A method for producing the walls of the cells of a sun warmth - collecting device and solar energy collecting units

摘要

A solar energy collector of low cost and high thermal effeciency is disclosed having a heat trap produced by zigzagging a thin strip of polyethylene terephthalate between opposite sides of the trap while wrapping the strip about rows of dowels positioned at opposite sides of the frame of the solar collector. A window of soda lime glass filters UV radiation to inhibit discoloration of the plastic heat trap walls. An absorber plate having fluid pipes therein is positioned underneath the heat trap and a first layer of fiberglass, and a second layer of polyurethene foam are positioned below the absorber plate. The fiberglass layer prevents overheating of the polyurethane foam layer to in turn inhibit the formation of toxic fluids, which may condense upon the underside of the window to reduce the efficiency of the collector. An automatic freeze protection system for the solar energy collector includes sensor means are provided within the collector to monitor the temperature of the water, and whenever it approaches the freezing point, the sensor will automatically actuate a valve means to rapidly drain the water from the collector. When the temperature within the collector thereafter rises to a predetermined safe level, the sensor means will again automatically actute the valve means to refill the collector with fresh water to be heated. The system provided thus avoids the need for anti-freeze or other freeze protection materials suggested by the prior art as well as isolated water loops, heat exchangers and other expensive safety equipment necessitated thereby.