Highly efficient solar collector including means for preventing cover plate fluid condensation

A solar energy collector comprising:

• a. a heat trap member having cells therein of polyethylene terephthalate for preventing radiation losses, and convection currents from being produced in said cells, and yet permitting very high transmittance of solar radiation into said collector;
• b. a window for covering said heat trap member, said window having high solar energy transmissivity while concurrently filtering out ultraviolet radiation;
• c. a heat absorption member positioned under said heat trap member for absorbing said solar radiation;
• d. a first heat insulating layer positioned under said heat absorption member;
• and
• e. a second heat insulating layer made of polyurethane foam positioned under said first heat insulating layer, said second insulating layer having characteristics which cause said second insulating layer to produce vapor capable of producing condensation on the inside surface of said window should said second insulating layer assume a temperature exceeding a given temperature level, said first heat insulating layer being capable of preventing said second heat insulating layer from assuming a temperature higher than said given temperature level.