Abstract: A solar collector converts solar radiation to heat energy over a specified surface area and collects the heat energy by trickle feeding a heat transfer fluid over a trickle feed absorber surface having improved absorber surface area to volume ratio. The elements of the solar collector include a glazing first layer for receiving and passing incident solar radiation over the specified surface area and an impervious backing layer spaced from the glazing first layer. The absorber layer is sandwiched between the glazing first layer and backing layer with the glazing first layer and backing layer contacting the absorber layer on opposite sides. The absorber layer is a layer of fiber material defining capillary channels and spaces in the absorber layer between the glazing first layer and backing layer.

Abstract: A portable collapsible tank for storing and insulating hot water or other liquid is contained by an elongate flexible and foldable outer sleeve which defines the outer perimeter of the tank and is formed with sufficient tensile strength to support the tank and stored water. A side wall of insulating material is contained within the sleeve extending around the inside circumference of the sleeve from the top to the bottom of the tank. The outer sleeve and side wall layer overlap and frictionally engage the edge of a floor or base disk of rigid insulating foam material for stability of the tank without tilting and to prevent ballooning of an inner liner from the bottom of the tank. An inner liner of impervious flexible material suitable for contacting hot water, for example, for consumptive use is removeably seated within the side wall and base and extends over the top of the tank.