Surface area versus enclosed volume plays a role in what form thermal management takes. The gold foil encasing space vehicles is a radiant barrier to block absorption of heat from the sun. The spacecraft were also engineered for a certain heat load which included dissipation from electrical equipment operating within the craft. And the ship was designed with an electrical heating system, as the engineering decisions were biased for the natural equilibrium to be on the cooler side.
The cold was bad enough; but, the crew’s source of water was the waste stream of the fuel cells-—hydrogen combined with oxygen results in electricity and water. The crew was sufficiently short of water to affect how much they could consume of food, thus less calories to burn fighting off the cold. Fat calories are more easily burned from exercise but little option for movement is available in the cramped spaces.
Under normal conditions they used refrigeration units, hooked to a pair of deployed CM radiators, I believe. The gold foil would just make the internal heating worse. The problem is getting rid of the internal body-generated heat, not solar heating, although that adds to it. As I said, ISS runs huge heat radiators. It's a known issue.