An Air Supply Heat Pump is a relatively straightforward unit, that works on the same basic principle to be a fridge BUT IN REVERSE. What this means will be the air from outside is sucked into a device and is blown over multiple tubes which are stuffed with a refrigerant. https://commercial-electricians-e79135.bloggerswise.com/41179912/heat-pumps-essex-things-to-know-before-you-buy