Heat Pumps

Solution advantages

  • Using renewable heat from the surroundings
  • Can be used both for space heating and cooling
  • Highly energy efficient
  • Diverse heat pump technologies suitable for a great variety of building contexts
  • Can be practically emission-free if driven from electricity produced from renewable energy sources (wind power or photovoltaics)


A heat pump makes the renewable energy stored in the soil, groundwater or the environment usable for heating purposes. The most common are electric heat pumps. A heat pump operates like a refrigerator in reverse: a refrigerant extracts low-temperature heat from the environment, which causes the refrigerant in the system to evaporate; the refrigerant is then compressed;  heat is released in a condenser and is transferred to the water circulating in the heating system.

Heat pumps work most efficiently the higher the source temperature, and when combined with distribution systems that work at lower temperatures. A high standard of comfort can be assured by using sufficiently dimensioned heating emitters (efficient radiators and/or embedded heating systems). Modern heat pumps can be used for space heating, domestic hot water preparations and can also be used for ventilating and cooling a building depending on the technology. They work very quietly and are virtually maintenance-free.

Closed-loop heat pumps: ground source heat pumps or brine/water

Closed-loop heat pumps are the most common type. They use a closed loop of pipe containing a water and anti-freeze solution to extract heat from the ground or ground water; they are often referred to as ground-source, geothermal or “brine/water” heat pumps. The heat is transferred to water for distribution in the building. The heat can be extracted from the ground or ground water using vertical collectors in boreholes or loops of pipes laid horizontally below the surface of the ground. Sufficient open land area must be available – to sink boreholes, but more so if horizontal collectors are to be used, and permits are often necessary. They are available with or without integrated hot water storage.

Open-loop heat pumps: water/water

Open-loop heat pumps use the almost uniformly level temperature of bodies of water. The water from the source is pumped through the actual heat pump itself where its heat is extracted. Evaporators need to be rustproof. Water/water heat pumps come with or without hot water storage tanks. Building cooling is also possible.

Air-source heat pumps: air/water

Air-source heat pumps extract environmental heat from the air. They are particularly suitable for installation in existing buildings and can be installed both inside or outside the building. They are easier and less costly to install as no boreholes or horizontal pipes are necessary. The air/water heat pumps can also be switched to operate in cooling mode.

Air/water heat pump (inside unit)
Air/water heat pump (inside unit)
Air/water heat pump (outside unit)
Air/water heat pump (outside unit)