FlexoCOMPACT exclusive heat pump

Selection of the heat pump. Learn the principles of operation of various types of devices for heating rooms and water

Selection of the heat pump

The right selection of a heat pump allows you to collect energy from the natural environment – water, air or soil in an ecological and economical way. Pump selection is largely analogous to the boiler selection (this applies to the thermal calculations of the building carried out at the beginning). However, the specificity of heat pumps requires several additional actions. Find out which heat pump will generate the optimal amount of energy and will significantly reduce bills in your home.

Vaillant_pump heat pump flexoCOMPACT exclusive
FlexoCOMPACT exclusive heat pump

From the text you will learn:

  • how does the age and condition of the building affect the selection of the heat pump,
  • what is the operating principle of the heat pump,
  • which pump to choose because of its heat source,
  • what are the benefits of choosing an air-to-water heat pump
  • what is the Split technology,
  • to control the heat pump as conveniently as possible.

Home and water heating have a significant impact on the operating costs of a building. This is particularly noticeable in the winter season because negative temperatures force more intensive consumption of thermal energy.

So if you care about lower bills, invest in solutions that will relieve the budget and at the same time ensure comfortable thermal conditions at home. Check what the right selection of a heat pump is – ground, water or air.

Selection of a heat pump due to the condition and age of the building

One of the factors to consider when choosing a heat pump is the condition of the building.

  • Selection of a heat pump for a new home

For new buildings, choosing a heat pump reduces investment costs. First of all, the construction of a gas connection and a flue can be avoided – thanks to this, the investment costs can be comparable to the costs of building a heating system with a boiler.

The heat pump has no special requirements for the built-in room. It may have a small volume, which should only depend on the type and amount of refrigerant.

New buildings must be built according to current standards (e.g. WT 2017 or even WT 2021). Due to the low thermal needs and low consumption of so-called primary energy (requirement according to WT 2017 and WT 2021) the selection of a heat pump is justified. It is also worth using underfloor heating, which can cover 100% of the building’s thermal needs – the low temperature of the heating water will definitely increase the energy efficiency of the heat pump. Thermal comfort will also be obtained at lower indoor air temperature.

  • Selection of a heat pump for an existing home

The use of a heat pump in an existing home is a common practice (especially in the absence of access to the gas network). The main difference here will be checking whether the heat pump will be able to cover the thermal needs of the building by itself. If the term modernization of the house was not very advanced, it is worth using the so-called hybrid heating system. This requires leaving a new boiler, which for functional reasons should work automatically – i.e. a boiler for gaseous, liquid fuels or possibly for pallets (wood pellets).

In existing buildings, there is usually traditional radiator heating. This does not prevent the use of a heat pump, especially if the house has undergone thermal modernization. Reducing heating needs allows you to reduce the temperature of heating water and the thermal efficiency of radiators. Lower radiator flow temperature (e.g. up to 55 ° C) will increase the heat pump’s operating time during the heating season. In this case, support from an additional heat source is usually needed (for 5-20% of the heating season).

Selection of a heat pump and its operating principle

Regardless of which heat pump you choose, the principle of operation will always be the same. The purpose of this device is to obtain heat from renewable energy sources that will be used to heat rooms or water in the home.

The heat pump operation consists of three stages called cycles.

Circuit 1. Circulation: heat consumption from the environment – An antifreeze liquid in the heat pump piping system that always has a lower temperature than the environment even at minus temperatures. The liquid draws heat from the lower source – soil, air and water – which is possible due to temperature differences between the liquid and the environment.

2nd circuit: raising the temperature – a warm liquid heats the refrigerant, which is able to boil even at very low temperatures. The temperature of the refrigerant begins to rise, which turns the liquid into gas. The produced gas then goes to the compressor, whereby increasing pressure it gains an even higher temperature.

3. circuit: use of heat – the gas obtained from the refrigerant heats the water in the heating system while reducing its temperature and turns into liquid. Finally, it goes to the expansion valve, where it loses high pressure and cools down even more. In this way, the heat pump can again take heat energy from the surroundings.

Learn the principles of how a heat pump works .

Pump selection due to heat source

The type of heat pump depends on its energy source. The following pumps are mainly available on the Polish market:

  • air,
  • Water,
  • ground.
Air heat pump Water heat pump Ground source heat pump
Energy carrier outside air water from reservoirs around the plot or deep wells geothermal energy
Temperature range from + 40 ° C to -25 ° C (for outside air temperature) from + 7 ° C to + 12 ° C
(for groundwater temperature)
without limits
COP indicator even about 5 (aroTHERM Split) approx. 5.03 up to 5.03
(flexoTHERM exclusive)
Requirements none, unless the plot is in a protected area geological works design and water law permit (if the excavation exceeds 30 m depth) geological works project, if the plot is located in mining areas or if excavations are to be above 30 m deep
Vaillant_ aroTHERM VWL air-to-water heat pump
AroTHERM VWL air-to-water heat pump

There are also devices that can use all types of sources. Pumps with the option of selecting a heat source allow a significant part of the energy needed to heat the building and water to be obtained. All types of pumps also have the function of active room cooling, so they can replace air conditioners in the summer. Unlike air conditioners, heat pumps reduce the temperature evenly throughout the home. This effect is possible by connecting them to surface heating, e.g. underfloor heating.

