An experimental technique for testing thermosyphon solar hot water systems is described which allows testing of the system indoors under nonirradiated conditions. The technique described is applicable to thermosyphon systems that utilize flat-plate solar collectors. Energy normally absorbed by the irradiated solar collectors is supplied by electric strip heaters attached to the back side of the absorber plates. Analytical expressions are developed that allow the power input to the strip heaters to be calculated for various environmental conditions. A description of the experimental apparatus and test procedure is given. Results are presented that show that the performance of a thermosyphon system tested under nonirradiated conditions using the electric strip heater technique closely duplicates system performance under outdoor irradiated conditions
Energy-efficient circulating pump in hydraulic circuit of solar collectors of hot-water systems
