACITY
(MW)

Fig. 3.2 Conversion Efficiency Vs Unfired Combined-Cycle Rated Capacity

(ISO Conditions and Lower Heating Value of Fuel)

The empirical Eq. 3.2 representing the plotted convers1on efficiencies 1n Fig.
3.2 1s shown below:
•
ns = 25.58 + 0.928 (MW) - 0.0165 (MW 2 ) + 0.000091 (MW 3 ) (Eq. 3.2)

here:

MW = rated el~ctrical power output (3.0 ~ MW ~ 120)

ICES TECHNOLOGY EVALUATION

13
 Any increase in electrical output of the steam portion by supplemental
firing of the exhaust heat recovery boiler is obtained at lower efficiency
which may be no better than 20-25% with a boiler efficiency of only 70% be-
16
cause of high excess air. For example, in Fig. 3.3 the combined-cycle con-
vers1on efficiency is plotted against the ratio of gas turbine output to tota
output.

44
:::,!2
0
42 8 PURE
>-
c...>
2
38
~
~GAS
TURBINE
'-'J

34
'
c...>
lL.
tl .•
w 30 /
2
0
(f)
26
0::
w
> 22
2
0
c...> 10
0 20 60 40 80 100
GAS-TURBINE POWER AS % OF TOTAL POWER

Fig •. 3.3 Electric Power Conversion Efficiency as a Funtion of the Gas

Turbine/Steam Tur.bine Contribution to Total Combined-Cycle Output

The plot is for a combined-cycle power plant with a gas turbine alone
having an efficiency of 26%, indicated by point A. By recuperation of its
exhaust heat in a low-grade steam cycle, e.g., 250 lb/in 2 , 600°F, the steam
output adds about SO% of gas turbine output to the total combined-cycle power
output and, results 1n a total conversion efficiency of 39%, shown as point B
in the figure.

By burning supplementary fuel in the exhaust, the output of the steam

portion can be increased; however, the total combined-cycle conversion effi-
ciency is reduced.

ICES TECHNOLOGY EVALUATION

14
 \

With more and more supplemental firing of the boiler, ultimately point I

C is reached in Fig. 3.3 where the whole of the power output is obtained by
the same low-grade steam cycle with an efficiency of about 25%.

Point A to B in Fig. 3.3 can be represented by Eq. 3.3 and B to C by

Eq. 3.4.
n = 114.8- 1.62163 (PG) + 0.007347 (PG 2 ) (Eq. 3.3)
ns = 25.08 + 0.17857 (PG) + 0.00059524 (PG 2) (Eq. 3 .4)
where:
PG = Gas turbine power as a percentage of total power

3.2 PART-LOAD CONVERSION EFFICIENCY

Part-load conversion (electric power generating) efficiency varies
considerably among various designs. For instance, a combined-cycle installa-
tion with more than one gas turbine shows higher part-load efficiencies than
a combined-cycle unit using a single gas turbine unit. Figure 3.4 shows
part-load efficiency curves for various combined-cycle systems with a single
7 12 13 17
gas turbine, waste heat recovery boiler, and steam turbine. ' , ,

100

'::i
4
z
:i 80
0
z
"'-
0
~
* REF. 10
7(26 MW 1 I
60 o REF. 12(1.4 MWl 101
~
u D REF. 13(3.0 MWl 101
z o REF.. 17(22 MW)COI
~
~ 40
"'-
~

z
0
u; 20
a:
w
>
z
8
0
0 20 40 60 80 100

ELECTRIC POWER LOAD

(-to Of BASE LOAD CAPACITY)

(a)
Refers to total rated electric power generating capacity
Fig. 3.4 Part-Load Conversion Efficiency for Unfired Combined-Cycle System

ICES TECHNOLOGY EVALUATION

15
The solid line within the shaded area 1n Fig. 3.4 is considered a representa-
tive part-load efficiency curve for a combined cycle with no supplementary
firing, and is represented by Eq. 3.5.

N = 22.4 + 1.125 (L) - 0.0035 (L 2 ) (Eq. 3.5)

where:

N % of nominal convers1on efficiency, and

L = % of base-loaded electrical power output

The share of electric output contributed by the steam turbine var1es

at part load. Table 3.2 shows the percent of total electrical output pro-
vided by the steam turbine at var1ous part-load condit;:ions. As thP. gRs tnr-
bine efficiency begins to drop, more
recoverable waste heat 1s produced,
T~ble 3.2 Steam Turbine and the percentage of steam turbine
Contribution contribution increases. The percent
at Part Load
of load satisfied by the steam tur-
bine as a function of part load for
% of % of load
full satisfied by the parti~ular design used to develop
load the steam turbine Table 3.2 can be represented by Eq.
100 29 3.6.
BOO 29 SL = 49.0 - 0.45 (L) + 0.0025 (L 2 )
60 31 (Eq. 3.6)
40 35
where:

% of load satisfied by the

stP.<~m t •.1rbinw
L = % of base load capacity
(40 < L < 100)

3.3 SUPPLEMENTARY FIRED BOILER

The combined cycle with an unfired waste-heat boiler has an advantage

over the use of fired boilers in that the heat rate at full load is lower
than for most fired cycles. At partial loads, however, the unfired cycle

ICES TECHNOLOGY EVALUATION

16
does not necessarily exhibit the lowest heat rates (as shown 1.n Fig. 3.5).

100

>-
L) 80
z:
>-~
L>L)
z-
LLJU....
-u.... 60
~LLJ
~Cl
LLl <!
__.
0
z 40 FIRED: N = 203- 10 73 (L) "t 0. 2664 (l) 2
Q__.
en__. -0.002478 (L) 3 t 0 00000776(L) 4
0:::::>
LLl LL
> UNFIRED: N= 22.4 t 1.125(L) - 0.0035(Ll 2
Zu....
8o 20

~
~

0 20 40 60 80 100

ELECTRIC LOAD
(% OF BASE LOAD CAPACITY}

Fig. 3.5 Unfired Vs Supplementary Fired Boiler

Part-Load Conversion Efficiency

The part-load conversion efficiency· for a combined eye le with an unfired wast
heat boiler is modeled by Eq. 3.5 and Eq. 3.7 represents the ·part-load effi-
cieny curve for the combined-cycle plant using a fired boiler.

N = 203.0 - 10.73(L) + 0.2664(L 2 ) - Q.002478(L 3 )

+ 0.00000776(L") (Eq. 3. 7)

where:

N = % of full-load convers1.on efficiency, and

L =%of base-loaded electric output.

The nominal full-load conversion efficiency is the efficiency of an unfired,

combined-cycle system at base-load rated conditions.

ICES TECHNOLOGY EVALUATION

17
3.4 FUEL

Two basic types of fuel that a gas turbine presently can accommodate
are: (1) the clean fuels which include natural gas, distillate oils, and
other derived fuels that are free from contaminants, and (2) the heavy fuels
which include crude, residual, heavy distillates, and derived fuels that ar£
contaminated with trace metals.

The heavy fuels are unsuitable 1n the as received c9ndition and re-
18
qu1re decontamination before firing. The major contaminants that must be
removed are those containing sodium, potassium, lead, and vanadium. The com-
bined concentration of these four elements usually is li.mit~r.l to a maximum
value of 3 ppm.
Vanadium compounds, present 1n the fuel levels greater than 0.5 ppm,
can cause hot corrosion of the turbine section. Vanadium occurs in petro-
leum fuels as an oil-soluble form that;: cannot be remoVF~rl frnm thP f•.Hill by
water washing or by mechanical separation. However, the corrosion effect
of vanadium can be counteracted by addition of a suitable magn,esium com-
19
pound.

3.5 WASTE HEAT RECOVERY

Figure 3.6 shows a representative breakdown of the major energy out-
puts from a combined-cycle power plant with provisions for waste recovery.

100 .---------------,r------,
MISCELLANEOUS HEAT LOSSES

2
80 "" : 33.8• 0.841(Ll. 0.00446(L)
>-
"'
a:
...'"'
.~

.......
::::>
60
~

...
0 2
.... 40 nI : -0.214 • 0.56821 (L)- 0.00205(L)
...a:z
u
...
Q.
2
20 n1 : ·0.3 t 0.42384(L)· O.OOI67(L)

0 20 40 60 100
PERCENT OF RATED ELECTRICAL LOAD ( L)

Fi . 3.6 Heat Balance -- Re resentative Unfired C

ICES TECHNOLOGY EVALUATION

18
The waste heat recovered shown 1s from the steam cycle portion of the com-
bined cycle plant. Figure 3.6 provides quantitative values but does not
indicate the recoverable temperature levels of the waste heat. The typical
combined cycle applied for only electrical power generation expands steam
through the steam turbine down to a low condensing temperature, typically
60° to l00°F, which is good either for preheating water for heat pump appli-
cation or for boiler feedwater.

Some efficiency of electrical generation has to be sacrificed to pro-

vide condensing steam at exhaust pressures that can provide hot water at
temperatures around 212°F. An infinite number of steam cycle modifications
can be made to balance the heat and electrical output with the loads. A
more indepth discussion of steam turbine modification for cogeneration of
b.oth electricity and useful heat from the steam turbine exhaust is provided
5
in the ICES Technology Evaluation, Steam Turbines.

The range of conversion efficiencies of a combined-cycle plant with

provision for waste-heat recovery at part-load conditions can be modeled by
Eq. 3. 8 and 3. 9.

n
s
=- 0.214 + 0.56821(L) - 0.00205(L 2 ) (Eq. 3 .8)

ns = - 0.3 + 0.42384(L) - 0.00167(L 2 ) (Eq. 3. 9)

where:

n = convers1on efficiency (% of fuel energy

s converted to electricity), and
L = % of rated electrical load

The range of fuel energy converted to electric power and recoverable

waste heat at part load can be modeled by Eq. 3.10 and 3.11.

n = 33.8 + 0.84l(L) - 0.00446(L 2 ) (Eq. 3.10)

te
n = 23.15 + 0.931(L) - O.OOS(L 2 ) (Eq. 3 .11)
te
whece:

n = total fuel energy converted to electric

. te
power and recoverable waste heat.

ICES TECHNOLOGY EVALUATION

19
 The amount of recoverable waste heat at var1ous part-load operating
conditions can be estimated by subtracting the convers1on efficiency n from
s
the total recoverable fuel energy n as follows:
te ·
recoverable waste heat = nte - ns (Eq. 3.12).

