Absorption chiller - conversion of heat to cold

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Lubomír Sovíček
Email: lubomir.sovicek@bpower.cz
Phone: +420 734 576 035

High efficiency, quiet operation, zero emissions, outputs from 30 kW and very low operating costs make absorption chillers the ideal solution for cold production.

An absorption chiller produces cold in the form of cold water. The main "fuel" for the absorption unit is heat, which can be extracted in various forms:

  • hot water
  • stea
  • flue gases
  • thermal oil

Illustration of an absorption chiller unit

The absorption cooling technology itself is very simple. It is a system of exchangers filled with a working substance (LiBr solution) and water. Absorption chillers are suitable wherever there is a heat source and a need for cooling:

  • ironworks
  • foundries
  • agriculture
  • chemical industry
  • cogeneration units
  • compressors for compressed air production

Standard compressor cooling technologies have a high power consumption, for the same cooling
capacity the actual consumption of an absorption cooling unit is only about 5% of the consumption compared to compressor cooling. Therefore, the installation of an absorption chiller will result in a significant reduction in the operating costs of refrigeration production.


Process diagram of an absorption chiller


In these systems, the refrigerant, i.e. water, absorbs heat at a lower temperature and lower pressure during evaporation, and releases heat at a higher temperature and higher pressure during condensation.

The working substance is a LiBr solution which acts as an absorbent, absorbing the vapours from the refrigerant and thereby cooling the cold water to the desired level.

Three circuits are connected to the absorption unit:

  • the heat source
  • the cooling circuit
  • the resulting chilled water circuit.

The heat source can be hot water from 70 °C and the resulting cold temperatures range from 2 to 20 °C.