Abstract: There is provided a heat exchanger system for transfer of heat in the warm exhaust air from a mine to the cold input air flow to the mine. In the system there is provided a heat supply means, which supplies heat, recovered from the exhaust air, to the input air heat exchanger when an exhaust air heat exchanger is disconnected for defrosting.

Abstract: A method is disclosed for manufacturing a tube coil useful as a heat exchanger wherein the tube coil comprises a plurality of slightly spaced, parallel tubes wound onto a supporting core. The tubes are wound at an angle to the radial plane of the support. The winding direction is reversed with respect to the radial plane at an odd number of radial angle positions of the coil and separate tubes of a subsequent winding turn are positioned in the spaces between adjacent tubes of the preceeding winding turn.

Abstract: There is provided a heat-exchanger system for heat-exchange between a gas such as air and a liquid such as water, comprising at least one heat exchanger unit which unit comprises at least one tube which is wound to form a hollow coil and which is arranged to conduct said liquid, characterized thereby, that said coil is closed or covered at one end; in that the other end of said coil which is open, is placed against a base plate having an opening which is aligned with the coil opening and has a size and shape corresponding to those of the coil opening; and in that the turns of the coil are slightly separated in order to permit the gas to flow perpendicularly across the tube during the passage through the wall of the coil.

Abstract: A hot water reservoir comprises buoys floating on the surface of a lake, and a flexible wall fastened to said buoys hanging down into the water. Weights are fastened to the lower edge of said wall. Cables extend from the buoys to the weights so as to reinforce said flexible wall. The buoys are fastened to anchoring wires extending toward the interior of the reservoir.

Abstract: There is provided a convector comprising a plastic tube arranged in the shape of a flattened helix, the major flat sides of which are displaced relative to each other in the axial direction of the helix, such that the bend radius of the tube at the minor sides of the helix is substantially longer than half the distance between the major sides of the flattened helix.The convector can be produced by starting with a supply of plastic tubing, forming a bend in the tube, inserting the bend in a slot in one of a pair of parallel support structures, each having a series of oblique and parallel slots, forming a fresh bend in the tube and inserting the bend in a slot on the other structure, and so on.

Abstract: A heat pump system having a vaporizer in heat exchange relationship with a glycol/water circuit which comprises an earth heat absorber and an ambient air heat absorber in parallel.

Abstract: There is provided a distillation plant of the multiple stage flash distillation type. The plant comprises a reinforced concrete shell which is divided into a large number of flash chambers and a heat supply chamber by means of separation walls. At least some of a bundle of continuous condensation tubes of plastic extend throughout all of the chambers. The tubes may be extruded in situ so that they directly move into position in the shell. The inlet and outlet manifolds for the tube bundle are defined by an end of the shell and an adjacent separation wall. The shell has preferably a plastic coating or consists of a polymer concrete. Preferably, the walls consist of or comprise plastic so that the bundle of plastic tubes may be sealed to apertures in the walls by gluing or welding.