Heat pumps

Heat pumps use the free available environmental heat to guarantee the heat supply of single, double, or multi-family houses. This one of the most economical, effective and at the same time environmentally friendly ways to ensure the hot water and heating comfort.

Heat pumps gain natural energy from the ground, the ground water or the air and make significant savings in heating costs while doing so. They produce no emissions and operate efficiently even at low ambient temperatures. Heat pumps take up to 75 per cent of the required energy from the environment. Only 25 per cent of the energy has to be added in the form of electricity. This energy provides the power to operate the heat pump. Heat pumps are particularly suitable for use with underfloor heating and radiators with low surface temperatures. Due to technical limitations the efficiency of heat pumps falls sharply at temperatures above 67 °C.

The advantages of a heat pump system from Vaillant:

  • The utilisation of natural, inexhaustible energy sources
  • Emission-free
  • Efficient: up to 75 per cent of the energy comes from the environment, only 25 per cent must be added in the form of electricity
  • Can be used for cooling in summer
  • Simple high-value technology with low maintenance and a long service life

How a heat pump works

The technology of heat pump works on the reverse principle of the refrigerator. While a refrigerator transfers heat from inside to the outside, the heat pump extracts the heat from its environment and passes it on. The heat of the groundwater, the ground or the atmosphere is absorbed by a refrigerant and used to supply heat after compression.

Overall, the heat pump goes through a cycle of four steps: evaporation, compression, liquefaction and relaxation.

1. In the first step the refrigerant absorbs the heat energy of the environment due to the low temperature of the refrigerant in the heat pump. In doing so, it changes to a gaseous state because of the low evaporation temperature of the refrigerant.

2. The resulting vapour is compressed using a compressor. The molecules of the gas rub against each other more as a result of the increased pressure in a confined space. This produces higher temperatures which are used for the heating circuit.

3. In the third step, the hot gas gives up its heat to the heating system. The refrigerant becomes liquid again.

4. Finally, an expansion valve reduces the pressure generated in step 2, so that the refrigerant re-absorbs ambient heat and the process can start again.

Vaillant heat pumps may also be used to cool the house during the summer months. In case of brine/water systems, heat is extracted from the living space via the underfloor heating system and then discharged via the collector into the ground.

Depending on the intensity of the required cooling performance and the existing supply system, active or passive cooling will be suitable.

Active cooling

With the active reversal of the heating circuit the heat pump may be used as a cooling module in summer. The heat extracted from the heating system is then actively transferred to the heat source – e.g. the ground, by means of the compressor.

The former liquefier works as an evaporator in cooling. It transfers the room heat to the coolant. The gaseous coolant is then led into the condenser and from there to the heat exchanger which releases the heat extracted from the rooms to the ground.

Passive cooling

If during the summer months the room temperatures exceed the temperatures of the energy source, the heat pumps may as well operate as "natural cooling". It is quite easy to realise this function from the technical point of view.

With "natural cooling" the primary circuit pump is switched on while the condenser is not operated. The heat transfer medium, e.g. the brine, is transported to the heat exchanger. There, it gets into contact with the heating water which is at room temperature, it has been transported there by the heating circuit pumps. Temperatures of these 2 fluids are brought to the same level now. The cooled down heating water then circulates in the heating system extracting heat from the rooms.

Passive saves electric power - active is more efficient

Both methods, the active as well as the passive method, allow for the production of domestic hot water. Passive cooling is extremely energy saving due to the low power consumption only required for the circulators. However, there are some cut-backs regarding performance and efficiency in case of the passive method. Especially at the end of the summer the ground has normally stored a large quantity of heat. As a result, the cooling output of this exchanger medium will decrease.

A cooling function is available for some of our heat pumps.

Air/water heat pumps

Instead of a ground probe, a well, or a plot of land, air/water heat pumps only require one installation location for the outdoor unit. An air/water heat pump is designed either as a single block with only one outdoor unit or as a multi-block system. A multi-block system consists of an outdoor and an indoor unit.

Air/water heat pumps don’t require retrofitting or separate areas. They are therefore ideally suited for modernising existing heating installations and properties with hard to access land. Systems with air/water heat pumps can be expanded easily, for example, with solar panels and condensing boilers. Air/water heat pumps are the cheapest option to purchase, but their power output is comparably low.

Brine/water heat pumps

Surface collectors or geothermal probes of up to 100 metres deep can be used depending on the space available and the nature of the ground. Deep drilling is necessary for the installation of a geothermal probe. In both cases, frost protected brine is used as a heat transfer medium. An appropriately equipped heat pump can also be used in summer for cooling rooms.

Water/water heat pumps

A water/water heat pump uses the energy of the groundwater.

A suction unit pumps groundwater to a heat pump from an extraction well. The heat of the groundwater is used to heat the building and domestic hot water. The cooled groundwater passes through the absorption wells back into the natural cycle. In general, already existing wells can be used for this heat pump system.

Drilling is not necessary for the installation of an extraction and absorption well. However, the quantity and quality of groundwater must be checked. Water/water heat pumps work very efficiently due to the high average temperature of groundwater of about 10 °C all year round. An appropriately equipped heat pump can also be used in summer for cooling rooms.