A thermally driven solution pump for NH3/H2O-absorption chillers

• Published in: International journal of refrigeration 2019-08, Vol.104, p.404-416
• Main Authors: Arnitz, Alexander, Rieberer, René
• Format: Article
• Language: English
• Subjects: Absorption; Ammonia; Chillers; Conception; Cooling; Design; Double course; Double-stroke; Generators; Heat pumps; Mass flow rate; Membrane pump; Pompe à chaleur à membrane; Pumps; Solenoid valves; Thermal energy
• ISSN: 0140-7007; 1879-2081
• DOI: 10.1016/j.ijrefrig.2019.05.013

•A thermally driven solution pump is realized as double stroke membrane piston pump.•The design of the thermally driven solution pump is presented.•The cooling capacity shows a maximum in dependence of the pumping mass flow rate.•Cooling capacity and COPc are reduced compared to an electrically driven pump.•The reasons for the lower cooling capacity and COPc are discussed. The solution circulation in NH3/H2O-absorption chillers and heat pumps is mostly maintained with electrically driven solution pumps. An alternative to the use of electrical driving energy is the use of thermal driving energy which is supplied to the generator. This work discusses a concept of a thermally driven solution pump using refrigerant vapor from the generator to move the piston of a double-stroke membrane pump, the so called “DoublePump”. The “DoublePump” is designed to reach a pumping mass flow rate of 600 kg h−1 at predefined operating conditions of an absorption chiller. This requires the determination of the piston geometry and the size of the check and solenoid valves. The cooling capacity and efficiency of an absorption chiller operated with the “DoublePump” are reduced compared to the operation with an electrically driven solution pump. However, less electrical driving energy is required to operate the absorption chiller with the “DoublePump”.