How Does a Heat Pump Work?

How Does a Heat Pump Work?


The application of heat pumps is very extensive, but many people may not know about heat pumps. So let’s talk about what a heat pump is and how it works.

How Does a Heat Pump Work?
the nature and working principle of the heat pump
As one of the main equipment to provide heat, heat pumps have been widely used in many fields due to their environmental friendliness and energy saving. Then the following will specifically introduce the nature and working principle of the heat pump.

What is a heat pump?

A heat pump is a device that can provide heating, cooling, and hot water for residential, commercial, and industrial applications. Any heat pump installation can provide heating and cool in parallel. Depending on which service is used predominantly, the machine is called a heat pump, an air-conditioning unit, or a cooling/refrigeration machine. 

Working principle of heat pump 

Heat pumps transform system energy from the air, ground, and water to useful heat. This transformation is done via the refrigerant cycle.


A heat pump always has an outdoor heat source and an indoor outlet. Outdoor sources can be ambient air, exhaust air, ground rock, groundwater, water, etc. The energy from these sources is infinite and therefore renewable. This energy makes up about 75% of the energy that is used to drive the heat pump.

The fluid in the underground pipes absorbs the heat from the ground. The outdoor heat exchanger, the evaporator, uses the thermal energy from the outdoor source to boil the refrigerant (the liquid in the heat pump) and turns it into a gaseous state.

Key to understand this: The ground has a stable temperature of around 10-12°C throughout the year. This temperature is enough to heat the refrigerant because it has a very low boiling point. This means that it only needs a very low temperature to heat up.


Then, the refrigerant arrives at the heart of a heat pump: the compressor. The compressor compresses the refrigerant - which is in a gaseous state - to a high pressure, which leads to a rise in temperature.
To drive the compressor, additional energy is needed: from electricity, gas, or thermal energy. This makes up 25% of the total energy needed to run the heat pump. If green electricity is used - e.g. by means of photovoltaics - then a heat pump is using 100% renewables and therefore CO2 neutral.


On the discharge side of the compressor now hot and highly pressurized vapor passes through the second heat exchanger, called the condenser. This heat exchanger allows the refrigerant to release the heat into the heating system for the house (air blower, floor heating, or radiators), as a result of the refrigerant then condenses, i.e. the refrigerant moves from gaseous into the liquid state.
The indoor outlet can be an air system (as the typical air conditioner units) or a hydronic (water-based) system, where the heat pump is connected to a floor-heating system or radiators. For the provision of sanitary hot water, the indoor unit (also) exists of a hot water storage tank of which the content can go up to several hundred liters.


The condensed refrigerant then passes through a pressure-lowering device, the expansion valve. The now low-pressure liquid refrigerant then enters another heat exchanger, the evaporator, in which the fluid absorbs heat and boils. From thereon the cycle starts again.

There may be some parts in the working principle of the heat pump that is mo complicated and difficult to understand. If you do not understand something during the reading process, you can also contact us for more detailed information and solutions, and we also produce high-quality Heat pump products.

As a professional heat pump manufacturer, Suoher has more than 20 years of rich experience in the field of R&D and the manufacturing of heat pump equipment. We not only have a strict quality control system but also provide customers with professional all-around services. If you want to buy our high-quality heat pumps and get related solutions, please contact us immediately!