IMPROVING LOAD-MATCHING CHARACTERISTICS OF A THERMOSIPHONIC SOLAR-SYSTEM BY THERMOSTATICALLY CONTROLLED CIRCULATION

The load matching characteristics of a thermosyphonic solar water heat er can be improved by utilizing a thermostatic flow control (TFC). Sim ulation of the performance of a typical thermosyphonic domestic solar heater, with and without a TFC, was used to evaluate the yearly requir ement of auxiliary energy to meet four different loads. The amount of yearly auxiliary energy required to fully match the load demands is us ed as a measure of the matching improvement. Results indicate that, fo r load temperatures of 40-degrees, 60-degrees, and 70-degrees-C, the t hermostatic flow controller improves the system's (multi- or single-pa ss) performance, while the common single-pass system without the therm ostatic flow controller is the best choice for a 50-degrees-C load tem perature.