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All about heat pumps

In recent years, heat pumps have become a very popular method of heating. The reasons are clear: it is an ecological and, in the long term, also financially economical solution. Heat pumps have minimal electricity consumption and low operating costs. What are the types of heat pumps and how to choose a suitable one?

Principle of operation

Heat pumps work on a very simple principle - they transfer thermal energy from the environment, most often from the air, but also from the ground or water. There is always enough heat energy in the environment even if the outdoor temperatures fall well below the freezing point.

During heat production by means of a heat pump, there is no interference with nature or combustion. It is therefore without a doubt the most environmentally friendly heating solution, which only needs a minimum of electrical energy needed to operate the pump. The heat itself is completely free.

Coefficient of performance of a heat pump

This coefficient is the most important factor of a heat pump, which basically says how efficient the pump is. It is calculated as the ratio between the heat produced and the electricity consumed. Therefore, the higher the coefficient, the more economical the operation of the heat pump.

It differs mainly according to the source of thermal energy. The highest and most stable is in a ground / water heat pump, which has a coefficient of around 5 even when freezing. The air / water heat pump's coefficient fluctuates during the year, (at -15 °C the coefficient is about 2).

Types of heat pumps

For greater clarity, heat pumps are marked by a combination of two words, where the first indicates a source of energy and the second (after the slash) indicates a transfer medium. The main types include:

Air/water heat pumps

Air/water heat pumps are the most common in many countries and are suitable for new buildings as well as for well-renovated buildings, underfloor heating and radiators. These pumps take heat energy from air outside and heat the water in the heating system.

Heat is taken through the heat pump evaporator, through which outside air flows. To achieve high heating output even at relatively low outdoor temperatures, gradual injection of steam helps significantly. Even at outdoor temperatures around -20 °C, this system reaches inlet temperatures around 60 °C, which ensures efficient heating. The lower the required heating inlet temperature, the higher the efficiency of the heat pump, of course.

Some main advantages of an air/water heat pump are relatively low purchasing costs and easy installation compared to other types of pumps. The disadvantage is the coefficient of performance, which is lower at very low temperatures.

Ground/water heat pumps

In the case of ground/water pumps, heat from the ground is transferred by the circulating antifreeze fluid. In the gaseous state, it removes heat from the pipeline, which is stored in the borehole. To achieve a high temperature a compressor included in the circuit is used. Several boreholes can be used when higher power is required. Thanks to modern design and technology, high efficiency is achieved, the limit of the coefficent of performance reaches the value of 5.

The system usually also includes expansion pressure vessels for antifreeze and for heating, as well as high-performance circulators used to operate the heating and antifreeze circuits.

The main advantage of this type of heat pump is the high and stable coefficient of performance even at freezing temperatures, and thus lower operating costs. The disadvantage is a more demanding and expensive installation with the need to place collectors in boreholes or under the ground.

Uncommon types of heat pumps

These are for example water / water pumps. However, their possibility of use in the Czech Republic are limited. Water / water heat pumps draw heat energy from large volumes of groundwater, which are in short supply in the Czech Republic. Another option is to pump thermal energy from water bodies, which is possible only if a suitable water surface is located in the immediate vicinity of the property. In addition, you would need the approval of the water administrator for this solution. In addition, regular and relatively demanding maintenance is required for water / water heat pumps.

Thermal energy can also be drawn from the surface soil in your garden. These ground / water heat pumps need a large area for collectors. However, the land used in this way has limited possibilities for further use - ie this area cannot be used for buildings or agriculturally cultivated.

Air/air heat pumps cannot be connected to a heating system or a DHW heating system, as they work similarly to direct heaters - ie they convert heat energy from the outside air into warm indoor air. It is not possible to heat a larger number of rooms in this way, but these pumps can be used, for example, in smaller recreational facilities.

Heat pumps for DHW and cooling

Heat pumps can be used not only for heating, but can also ve connected to the domestic hot water (DHW) and cooling system of the building. The use of a heat pump can thus be truly universal and will help reduce the cost of running a household.

Heat pumps with an extended heating function are used to heat DHW, where part of the thermal energy is used for this purpose. The circuit then includes a hot water tank, which can be easily connected and achieves excellent efficiency thanks to thorough thermal insulation. Thanks to this, energy consumption costs can be significantly reduced by up to 50%.

You can also use a heat pump to cool a building. With this function, you get low-energy air conditioning, which is also completely environmentally friendly. Operating costs are fractional compared to conventional air conditioning.

Accessories for heat pumps

To take full advantage of all functions of a heat pump, purchase additional equipment for it that affects the efficiency of the entire heating system. A good designer should design a comprehensive heating, air conditioning and DHW heating system considering your requirements.

An integral part of the heating is the circulation pump, which distributes the heat transfer medium to the heating system, ie to the radiators or underfloor heating. The circulation pump thus significantly increases the efficiency of the heating system and thermal comfort, and in addition reduces heating costs.

For proper regulation and optimization of the heating system, we recommend choosing quality control units, controllers and smart apps. You can then control your heat pump from your phone and switch on the heating, for example, an hour before arriving home.

A heat pump for DHW heating requires a sufficiently large storage tank. With the help of a cooling module, your heat pump will gain the ability to cool the building on summer days. Invest in a backup power supply, which ensures continuous operation of the pump even in the event of a power failure.