Solar Collector Testing Program. Part II: All-Day Efficiency Tests. Final Report

摘要

Twenty-five hydronic flat-plate collectors used in nationwide commercial demonstration projects were tested. In addition to the performance tests conducted according to ASHRAE 93-77 and a 30-day exposure test as described by FSEC 77-5, most of the collectors were tested for efficiency while operating for an entire day at a constant fluid inlet temperature and flow rate. All-day tests were run on 23 of the collectors at a nominal inlet temperature of 70 exp 0 C, a representative operating temperature for solar space heating collectors. On the collectors with flat black absorber coatings and a single cover, another all-day test was run at 50 exp 0 C inlet temperature, and the collectors with selective surfaces were tested a second time at 85 exp 0 C inlet temperature. These temperatures are typical for collectors in solar water heating and air conditioning systems respectively. Part I, a separate volume of this report, contains the results of performance tests (ASHRAE Standard 93-77) before and after the non-operational exposure test, and the all-day test at 70 exp 0 C. In this volume the results of 54 all-day tests on 23 of the collectors are summarized and compared to estimated all-day efficiency derived from the ASHRAE test data. Estimated efficiencies were found to average about 5 points lower than the measured values. (ERA citation 09:030566)