A computer code, "ORCENT"- a digital computer program for saturated

and low superheat steam turbine analysis---(ORNL-TM 2395), has been devel-
oped by Howard Bowers at Oak Ridge National Laboratory and may be useful
for studying the effect qf various waste-heat recovery schemes from the steam
cycle applied in ICES communities.

In general, two commonly used steam turbine types are availablP. fo~

heat ~ecovery: ( 1) back-pre~? sure steflm tn~hinlilil, :md (2) extra.-.t iuu sL~am
turbines. The back-pressure steam turbine is used for cogeneration applica-
tions with relatively fixed electric-to-heat ratios; whereas, the extraction
turbine can be governed to balance the fraction of steam bled off to meet
more variable heat and electrical loads.

ICES TECHNOLOGY EVALUATION

20
 4 ENVIRONMENTAL EFFECTS

The ·major environmental impacts of installing and ope·rating a .com-

bineo-cyc le power plant are ,similar to those of a simp1e-cycle ·gas ·turbine .• ·2
Air pollutant -emissions include: sulfur dioxide, NO , CO, and unburned
X
hydrocarbons; ·other env.ironmenta1 effects include noise and th.e aes·thetic
visual impac.t ·of the equipment building .and stack.

4. 1 AIR POLLUTION

Mode.rn gas turbines address the sulfur oxide em1.ss1on standards by

' limiting the sulfur content of the fuel to 0.3-1.0% depending on 'local con-
. d it ions and ·requirements. ·2 · 0 •

The Environmental Protection Agency's (EPA's) Office of Air Quality

Planning and Standards (OAQPS) is expected to propose a New Sourc-e Per-
_formance Standard for gas turbines. Typic-al, uncontrolled NO emissions
X
from large gas turbines can range to 250 ppm. OAQPS recommends that the
limit be 75 ppm (at 15% oxygen) for units above 7.5 million Btu/h ("'6 MW).
Be.cau.se smaller gas .turbi-nes emit negligible amounts of ·No , a standard
X
for them will not be issued.

The 75 ppm goal is based on water or steam injection into the turbine
· -- the so called "we.t" NO ·control system. This method can cut NO output by
X X
over 80% at .an increase in the gas turbine heat rate of about 3% (above the
21
-heat r.ate values shown in Table 3.1) versus uncontrolled operation.

However, the NO emissions ·of the combined-cycle plant are less .than
X
those from a straight gas turbine plant of the ·same capacity. As shown in
Tables 3.1 and 3.2, about 25 to 40% of the combined cycle electrical output
1s produced by the steam turbine which does not emit NO .
X

At though several g:r.oups now are trying to perfect "dry" me-thods for
NO control_, i.e., those based on operations or combustor design modi fi-
x
cations, demonstrated technology .remains at least several years away.

ICES TECHNOLOGY EVALUATION

21
 Calculations of the short-term or annual arithmetic mean ground-level
concentration of pollutants can be made using the Air Quality Display Model
Computer Program developed for the EPA and the meteorological record of the
diRtribution of wind direction, speed, and stability class.* The calculated
ground-level concentration of pollutants then can be superimposed upon ex-
isting ground-level concentrations for proposed plant sites, and the results
compared with ambient air quality regulations to determine if the site is
suitable for the proposed plant.

4.2 NOISE

Provisions can be made to provide space for installing stlencing,in

the exhaust ducting between the gas turbine and heat recovery steam genera-
tor. For sound attenuation on combined cycle, $2/kW is added to the total
17
installed cost.

*TRW Systems Group, "Air Quality Display Model" PB-189...;.194, ( 1696).

ICES TECHNOLOGY EVALUATION

22
 5 OPERATING REQUIREMENTS

5. 1 CAPAC! TY CONTROL

5.1.1 Unfired Combined-Cycle Heat Recovery Boiler

The most common application of the combined-cycle power plant today

1s to meet the electric utility intermediate power demands. If the plant
1s grid connected, adjusting to rapid demand fluctuations may be not neces-
sary. Generally the steam turbine electric capacity "floats", based on the
amount of'steam generated as a result of the electric loads on the gas tur-
bine. The gas turbine responds to the electric load selector device which
usually is designed for semi-automatic control; however, with additional
controls the entire combined cycle can be made fully automatic.

The steam turbine generally is equipped with an inlet pressure gov-

ernor that maintains steam pressure at the rated level throughout the load
range. The unfired heat recovery boiler combined-cycle plant using a S1n-
gle shaft gas turbine with modulating compressor inlet guide vanes can
maintain fairly constant steam temperatures and flow delivered to the steam
turbine over the upper 30% of the load range. This feature eliminates one
criticism that commonly has been directed toward the unfired combined cycle,
15
namely, poor steam temperature control with load variation. Some unfired,
combined-cycle systems have been designed to start the steam system as low
as a part load of 40% of the total rated plant output. 17

Bypaoo stacks and damper.$ for. conducting the gas turbine exhaust
gases directly to the atmosphere commonly are used for control of the heat
'-1

recovery boiler output and for startup. Thus, at very low electrical and
thermal loads, the combined cycle can be operated as a simple-cycle, gas
turbine.

The gas turbine portion of the plant can be brought on line in 10-15
l!linutes from a cold start; the steam portion of the plant cau L~ 011 line in
1
bO min from a standby situation and in about four hours from a cold start.

ICES TECHNOLOGY EVALUATION

23
 Automatic relaying to shed the least essential load ts very important.
Any sudden overload on a steam turbine generator will slow it down, and this
can happen if turbines are operated in parallel with a utility and the util-
ity tie ts interrupted, or if one of several turbines operating without a
utility tie is tripped off line. In either situation, high-speed relaying
which takes off blocks of least-essential loads should be installed. 20

5.1.2 Supplementary-Fired Heat Recovery Combined Cycle

The supplementary-fired, combined cycle has the advantage of provid-

ing better. part-load ~onversion efficiencies; however, becausP fuel combus-
tion takes place in two places in the cycle, the system is sll.ghtly more
difficult to control. Supplemental firing of the boiler increases the out-
put of the steam system over that of the unfired boiler system, and the
range of steam system is 35-60% of the total plant output. Supplemental
fuPl requirement expands fuel options. The supplemental fuel could be coal
or possibly a mixture of coal and bimass; hoth fuels cannot be used pres-
ently in simple-cycle turbines directly.

Supplemental heat sometimes is required from steam extracted from

the steam turbine at high loads on the system -- those in which more than
about 45% of plant capacity is produced by the steam system. For example,
if the combined cycle already is putting out 100% of its peak electric out-
put and additional heat is called for, supplemental burners in the waste-
heat rerovery boiler can produce the additional steam to meet the heat load
while keeping the electrical output (contributed by the steam turbine gen-
erator) constant. The supplementary-fired heat recovery combined-
cycle system can be designed for good part-load heat rate by maximum util-
izalion of gas turbine power, with minimum or no firing ot the boiler un-
less the gas turbines are fully loaded.

The major disadvantage of the supplementary fired system is the

sharp variation in steam temperature with load, because air flow is not
varied with steam flow when the boiler ts fired, and the superheater is
the element nearest the burners. This situation is alleviated by plac-
tng the superheater upstream of the burners.

ICES TECHNOLOGY EVALUATION

24
 5.1.3 Multiple-Unit Installation

Multiple gas turbine and waste-heat boiler combined cycle installa.-·

tions improve plant re.liabili.ty, availability, and part-load efficiency,
although they are more complex to control. Figure 5 •.1 shows heat rat..e vers·us
total plant output for a 125 MW plant. a

.....
~

a:·
13.000

12.000
!C-
w.~
::Z::z:
~-

....
"''"'
c:z:
-'•
.. ~
11.000

' 4 GAS TURBIN S 2 BOILERS

... ::::>
~~
CID
lll.
10.000
\. ~ v
;:: 9.000
..."' ;.~ GAS TURBINES +-+--fl----1---lf-f-f--~
I BOILER I I
8.000
40 60 80 100 120 140 160 180

PLANT ELECTRIC OUTPUT- IIW

Fig. 5.1 125-MW Combined-Cycle Plant

Turndown Capability

Although the size geneally exceeds the 100-MW range considered potentially
applicable for ICES communities, the advantage of having multiple compo-
nents is clearly illustrated. Multiple components provide a very low heat
rate at fixed part-load conditions. Thus, by proper load management, low
average heat rates can be achieved by operating the plant at or slightly
less than the capacity levels offering the minimum heat rate.

One potential control strategy employed by multiple-component, com-

bined-cycle installations is to basel~ad one gas turbine and use the ex-
haust temperature as the controlling criterion. The steam turbine is base-
loaded according to average extraction steam demand with minimum flow to
the condensor. '
The other gas turbine carries the remainder of the load.
Upon a load fluctuation, either up or down, the steam turb1ne with its
governing system: (1) takes the load change to hold frequency constant;
.and (2) through use of a slave controller, transfers the load to the
lesser loaded gas turbine. It then works back to its optimum efficiency

ICES TECHNOLOGY EVALUATION

25
point; 1.e., m1n1mum flow to the condenser. 13 The steam is produced by
the waste heat boilers according to load which varies the inlet guide
vane position.

The combined-cycle plant with multiple component installations can

be operated in many ways to taylor-fit the system to an ICES electric-to-
heat load ratio. One gas turbine could be baseloaded and another could come
on line if the "floating" steam turbine cannot handle the increased load.
Other configurations might utilize extraction-pressure and exhaust-pres-
sure govern1ng -- with one turbine operated as an exhaust or back-pressure
type, carrying a base load, while swings are handled by the other turbine,
acting as an extraction-pressure unit.

5.1.4 Integration into an ICES

Most of the discussion on combined cycles, up to this point, has been

focused on electrical power generation. However, to integrate this cycle
into an ICES, some variation on the steam turbine portion is necessary. More-
over, if the plant is to be run independently of the local power grid, supple-
mental firing probably will be needed to improve the overall reliability and
to provide lower heat rates at part-load conditions. A more indepth discus-
sion on waste-heat recovery can be found in the ICES Technology Evaluation,
5
Steam Turbines. The following only suggests possible configurations to be
consid~red.

Steam for district heating and absorption a1r conditioning can be sup-
pi ted directly from: (1) the heat recovery boiler, (2) a suitable extraction

po1rrt on the steam turbine; or (3) use of a back-pressure turbine design.

