With the advent of the Heatgate, thermal fluids are affordably able to change pressure backwards and forwards, to facilitate Peer to Peer Pressure Heat Exchange both when they accept heat and when they reject heat. In initial design work, I have found my designs tending towards unlimited surface area, and ever thinner materials. Pressure equalization across the thin membranes is a design cinch, and a gas cooler is now a lightweight replaceable cassette.
Method, Maths, and pics attached.