How is a space suit climate controlled?

Question

I understand how one could be heated, but how does the space suit cool the water that is noodled throughout it exchanging heat with the body? Why is this method used over traditional methods like a heat pump?

Answer 1

Apollo EVA suits and the shuttle/International Space Station Extravehicular Mobility Units (suits) use(d) a sublimator for heat rejection. This device is a sort of heat exchanger that the suit's water cooling loop passes through. Water from storage tanks — a consumable — is supplied to the sublimator and becomes ice in the low ambient pressure environment. This ice then transforms directly to water vapor — "sublimes" — and is vented to space, carrying heat with it.

As the reference puts it:

However, the primary purpose of the water tanks is to feed water to the sublimator. The sublimator works on the principle of sublimation, that is, the process by which a solid turns directly into a vapor, bypassing the liquid phase. In this case, ice is formed on the sublimator evaporator sieve and is allowed to vaporize to space, removing heat with it. Air and cooling water are passed through fins in the sublimator, which extracts heat from each system.

Source

I could not find a picture of the shuttle sublimator, but here is a drawing showing the Apollo one. From here