Actual conditions of the recovered heat depend on both the procedure for ex-
traction or recovery and the heat use. For example, during summer operation,
it might be preferable to extract steam at 125-150 psig for use ~n a two-stage
absorption chiller with a COP of about 1.0 rather than 1n a stngle-effect ab-
sorption unit requir.ing 12-16 psig steam and providing a COP of about 0.6.

ICES TECHNOLOGY EVALUATION

26
 Many configrations utilizing a combined-gas-steam turbine cycle can be
envisioned. For instance, a noncondensing (or back-pressure) turbine coupled
to a centrifugal chiller that shares the cooling load with one or more absorp
tion units could be used. The exhaust steam from the turbine, commonly at
about 15 psig, serves as the heat energy source for the absorption unit's
generator (concentrator).

A good subsystem optimization study could include an analysis of Which

configuration would be more energy-effective for a given community: a back-
pressure steam turbine generating waste heat for a single-effect absorption
chiller or an extraction steam turbine providing steam at high enough pres-
sures to operate a double-effect absorption unit.

When optimizing for one component (steam turbine), every effort should
; be made to use steam at the lowest possible pressure; conversely, When employ
ing waste heat for absorption chillers, a higher pressure (125-150 psig) pro-
vides a more appealing COP.

While examining the potential combined-cycle arrangements applicable

for a particular ICES corrnnunity, it is important to remember that. when using
a single gas turbine .coupled with a single back-pressure (noncondensing)
steam turbine, the heat load must be relatively in phase with the electric
load, or sufficient cooling capacity to reject the unneeded thermal energy·
must be provided. Without a condensing section, one of the following steps
would have to be taken when the full waste-heat load from the steam t. urbine
portion of the combined cycle cannot be utilized:

1. Reduce electric load, and purchase the balance from

the local electric utility (with possible high elec-
tric demand charges).
2. Generate noncondensing power, and reject steam to
the atmosphere if no heat storage is available.

It may be ·preferable to have a 'condensing steam turbine with one, two,

or even three automatically controlled extraction openings to allow adjust-
ments for various electric-to-heat ratios by automatically increasing or
decreasing the steam flow to the condenser.

ICES .TECHNO LOGY EVALUATION

27
 A combined-cycle power plant employed 1n an ICES community will show
enhanced performance if coupled to the local electric power grid. The heat
rate is a minimum at full load and Increases at part loads. Thus, if the
plant could operate at optimum loads by selling and buying electric power
from the local utility, the overall performance of the combtned cycle (and
possibly the local power utility) could be improved.

5.2 SAFETY REQUIREMENTS

The following list of applicable standards applies not only to safety,

but also to design, construction, procurement, and operation of stationary
gas turbines; thus they would apply equally well to combined-Lycle installa-
tions.

(1) The American Society of Mechanical Engineers (ASME) has

compile·d a standard tit led, Gas Turbine Power Plants
(Rl973), PTC 22- 1966, Book No. C00015. This standard
can be obtained by writing the American Society of
Mechanical Engineers, United Engineering Center, 345
East 47th Street, New York, New York 10017.
(2) American National Standards Institute, 1430 Broadway,
New York, New York 10018, has formed Committee B-133
for the purpose of generating a Gas Turbine Procurement
Standard to meet the needs of U.S. gas turbine users,
consulting engineering firms, government, manufacturers,
etc. It is planned that one of the 13 sections will
cover Gas Turbine Maintenance and Safety.
(3) International Standards Organization Technical Cooonittee,
70/Sub Committee 6 has drafted a document ISO/DIS 3977
Gas Turbine -Procurement·
(4) National Fire Protection Association, 470 Atlantic Avenue,
Boston~ Massachusetts 02210, developed a ~t~ndad for the
installation and use of stationary combustion engines and
gas turbines (NFPA No. 37-1975) encompassing: general
provision, protective devices, full supplies, exhaust pip-
ing, lubricating oil, instructions and fire proteLtion.

Safety requirements, applicable to the steam turbine portion of the

combined cycle, can be found in the ICES Technology Evaluation, Steam Tur-
5
bines·

ICES TECHNOLOGY EVALUATION

28
 6 MAINTENANCE AND RELIABILITY

6.1 MAINTENANCE REQUIREMENTS

The major portion of the maintenance cost of a combined-cycle power

plant is expected to be that associated with the gas turbine, including the
exhaust heat recovery boiler. Air craft derivative gas turbines burning
liquid fuel in rugged peaking applications generally undergo modular main-
tenance between 3,000 and 5,000 hours of operation, and heavy industrial
23
units experience overhauls between 8,000 and 10,000 hours. However, gas
turbine maintenance in combined-cycle operation should be less than the
maintenance cost of the simple cycle for peaking plants because the gas tur-
bine will be operated with fewer starts and stops in an ICES installation.
Maintenance cost is a function of both fuel type and the number of starts
and stops.

Hibtorically, planned outage time accounts for the largest loss of

team turb1ne generator availability. With major inspections, including a
steam turbine opening, scheduled at three-year intervals, planned turbine-
generator outage time for this cause will vary on a prorated annual basis,
from approximately 50 h for 5,000 kW unit to approximately 120 h for a
40,000 kW unit. It is common practice to open marine turbines for inspec-
tion only every fifth year. However, any decision to extend the interval
between major inspections should be based on more extensive monitoring of
machine operation and with maximum use of partial inspection te~hniques. 2
-

An unfired waste heat boiler m1n1m1zes refractory maintenance because

the refractory is not subject to the high cyclic temperatures commonly found
in a fired boiler.

6.2 ECONOMIC LIFE

The estimated econom1c life of· a combined-cycle system operating 1n

an ICES-type application should be between 15 and 25 years. The useful life
of large steam turbines and gas turbines often 1s estimated at 20-40 years
25
and sma 11 gas turbines from 15-i5 years.

ICES TECHNOLOGY EVALUATION

29
6.3 RELIABILITY

The plant cycle reliability is estimated by exam1n1ng the percent of

26
availabillty of the three major components within a combined cycle.

Component % availability
LOmbustion turbine 87.5
boiler 95.0
steam turbine 99.0
The equivalent forced outage rate for a combined-cycle power plant
can be estimated by the following equation:

n
EFR FR + L [(1.0 - PA) x FCU)
i=J

where:

PR ratio of the time that a plant is completely forced out of ser-

vtce to the time it is not on planned maintenance. Reference 26
suggests 0.014 for a 400 MW combined cycle power plant.
PA Percent availability for each major component/
FCU Fraction of total plant capacity made unavailable by component;
outage.

The equivalent forced outage rate for a combined cycle power. plant
with a single gas turbine, heat-recovery boiler and steam turbine is esti-
mated at 16%. The average annual ava1lability for a combined-cycle power
plant with a single gas turbine, waste-heat recovery boiler, and steam tur-
bine is estimated at 77%.* The planned outage on all equipment ts esti-
mated at 10% to carry out an adequate preventative maintenance prvgram.
Multiple installations will enhance the overall availability.

If the ICES is to be operated independently of the local power util-

ity, at least two gas turbines have to be in the cycle. Otherwise, the
supercharged boiler cycle in which the combustion chamber is combined with
the boiler of the steam cycle is not acceptable, because tripping of the
gas turbine will necessarily result in a complete shutdown of the station.

*Average annual availability= (1 - equivalent forced outage rate) X

(1 - planned outage rate)

ICES TECHNOLOGY EVALUATION

30
 7 COST CONSIDERATIONS

7.1 CAPITAL COST

Figure 7.1 sh~ws representative total installed cost (in 1976 dolla'rs)
for gas steam turbine combined-cycle power plants. The costs are for systems
with no supplementary fired boilers.
l
In an unfired combined-eye le, the stea
·.turbine generally contributes 30-35% of the total plant electrical power gen-
erating capacity.

1000 .. - - - - - - - -

/
27 /
Y.. /r
25 / 0¢fs '
7 /26
27 / /
Y. /
/ /

-
"0'
,_
2800
/
6//

/
/
/

en
/ /
0
'-'
// /
n/ /
n. /
/ / :/25
/ /26
/ /
/ / TOTAL
/ // INSTALLED MW\·93
COST 21 (10/
/ /
(10 6 $I
0"
REF. 12

0 .I .___ _...__.1.,__._-L....
I 2 3 4 5 10 20 30 50 70 100 200

PEAK ElECTRIC POWER OUTPUT (MW)

Fig. 7".1 Representative Total Installed Cost for Gas-Steam

Turbine Combined-Cycle (in 1976 Dollars)

"ICES TECHNOLOGY EVALUATiON

. 31
 Figure 7.2 shows the total installed costs 1n $/kW (1976 dollars) for
a gas-steam turbine combined-cycle power plant.

220
210

3:: 200
-~
.....
-<f)- 190

180

llO
160

150 ,,,j__J,~---'---~
0 80 100 120 140
PEAK ELECTRIC POWER OUTPUT ( MW)

Fig. 7.2 Total In~talled Costs for Gas-Steam Turbine

Combined Cycle in $/kW (1976 Dollars)

In a supplemental-fired cycle the total inst~lled cost is estimated

to increase above the costs shown in Fig. 7.1 by about 7%. The steam tur-
bine contributes 35-60% of the total plant capability with a supplemental-
fired boiler.

The costs shown in Fig. 7.1 do not include the cool.ing tower nor
abnormal siting costs such as high priced land. The costs were obtAined
from records of combined cycles installed in the past, manufacturers, and
other paper studies on combined cycles.

Additional cost must be added to the total combined cycle installa-

tion cost for the following additional auxiliary equipment if needed:

(1) fuel forwarding and treating equipment (i.e., $17/kW for a

20-MW gas turbine residual fuel oil washing system 27 ) ·

ICES TECHNOLOGY EVALUATION

32
 (2) accoustical packages for sound attenuation to specified
levels (add about $2/kW to meet sound level requirements
in a commercial area)
(3} environmental control equipment, i.e.:
(a) exhaust stack extensions (for costs see Ref. 32).
(b) water.injection in the gas turbines for NOX con-
trol when burning heavy distillate or resiaual
oils. 21

7.2 MAINTENANCE COSTS

The major portion of the maintenance cost 1s expected to be that asso-

ciated with gas turbines. Experience with industrial simple-cycle gas tur- ·
hines suggests that the operation and maintenance costs for a combined-cycle
1
power plant will vary from l.l-4.3 mils per kWh.

