to fig1 3 to provide a collecting module unit the unit is easily attached to a roof structure fig6 by sliding it on to track 54 having a base plate 58 for attaching to a roof structure by screw fasteners 60 referring now to fig7 of the drawing there is shown a modified embodiment of collecting module unit in accordance with the present invention as illustrated a metal mould base 62 contains insulation 64 positioned on the top surface 66 of the metal base mould 62 is the heat exchanger 68 comprising metal tubing through which a heat exchange fluid is circulated positioned above and in heat exchange relationship with heat exchanger 68 is the energy receiving surface 70 having a black upper surface to receive the radiant solar energy which is transmitted through the transparent cover 72 in this embodiment the base 62 and the energy receiving surface 70 can be formed of metals such as aluminum copper tin and alloys thereof in an alternate form of this embodiment of the invention the energy receiving surface 70 is omitted in this case the heat exchanger tubing 68 and surface 66 are provided with a black coat and serve as the energy receiving surface to transmit heat converted from the absorbed radiant energy to the heat exchange fluid referring now to fig7 there is shown an embodiment of the present invention in which insulation employed to reduce loss of heat due to conduction and convection is achieved by vacuum spaces as shown the space 74 between the cover 75 and the energy receiving surface 78 is evacuated and vacuum sealed to.