Waste heat recovery of power plant with large scale serial absorption heat pumps

• Published in: Energy (Oxford) Vol. 165; pp. 1097 - 1105
• Main Authors: Xu, Z.Y., Mao, H.C., Liu, D.S., Wang, R.Z.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 15-12-2018; Elsevier BV
• Subjects: Absorption; Absorption heat pump; District heating; Environment pollution; Heat exchangers; Heat pumps; Heat recovery; Heat recovery systems; Heating; Large scale; Pollution; Power plant; Power plants; Pumps; Steam; Temperature effects; Theoretical analysis; Turbines; Waste heat; Waste heat recovery; Waste materials; Water absorption; Water pollution; Absorption heat pump; Large scale; Power plant; District heating; Waste heat
• ISSN: 0360-5442; 1873-6785
• DOI: 10.1016/j.energy.2018.10.052

Large amount of waste heat is dissipated in industries, resulting in energy waste and environment pollution. Waste heat recovery with absorption heat pump is one of the attractive solutions. In this paper, we present the theoretical study and test of a power plant waste heat recovery system with large scale LiBr-water absorption heat pumps for district heating. Waste heat from steam condenser with temperature of ∼35 °C is recovered by the absorption heat pumps driven by steam with pressure of ∼0.25 MPa from the turbine. Heat output from the absorption heat pumps is used to preheat the return water of district heating network from ∼45 °C to ∼80 °C. The return water is further heated by the steam to ∼105 °C for heating supply. Large temperature lift of the return water is achieved by the serial absorption heat pumps. Theoretical analysis of the system is presented, showing advantages compared to the conventional absorption heat pump and original heating supply system. On-site test showed that COP of 1.77 and heating capacity of 63.57 MW were achieved by one serial absorption heat pump, with waste heat inlet/outlet temperature of 34.63/28.33 °C and return water inlet/outlet temperature of 45.94/81.34 °C.
•District heating system in power plant is improved by waste heat recovery.•Serial absorption heat pumps are used for large output temperature lift.•Theoretical study and on-site test are carried out.•COP of 1.77 and heat output of 63.57 MW are achieved by one absorption heat pump.