The solar total energy system (STES) was to provide 50% of the total electrical and thermal energy requirements of the 25,000 sq ft Bleyle of America knitwear plant located at the Shenandoah Site. The system will provide 400 kilowatts electrical and 3 megawatts of thermal energy. The STES has a classical, cascaded total energy system configuration. It utilizes one hundred twenty (120), parabolic dish collectors, high temperature (750 F) trickle oil thermal energy storage and a steam turbine generator. The electrical load shaving system was designed for interconnected operation with the Georgia Power system and for operation in a stand alone mode

Poche, A. J.

English

NASA Technical Reports Server

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bOLAIt TlY1Al. ENENI ; I' PN(i.IECT AT ;AA NAhI ►()A11,
GEORG IA SYS1 EM DESI(.N
oRIGINAL PAVE; 1t)
A. J. I'ucht, ' .enerel Electric Company, King of Prussia, Pa. 194ob OF Y(x)i{ QUALITY
A Flt T RA CT
The U . S. Department of V nergN , with Saxila libura-
torles providing technical support and management, Is
near completion of the I)eflmtive IHesign Phase of the
Solar Total Energy Project to be constructed at Men-
andosh, Georgia, General Electric Company dsoalgntd
the Solar Total Energy System (814,11) with the eapbelty
to provide, 50`17 of the total electrical +uui thermal ener-
gy requirements of the 25,000-square-font tileyle of
America knitwear plant located at the Shenandoah mts.
The sy stem w Ill provide 400 kilowatts electrical and ;i
megawatts of thermal energy,
The STEli has a classical, cascaded total enurgy sys-
tum configuration, it utilizes one hundred twonty ( 120),
parabolic dish olltelors, high tenynerature (7500f)
trickle oil thermal energy storage and a steam turbine-
generator. The electrical load peak shaving system
has Iwen designed for intercunnec •ted up ersuon with the
Georgia Power system and for tp,tration to a stand a-
lone mode.
INTRODUCTION
The Solar Total Energy bystem at Shenandoah, Geonstia,
will be a large scale prototype of a classical cascaded
system utilizing solar energy. Definitive performance
and cost data for a solar system will be obla,med during
the operation of the system and an Industrial solar total
energy capability established.
F lgure 1 is an Illustration of the Project Site after In-
stallation of the STES. A high temperature silicone
heat transfer fluid in used to transport solar energy
from the parabolic dish collectors to thermal storage
or a steam generator. Thermal encrgy :ntorage is ac-
complished by use of a low cost, trickle nil system
using an iron ore storage media. The power conver-
sion enstein employs a steam IlaiJcine cycle and high
speed (42, 500 rpm) turbine.
r	 ^^
FIG, 1, SOLAR TOTAI. ENERGY sYSTEbt
SHENANDOAH, CA
'I he STLh has the fitxihlilty to uprrste In either a
stand alone us peal. shming mode whlie satisfying
electrical power, piocebs steam, stating and cooling
requlrennents of the knitwear fabrication plaint adiscunt
4n the STES site.
Sheonandoah Is near Newman. Georgia aocl Is an Indus-
trial-residential planned community. Sun right uaae-
ments have been obtalntd on the land Ixxir,dlcy t the
5.74-acre 1f Lb site to prevunt ulatruutlon of the field
msolationn.
SYS'I'bM DESC u1P11'101%
Figure ;: depicts the three major loops of the STES;
solar collection anti etotage, power conversion snd
thermal utilization.
A leak energy delivery rate of 10 x lob
 litu/hr Is obtain-
ed from the solar collector fluid.
The solar cwile-tor field consists of twt.-.c parallel
branches with ten paraolic dish collectors In each
branch. Energy is transported from the sc%vral col-
lectors to thetrnal storage or the steam generator by a
high temperature silicone ( Sylthr. rm irm Ji0o) heat trans-
fer fluid, which 1s stable over the operating temperature
range cif the solar collector field (bunu F' Inlet, 750o1'
gullet). During periods of low Insulation or inclement
woather, the system can be operating with energy from
the thcrnnal energy storage system or a fossil fired
heater.
The power conversion loop whicn includes the steain
generator, turbine-generator and condennor is located
