I'm not quite sure what you mean your first question, but I think heat pumps using air, ground or water as heat reservoirs would qualify. They are in common hou

I'm not quite sure what you mean your first question, but I think heat pumps using air, ground or water as heat reservoirs would qualify. They are in common household use at least where I am located, and have a input-power-to-heat efficiency of up to 400% (the Carnot cycle imposes a limit of roughly 7-10x depending on which exact scenario you calculate) Here's an example of one manufacturer and products: http://www.nibe.eu/Domestic-heatingcooling/Airwater-heat-pumps/ http://www.nibe.eu/Domestic-heatingcooling/Airwater-heat-pum...