Maintenance costs of the combined cycle are related directly to the

number of starts as well as the hours operated and type of fuel. The mainte-
nance costs for a diesel oil fired turbine started daily is approximately 30%
27
more than for those started weekly.

Table 7.1 shows the maintenance cost correction factors for a variety
of potential fuels.

Table 7.1 Maintenance Cost

Correction Factors
as a Function of
Fue 1 Type • 3 3

Fuel <.:orn:!c 1: ion

type factor

natural gas l.O

distillate oil 1.3
crude oil 2.0
residue oil 3.3
--········---~~-------

ICES TECHNOLOGY EVALUATION

·33
 8 STATUS OF DEVELOPMENT AND POTENTIAL FOR IMPROVEMENT
Two areas of research and development are currently underway which
will significantly affect the future application of combined cycles tn an
ICES. The first is the work on gas turbines. If turbines can be designed
to handle higher combustion temperatures, the efficiency of the gas turbine
improves as well as the efficiency of the combined cycle, not only because
of the enhanced performance of the gas turbine, but also with a potentially
higher exhaust temperature from the gas turbine higher temperature steam can
be obtained for expansion through the steam turbine. The second area of de-
velopment is combustion turbine development which allows the use of coal by
either prefuel treatment such as gasification or liquefaction or some type
of external combustion turbine such as one coupled with a fluidtzed bed
boiler. 3't

8.1 GAS TURBINE DEVELOPMENT WORK

The Electric Power Research Institute (EPRI) and the Department of
Energy (DOE) presently have much to say as to where the combined cycle sys-
tem will advance. They are sponsoring research to improve the performance
of today's turbines while also developing high-temperature technology for
future high efficiency designs.

The projected efficiencies of combined cycles with proposed designs

incorporated and developed are shown in Fig. 8.1 for larger units.
~
.......
~
(")
CD
0
TARGET GAS TURBINE INLET II:
m
..._
0
0
TEMPERATURES NOTED ON ...z
Cl
~ CURVES
" 56% 54% Q
>
:z:
-1 ...
0
r-

,_
u
54% 52%
.......
::r:
:a
z a:
J>
~ 52% 50% r-
......
u
;..,
...,
w
50%
...,
48% ;:;
-1 ;n
z
""
~ n
...""
:z:
t-
48% 46% -<

...
-1
46%
::r:
44% :s:
,_
u <
u

...l'!E
c:> ....
44% 42% t
CD 0
~ 2!
u c:
120 200 280 360 440 520 .......
;;
SPECIFIC OUTPUT ( Mw/PPS)
Fig. 8.1 Target Thermal Efficiencies
Source: Gas Turbine World, November 1975.

ICES TECHNOLOGY EVALUATION

34
Whether th'e projected efficiencies will be reached depends on factors, such
as an advanced blade cooling system by circulating water through small chan-
nels drilled through the blades.

In practice, the attainable efficiencies are considerably lower than

those given i.n Table 8.1; e.g., the average efficiency of large modern
steam plants is presently around 40%. Nevertheless, the values of the Car-
not efficiency shown in Table 8.1 give an indication of the potential of
the combined cycle. 28

· Table 8.1 'Theoretical Thermal Effie iencies of Power Cycles2a

., _____
Source Temp. Sink Temp. Carnot
Cycle CF) CF) Effie iency

Gas turbine 1600 801 0.19

Conventional steam 1051 270 0.52
Combined 1600 270 0.65

8.2 USE OF COAL

The present fuel outlook indicates that in the foreseeable future,

coal-derived ftiels will be the primary source for gas turbines. To make
the comb-ined cycle an attractive option for an ICES application, an effi-
cient coal conversion process that will.handle a wide range of coals with
varying analysis and characterist'ics needs to be developed along with a
high temperature gas turbine that can utilize the coal-derived fuels.

8.3 ADVANCED COIMBINED CYCLES

Solar, a division of International Harvestor is presently working on

gas turbines which could be adapted for combined cycle application. The
turbine is envisioned to have dual fuel burning capabilities. An external

ICES TECHNOLOGY EVALUATION

3.5
combustion chamber burns coal, municipal waste, wood • • . and a secondary
35
chamber burns distillate oil to even the heat release from both chambers.
This technology is not expected to be available before 1981.

Solar is also developing a packaged combined cycle system which will

produce about 5~12 MW with a predicted thermal efficiency of 40.8%. A stm-
plified· single-pass stainless steel heat recovery boiler is now undergoing
intial tests and concurrently an efficient, compact steam turbine, is being
35 36
developed. • Solar development work is expected to encompass a 7.18 MW
untt and possibly a 1.4 MW unit. Presently, the steam turbine is being de-
signed as a full condensing steam turbine. However, modification of an
induction-extraction turbine is possible and would satisfy ICES electric and
thermal needs. An induction-extraction turbine has the capability of either
exhausting or admitting a supplement~! flow of steam thro~gh an intermediate
port in the casing, thereby acting to maintain a process heat balance.

8.4 RESEARCH AND DEVELOPMENT NEEDS

The uncertainties in the availability of natural gas and distillate

oil required for the operation of the combustion turbines and the reliabil-
ity and availability of combined units in baseload electrtcal power ser-
vtce, have prevented widespread adoption of the gas-steam turbine combined-
cycle power plant to date .. Therefore, research devoted to the improvement
in combined cycle reliability and availability should be given high prior-
ity followed by the development of combined-cycle power plant utilization
of coal.

ICES TECHNOLOGY EVALUATION

36
REFERENCES

l. Friddy, A.P., J. Sullivan, Eng1neering Considerations o.f Combined Cycles

Proc. of the American Power Conference, Vol. 34, pp. 282-291 0972).
2. Farahan, E. and J.P. Eudaly, ICES Technology Evaluation- Gas Turb·ines,
ANL/CES/TE 78-8 (in publication).
3. Tomlinson, L.O., and R.W. Snyder, Optimization of Stag Comb1nerl- Cycle
Plants, Proc. of the American Power Conference, Vol.• 36, pp. 300-312
0974).
4. Segaser, C.L., ICES Technology Evaluation- Waste Heat Recovery EqUipmen
for Engines, ANL/CES/TE 77-4 (April 1977).
5. Meador, J.T., ICES Technology Evaluation- Steam Turbines, (in publica-
tion).
6. Lackey, M.E., and A.S. Thompson, Summary of the Development of Open-CyclE
Gas Turb1ne-Steam Combined Cycles, Oak Ridge National. Laboratory, ORNL-·
TM-6252 (July 1977) (to be published).
7. Kindl, F.H., and J.L. Haley, Design and Operation of a 26-MW Stag Plant,
An American Society of Mechanical Engineers Publication, 75-GT-18
(November 22, 1974).
8. Ruhle, D., Combined-Cycle Plants for Generating Economical Med1um- Load
Power, Brown Boveri Review, pp 34-38 (January- February, 1971).
9. Electrical Generator Drives, Industrial Gas Turbine Handbook and Direc-
tory, pp 50-63 (1976).

10. Pract1cal Examples of Utilizing the Waste Heat of Gas Turbines 1n Com-
blned Installations, Bulletin No. 2868E, Boveri and Company, Ltd.
0965).
11. Berman, P.A. and G.E. Baker, Combined Cycle Packaged Power Plan.t, Gas
Turbine Internationl, pp 34-38 (January- February, 1971).
·12. Personal conununication, Institute of Gas Technoloy (January 1977').
13. S~nai, J., and J. Rozewicz, Technical and Economical· Aspects of Combined
Ga.s -Vapor Power Plants of Small Output, Israel Journal of Technology,
11(4) ll973).
14. Fre 1, D., Gas Turbines for the Process Improvement. of lndust rial Thermal
Power Plants, Combustion, 47(10) pp 36-41 (April 1976).
15. Boyer, J.L., Practical Heat Recovery, John ·wiley & Sons (1975).
16. Wood, B., Combined Cycles: A General Review of Ach1evements, Institute
of Mechanical Engineers, 76/71 (November 1970).
17. Lomberdo, E., Technical Director of Combined Cycle Dept., Curtis Wright
Corp. , Woodridge, New Jersey, personal conununicat ion (May 2, 19 77).

ICES TECHNOLOGY EVALUATION

37
18. Patterson, J.P., Operating and Maintenance Experience for Base load Gas
Turbine Using Heavy Fuels - A Case Study, ASME Paper No. 75-GT-74 (March
1975).
19. Foster, A.D., H. E. Doering, and J.W. Hickey, Fuel Flexibility in
Heavy Duty Gas Turbines, General Electric, GER-2222K (June 1976).
20. W. O'Keefe, In-Plant Electric Generation, Power, 119(4) pp S.l-S.l7
(April 1975).
21. M1x1ng NOx Emissions, Chemical Engineering, 84(8) pp 84-90 (April 11,
1977).
22. Boland, C.R., and R.D. Patterson, A Unique Combined-Cycle System to Meet
Ut1lzty Intermediate Cycling Loads, Proc. of the American Power Confer-
ence, Vol. 34, pp 302-304 (1972).
23. Gas Technology Institute, Editorial Staff, Gas Turbine Maintenance Costs,
Gas Turbine International (January-February 1977).
24. Sperry, R.E., and J.R. Hull, Factors Affecting Turbine-Generator Relia-
bllity and Availability, Tappi, 54(11) (1971).
25. Sawyer's Gas Turbine Engineering Handbook, Second Edition, Volume II
Application, Gas Turbine Publications, Inc., Stanford, Connecticut,
(1976).
26. Technical Assessment Guide, Technical Asessment Group, EPRI-PS-866SR,
(February 1977).
27. Geiringer, S.L., Construction and Operating Cost Comparison Between
f1eld -Erected and Package Combined - Cycle Units, Proc. of the Ameri-
can Power Conference, Vol. 36, pp 313-319 (1974).
28. Peeler, J.P.K., and K.L. Piggott, The Comh.ined Gas Turbine -Steam CyclE
for Power Generation, Mechanical & Chemical Engineering Transactions,
I.E. Aust, MC8(2) pp 125-130 (November 1972).
29. Schuster, R., The Growing Presence of Gas Turbine Comb1ned Cycles, Powet
Engineering, 76(1) pp 28-34 (January 1972).
30. Sternlicht, B., The Equipment Side of Low-Level Heat Recovery, Power,
19(6) pp 71-77 (June 1975).
31. Aliat, J., Power Systems Group of Curtis-Wr.ight Company, Wood Rid~e,
New J~rsey, personal communication (April 29, 1977).
32. Ottaviano, V.B., National Mechanical Estimator, Ottaviano Technical Ser-
vices, 150 .Broad Hollow Road, Melville, N.Y. 11746 (1977).
33. Knorr, R.H., and G. Jarvis, Maintenance of Industri;;d Gas Turb1nes, The
American Society of Mechanical Engineers, 75-61-93 (March 1975).
34. Frass, A.P., Conceptual Design of a Coal Fired Gas Turbine for MIUS
Applications - Phase ll, Summary Report, ORNL-HUD/MIUS-3'>.

