Heat exchanger

In a heat exchanger having a plurality of layered tube units for refrigerant in a gas phase and a liquid phase, the tube units being disposed substantially one above the other, each of the tube units comprising at least one tube made of two elongated plates and having a refrigerant inlet side and a refrigerant outlet side at opposite elongated ends, and spacer blocks disposed between said tubes of said tube units forming air passages between said tubes of said tube units, said air passages having an air inlet side and an air outlet side, adjacent upper and lower of the tube units being alternately arranged in relation to respective said refrigerant inlet and outlet sides, said spacer blocks defining refrigerant flow passages between said tubes of each said tube units and respectively between alternately arranged respective and said refrigerant inlet and outlet sides of said adjacent upper and lower of the tube units, the improvement wherein

• each of said at least one tube of a common of said tube units has said refrigerant inlet and outlet sides on common sides respectively and constitutes means for the refrigerant to flow therethrough in the same direction defining a single refrigerant tubular passage in said common tube unit,
• a single refrigerant inlet opening formed in a lower most of said plates in each of said tube units at said refrigerant inlet side and adjacent said air inlet side,
• at least one refrigerant outlet opening formed in an uppermost of said plates of said tube units, respectively, at the refrigerant outlet side of each said tube units,
• an elongated inside fin disposed in each said tube dividing said tube cross-sectionally in width into a plurality of elongated separated channels for guiding refrigerant flow from said refrigerant inlet side to the refrigerant outlet side, and
• said inside fin in the lowermost of said tubes is spaced from sad inlet opening and said refrigerant inlet side leaving a free space between said refrigerant inlet opening and said refrigerant inlet side, respectively, and said inside fin,
• at least one of said spacer blocks is formed with only one of said refrigerant flow passages extending substantially from said air inlet side to said air outlet side constituting means for spreading out and mixing the refrigerant flowing upwardly therethrough and for passing downwardly flowing portions of the refrigerant at said air outlet side, such that there is a refrigerant distribution with most of the refrigerant flowing in the tubes adjacent said air inlet side, with the gas phase primarily at said air outlet side and the liquid phase primarily at said air inlet side, and said inside fins maintaining said distribution in said tubes.