in the mechanical building shown In Figure 1. Process
steam ( 1380 lha/hr) for the knitwear facility is extracted
at an internedlate turbine stage. Thermal energy fron;
the turbine exhaust steam Is extracted via condensor and
trr.neforred to the thermal utilization loop fur heating
and cooling ( by,
 chilled water from an absorption unit) of
the fileyle Plant and the STES Muchanlcal Building. The
major components of the thermal utilization loop (Figure
2) are the low temperature storage tank, cooling towtra
and the absorption air conditioner.
In the peak s"vlug mode, the STES operatea wlth a 50 to
75 Me
 baneioad provided by the local utility. A sum-
mary of the system eapabllitlee Cld load requirements is
presented In Table 1. Fifty percent ( 50%) of the annual
energy requirements of the bleyle knitwear plant will be
satisfied li) solar energy conversion.
When operating in the automatic male, start - up and op-
erattun of the STES will be bastd or a rcai time clock,
as well as measurements of sy bton, status, demand and
environmental cond;ttons. A typical Operating Timeline
for the systeir, is shown I n Figure 3.
251
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SOLAR COLLECTOR SUBSYSTEM	 POWER CONVERSION SUBSYSTEM
1	 STEAM SUPPLIED
TO BLCYLE
. ..A,	
.^
CONDCNSATE RETURN FRUM IiLLYLE
THERMAL UTILIZATION SUBSYSTEM
FIG, 2, STES - THREE MAJOR LOOPS
TABLE 1. PEAK DEMANDS AND ANNUAL, STES
ENERGY CONTRIBUTION
l0.0 NOCINa1Mts
- sti)	 Y•1Mt Stts{slnl	 Sri► CY4IIIt1	 C0Mt01o1111e)
IC•) IH al	 Ili q 100 q	 ____ „+
a	 ,%G 111 VMS
	 to tabs 1))	 10111	 111
•I.lia It+	 1	 k IN	 Mt
.OTId"	 4tut•M 4,,11.1
'emss I	 +.100
	 1 A	 sIs
"11111 8TWO1 ./No11 3401{$t•• •
m•r)
wr. u.<.r•r wrr•ar n.r ••a -r,-r.,,	 ^^^ wu uwr.v
.n
,.^^ •r	 u+•	 w	 •w
rr.r•u	 •+^	 wu.r
FIG. 3. WEEKDAY STES OPERATING TIMELINE
CASE: APRIL 13TH SSMY
Is initiated by solar clock (with a measured isolation
permissive) for startup, and operation continues through
the dal as long an sufficient Insulation is avallal.le•
Lined on solar availability, thermal storage status, and
demands, a backup fossil heater is activated, so that the
Bleyle plant loads are always AILIPPIted.
For the case shown in Figure :1, which was abstracted
fro	 , annual system simulation using Shenandoah
Solar Model Year climatology, the storage tanks were
depletod u1 the early morning. The fossil heater was
zetivated, the Power conversion s y stem aril thermal
utilization were :+farted, and the turbine -generator syn-
c • hroniTad with the utility. All this occurred prior to the
Blevle lot shift startup. The collector field started up
at approximately 6 o'clock and solar energy w • as pro-
idrd to the system at 8 o'clock,
Solar collector (SC
The solar collector is a 7-meter diameter, paraholoidai
dish with a cavity receiver. Reflected solar energy is
focused onto a cylindrical coil of blackened stainless
steel tubing ( 1/2-inch diameter) within the receiver. As
the collectors are hydraulicall y connected in parallel,
the total field temperature rise occurs in each receiver
(2500 F). The reflector assembly consists of 21 die-
stamped aluminum petals with a highly reflective lamirl-
ated surface (FEK 244).
Each collector tracks the sun through its / laily and sea-
The solar collector field operates independently of the	 sonal variations by use of a polar - declination gimisl
electrical and thermal load supply equipment. Operation 	 arrary,ement. A hybrid swi tracking technique is em
252
$two eLUWI
I MAr a OUTL/I
0.11 Qr telrew A. ?tog
MIT OAR W IMP 1r. R +e oAMM.t4LLc^1) WOMFI l..lfrtai.'	 — -	 -- ,.
;40 	 it 	 r r •n 11.•rw
r 1^ ,.+	 ^..^'^^ ICY • owl i'. a.
.I "L2 ....•...r n. -Ir•Ie. Tell s ur T T1N• 0.1111111 Ue eUIL T IN /UM TMICMI I UM
UIIAI M1 nIA1W*MATIUN
FIG. G, TRICKLE 011. 7'111 R\IAL ENERGY
STt ► Its► G 1.'
.1^
OF p(()R QUALITY
ployed: course trackinA of the run JQ o, g") Is computer
controlled; and fine trackliam Irf the sum (+ 1/4y is ub-
taired by nulling the output of optical sensors. The
optical tracker ompluys a pair of sensors on each axis.
Sensors of each pair are Icx • atud on opposite sides of the
revolver apiertuir plate, and the collector is p ositlutted
