Base-load thermoelectric power generation using evacuated tube solar collector and water storage tank

摘要

The concept of using low temperature solar heated water to produce electricity is not new but so far very few attempts have been made to produce continuous power (24 hours - 7days) from low grade solar thermal systems. In this study we are looking at continuous electricity production during not only sunny days but also night times and or cloudy days. Thermoelectric technology has a good potential for reliable electricity generation form low temperature heat source like solar heated hot water. A series of "electricity generation apparatus inside thermoelectric" abbreviated as ELEGANT have been designed and fabricated and the latest, ELEGANT-24 which produces almost 22 W(e) and comprises 24 market-available Peltier module, operating as generator, successfully operated for two months. Eight evacuated tube solar collectors are used to heat the water up and then store into an insulated storage tank during day time. In this period ELEGANT-24 uses outlet hot water of solar collectors, as a source of heat. Cold water from a non-insulated storage tank passes ELEGANT-24 in as coolant and gets preheated and then enters the solar collectors thru same non-insulated tank. This pre-heated water entered into the collector helps to improve the overall energy conversion efficiency of the whole system. Through this process heat is converted to electricity with minimum heat loss. This process can be continued during night time while hot water is supplied through circulating of insulated storage tank. As well as addressing base load power production, above configuration dramatically increases the efficiency of heat to electricity conversion via thermoelectric technology. This is due to that dissipated heat from cold side of TEGs would not be wasted and goes back to the heating circle. It means that except very small heat loss through walls of ELEGANT-24 and piping, there is no other heat loss.