A heat pump is a device that is used to transfer and transform thermal energy. The main purpose of installing a heat pump is to heat rooms and domestic water. In its essence, the principle of heat pumps is similar to well-known appliances such as a refrigerator or air conditioner. The difference is that a heat pump does not produce heat – it takes energy from the air, water or ground and transfers it to the room.
The principle of the heat pump
The main component of a heat pump is the compressor, which compresses the refrigerant to raise its pressure and temperature. As the refrigerant is compressed, its temperature and pressure rise rapidly, reaching 140°C and 40 bar respectively, so that the refrigerant is converted into hot steam. The compressed gas is then transferred to the condenser, where it transfers heat to the consumer. The consumer in this case can be the ambient air or the heat transfer medium (water or antifreeze), which distributes the energy throughout the heating system. In this process, the temperature of the gas naturally decreases and it changes back from a gaseous state to a liquid state.
The liquid refrigerant is then sent to the evaporator, which is fitted with a thermostatic expansion valve to reduce pressure and accurately dispense the amount of refrigerant entering the evaporator coil. As it passes through the evaporator channels, a phase change occurs due to the reduction in pressure and the refrigerant changes back to a gaseous state. This causes the entropy of the gas to decrease, resulting in a sharp drop in temperature and heat is extracted from the environment (street air, groundwater, rivers or lakes). The cooled Freon gas is then returned to the compressor and the process is repeated all over again.
The process of converting and transferring heat energy from the environment to the room requires electrical energy, the main consumer of which is the compressor. The conversion coefficient (COP), defined as the ratio of thermal output to electrical output – depends on the type of heat pump, its manufacturer and the operating conditions and can range from 2 to 6. It is worth noting that heat pumps are an ecological solution, as ozone-friendly refrigerants such as R410A, R407C and R32, which are not very harmful to the environment, are used for their operation.
To avoid making a mistake when choosing the right heat pump, it is important to turn to the experts. Kliwenta provides a service for selecting the right equipment, taking into account the characteristics of the room, such as its volume, purpose, location of windows and the required installation power. The type of heat pump is selected individually for each building.
Depending on the type of source from which heat is extracted, as well as the design and application, the following types of heat pumps are distinguished.
Air-to-air heat pump
This type of unit uses the outside air as an energy source to heat a space. The operation of the air-to-air heat pump is very similar to that of a split air-conditioning system, but has functional features that allow it to operate at low temperatures (down to -30°C) and extract energy from the environment. The space is heated by warm air, which is heated in the condenser of the heat pump. Most often, this type of system is not used as the main heating source, but only as a supplementary device for seasonal accommodation.
The main advantages of air-to-air heat pumps are their low cost and ease and speed of installation. This device works well at temperatures as low as -20°C, but it is worth noting that the efficiency of this type of heat pump decreases significantly at low temperatures. In addition, such a device is not capable of heating domestic water.
It is important to note that for an air-to-air heat pump, it is necessary to install an indoor unit in each room to be heated or to install an air duct system to bring heated air to all rooms.
Air-to-water heat pump
This type of unit works on a similar principle to the previous one, but instead of heating the room air directly, it heats a heating medium, which is then used to heat the house and provide hot water. Air-to-water heat pumps are popular because they have a high degree of reliability and durability throughout their service life. These units also boast high efficiency during the autumn and spring seasons.
An air-to-water heat pump is not able to operate properly at temperatures below -25°C. It is also worth bearing in mind that automatic defrosting of the outdoor unit is necessary during the winter period, which means that the conversion factor can drop to as low as 1.2 at low temperatures.
CSuch heat pumps are often installed in combination with additional heating appliances, such as an electric boiler or a fireplace with a water jacket. This combination of pumps and other equipment is also suitable for automating and refurbishing older boilers that run on traditional fuels. As a result, the system can operate automatically for most of the year, without the need to manually load solid fuel or top up diesel, using only the power of the pumps.
Kliwenta has been involved in heating, air-conditioning and ventilation systems for 10 years. A serious approach, the availability of all the necessary tools and a large team of diverse specialists allow us to provide the best quality service for the installation and servicing of heat pumps of various types. Trust the specialists and arrange a free quote for the installation of a heat pump in your property.