by balancing the Intensity of the "tails" on the refle"ted,
focused Image straddlH4 the ape • rlure. I he use of a , fiu
computer limit preitentM wa.: leruig of the collector Ie-
cause of extraneous reflections, i.e. , cloud ichi.l.
Four full site prolotvI)v solar collections (Figure 4)
were built and tested In the saitdla laboratories' (load-
rant facility to verify the performance and design ad-
egwvy of the Shenandoah Solar Collector. Tae It-at pro-
grant 	 that excellent performance can be ob-
tained from a high temperature (7.5o0 l fluid outlet
tempiersture) paralrulle dish collector fahric •atcd with
existing Industrial processes, On a ciear day, a col-
lector thermal efflclenty of 61' was reallivd, Figure fl,
ulg. lit addition, the Ip/acy used to sliffon the cups of the
fiber olNle sensor hurdles (k•grakd and distorted the
Mcnsur measurement, lhir As* eliminated to) rel4sc•un;
the olttic• bwldle ends with a build cast& design tha • IS
compatible with the With temperatures ucc •urriog during
acquisition and Liefcxus of tae collector. subsequent
tracking experimentation showed that the olllic•al track-
Ing system focused the re•culter within the Resign toler-
uice L 1/4c).
A major design cor(vrn sou the slolie error of the dish
and Its a►,Ilit) to concentrate the solar er►e• i'p(♦ to selish,
the design Intercept factor requirement (bb i , A
nucro drositometer u%aluatlon ws* made of the re-
fluctud itlumitetiun front 	 dishes while lrackitig the
moon and while focused on a Itores ►ghl light. 'I here
measurements cotdlrmed that the de,.ign intercept factor
war satisfied.
Ilitth-Tymtx• raturc 'I hcrinal Frienn m o ragg- SUIT l •Mtem
(Ills)
Excess collected enerpq' will I* stored for use duritig
pierlods when the collector field cannot pro%ide suf-
ficient energy l u operate the P) stern. To minimize the
capital in%estment lit 	 transfer fluid, the STVs
utilizes a trickle oil storage s) stem, I Ip,ure I;,
11.41t A 1110
TA T MN
MA%.It 1
1110011,661
MI OIA
INUr• 001 .
lop
MAIIIII1rt U
F16. 4. UlUANDRANI' TEST' OF bliENANMA11
SOIAR COLLECTOR
bltr v
0W UiU
-: - ':-1- ` - .i• " Z^ 'Siir Iii Si• •	 . •	 w iMt •e/A,
FIG. S, QUADRANT TEST SOLAR COLLECTORS
I %oral required design mo.lifications were identified
and Implemented during the tent program. As a result
of the high heating rate imposed on the receiver Ic•on-
centration ratio of 23•1), it was necceAary to acid a
quartz cloth covering to the receiver aperture plate.
This layer reduced the stainless steel aperture plate
temperature leccl sufficsetitk to eliminate plate %Narp-
I he,
 heat transfer fluid Is introduced at the top of the
taro. bN u distribution manifold and allowed to trickle
through a loft cost, Iron ore storage media, lit both tae
charging m(Kie and discharging mode, energy is tearis-
ferred betuven the storage media and a thin film of the
heat transfer fluid, fur ths. STtCS, three storage tanks
%Ttil be emploied with a combined tapucit% of 6 41 nlsilulti
Btu. Maximum charge and discharge requirements for
the thermal storage subsystem.- arc In million Btu, hr.
To %alidate the trickle oil concept, u column test rep-
resentati%c of the S'1 LS opierational conditions, %%as per-
formed. It was shown that uruforni heating and cooling
of the tied, during charging and discharging , occurred
253
it tho iluld wus distributed uniformly at the top of the
tank, Figure 7, and that sharp thormocitnos resulted,
1,,E
4
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1 ^	 tw,h,A	 A
O,a
e - nA,. xatd saes ClSAt si'-A :A Vl tc,'a c u e/, lf!;taFl.G;
h7	 0WU46#At;.tHA 7:A'A to At t:9 t;t L*'0;6M`Yr. [3,
+^'`	 AiA4t,a )/ak 1AAS^UU •9 fe St•=.nAA.-A•3 KA.t..h'.t
t. J 6
slat"."3.:fe'::y cAt C ie
+	 31	 fl	 ti	 IQ	 o -_— ll
	 ^ -1
I s j^;l irye
FIG, 7. TAICKLI OIL COLUMN TEST,
CltAMING MOUE
Its addition, the test showed that the temperature gradl-
ant in a partially charged or discharged tank would not
Warlonce significant axial heat flow during normal
operation, which would degrade ilia temperature of the
storod energy in ilia charged portion of the tank, fig-
ure S.
♦oo
'^ 	 ,rE CHARGE HOLD
aEO	 .
FOLMINO0661MCHAIIGE
ASOt °	
,.Fi npS
^4 6	 SYMBOLS;TIME
-420k	 ^u	 , S	 al1R
00?
	
