the absorption plate 9 in this manner a sinusoidal path is formed by the channels of film 12 which is selectively sealed to the underside of absorption plate 9 the heat transfer fluid is pumped against gravity entering inlet conduit 18 and exiting through outlet conduit 20 which are substantially at the same elevation by keeping the heat transfer fluid in chamber 10 directly in contact with the majority of surface 8 or absorption plate 9 heat will flow more rapidly from the absorption plate 9 to the heat transfer fluid than would flow if small passageways separated from each other or tubing bonded to the absorption plate were used the concept of faster more uniform heat transference increases the overall efficiency of the collector by limiting the time of exposure to dead air space 13 and also limiting the rate of black body radiation by the absorption plate the overall efficiency of the collector is also increased because absorption plate 9 is kept at a relatively uniform temperature as opposed to having those areas farthest away from the heat transfer fluid as in the case of tubing or narrow channels spaced a considerable distance apart from building up higher temperatures resulting in a greater percentage of heat loss caused by conduction convection and radiation absorption plate 9 is made of copper or.