Abstract: A fluid reservoir includes a housing shell defining a cavity, and a flexible, resilient water impervious bag-shaped liner mounted in the cavity so as to substantially fill the cavity when the liner is filled with fluid. The liner is formed from a flexible water-imperious sheet by forming the sheet into a cylinder, then forming a water-tight first seam along a bottom edge of the cylinder, then folding outer corners of the first seam over, so as to overlap a center portion of the first seam, and so that bottom edges of the outer corners, once so folded over, register substantially co-linearly within a bottom edge of the center portion of the first seam. An upper portion of the liner is thereby urged to bag open. The upper portion thus forms a substantially frustoconical shape. The upper portion is contiguous with a lower portion of the liner. The lower is portion substantially wedge shaped.

Abstract: A heat exchanger element for a heat exchanger includes a curved thermally conductive sheet having a curved end and a pair of legs extending contiguously from the curved end. The sheet has a substantially horizontal base edge along a lower edge of the sheet when, in an operational position, the curved end and the pair of legs are substantially horizontally aligned relative to one another. The base edge lays on a horizontal floor surface of a fluid filled cavity in a fluid reservoir when the sheet is operably positioned in the operational position in the cavity. The curved end and the pair of legs form substantially vertically extending walls. A plurality of horizontal tubes are mounted in the sheet so as to extend substantially horizontally in a vertically spaced apart array of tubes spaced apart along a height of the walls when the sheet is in the operational position. Each tube is mounted in a corresponding sleeve formed in the sheet.

Abstract: A solar panel includes a circumferential upstanding rim defining a cavity therein. An insulating layer is mounted in the cavity and extends substantially completely across the cavity. A metal heat-exchanger sheet is overlaid onto the insulating layer and substantially entirely covers said insulating layer. A light-transmissive sheet overlays the heat exchanger sheet and is mounted to the rim. An array of fluid transmission tubes are mounted to the heat-exchanger sheet by welding closed of channels in the sheet so as to tightly encase the tubes in the channels. The fluid transmission tubes conduct a flow of heat-exchanger fluid in a heat exchange circuit.