a 1 RS
.do0,,.	
a	 A !OHMS
a3W370,
360,
960.
310-
'15o! - TEMPERATURE OF FULLV CHARGED PORTIONOF TIED
NFARLYEONSTANT
310,.1. CONDUCTION AND FLUID DRAINAGE SWARM UMP PROPILt.
200 .1 UNDER CONDUCTION ONLY CONDITIONS- SMEARING 10 W61,10-01,9
DLO POSITION. INCHES
0 jig (1t4 96 ^ is ib ^a ao da l3 i8 ^d ^b 5a ivQ
Tap
	BOTTOM
FIG, B. TRICKLE OIL COLUMN TEST,
BOLDING MOUE
PoNyer Conversion Subsystem (PCS).
Major elements of the power =verslon subsystem are
a drum-type steam generator with preheat and super-
bear sections, a high-speed steam turbine-gonerator
set rated at 400 16Ve, a condenser, a condensate stor-
age tank, a make-up demineri:lizor, a deacrator, re-
quired pumps and local controls,
The recirculating heat transfer flulo 1. nm the solar
collector field can deliver 10 million utu/hr to the
steam generator and provide up to 10, 000 lb/hr super-
heated steam at 700 psig/7200I' to the steam turbine,
AItornately, in tho event of turbine outage or no elec-
tric power demand, the steart turbino run provide
saturated steam at 110 pant for process and other
thermal uses. `1'o avoid particulate erosion of the high-
speed turbine Wading (42,500 rpm), the steam flow is
filtered to reduce the contaminate level to + ► ,1 ppm,
with 95,"a of the parUclos less than 4 microns,
The steam turbine gonorator produces electric power in
the range of 100-400 MV at 480 volts, a phase, 00 Ilz.
The steam turbine to it hetgh specific epeed/ldp;h of-
ficlency design, high pressure stake efficiency is 00;_'j
and low pressure stage efficiency is 761% Controlled
extraction of superheated steam (110 psi g) front the
turbine provides process steam for the Bloylo plant
and doacrator,
The turbine exhaust Is condensed at 0 psis; acid the con-
denser cooling water (2100F) ft; used as the cnargy
transport to the Thermal Utilization tiubsystcm.
'thermal Utilization Subsystom (Tti:)
The thermal utilization subsystom consists of a 10
million Btu low temperature wator (210 011 storage sys-
tem, a 250-ton absorption air conditioner do-rated to
130 tons with Inlet water at 210 0,V, and two cooling
towers for heat rejection from the absorption air con-
ditioner aiid excess ermrgy 11-Mm tho 111CS,
On an annual basis, the thermal utilization subsystem
will provide 78;' and OiIMI of the combined STES Mech-
anical Building and Moyle Plant cooling and heating
loads, respectively.
Controls and Instrumentation Subsystem (CAM
The control and instrumentation subsystem Initiates,
regulates and terminates collector tracking, enemy
storage, power generation and thermal utilization for
heating and cooling of the Bleyle plant and the STES
Mochanical Building. Whon operating in the peak shav-
ing mode, the control and instrumentation subsystem
monitors and regulates the generation of power to sat-
Isfy system requirements.
The control and instrumentation subsystem includes a
central control console, a central minicomputer and
romote microprocessor control units. The control sys-
tom has the flexibility to by operated in a manual or
automatic mode, and permits the operator to monitor
or wntrol the system functions from the control panel,
Both mimics And color graphic CRT l s are omployed for
data display, Data archiving is performed with mag-
netic storage tapes, and real time data In hard copy
form Is available via the computer line printer.
SUMMARY
A solar total energy system utilizing parabolic E116h
collectors has been designed that has the capability to
provide greater than 00;i) of the. energy requirements of
a knitwear fabrication plant with 2"t, 000 square feet of
floor space.
254
rV
The polar collector test program performed at the
	
Q .
Sandia Laboratories toot facility in Albuquotquo has
demonstrated that high thermal officlencies (Wo moa-
ourod) can be obtained from a parabolic dish built with
existing tabrivation technology, 'thermal efficiency and
optical moasurontonta have voriflod that the Shenandoah
solar collector design will satisfy design criteria and
performance requirements.
Column tests havo demonstrated that the trickle oil
thermal energy otorago system will provide an efficient
and cost-effective moans of storing thermal energy,
ACKNOWLEDGIZICNT
The Information presented to the result of work per-
formed for the U. S, Department of Energy under con-
tracts D077-C-04-3085 and Di:-AC04-77ET20200, for
design of Solar Total Energy :project at Shenandoah,
Lwbora orl^.-ou , x lbuqu,--xn.wn N. M .•	 v,
provided technical management for the Department of
Enorgy.
255


Solar total energy project at Shenandoah, Georgia system design

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