DoublePump - New concept of a thermally driven solution pump suitable for small-capacity ammonia/water-absorption heat pumping systems

Low-capacity ammonia/water absorption heat pumping systems have a large economical and ecological potential for both cooling and heating applications. The core element of an absorption heat pumping system is the solution pump which is most commonly an electrically driven pump. The presently used electrically driven solution pumps for small capacity systems are relatively complex, expensive and have substantial potential for improvements regarding efficiency, safety, and reliability. In order to improve this situation a new concept for the solution pump, which is driven by a thermodynamic process instead of electricity, will be investigated within this project. This concept possibly offers following advantages in comparison to an electrically driven pump: cheap production low electricity consumption hermetic design, i.e. no leakage problems simple design and no maintenance effort. Within the already finished research project ThermoPump a new pump concept, driven by a portion of high-pressure refrigerant steam from the generator, has been investigated. Based on the results and experiences from this project further potential of optimization regarding first cost and efficiency will be identified and new concepts for a thermally driven pump will be developed. For the most promising concept a functional model for the new pump concept will be designed, constructed, and integrated in an adapted absorption heat pumping system available on the market. The thermally driven solution pump will be operated at different working conditions, the control and efficiency will be experimentally investigated and as much as possible optimized. The potential of this technology for the application in the systems of the industrial partners, i.e. for heating & cooling, shall be investigated based on the experiences with the test rig and the results of a verified simulation model. Finally, successful project results should contribute to a technological improvement of ammonia/water absorption heat pumping systems and to a wider spread of this technology.