Just like the heat pumps don't workup north. They F\ing freze up. A reverse cycle has the Reverse cycle. The hot air gas freezes up. Actually we don't have them, smart people, don't have heat pumps down south, stupid. Some times, like last night, got to 48 degrees and cold enough to freeze the pipes. Weird, but it does. Battery packed autos are the 1st to freeze. Hit emergancy heat to thaw. I have worked on chillers that use waste heat to produce chill water. One end of the so called chiller is 28 degrees [F] and the other end 1,200 degrees. Called an absorbtion chiller running off chroium bromide, salt water, used by sea world and the likes, productions very low humidity, very low. Likes vitamine suppliers where their is 15% RH and makes your nose bleed. Have worked in M & M Mars plants that use em to keep the chocolate from melting. Poor Tesla.