Heat retaining protective cover for swimming pool - has solar energy transparent upper layer spaced from blackened lower layer and preventing convective heat loss

摘要

A swimming pool has a removable cover which is placed over when the pool is not in use to prevent loss of heat to the atmosphere and pollution by dirt from the atmosphere. The cover has an upper layer (3) which is in contact with the air and is made of a plastic transparent to solar energy but not transparent to low temperature radiation. The cover also has a bottom layer (5) which rests on the water surface and is blackened on its upper side to make it a good absorber of radiation. The upper and lower layers are spaced apart by an intermediate layer (4) of corrugated plastic with radiation transmission properties similar to those of the upper layer.