The air is cooled until the humidity condenses. Normally, the necessary high cold demand for this procedure is met by electric refrigerating machines. At the Institute for Technical Thermodynamics of the TU Hamburg-Harburg it has been verified, that airconditioning without refrigeration machines is environmentally friendly and economically possible. For an office building in Hamburg-Stellingen an adsorption wheel, combined with a block-type thermal power station,was used for the dehumidifcation, supported by the cool soil for the building refrigeration.

Special feature of the adsorption-aided air-conditioning concept: the outside air is no longer electrically dried but through an adsorption wheel by using a material that stores air humidity. The waste heat of the block-type thermal power station serves to remove this humidity out of the reservoir. In comparison to the test object, a building with an electricallydriven air-conditioning needs 22 % more primary energy per annum.

The new procedure allows a meaningful use of surplus heat from block-type thermal power stations, fuel cells or solar panels, respectively. The reduced cold demand permits the use of natural, regenerative cold sources and makes electric refrigeration machines superfluous.