Solar energy collector fitted with movable screen - controllable automatically to cover surface when circulating water temp. is too low, increasing efficiency

摘要

A solar energy collector having a flat absorber, under a transparent surface, in which a heat transfer fluid circulates, incorporates as well a movable shutter to cover temporarily the surface. The shutter is fitted with a thermostat which compares the outlet liq. temp. with a reference temp. and controls a motor operating the screen. Pref. the thermostat compares the temp. of water leaving the absorber with that of water in a reservoir and stops a circulation pump when the outlet temp. is lower than the reservoir temp. and operates the shutter at the same time. Loss of heat by radiation and thermal inertia is reduced without redn. of vol. of water contd. in the collector and thermal efficiency. It allows circulation to be restarted when the sun appears and the temp. is higher than that of the water, without the need to wait for the water to be reheated.