Multilayer sheets for heat exchangers

An air thermal conditioning system for at least one of heating air and cooling air, the air thermal conditioning system comprising:

• a cross-flow heat exchanger array that includes:
• a housing;
• a plurality of at least 25 stacked planar membrane heat exchanger units disposed in parallel and held in tension by the housing via respective opposing top and bottom ends of the respective planar membrane heat exchanger units, the planar membrane heat exchanger units stacked in parallel with a space separating each of the planar membrane heat exchanger units, with each of the planar membrane heat exchanger units comprising:
• at least one fluid chamber defined by first and second planar multilayer polymer sheets and a welded seam, with the at least one fluid chamber extending between the opposing top and bottom ends and opening to a first and second port defined by the first and second planar multilayer polymer sheets at the top and bottom ends respectively;
• and
• the first and second planar multilayer polymer sheets having a thickness between 80 and 110 μm, and each comprising:
• an inner layer directly defining and facing the at least one fluid chamber, the inner layer having a thickness between 50 and 90 μm and consisting essentially of one of:
• polypropylene, cast un-oriented polypropylene (CPP), polyethylene, polyethylene terephthalate (PET), a fluoropolymer, a polyimide, or a polyamide;
• a middle layer consisting essentially of a material with a lower permeability and a higher melting point than the inner layer, the middle layer having a thickness between 8 and 10 μm and consisting of aluminum, silicon oxide, or aluminum oxide;
• and
• an outer layer that defines external opposing faces of the planar membrane heat exchanger unit that has a thickness between 10 and 20 μm and consists essentially of one of biaxially-oriented polyethylene terephthalate (BOPET) or biaxially oriented polypropylene, the middle layer disposed between the inner layer and outer layer and coupled together to define a unitary planar multilayer polymer sheet without cavities, gaps or un-joined portions between layers;
• and
• a first and second fluid conduit respectively disposed at and communicating with the first and second ports of the planar membrane heat exchanger units, the first and second fluid conduits fluidically coupling the plurality of planar membrane heat exchanger units and configured to generate a fluid flow within the fluid chambers of the plurality of planar membrane heat exchanger units, the fluid flow:
• flowing into the first fluid conduit,
• flowing between the top and bottom ends within the respective chambers, and
• flowing out the second fluid conduit, with fluid flowing in and out of the first and second fluid conduits respectively on the same side of the cross-flow heat exchanger array.