Heat pumps with the possibility of choosing a heat source (e.g. flexoTHERM exclusive or flexoCOMPACT exclusive ) are in their basic version brine-water pumps and therefore intended for drawing renewable energy from the ground. However, thanks to additional modules, they can be easily adapted to use other sources: air, surface and groundwater.

Selection of the air-water heat pump. Is it worth investing in it?

The choice of the air-water heat pump guarantees high energy efficiency because they use generally available energy obtained from the ambient temperature (up to even -20 ° C). Thanks to this, they save up to 75% of heat energy costs. They also significantly reduce the emission of harmful substances and carbon dioxide to the environment. The efficiency class of these devices is A ++ or A +++ (in heating mode).

The type of regulator is also important here. It is advisable that in addition to weather work, it allows you to regulate the efficiency of the heating system in several areas of the building. Then, in the total calculated efficiency of the heat pump, the so-called additional bonus (up to 5%). This often allows the heat pump to switch from A ++ to the highest A +++.

See if it pays to heat your home and air with a heat pump.

The selection of an air-water heat pump works even in moderate climates – provided that these are devices from a proven and reliable manufacturer who is able to adapt their technological solutions to the prevailing conditions. Vaillant air heat pumps undergo a series of tests that confirm that they work with very high efficiency both during hot summer and cold winter when the temperature drops even to -20 ° C.

See how air heat pumps work .

A very important advantage of an air source heat pump is its economy. These types of devices belong to one of the cheapest ecological heating systems. Before installing the device, you do not need to build a system for the lower heat source, and the entire process of mounting the pump takes an average of 1-2 days. Thanks to this, an air heat pump can be chosen by the owners:

  • a house on a small plot,
  • finished garden, which they do not want to destroy with earthworks,
  • plots in dense urban buildings,
  • an existing home where the heating system is being modernized.

Installation of an air-water heat pump does not require much interference in the building structure itself. However, it is worth remembering that the greatest benefits of a heat pump can be obtained when the installation of the device is included in the building design.

See why air heat pumps are becoming more and more popular.

A new generation of air heat pumps in Split technology

Air-source heat pumps will work in small houses inhabited by two or three people, as well as in large buildings. The device that is worth installing, especially in smaller homes, is the Vaillant aroTHERM Split heat pump. Its basic module is mounted outside – directly against the building wall, on the terrace or in the garden. Inside the house, central heating installation or only a small hydraulic module hanging on the wall, a multiMATIC VRC 700 system controller and a hot water tank are installed.

An important advantage of heat pumps made in Split technology is their very quiet operation. Outdoor units of aroTHERM Split pumps emit only 32 dB (A) of noise (at a distance of 3 m), making them one of the quietest devices of this type on the market . This is due to the vibration dampers used, compressor insulation, housing insulation and top sound insulation. If you want to see how Split heat pumps from Vaillant work, turn on the SoundBox. You will see for yourself that the sounds produced by the device will not disturb your everyday functioning.

Split heat pumps are also very easy and quick to install. Thanks to this, the cost of installing the entire system is quite low. The possibility of placing the outdoor and indoor unit at a distance of up to 25 m from each other allows for any arrangement of the installation on the plot.

Selecting a heat pump for the surface of the house. What to look for when choosing a heat pump?

The type of heat pump is very important, but it’s not the only thing that affects its efficiency. To make sure that the pump will best fulfil its task, it is also important to select a heat pump for the surface of the house and the related efficiency and power of the device.

  • Heat pump power

The pump power should be adjusted to the building’s thermal parameters and the amount of hot water consumed. If the house has a small area, good insulation and a maximum of three people live in it, it is best to choose a pump with a heating power of 3.6–5.3 kW. An 8-10 kW pump can be used to heat air and water in larger homes, and above 11 kW in multi-family buildings or businesses.

  • Heat pump efficiency

Before buying a heat pump, it is also worth paying attention to the COP indicator. It determines the efficiency of the pump, i.e. its degree of obtaining heat from the environment in relation to the electricity it consumes. However, it should be remembered that the COP indicator is a variable value and depends on the temperature of the upper and lower source. The devices that are part of the pump system also affect the height of the COP – including a compressor and expansion valve.

What is the most convenient way to operate a heat pump? Choose modern solutions

Vaillant_multiMATIC VRC 700 and multiMATIC App
MultiMATIC VRC 700 weather compensator and the multiMATIC App

Modern heat pumps can be equipped with an intelligent control system. Vaillant devices can, for example, be connected to the multiMATIC weather regulator and internet communication module. Thanks to this, the heat pump can be controlled even via a smartphone. One application is enough to remotely start and stop the pump or change its settings. This function is especially useful when you are away from home for a long time and want to start heating the building the day before you return.