Page 168 - Design of Solar Thermal Power Plants

3.3 THERMAL PERFORMANCE OF PARABOLIC TROUGH COLLECTOR 153

relevant industries to realize that it was highly necessary to conduct
systematic and standardized testing and evaluation toward collectors; it
would help to enable potential users evaluate such technology through
unified tests. In 1973, with the help from the DOE, Sandia National
Laboratories of America (SNLA) located in Albuquerque carried out
studies on the testing of tracking parabolic trough collectors for the first
time. In 1975, SNLA’s mid-temperature solar system testing facility star-
ted to function, which included the parabolic trough collector module
testing platform and system testing platform.
In 1977, American Society of Heating, Refrigerating and Air Condi-
tioning Engineers (ASHRAE) published the standard test method
ASHRAE 93-77, which provided guiding principles for testing non-
tracking and tracking solar collectors. Henceforth, it was developed
synchronously with the construction of tracking solar collector testing
platform. Presided by the American Society for Testing Materials
(ASTM), many investors participated in the development and evaluation
of solar collectors. They applied themselves in developing the test
method for tracking solar collectors, and finally published the standard
test method ASTM E905 in 1983. However, as tracking solar collectors
was normally used in the large-scale array, it was necessary to under-
stand the performance of the entire system before testing a single col-
lector module. These systems included pipelines and other system
balance members, as well as unsteady state conditions. In order to ac-
quire such data, DOE initiated a series of projects. The first project
involved a large amount of field tests. These tests had focused on
numerous large-scale parabolic trough thermal collecting systems on
industrial sites. The second project was called the Modular Industrial
Solar Retrofit project, which focused on advanced parabolic trough
thermal collecting system for industrial steam and carried out devel-
opment and testing works.
SNLA’s parabolic trough collector module test platform includes three
test stations (each test station has an independent fluid loop), a data
collection system and a parabolic trough collector with an aperture area
2
up to 45 m . Based on the heat-transfer fluid in the loop, different testing
temperatures can be defined. For example, loop 1 applies Therminol 66

synthetic oil, the maximum operating temperature of which is 315 C; loop
2 applies Syltherm 800 synthetic oil, the maximum operating temperature

of which is 425 C(referto Fig. 3.22). Biaxial rotation test platform is able
to make the aperture of receiver of parabolic trough collector face a
random direction within a specific test period. In addition, the meteoro-
logical station collects all necessary data about natural conditions. The
laboratory also published some important testing research reports related
to the performance of parabolic trough collectors, such as the 30 MWe
SEGS Power Plant Simulation Report [25], Test Report for LS-2 Parabolic