ICES TECHNOLOGY EVALUATION

38
35. Doorly E., Manager, Advanced Projects at Solar, Division of Interna-
ttonal Harvestor, San Diego, California, personal communication (April
22' 19 77) .
·36. Wadman, B., Broad Use Capability Combined Cycle Gas Turbine Sy~tems,
Diesel & Gas Turbine Progress, XLIII(3) pp 24-26 (March 1977).

ICES TECHNOLOGY EVALUATION

39
 DISTRIBUTION LIST

Internal:
J.G. Asbury L.J. Hoover
B.A. Biederman R.O. Ivins
D.C. Bingaman I. Johnson
E.M. Bohn A. S. Kennedy
L. Burris A.B. Krisciunas
E.J. Croke C.M. Lee
J.M. Calm G. Leppert
A.A. Davis K.S. Macal
S.A. Davis T .J. Marciniak (75)
P.F. Donnelly R.G. Matlock
R.J. Faddis I.M. Pacl (25)
J. Fischer J. Pascual
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C.H. Gartsirle .T • .J. Roberts
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R.M. Gras en K.L. UhP.rka
B.L. Graves N.P. Yao
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R.E. Holtz TIS Files

External:
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Manager, Chicago Operations Office
Chief, Office of Patent Counsel, Chicago
President, Argonne Universities Association
Energy and Environmental Systems Division Review Committee:
T.G. Frangos, Madison, Wis.
J.H. Gibbons, U. Tennessee
R.E. Gordon, U. Notre Dame
W. Hynan, National Coal Association
D.E. Kash, U.S. Geological Survey, Reston, Va.
D.M. McAllister, lJ, Californi;:~, Ll:'li Angelco
L.R. Pomeroy,. U. Georgia
~.A. Rohlich, U. Texas, Austin
R.A. Schmidt, Electric Power Research Inst.
J.W. Winchester, Florida State U.
Abeles, Tom P., PhD., IE Associates, Minneapolis, Minn.
Abrams, R.N., V.P., Gilbert Associates, Inc., Reading, Penn.
A.C. Kirkwood & Associates, Kansas City, Mo.
Adamaut iades, A.G., E. P.R. I., Washington, D.C.
Adamczyk, T.J., BRI Systems, Inc., Phoenix
Agee, Mr. Damon, Florida Energy Office, Tallahassee
Al~tn~, Raymond G., Raymond G. Alvine & Assoc., Omaha
Amer1~an Association for Hospital Planning, Jefferson City, Mo.
AmeriLan Society of Planning Officials, Chicago
Anderson, Brant, Lawrence Berkeley LabR.
Anderson, Paul A., Energy Resources Center, Honeywell, Inc., Minneapolis

40
 Anderson, Robert B., Exec. V.P., Farm & Land Institute, Chicago
Anson, Mr. Bert III, Southwest Center for Urban Research, Houston
Anuskiewicz, Todd, Michigan Energy & Resource Research Assn~, Detroit
Arnold, R.S., Carrier Air Conditioning, Syracuse
Askew; Alvin, Exec. Dir., The Governors Energy Advisory Council, Houston
Assur, Andre, U.S.A. Cold Region RES & Engr. Lab., Hanover, N.H.
Aungst , w. K. , Assoc. Prof., Penn State lJ., Middletown, Penn.
Ayres, J. Marx, Pres., Ayres Associates, Los Angeles
Bain, Lewis J., Chief M.E., Keyes Assoc., Providence, R.I.
Baker, James L., President, DSI Resource Systems Group, Inc., Boston, Mass.
Balzhiser, R.E., Director, Elec. Power Research Institute, Palo Alto, Calif.
Barbee, Robert W. Jr., Allen & Hoshall, Inc., Memphis
Bartman, Jerome, Naval Air Develop. Center, Warminster, Penn.
Basilica, James V., Office of Research and Develop., EPA, D.C.
Beason, Fred, Energy Consultant, AFCEC/DEM, Tyndall AFB, Fla.
Becker, Mr. Burton C., Rittman Assc., Inc., Columbia, Md.
Beeman, Robert, Planner, Office of Economic Planning & Development, Phoenix
Beltz, Philip, Economist, Battelle, Columbus, Ohio
Benson, Glendon M., Energy Research & Generation, Inc., Oaklanq, Calif.
Benson, Harold, Acting Chief, NASA-JSC, Systems Analysis Office, Houston
Benson, Mr. Walter, Midwest Research Institute, Kansas City
Bertz, Edward J., Secretary, American St>ciety for Hospital Engineering, Chicago
Bergwager, Sydney D., Federal Energv Administration, D.C.
Bernor, Stephen, Energy Systems Research Group, Albany, N.Y.
Best, W.C., U.S. Army Facilities Engineering Support Group, Fort Belvoir, Va.
Biederman, B.F., Eaton Corporation, Controls Division, Carol Stream, Ill.
Biederman, N.P., Institute of Gas Technology, Chicago
Biese, Rubert J., Asst. Project Mgr., Gilbert Associates, Inc., Reading, Penn.
Bigler, Mr. Alexander, Alexander B. Bigler Associates, Oakton, Va.
Bish"'' F'red, Environmental Protect ion Agency, Cincinnati
BodzLn, J.J., Michigan Energy & Resource Research Assn., Detroit
.Bu.-,gly, Wllliam Jr., Engineer, Oak Ridge National Laboratory, Oak Ridge, Tenn.
Bonev, David W., V.P., Atlantic City Electric Co., New Jersey
Boobar, M.G., Atomics Int'l Division, Canoga Park, Calif.
Boone, Mr. Richard, QES, Inc., Atlanta
Borda, Jos~ph R., Joseph R. Borda Consulting Engineers, Merchantville, N.J.
Bortz, Susan, Consultant, Bradford National Corporation, Rockville, Md.
Boughner, H.ichard T., Control Data Corpor~tion, Knoxvllle, Tenn.
Bourne, J.G., Mgr. Thermal Engineering Group, Dynatech R/D Co., Cambridge, Mass.
"sayee, Dr. David E., Regional Science Assoc., University of Pennsylvania
Brandon, Robert E., Air Force Civil Engineer Center, Tyndall AFB, Fla.
Brasch, Mr. Ben F., Industrial Systems, Corp., Medina, Ohio
Br~itstein, Leonard, Senior Staff Engineer, Dynalectron Corp., Bethesda, Md.
Brett, Dr. C. Everett, Dir., Natural Resources Center, University of Alabama
Brt->ymann, Bernard H., Eco-Tt!r·ra Corp., Chic.ago
Brodie, Mr. J.I., Genge Consultants, Los Angeles
Br,•rlle, L.T., Bergstedt, Wahlberg, Berquist, Rohkohl, St. Paul
Browder, R.M., General Manager, Bristol Tenn. Electric System, Bristol, Tenn.
Brown, Dale H., Energy Systems Engineer, General Electric, Schenectady
Brown, Seymour, President, Michael Baker, Jr. of N.Y., Inc. New York, N.Y.
Bruns, D.D., University of Tennessee, Knoxville
Buehrer, Huber H., Buehrer & Strough, Toledo, Ohio
Sullens, D., Exec. Dir. of Energy Programs, American lnst. of Architects, D.C.

41
Burton, David, Supervisor Power Sys. Anal., Gilbert Assoc., Reading, Penn.
Bus~emi, V.P., Consulting Engineer, Gibbs & Hill, New York, N.Y.
Buthmann, Mr. R.A., General Electric, D.C.
Bussiere, Loretta, Supervisor, Florida State Energy Office, Tallahasse
Gabel, John, Chief, Department of Energy, Washington, D.C.
Calvaresi, F.M., Energy Research Library, Gilbert Assoc., Inc., Reading, Penn.
Campbell, George W., Smith & Fass Consulting Engineers, Inc., D.C.
Carlsmith, R.S., Mgr., Oak Ridge National Laboratory, Oak Ridge, Tenn.
Carrol, R., Mgr., Lawrence Livemore Lab, u. of California
Carter, Lee, St. Louis, Mo.
Casberg, T.R., Office of the Deputy Assistant Secretary of Defense, D.C.
Cavanaugh, Gregory, U.S. DOE, D.C.
Cavros, S.N., Chief, Comm. Syst. Branch, Div. of Bldg. & Comm. Syst., DOE D.C.
Ceglia, Michael, President, MGC Electronics, Cherry Hill, N.J.
Chalmers, S.M., Salt River Projects, Phoenix
Chapman, Dr. Alan J., Dean of Engineering, Rice University, Houston
Cherry, Steve, Sr. Engr., KVB, Tustin, Calif.
Chmielewski, R., Catalytic, Inc., Phildelphia
Christensen, A.T., Mgr. Program Development, General Electric, D.C.
Cissna, Mr. Volney J. Jr., Office of the Governor, State of Mississippi
Clauder, Hersel, Systems Control Inc.., Palo Alto, Calif.
Cohen, Sanford, Mgr., Teknetron, Inc., D.C.
Collins, R.N., C.F. Braun & Co., Alhambra, Calif.
Colm, Howard, Director, Colm Engineering, Cherry Hill, N.J.
Conrad, Mr. Tom, SCS Engineers, Reston, Va.
Conta, L.D., University of Rhode Island, Kingston
Costello, Milton, P.E., Consulting Engineer, Old Library, Amityville, N.Y.
Coxe, Mr. E.C., Reynolds, Smith and Hills, Jacksonville, Fla.
Coxe 1 E.F., PhD, P.E., Applied Energy Sciences, Inc., Atlanta, Ga.
Crane, David A., Pres., The Crane Design Group, Houston
Crawford, Russell, L., Solid Waste Coordinator, Commonwealth of Pennsylvania
Crawford, W. Donham, Edison Electric lnstitute, New York
Credle, K., Department of HUD, D.C.
Creel, Russel K., Exec. Sec., Comm. for Nat.'l Land Dovclopm~nt Polit.:y, Chicago
Cucctnellt, kenneth, American Gas Association, Arlington, Va
Cumalt, Z., Pres., Consultants Computation Bureau, San FrancisLo
Cunntngham, Walter, Senior Vice Pres., Engineering/Planning, Houston
Curron, Dr. H.M., Senior Principal Engineer, Rittman Assoc. Inc., Columbia, Md.
Daman, E.L., Vtce Pres., Foster Wheeler C:orporatiL'n, Livingoton, N.J.
Davis, Paul, Deputy Gen. Mgr., Gulf Coast Waste Disposal Authority, Houston
Dawson, Roland H. Jr., Board of Public Utilities, McPherson, Kansas
DeAngelis, R.F., Chief Librarian, Gibbs & Hill, Inc., N.Y.
Dechoim, Phil, Columbia Gas, Columbus, Ohio
DeLima, Henry, Booz, Allen & Hamilton, Bether::da, Md.
Derrak, William, Vice Pres., Larry Smith & Co., Ltd., Northfield, Ill.
Deyoung, J.Y., V.P., Pacific Gas & Electric Co., San Francisco
Dinwiddie, J.F., Office of Fossil Energy, DOE, D.C.
Dirienzo, A.C., Mech. Lab. Mgr., Foster Wheeler Corporation, Livingston, N.J.
Diskant, William, Exec. Vice Pres., American Hydrotherm Corp., New York
Dougan, Davtd, UTC Corp., Houston
Doyle, Edward J. Jr., Greenwich, Conn.
Dubin, Mr. Fred, Dubin-Bloom Associates, New York
Dugas, Lester J., Commonwealth Edison Company, Chicago

