Solar energy utilisation without a pressurised circuit - involves circulating heat transfer fluid only when fluid in the collector is hotter than fluid in the storage tank

摘要

The heat conveying medium pref. water, is only circulated when the temp. in the collector exceeds that in the heat energy storage tank, and when the temp. of the medium is lower than its temp. of vaporization less a safety factor, (in the case of water, is 80 degrees C). A high degree of efficiency is achieved in a solar heating installation for which the mfg., installation and maintenance costs are low, since the system is not pressurised.