They extract heat from the outside air, even in cold temperature. They function by absorbing heat from the skin air using a refrigerant, which then evaporates at a very low temperature. Numerous highly economical industrial vegetation with cogeneration or mixed cycle units make use of a gas-turbine (effectively a jet https://high-temperature-heat-pum88653.blogpixi.com/31585950/getting-my-industrial-heat-pumps-to-work