42
Duker, P.A., Vice Pres., Customer & Marketing Policy, Detroit Edison Co.
Dunzer, J.B., Ultrasystems, inc., Irvine, Calif.
Eberhard, John P., Pres., AlA Research Corp., D.C.
Eckley, Robert C., San Diego
Edgerley, E., Rychkman, Edgerley, Tomlinson & Assoc., St. Louis
Eisenhammer, F., Electrical Supervisor, Copeland Systems Inc., Oak Brook, Ill.
Eley, Charles, Principal, Charles Eley Assoc., San Francisco, Calif.
Energy Research & Development Center, Director, University of Nebraska-Lincoln
Engstrom, Robert E., Pres., Robert Engstrom Assoc., Minneapolis
Faris, Frank, Pres., Interdevelopment, Inc., Arlington, Va.
Faulders, Charles, Atomics International - Rockwell, Canoga Park, Calif.
Fernandez, Bruce, Vice Pres., Energy Unlimited, New Britian, Conn.
Ferretti, Emmett, Dravo, Inc., Pittsburgh
Ferry, J., Energy & Environment, Temple Barker & Sloane, Wellesley Hills, Mass.
Finke, J., Dept. Mgr., Advanced Tech. Div., Kaiser Center, Oakland, Calif.
Fischer, William, Consulting Scientist, Gilbert Assoc. Inc., Reading, Penn.
Fleming, Duane, Dept. of Planning, City of Dayton
Flynn, D.C., Project Engr., RF Weston Inc., Westchester, Penn.
Fox, Richard, WED Enterprises, Glendale, Calif.
Fraas, A.P., Oak Ridge National Laboratory, Oak Ridge, Tenn.
Frank, C.B., Vice Pres., Nat'l. Assn. of Industrial Parks, Arlington, Va.
Frauel, H. Dean, National Assoc., of Govt. Engineers, D.C.
Freeman, S. David, Bethesda, Md.
Frumerman, Mr. Robert, Frumerman Associates, Pittsburgh
Furlong, D.A., Vice Pres., Combustion Power Company, Inc., Menlo Park, Calif.
Gallina, R.J., Senior Engineer, Baltimore Gas & Electri~ Co.
Gamze, Maurice G., V.P., Korobkin & Caloger, Inc., Chicago
Garcia, Carlos A., Energy Programs Department, IBM, White Plains, N.Y.
Gardner, Dr. Dwayne, Dir., Cnsl. of Educational Facility Planners, Columbus, Ohio
Gary, William, Supervisor, San Diego Gas & Electric Co.
Geiringer, Stefan L., PaulL. Geiringer & Associates, New York
Gibson, Mr. Urban, Texas Power & Light Co., Dallas
Given, Willard W., Willard Given & Associates, St. Louis
Glaser, Dr. Peter, Vice Pres., Arthur D. Little Co., Cambr1dge, Mass.
Glass, C.D., V.P., Gulf States Utilities Co., Beaumont, Texas
Glenn, Ms. Reg1na L., Technology Transfer Center, Tacoma, Wash.
Goble, Robert L., Clark University, Worcester, Mass.
Goldin, W.J., Vice Pres., Aelanta Gas & Light Co.
Goldschmidt, Victor, Ray W. Herrick Laboratories, West Lafay~tte. Ind.
Gordon, Mr. R.H., Gibbs & Hill, Inc., New York
Gorham, William, Pres., Urban Institute, D.C.
Green, Dr. Richard, Mgr., Jet Propulsion Lab, Pasadena
Greingard, R.L., Vice Pres., Ultrasystems Inc., Irvine, Calif.
Grifalconi, John W., Environs Associates, Kingston, R.I.
Grifftn, Johnetta, Technical Librarian, Rittman Assoc., Inc., Columbia Md.
GulatL, R1pudaman, Consultants Computation Bureau, Oakland, Calif.
Gutstein, Martin, Nat'l. Aeronaulics & Space ProjP.cts, Cleveland
Guyer, Eric, Principal Engineer, Dynatech R/D Co., Cambridge, Mass.
Hadden, Leonard D., Dir. of Contracted Rsrch., Billings Energy Corp., Provo, Utah
Hagler, Harold, Principal, Resource Planning Associates, D.C.
Halfon, Amos, President, Dubin-Bloome Assoc., P.C., New York
Hal 1ff, B., Albert H. Haliff Associates, Inc., Dallas
Hamrick, John, V.P., Marketing; San Diego Gas & Electric Co.
Handy, D.G., Staff Dir.s Illinois Energy Resources Commission, Springfield~ Ill.

43
Hankinson, William B., Syska & Hennessey, Inc. Engineers, New York
Harrington, W.G., Nat'l. Assn. of County Engineers, Cedar Rapids, Iowa
Harris, B.L., Technical Dir., Edgewood Arsenal, Aberdeen Proving Ground, Md.
Harrigan, Raymond, Member of Technical Staff, Sandia Labs, Albuquerque
Hart, F. Donald, Pres., American Gas Association, Arlington, Va.
Hays, E.L., 106 Harborcrest Drive, Seabrook, Texas
Heimsath, Clovis, Pres., Clovis Heimsath Associates, Houston
Henry, John P. Jr., Dir., Stanford Research Institute, Menlo Park, Calif.
Hillenbrand, Bernard F., National Assoc. of Counties, D.C.
HinLks, Mr. Joel P., Gulf Oil Real Estate Development Co., Reston, Va.
Hines, Gerald B., Houston, Texas
Hirsch, Jeff, Lawrence Berkeley Lab., Berkeley, Calif.
Hittle, Douglas C., Dept. of the Army, Champaign, Ill.
Hoffer, Mr. Stu, Hamilton-Standard, Windsor Locks, Conn.
Hoffman, J.R., HDQT DAEN-FEP, D.C.
Holt, Charles F., Energy & Thermal Tech. Sect., Battelle Memorial lost., Columbus
Holter, Marvin, Exec. Mgr., Environmental Research Institute, Ann Arbor, Mich.
Howell, John, Dir., University of Houston
Howell, Ronald H., University of Missouri-Rolla
Hufford, Paul E., Exec. V.P., Energy Ltd., Unlimited, New Britain, Conn.
Hullinger, Mr. E. Paul, Utah State University, Logan
Hunn, Bruce D., Los Almos Scientific Lab, N.M.
Hunt, Florine E., Public Serv. Elec. & Gas Co., Newark, N.J.
Iles, Mr. Tom, AiResearch Mfg. Co., Torrance, Calif.
Inselberg, Dr. A., Scientific Staff Member, IBM, Data Proc. Div., Los Angeles
Ingles, Joseph L., Adm. Sectetary, Committee of Consumer Services, Salt Lake City
Ingram, James M. Jr., Leo A. Daly Co., Omaha
Irvine Co., Newport Beach, Calif.
Jacobs, John F., Senior Vice Pr.es., Mitre Corp., Bedford, Mass.
Jacoby, Earl F., Ziel-Blossom & Associates, Inc., Cincinnati
Jaehne, Herb, Mech. Engr., Northern States Power Co., Minneapolis
Jarshow, Bruce, City of Chicago, Dept. of Development & Planning
Jatana, S.C., Research Engineer, Columbia Gas System, Columbus, Ohio
Jaumotte, Joe, Dynatech R/D6, Northfield, Ill.
Johnson, Mr. Dale R., Pres., Nelson & Johnson Engineering, Inc., Boulder, Colo.
Johnson, Greg, Grad. Res. Asst., Ray W. Herrick Labs, W. Lafayette, Ind.
Johnson, Mr. Ralph J., NAUB Research Foundation Inc., Rockville, Md.
Johnson, William L., Hennington, Durham and Richardson, Des Plaines, Ill.
Jones, Mr. Harvey C., Reedy Creek Utilities Co., Tn~ .• Lake Buena Vi3ta, Fla.
Junes, Mr. Ron, Pres., Research & Planning Consultants, Austin, Texas
Jordan, Richard C., University of Minnesota, Minneapolis
Joyner, Fred, Tennessee Public Service Commission, Nashville
Kalkstein, Howard, International Council of Shopping Centers, New York
Katter, Lin<.oln B., Rocket Research Co., York Center, Redmond, Wash.
KatGel, 1., Assoc. Editor, Munic~pal Publlshing Company, Barrington, Ill.
Kelly, Michael, F., Pres., Dayton Hudson Properties, Minneapolis
Kepler, E.C., Program Mer.., United Tet.:h. Research Center, E. Hartford, Conn.
Klett. M.G., Process Engineer, Gilbert Associates, Reading, Penn.
K1ll1an, R.D., Mgr., Research & Develop., State of Illinois, Springfield
Kirkwood, Roderick R., John Graham & Co., Seattle
Kirmse, Dale W., University of Flor1da, Ganesville
Kletn, E.L., Williams Research Corp., Walled Lake, Mich.
Kleinau, J.H., Vice Pres., Copeland Systems, Inc., Oak Brook, Ill.

