South Korean scientists built an air source heat pump integrated with a photovoltaic thermal unit that can reportedly achieve an average heating and cooling coefficient of performance (COP ...

Help is at hand though courtesy of [petey53], who made his own ground source heat pump for his Toronto house using a pair of window-mounted air conditioning units. A custom copper “trombone ...

The device’s polymer films expand and contract like an accordion to pump heat away from a source, cooling it by about 16 degrees Fahrenheit.