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