Hello, I would like to open an old topic again, because I am convinced of the principle itself. Our cars (especially the petrol engines) consume a lot of fuel with a cold engine. The idea of a heat storage tank is still attractive: – You store the heat in a medium and retrieve it the next cold morning. In the past a salt was probably used, which destroyed the engine. This is probably not done now. Nevertheless, it is quiet about the topic. The car manufacturers are also researching the topic because, unlike the heater, no additional energy is consumed. Nevertheless, I wanted to ask you if you know SERIÖSE companies that offer such a system…