Thermally driven absorption heat pumps offer excellent opportunities to significantly increase the efficiency of heat supply. When integrated into existing heating systems, this type of heat pump can achieve fuel savings of 25% to 40% in the simplest of designs. Across Europe, sales figures in the order of several 100,000 per year are possible for this technology. This means that the requirement to significantly reduce CO₂ emissions in the provision of heat can be met quickly.

The technology is limited by the disadvantageous properties of conventional working materials. So-called ionic liquids promise a solution, but have a low intensity of heat release, which results in high costs for heat transfer. The intensity of the heat release is significantly influenced by the mass transfer that takes place on the surface of a fluid film through diffusion.

The problem of poorly coupled heat and mass transfer is solved by the invention of the fluid-irradiated plate. This makes it possible to use ionic liquids as a working fluid for the heat pump. Difficulties in the use of known fluid distribution systems have also been solved by the design.

With the arrangement according to the invention, heat flow densities of up to 5 kW/m² are achieved with comparatively low driving forces.