How does the space stations cooling system work?
The space station’s Active Thermal Control System (ATCS) has internal and external components that are designed to maintain specific temperatures aboard the station. The system uses mechanically pumped fluid in closed-loop circuits that control heat collection, heat transportation and heat rejection. Energy from the station’s solar arrays powers the electronics and various other systems. The process creates excess heat that must be removed. Cold plates and heat exchangers, which are cooled by the circulating water loop, help regulate the spacecraft’s internal atmosphere. This liquid heat-exchange system removes the excess heat, and the energy is then sent to radiators that eject the heat into space. Before this can happen, the waste heat must be exchanged a second time through the loop that contains liquid ammonia (rather than water, which would freeze if circulated in pipes outside of the station). Ammonia freezes at minus 107 degrees Fahrenheit (minus 77 degrees Celsius) at standard
