Another idea hardly feasible) — logbook Toyota Corolla 2003

A thermal accumulator for a car (it heats up from a warm engine) is kept warm, like in a thermos, and is then used to warm up a cold engine. Heat storage material (TAM) - Paraffin because. has a melting temperature of 40-60g. Thus, it stores more energy in the molten state. When hardened, it releases it into heat.