Efficient and climate-neutral heating concept by a novel drive of an absorption heat pump using a commercially available gas heater

Brief description

Due to the continuing climate change, carbon dioxide emissions need to be significantly reduced in the next years, in a comprehensive energy transition. It is essential to convert to climate-neutral energy sources as well as to produce and provide thermal energy and electricity with energy-efficient technologies. In the heat supply sector, IGTE are active in the research of absorption heat pumps (AHP). These heat pumps can lift the ambient heat from a low temperature level and utilize it for heating.

Compared to compression heat pumps, absorption heat pumps hardly need electric energy in operation and are mainly driven by thermal energy in the form of a fluid flow (90-140 °C). Fluid flows at this temperature level are possible e.g. by combusting (bio)gas, biomass or by district heating; fluid flows at this temperature level can be used more efficiently in absorption heat pumps. In addition to the flexibility, the hydraulic coupling with a fluid circuit via plate heat exchangers has the advantage that the high temperatures, resulting from combustion, are not in direct thermal contact with the ammonia/water solution. Therefore, there is no corrosion caused by too high spot temperatures.

The objective of the research project is to test and demonstrate a prototype in a commercially available heating system (Figure 1), exemplified by a gas heater. The gas heater does not heat the building as usual but drives the absorption heat pump by a hydraulic coupling. The absorption heat pump absorbes ambient heat, in addition to the drive heat, and emits both to the building. Thus, more heat is supplied to the building than contained in the fuel. Drive circuit and heating circuit can be optionally coupled in case that a higher supply temperature is needed.

Figure 1: Schematic diagram of the planned prototype
Figure 1: Schematic diagram of the planned prototype

Project duration

10/2022 - 09/2023



The AbsorpTherm research project is funded within the “CZS Prototypes” funding program by Carl Zeiss Foundation. We would like to sincerely thank for their support.


This image shows Johannes Brunder, M.Sc.

Johannes Brunder, M.Sc.


Academic employee

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