44
Knipe, Edward C., Vice Pres., Gordon Associates, Corvallis, Ore.
Kohl, Bob, Mgr., Wtr. & Waste, Reedy Creek Util. Co., Inc., Lake Buena Vista, Fla.
Kosk1, Dr. J.A., Bechtel Corporation, San Francisco
Kranish, A., Editor, Trends Publishing, Inc., Washington, D.C.
Krause, Ed, Electrical Administrator, Garland, Texas
Kremer, Peter C., Exec. Vice Pres., Newhall Land & Farming Co., Valencia, Calif.
Kroner, Walter M., Rensselaer Polytechnic Institute, Troy, N.Y.
Kugelman, lrwin Jay, MERL-EPA, Cincinnati
Kurht, W.A., Vice Pres., Tech., United Technologies Corp., Hartford, Conn.
Kwok, C.F., U.S. Veterans Administration,- D.C.
Lagerstrom, J.E., Dir., Engineering Extension, U. of Nebraska, Lincoln
Lambert, Rob~rt E., Environment Research Institute of Michigan, Ann Arbor
Landsberg, H., Dir., Resources for the Future, D.C.
LaRock, Ralph I., Director, NASA Headquarters, Solar Energy Div., D.C.
Lau, T.K., Office of Fossil Energy, DOE, D.C.
Leigh, Richard, Brookhaven National Laboratory, Upton, N.Y.
Leighton, G.S., Office of Conservation, DOE, D.C.
Leonard, Robert, Associate Prof., Purdue University, W. Lafayette, Ind.
LePera, Maurice, Woodbridge, Va.
Lev1nson, Joel, Levinson, Lebowitz & Zapravskis, Philadelphia
Lewis, Milt, U.S. Dept. of Health, Ed. & Welfare, D.C.
Liles, James, Federal Power Commission, D.C.
Linsteadt, G.F., Naval Weapons Center, China Lake, Calif.
Lockw,>od, Rodney, Pres., Rodney Lockwood & Co., Birmingham, Mich.
Loftness, Dr. Robert L., Electric Power Research Institute, D.C.
Lollar, Robert M., Technical Dir., Tanners' Council Lab, U. of Cincinnati (14)
Lorsch, Dr. Harold G., Franklin Inst. Research Labs., Philadelphia
Love, Nash M., Consulting Engineer, Nash M. Love & Assoc., D.C.
Lovelv, Joseph D., St. Clair Shore, Mich.
Lovin, Glenn H., Edison Electric Institute, D.C.
~ow, Dr. D.W., Los Angeles Data Processing Div., Scientific Center
Loyd, harold L., Turner, Colie & Braden, Houston
MacDonald, Robert, Tech. Agent, Conference ,,f Municipalities, New Haven, Conn.
Mackay, Mr. Robin, Garrett Corp., Los Angeles
Maffin, Robert W., Nat'l Assoc. of Housing & Redevelopment Officials, D.C.
Maggard, James E., Watkins and Associates, Inc., Lexington, Ky.
Magnus, D.E., KLD Associates, Inc., Huntington, N.Y.
Ma I •mey, Laurence J., Love, Friberg & Assoc., Inc., Fort Worth
Manning, David, Stewart & Stevenson, Houston
Marcus, Genevieve, Exec .. Dir., Experimental Cities, Pacific Palisades, Calif.
Marder, Sidney M., ESCOR, Inc., Springfield, Ill.
Martin, John H., Sheaffer & Rolan, Chicago
Marttn, Joseph, Associate Dir., The University of Michigan, Ann Arbor
Mascenik, William, Prog. Mgr., Public Technology, Tnc., Washington, D.C.
Maschke, H.H., Department of Defense, HQDA (DAEN-MCE-U) D.C.
Masella, Charles Y., Seuiur Assoc., Masella Associates~ Washington, D.C.
Mason, J.L., V.P. Engineering, Garrett Corp., Los Angeles
Mavro, Robert L., Dir. of Energy Research, American Public Power Assn., D.C.
Mazarakis, Gus, Peoples Gas Light & Coke Co., Chicago
McBride, M.F., Owens Corning Fiberglas, Bldg. Research Lab., Granville, Ohio
McClernon, Dr. Mark F., Black & Veatch, Kansas City, Mo.
McClure, Charles J.R., Pres., McClure & Assoc., Inc., St. Louis
McCrystal, Ms. Deirdre, Architectural St~dent, Boulder, Colo.

45
McGinty, Mr. John M., The McGinty Partnership, Houston
McPherson, Harry, Construction Battalion Center, Port Hueme, Calif.
Mendenhall, Mr. Jerry, Lloyd Jones Brewer, Houston
Meriwether, Ross F., Pres., Ross F. Meriwether & Assoc., lnc., San Antonio
Mermelstein, Mrs. Betty, The Futures Group, Glastonbury, Conn.
Mesko, Mr. John, Pope, Evans & Robbins, Inc., New York
Michaelson, William G., Mgr., Public Service Electric & Gas Co., Newark, N.J.
Milder, Nelson L., Mgr., Civil Systems Program, NASA Headquarters, D.C.
Miller, A.J., Knoxville, Tenn.
Mixon, W.R., Oak Ridge National Laboratory, Oak Ridge, Tenn. (75)
Mlad1nov, John K., NYS Dept. of Transportation, Albany, N.Y.
Moeller, Griswold L., Michael Baker Jr. of New York
Mollura, Frank J., Mech. Engr., Rome Air Dev. Center, Griffissafb, N.Y.
Montanerilli, Nicholas, National Science Foundation, D.C.
Morris, George L., Senior Vice Pres., Brown & Root, Inc., Houston
Morrison, Dr, David T.., 1:\at tell a Columbus LaboratQt ies, Go lnmht• s, Ohio
Morrison, J.E., DeLaureal Engineers, lnc., New Orleans
Mulf, Richard, U.S. Dept. of HUD, D.C.
Murphy, James S., Project Engr., Rittman Associates, Inc., Columbia, Md.
Murphy, Timothy J., Engineering Mgr.., Grumman Aerospace Corp., Bethpage, N.Y.
Murray, James, Project Engineer, Rittman Associates, Inc., Columbia, Md.
Myers, Edward A., Chairman EEl, Southern California Edison Co., Rosemead
Nakata, Clifford S., Clifford S. Nakata & Associates, Colorado Springs
Nash, Herbert D., Vice Pres., Pennsylvania Power & Light Co., Allentown
Nawr.)cki, A. David, Staff Consultant, Southwest Research Inst., San Antonio
Nayamark, Ronald, NPL, Inc., Campbell, Calif.
Neal, John, U.S. DOE, D.C.
Neff, N. Thomas, Vice Pres., Consulting Engineer, Cincinnati
Nield, Willtam H., San Diego Gas and Electric Co., San Diego
Nelson, Ralph, Ch. Mech. Engr., Dana-Larson-Roubal, Omaha
Nelson, Dr. S.H., Energy Syst~ms Research Group, Inc., Rochester, N.Y.
Newell, Mr. J.C., West Chester, Penn.
Nicholls, G.L., Energy Resources, Bellevue, Wash.
Nimmo, Morris, National Bureau of Standards, D.C.
Northrup, Lynn L. Jr., Pres., Northrup, Inc., Hutchins, Texas
Novinsky, M.H., Office of Planning and Development, Dept. of HEW-OFEPM, D.C.
O'Connor, W.G., Williams Research Corp., Walled Lake, Mich.
Olivier1, Joseph B., OEM Associates rnc., St. Clair Shores, Mich.
Olson, G. Perr:y, City of St., Cloud, City l:h.lll, Minn.
Opperman, A. Peter, University of M1chigan, Ann Arbor
Orlando, J., Mathematica, Inc., Washangton, D.C.
O'Sulltvan, Michael, Los Angeles
Overman, Mr. Jack, Rittman Assoc., Inc., Columbia, Md.
Parante, Mr. Emtl .J., Ralph M. Parsons Co., Pasadena, Calif.
Parker, Dr. Jerald, Professor, Aerospace & Mech. Engr. Dept., Stillwater, Okla.
Partridge, Robert D., Exec. V.P., ·Nat' l. Rural Electric CooperativP Assn., D.C.
Paster, J.H., Inter-Technology Corp.,, Warrenton, Va.
Patten, Thomas W., V.P., M.C. Patten & Co., Inc., Costa Mesa, Calif.
Patterson, Mr. Neil, Mgr., The Trane Co., LaCrosse, Wis.
Pavle, James, Asst. Mgr., Applied Research Div., Dynalectron Corp., Bethesda, Md.
PeaLu~k, Thomas, Mech. Engr., U.S. Navy, Millersville, Md.
Pearson, F.J., Chief Mech. Engr., Henry Adams, Inc., Baltimore
Perkins, Virginia, Corporate LibrarLan, Wisconsin Electric Power, Milwaukee
Perks, Ruth, L1brary, DOE, D.C.
Peters, G.T., United Tech. Res. Center, East Hartford, Conn.

