Abstract: Heat exchanger apparatus which includes a substantially horizontal countercurrent heat exchanger of the shell-and-tube type, particularly for hybrid heat pumps operated with non-azeotropic work fluids. The apparatus further includes fluid distributor with fluid outlets the number of which corresponds to the number of the heat exchanger tubes of the heat exchanger is provided upstream the heat exchanger, the heat exchanger tubes of which are connected each to one fluid outlet of the fluid distributor.

Abstract: A heat exchanger having a plurality of parallel pipes arranged in lines and strips of fin plates fixed to the pipes perpendicularly to the lengths thereof. Turbulence-forming structures are cut out of the fin plates and are bent up at 90.degree. with respect to the planes of the plates, such structures functioning as fin plate spacers and as baffles to direct a fluid medium of inferior heat transfer coefficient which flows in a direction parallel to the planes of the finned plates and perpendicularly to the pipes. The pipes are adapted to conduct a fluid medium of superior heat transfer coefficient. The turbulence-forming structures are disposed in lines on each side of the lines of pipes and in rows which are substantially tangential to the opposite sides of the pipes. The heat exchanger may have a plurality of lines of pipes spaced equally transversely from each other and transvetsely of the direction of flow of the fluid medium of inferior heat transfer coefficient.

Abstract: In a cooling apparatus operated by ambient air and an agent to be cooled which can have solid state at atmospherical temperatures, a housing such as a cooling tower (100) with air inlets and air closure means at the air inlets and large surface heat exchangers (3) arranged within the cooling tower (100) at its air inlets and divided into groups or sectors being in parallel connection are provided, with which the agent is cooled by the air streaming through the large surface heat exchangers (3). At least one pre-heating heat exchanger (20) is arranged in the air space (29) of each sector of the large surface heat exchangers (3), and the pre-heating heat exchangers (20) are in parallel connection with the large surface heat exchangers (3) of each sector.

Abstract: A hybrid heat pump wherein the operating medium is a mixture of media which dissolve in each other and have different boiling points. The condensation and/or the evaporation is performed on more than one pressure levels and at variable temperatures. The compressor performs the suction on more than one pressure levels and performs the discharge on more than one pressure level. Between low pressure operating medium (p.sub.1, p.sub.2) and large pressure operating medium (p.sub.3, p.sub.4, p.sub.5) the heat transfer is performed by the internal heat exchangers.

Abstract: A helicoidally finned tube for use mainly in heat exchangers. The tube comprises a cylindrical tubular member which carries or is integral with a helical member the turns of which form the fins of the tube. The fins are provided with ripples which extend from the outer rim of the fins inwardly and the depth of which diminishes toward the tube center. The ripples serve for diverting a cooling medium inwardly to hotter parts of the tube thereby improving its heat transfer performance. The helicoidal member has rippled sections alternately with level sections, the rippled sections subtending an angle not exceeding about 90 degrees and both types of sections on successive turns registering with one another in the direction of the axis of the tubular member.

Abstract: The difference in density between heated and unheated air is used to provide flow of air across a heat transfer means located underground. An underground passageway connects an inlet orifice with an outlet orifice for flow of ambient air therethrough. The passageway comprises at least one essentially vertical shaft, said vertical shaft terminating at the outlet orifice and containing proximate its lower end said heat transfer means.