Heat pump is an efficient and energy-saving device that makes full use of low-grade heat energy. Heat can spontaneously transfer from a high-temperature object to a low-temperature object, but not in the opposite direction. The working principle of a heat pump is a mechanical device that forces heat to flow from low-temperature objects to high-temperature objects in a reverse cycle. It only consumes a small amount of reverse cycle net work to obtain a larger heat supply, and can effectively convert low-grade materials that are difficult to apply. Heat energy is utilized to achieve energy saving purposes.