46
Philadelphia Electric Co., Vice President for Planning
Phillips, C.W., National Bureau of Standards, D.C.
Piccirelli, Mr. Robert A., Michigan Energy and Research Assn., Detroit
Piper, James R., Piper Hydro, Anaheim, Calif.
Plunkett, Mr. J.D., Montana Energy and MHD Research and Develop. Inst., Inc.
Pollard, Thomas E., Mgr., Field Facilities Engr. & Operations, IBM, Chicago
Powell, William R., Johns Hopkins U., Laurel, Md.
Pozzo, R.J., Energy Analyst, State Energy Office, Tallahassee
Pripusich, J.F., Inter-Development, lnc., Arlington, Va.
Pritchard, Ms. Barbara, Librarian, Day & Zimmerman, Inc., Philadelph1a
Pronk, Dick, U.S. General Service Admin., D.C.
Public Technology Inc., Washington, D.C.
Puri, Virender, M.E., TheE/A Design Group, Burke, Va.
Qureshi, Mr. A.S., P.E., Asst. V.P., Michael Baker Jr. of New York, Inc.
Radin, Alex, Gen. Manager, American Public Power Association, D.C.
Rahm, Allen M., Consultant, Colts Neck, N.J.
Rajan, Mr. S.D., Mitre Corp, McLean, Va.
Rastelli, Dr. Leonard, Dir., Southwest Research Institute, San Antonio
Reese, Mr. William R., Interstate Development Corp., St. Charles, Md.
Reeves, George, Manager, Long Range Planning, Electric Energy Institute, N.Y.
Reich, Larry, Dir. of Planning, City of Baltimore
Reid, Robert 0., Energy & Environmental Analysis, Inc., Washington, D.C.
Reikenis, Richard, Vice Pres., Century Engineer, Inc., Towson, Md.
Research and Tech. Support Div., DOE, Oak Ridge, Tenn.
Resources for the Future, Energy Library, Washington, D.C.
Restall, Wesley F., Keyes Associates, Waltham, Mass.
Riegel, Kurt, Ch1ef, Department of Energy, Washington, D.C.
Riddle, William G., Riddle Engineering, Inc., Kansas City
RippPy, JamP~, Project Engineer, NASA-JSC, Houston, Texas
Rienerth, Thumas, Dir., Delmarva Advisory Council, Salisbury, Md.
Rigo, H. t.regor, Principal, DSI Resource Systems Group, Inc., Boston, Mass.
Rittleman, Bernard, Burt, Hill & Assoc., Butler, Penn.
Robb, Tom H., Jr., Houston Lighting and Power Co.
Roberts, James S., First National Bank of Chicago
Rodgers, Paul, Nat'l. Assn. of Regulatory Utility Commissioners, D.C.
Rodousakis, John C., Program Manager, Community Systems Branch, DOE, D.C.
Rogan, James E., Branch Mgr., McDonnell Douglas Astronautics Co., Huntington Beach
Romancheck, Bob, Penna Power & Light Co., Allentown, Penn.
Rom1ne, Thomas, B. Jr., Romine & Romine, Consulting Engineers, Fort Worth
RosP., L.J., Tech. Utilization Engr., NASA-Langley Research Ctr., Hampton, Va.
Rosenberry, Robert, Veterans Administration, D.C.
Rosoff, David, U.S. Dept. of HUD, D.C.
Ross, C.F., LTC, DAEN-FEU, Washington, D.C.
Ross, Uorta.ld K., Ross & Barruz:dni, Tnt,, St. Louis
Rothenberg, J.H., HUD-MIUS, Program Manager, Dept. of HUD, D.C.
Kouba.l, Jawes P., Dana, Rouhal and Associates, Omaha
Rudy, William, Prof., University of Pittsburgh
Russell, May, Pres., Community Assoc. Institute, D.C.
Ryan, J.D., National Bureau of Standards, D.C.
Samos, John, Langley Research Center, Hampton, Va. (2)
Sander, Dr., Program Mgr., Thermo Electron Corp., Waltham, Mass.
Sarkes, Louis A., Director, A.G.A., Arlington, Va.
Sasso, John A., Nat'l. Model Cities Community Develop. Directors Assn., D.C.
Saunders, Walt, Office of Fossil Energy, Fossil Fuel Utilization, DOE, D.C.

47
Sayan, Michael, Rochester Public Utility, Minn.
Scause, James W., Scause & Associates, Phoenix
Schmalz, Mr. Arvid, IBM,_ Energy Research Project, Los Angeles
Schneider, Burkhard, H., Manager Planning & Research, Detroit Edison Co.
Schn1~er, Arthur W., Tech. Dir., Day & Zimmerman, Inc., Philadelphia
Schoen, Richard, University of California, Los Angeles
Schuster, Ray, Comm. Div., Electrical Power Research Inst., Palo Alto, Calif.
Schwendinger, D., P.E., Consultant Engr., Nuclear Services Corp., Campbell, Calif.
Schwinn, Gerald Allan, Librarian, Resource Planning Assoc., Washington, D.C.
Sebastian, E.J., Chief Mechanical Engr., DeLeuw, Cather & Company, Chicago
Sedlacek, Frank E., Pres., Fast Hills, Inc., Omaha
Shaffer, Richard, Combustion Power Co. Inc., Menlo Park, Calif.
Shah, R.P., Systems Engr., General Electric, Schenectady
Shane, E. Martin, Supervisor, Tech. Services, Philadelphia Electric Company
Shannon, Wayne E., Lockheed Missiles & Space Co., Palo Alto, Calif.
Sharp, E.G., The Mitre Corp., McLean, Va.
Sheffield, David G., The Architects Collaborative, Inc., Cambridge, Mass.
Sherfy, James D., Bristol Tennessee Electrical System, Bristol
Sherman, J., Department of HUD~ D.C.
Shivers, Lyman T., Electrical Systems Analyst, Brown & Root, Inc., Houston
Siegel, A.R., Director, Dept. of HUD, D.C.
Sizemore, Michael M., Sizemore & Associates, Atlanta
Smith, Robert Lee, Pres., Experimental Cities, Pacific Palisades, Calif.
Smullen, William, Regional Planning Commission, New Orleans
Soler, Martha E., Lawrence, Kansas
Spiegel, Walter F., W.F. Spiegel, Inc., Jenkintown, Penn.
L.G. Spielvogel, Engineer, Lawrence G. Spielvogel, Inc., Wyncote, Penn.
Stamper, D.E., Chairman, New Jersey Institute of Technology, Newark
Stautz, Mr. C. David, Director of Planning, Homart Development Co., Chicago
Steger, Wilbur A., Consad Research Corp., Pittsburgh
Steigelmann, Mr. William, Frankl1n Institute Research Labs, Philadelphia
Stenhouse, Douglas S., Los Angeles
Stolz, Otto G., U.S. Dept. of HUD, D.C.
Sutz, Chief Conservation Section, Ar1zona State Fuel & Energy Office, Phoenix
Sykora, Mr. Don, Gen. Mgr., Houston Lighting and Power Co., Houston
Talwar, Rajesh, Research Assoc., Florida Solar Energy Center, Cape Canaveral
Tanner, Howard, Director, Department of Natural Resources, Lansing, Mich.
Tao, William K.Y., William Tao & Associates~ St. Louis
Taravella, J.P., Westinghouse Electric Corp., Coral Spring, Fla.
Tauss1g, Robert T., Mathemat1cal Sciences NorthWest, Inc., Bellevue, Wash.
Taylor, L.D., Prof. of Economics, University of Arizona, Tucson
Telkes, Dr. Maria, American Technical University, Texas
Tenza, R.M., V.P., BRI Systems, lnL., Phoenix
Terry, Gary A., Exec. Vice Pres., American Land Development Assoc., D.C.
Thomas, John P., National Assn. of County Admin., D.C.
Thompson, Mr. Russell G., Research for Growth and Transfer, Inc., Houston
Tiedman, Thomas, Program Mgr., Public Technology, Inc., Washtngton, D.C.
Todd, J.W., Presiding & Chief Operatin~ Officer, Gulf Reston, Reston, Va.
Trevino, Mr. Alberto, Urban Interface Group, Laguna Beach, Calif.
Tulley, Gordon F., Massdesign Architects & Planners, Inc., Cambridge, Mass.
Tum1lty, Jack, Chairman, Consulting Engineer, Tulsa, Okla.
Turner, John B., Pres., Friendswood Development Co., Houston
Twombly, Carole E., Librarian, Keyes Assoc., Providence, R.I.
Uhl, Mr. Robert H., Watkins & Associates Inc., Lexington, Ky.

48
 University of Tennessee, Engineering L1brary, Knoxville
U.S. Army Engineer R&D Laboratories Library, Fort Belvoir, Va.
U.S. Naval Civil Engineering Laboratories, Port Hueneme, Calif.
Vandegriff, A.E., Midwest Research Institute, Minneapolis
Van Horn, A.N., Supvr., Cons. Progs., Penn. Pwr. & Lt., Co., Allentown, Penn.
Ver Eecke, W., Supervisory Mech. Engr., Reynolds, Smith & Hills Jacksonville, Fla.
Vora, K.T., Resourc~ Planning Associates, Cambridge, Mass.
Wade, D.W .. P.E., Commty. Energy Syst. Branch, Georgia Tech Rsrch. lnst., Atlanta
Wagner, John, Research Analyst, South Dakota Office of Energy PolLey, Pierre
Walker, Ina, Assoc., Librarian, Ohi~, Public Utilities Comm., Columbus
Wasel, Robert A., Solar Heating & Cool1ng Prog., Mgr., Washington, D.C.
Weaver, Rose, Info. Asst., ORNL/EERC, Oak Ridge, Tenn.
Webb, Jerry L., Staff Engr., Public ServiLe Comm1ssion of Ind1ana
Weinberg, A.M., DlrPttor, Institute of Energy Analysis, Oak Ridge, Tenn.
Wheeler, Arthur E., Consulting Engineer, Henry Adams, Inc., Towson, Md.
White, RobPrt E., Loup River Public Power District, Columbus, Neb.
Widowskv, Arthur, NASA Headquarters, D.C.
Winders, M~rvin S., Engineering Supervisor Co., Newport Beach, Calif.
Wolfe, Ja, k, Southwest Research InstLtute, San Antonio
Woodburn, James D., Public Service Department, Burbank, Calif.
'Woolman, Clancy, Marketing Director, Cangas, Lincoln, Neb.
Yallaly, James G., Delta Engineering Consultants, Cape Girardeau, Mo.
Yarosh, M.M., DLrector, Florida Solar Energy Center, Cape Canaveral
Young, M.G., Caltex Petroleum Corp., Power and Utility Supervisor, N.Y.
Young, Thomas C., Exec. Director, Engine Manufa~turers Assoc., Chicago
,. Yudow, Bernard, Assoc. Chern. Engr., Institute of Gas Technology, Chicago
Zaloudek, Bob, Larry Smith & Co., Ltd., Northfield, Ill.
Zaworski, Jeseph R., P.E., Chief Engr., Critter Engineering, Corvallis, Ore.
Zoues, Tom, Walt Disney World, Lake Buena Vista, Fla.
Zovich, John, WED Enterprises, Glendale, Calif.

49