QUALIFICATION AND ENDURANCE TESTING OF FLAT PLATE COLLECTORS

Abstract

A set of tests for flat plate collectors is proposed which would evaluate their quality and ability to resist weathering. This set of tests is partly based on tests already described in the literature(1). The sequence of tests is:(1)Documentation and receiving inspection, including complete and detailed documentation (drawings, materials descriptions, specifications) and appraisal of construction.(2)Static pressure test: Overpressure test of the absorber at 1.5 times the rated operating pressure (hydraulic), and leak test (pneumatic).(3)Preconditioning, which is one test chosen from: Outdoor exposure (three days of cumulative exposure to 17 MJ/m2. Indoor exposure (three cycles of cumulative exposure to 17 MJ/m2 at 800 W/m2). Hot fluid conditioning (24 hours at about 100°C).(4)Thermal performance test: Measurements of the instantaneous efficiency curve according to “Recommendations for European Solar Collector Test Methods” or with a solar simulator.(5)Dry degradation, which is one test chosen from: Outdoor exposure (30 days of cumulative exposure to 17 MJ/m2 with one 4 hours period at 950 W/m2). Indoor exposure (4 hours at 950 W/m2 at 27°C ambient temperature or at higher irradiation if the ambient temperature is lower).(6)Thermal shock by cold fill: Fill the hot collector with cold fluid during the 950 W/m2 irradiation.(7)Thermal shock by water spray: Spray cold water on hot collector and check for water tightness.(8)Repetition of Thermal Performance Test (No. 4 above).(9)Hail Test, which is one test chosen from: Hail gun, shooting ice balls with diameters up to 4 cm at 35 m/s. Simulated hail test by steel ball dropping (227 g, 3 m of height). Final visual inspections.