A heat exchanger including inlet and outlet header portions for a refrigerant
(such
as CO2), serpentine multiport tubes each with a plurality of aligned
tube runs, and at least three plate assembly fluid paths. Each plate assembly fluid
path includes a pair of spaced plates secured together at their edges to define
an enclosed space with a fluid inlet and fluid outlet on opposite sides of the
space. One plate of one fluid path is positioned against first aligned tube runs,
one plate of a second of the fluid paths is positioned against second aligned tube
runs, and a third fluid path is positioned between the first and second aligned
tube runs. The plates may be substantially identical to one another.
