They extract heat from the outside air, even in cold climate. They operate by absorbing heat from the skin air employing a refrigerant, which then evaporates in a small temperature. Help or Disable Cookies For those who disable this cookie, we will not be able to help save your preferences. https://wasteheatrecovery21964.theisblog.com/31509134/the-smart-trick-of-waste-heat-recovery-that-nobody-is-discussing