Double-layer solar energy collector with variable transmissivity - esp. for use on greenhouses

摘要

The solar collector consists of two transparent layers placed one above the other. A transparent liq. or gas flows through the upper layer and the lower layer can vary through all the stages from transparent to fully absorbent. The temp. inside the greenhouse can be controlled by making the collector absorbent during the day to reduce the heat entering and collect the heat for use during the night. Max. use can be made of evening sunlight by having the west side of the greenhouse transparent and the east side absorbent.