In recent years, heat pumps have become a very popular heating method, used in almost every tenth new building in the Czech Republic. The reasons are clear: it is an ecological and, in the long term, financially economical solution. Heat pumps have minimal electricity consumption and low operating costs. What are the types of heat pumps and how to choose one?
Heat pumps operate on a very simple principle – they extract thermal energy from the surrounding environment, most commonly from the air, but also from the ground or water. There is plenty of thermal energy in the environment even when outdoor temperatures drop well below freezing.
When generating heat using a heat pump, there is no interference with nature or combustion. Therefore, it is undoubtedly the most ecological heating solution, requiring only a minimal amount of electricity to operate the pump. The heat itself is completely free.
The coefficient of performance is the most important parameter of a heat pump, essentially indicating how efficient the pump is. It is calculated as the ratio between the heat produced and the electricity consumed. The higher the coefficient of performance, the more economical the operation of the heat pump.
The coefficient of performance varies mainly according to the source of thermal energy. The highest and most stable is in the case of a ground/water heat pump, which has a coefficient of performance around 5 even in freezing conditions. The coefficient of performance of an air/water heat pump fluctuates throughout the year, and in freezing conditions, the difference compared to ground/water pumps is significant (at -15 °C, the coefficient of performance is approximately 2).
For better clarity, heat pumps are designated by a combination of two words, where the first always indicates the source of the extracted energy and the second (after the slash) indicates the heat transfer medium. The main types include:
Air/water heat pumps are the most common in the Czech Republic and are suitable for new buildings as well as well-renovated properties, for underfloor heating and radiators. These pumps extract thermal energy from the outdoor air and heat the water in the heating system.
Heat is extracted through the evaporator of the heat pump, through which outdoor air flows. To achieve high heating performance even at relatively low outdoor temperatures, gradual steam injection significantly helps. Even at outdoor temperatures around -20 °C, this system achieves inlet temperatures of about 60 °C, ensuring the necessary input value for efficient heating. The lower the required inlet temperature for heating, the higher the efficiency of the heat pump.
The main advantages of an air/water heat pump include relatively low purchase costs and easy installation compared to other types of pumps. The disadvantage is the coefficient of performance, which is lower at very low temperatures.
In the case of ground/water pumps, heat is transferred from the ground by circulating antifreeze fluid. In its gaseous state, it absorbs heat in the piping, which is placed in a borehole. A compressor included in the circuit is used to achieve high temperatures. For higher performance needs, several boreholes are used. Thanks to modern design and technology, this system achieves high efficiency, with the coefficient of performance reaching up to 5.
The system typically includes expansion pressure vessels for the antifreeze mixture and heating, as well as high-performance circulation pumps for operating the heating circuit and the antifreeze mixture circuit.
The main advantage of this type of heat pump is a high and stable coefficient of performance even in freezing conditions, resulting in lower operating costs. The disadvantage is the more demanding and costly installation, requiring the placement of collectors in boreholes or below the ground surface.
For completeness, we also mention water/water pumps. Their use in the Czech Republic is limited. Water/water heat pumps extract thermal energy from large volumes of groundwater, which are scarce in the Czech Republic. Another option is to extract thermal energy from water bodies, which is only possible if a suitable water body is located in close proximity to the property. Additionally, you would need the consent of the water body manager for this solution. Water/water heat pumps also require regular and relatively demanding maintenance.
Thermal energy can also be extracted from the surface soil in the garden. These ground/water heat pumps require a large area where the collectors are placed. However, the land used in this way has limited possibilities for further use – i.e., this area cannot be built on or agriculturally cultivated.
Air/air heat pumps cannot be connected to a heating system or a hot water system, as they function similarly to direct heaters – converting thermal energy from outdoor air into warm indoor air. This method cannot heat a large number of rooms, but these pumps can be used in smaller recreational properties, for example.
A heat pump can be used not only for heating but can also be integrated into a system for domestic hot water (DHW) preparation and building cooling. The use of a heat pump can thus be truly versatile and help reduce household operating costs.
For DHW preparation, heat pumps with extended heating functions are used, where part of the thermal energy is used for this purpose. The circuit also includes a hot water tank, which can be easily connected and, thanks to thorough thermal insulation, achieves excellent efficiency. This can significantly reduce energy consumption costs by up to 50%.
You can also use a heat pump for building cooling. With this function, you get a low-energy air conditioning system that is also completely ecological. Operating costs are a fraction compared to traditional air conditioning.
To fully utilize all the functions of a heat pump, purchase additional equipment that affects the efficiency of the entire heating system. A good designer should propose a comprehensive system of heating, air conditioning, and DHW heating based on your requirements.
An integral part of heating is the circulation pump, which distributes the heat transfer medium into the heating system, i.e., into radiators or underfloor heating. The circulation pump significantly increases the efficiency of the heating system and thermal comfort, and also reduces heating costs.
For proper regulation and optimization of the heating system, we recommend selecting quality control units, regulators, and smart applications. You can then control the heat pump from your phone and, for example, turn on the heating an hour before arriving home.
When using a heat pump for DHW heating, don't forget a sufficiently large tank. With a cooling module, your heat pump gains the ability to cool the building on summer days. A suitable accessory is also a backup power source, which ensures the continuous operation of the pump even in the event of a power outage.