24 June 2014


Only a few electrical solution pumps are available on the market suitable for smallcapacity ammonia/water absorption heat pumps with an evaporator capacity below 20 kW. In
order to improve this situation a “thermally driven” solution pump can be considered, which offers several advantages, as e.g. an oil-free, leak-proof and simple design. “Thermally
driven” means that the pump is “internally” driven by a thermodynamic power process within
the absorption heat pumping cycle instead of electricity. Further, this novel pump (“ThermoPump”) can be easily integrated in any plant without special efforts regarding its basic layout. The experimental analysis of the ThermoPump operating in a commercially available absorption heat pump shows that this concept works without any relevant operating-limits, negative influence on the dynamic behaviour or electricity demand.
However, the measured COP of the plant is decreased by at least 15% by the ThermoPump compared to the existing electrical pump. Nevertheless, thermal energy (e.g. CO2-free waste
heat) can be used to drive the solution pump instead of electricity, and this can be of interest from an economical and ecological point of view.