Heat exchange coil

In an air heating or cooling apparatus, an evaporator comprising:

• a plurality of exteriorly-finless hollow refrigerant-carrying spirally-wound coils being of oblong shape in cross-section, said coils having a two-phase refrigerant fluid therein;
• and
• means for supporting said coils in spaced-apart relation and generally aligned in rows in annular-shaped stack thereof having a hollow interior for permitting the passage of an external flow of air across and between the rows of coils and through the stack interior;
• said oblong cross-sectional shape of said coils defining a pair of generally arcuate opposite side wall portions and a pair of vertically spaced generally planar opposite top and bottom wall portions extending between and interconnecting said arcuate side wall portions such that in an axial section taken through said coil stack said arcuate side wall portions of adjacent coils are disposed in facing relation and said planar wall portion of adjacent coils are disposed in spaced apart generally facing relation and define therebetween air flow channels, the arcuate side wall portions of adjacent said coils almost touching such that said air channels have generally laminar flow-generating characteristics for permitting flow of air through said channels at an improved rate with reduced turbulence.

In an air heating or cooling apparatus, the combination comprising:

• an evaporator core including a plurality of exteriorly-finless hollow spirally-wound refrigerant-carrying coils being of oblong shape in cross section, said coils having a two-phase refrigerant fluid therein, and means for supporting said coils in stacked spaced-apart relation and generally aligned in columns and rows to form an annular-shaped stack thereof having a hollow interior for permitting the passage of an external flow of air across and between air entry and exit sides of said coils and through said stack interior;
• and
• a motor-driven fan mounted to said coil-supporting means and aligned with said hollow interior of said coil stack for moving air through said stack interior, over said coils and through channels defined therebetween from said entry to exit sides of said coil stack,
• said oblong cross-sectional shape of said coils defining a pair of generally arcuate opposite side wall portions and a pair of vertically spaced generally planar opposite top and bottom wall portions extending between and interconnecting said arcuate side wall portions such that in an axial section taken through said coil stack said arcuate side wall portions of adjacent coils are disposed in facing relation, the arcuate side wall portions of adjacent said coils being in sufficiently close proximity that air flows through said channels in a laminar fashion at an improved rate with low turbulence, each of said channels having a radially inner opening communicating directly with the hollow interior and a radially outer opening communicating directly with the surrounding ambient.

An evaporator comprising:

• a plurality of exteriorly finless hollow coils of tubing having a two-phase refrigerant fluid therein, said tubing being of flattened oval shape in transverse cross-section having arcuate opposite side wall portions and vertically spaced top and bottom wall portions, said bottom wall portion being much flatter interiorly than said side wall portions so that refrigerant flowing through said tubing has increased surface area contact with said bottom wall portion;
• means for supporting said coils in spaced-apart stacked relation and generally aligned in rows such that adjacent coils in a row are arranged end-to-end;
• and
• means for causing air to flow through the stack of coils;
• said rows being spaced apart to form open air channels parallel to the direction of air flow through the stack of coils.