Condenser heat exchanger

A method for preventing ice formation in a condenser heat exchanger, comprising:

• providing a plurality of heat transfer elements defining cold fluid flow paths with inlet and outlet ends for flow therethrough of a relatively cold fluid in a first direction;
• providing a plurality of heat transfer elements defining hot fluid flow paths with inlet and outlet ends for flow therethrough of a relatively hot fluid, each said hot fluid flow path comprising a first portion, called an inlet portion, which flows in a first non-parallel direction with respect to said first direction, a second portion, called a parallel-flow portion, which flows substantially in said first direction parallel to said cold fluid flow paths;
• and a third portion, called an exit portion, which flows in a second non-parallel direction with respect to said first direction, wherein said inlet portion, said parallel-flow portion, and said exit portion each have a length, wherein the total length of the hot fluid flow path equals the sum of the lengths of said inlet portion, said parallel-flow portion, and said exit portion;
• arranging said hot fluid flow paths side by side from a region near said cold fluid flow path inlet end to a region near said cold fluid flow path outlet end, wherein the total lengths of each of the hot fluid flow paths are generally equal, wherein the lengths of the parallel-flow portions of the hot fluid flow paths are generally equal and the lengths of the inlet portions gradually decrease in said first direction, the length of the inlet portion closest to said cold fluid flow path inlet end being the longest length of the inlet portion, and the lengths of the exit portions gradually increase in said first direction, the length of the exit portion closest to said cold fluid flow path outlet end being, the longest length of the exit portion, and wherein said plurality of heat transfer elements comprise a plurality of finned passageways, and wherein fins in said exit portions are spaced closer together than fins in said inlet portions;
• and
• preventing ice formation due to freezing of at least one component of either of said relatively hot fluid and said relatively cold fluid, by maintaining a thermal resistance between said heat transfer elements and said flow of said fluids therethrough, and maintaining a temperature difference between said hot and said cold fluid flow paths over a portion of said heat exchanger.