Heat Pumps

Technical Description

Heat pumps employ the same technology as refrigerators, moving heat from a low-temperature level to a higher temperature level. Heat pumps draw heat from a heat source (input heat) and convert the heat to a higher temperature (output heat) through a closed process; either compression-type heat pumps (consuming electricity or fuels) or absorption heat pumps (using heat; e.g. steam, hot water or oil). There exist many different variations of heat pumps that can overall be divided as below (or combinations).

  • Compression heat pumps, using electricity
  • Compression heat pumps, using a combustion engine
  • Absorption heat pumps, direct fired/indirect fired

An important point regarding heat pumps is the ability to “produce” both heating and cooling. When applied with the primary purpose of cooling, the cooling demand defines the capacity. A heat pump with combined heating and cooling can utilize different heat sources in combination. The combined solution will often be efficient because it can increase the number of full load hours for the heat pump compared to only combined heating and cooling. The primary purpose of the heat pumps in the technology catalogue is heating.

Large-scale heat pumps are often designed after the size of the heat source available and due to high specific investment costs; a high number of full load hours are required to make a feasible business case. Therefore is, large-scale heat pumps often designed for baseload rather than peak load.[1]

Working principle of Heat Pumps [2]

Technology Flowchart


Sketch of the heat pump cycle with components

Documentation (Links, References)

  1. Danish Energy Agency, Technology Data for Generation of Electricity and District Heating, February 2024, https://ens.dk/sites/ens.dk/files/Analyser/technology_data_catalogue_for_el_and_dh.pdf
  2. https://www.iea.org/reports/the-future-of-heat-pumps/how-a-heat-pump-works