Dual-pressure condensation high temperature heat pump system for waste heat recovery: Energetic and exergetic assessment. (15th August 2020)

• Record Type: Journal Article
• Authors: Dai, Baomin; Liu, Xiao; Liu, Shengchun; Zhang, Yingying; Zhong, Dan; Feng, Yining; Nian, Victor; Hao, Ying
• Is Part Of: Energy conversion and management. Volume 218(2020)
• Publication Date: 2020-08-15
• Subjects: Dual-pressure condensation -- High temperature heat pump -- Waste heat recovery -- Thermal matching -- Refrigerant selection -- Energetic and exergetic analysis; Direct energy conversion -- Periodicals; Energy storage -- Periodicals; Energy transfer -- Periodicals; Énergie -- Conversion directe -- Périodiques; Direct energy conversion; Periodicals; 621.3105
• DOI: 10.1016/j.enconman.2020.112997
• Languages: English
• ISSNs: 0196-8904

Abstract

Highlights: Five configurations of dual-pressure condensation HTHP are proposed for waste heat recovery. The energetic and exergetic model of traditional and new HTHPs are developed. The COP of new HTHPs can be improved by up to 3.37–9.34% compared with traditional ones. The exergy destruction is significantly reduced due to the improvement in thermal matching. DWSAS by using R1234ze(Z) is the most recommended solution. Abstract: High temperature heat pump (HTHP) is an energy-saving solution to recover the industrial waste heat. Five configurations of dual-pressure condensation HTHP are proposed and studied to improve thermal matching in the heat sink. The energy and exergy models are established, and the performance of dual-pressure condensation HTHP systems is assessed and compared with that of traditional single-stage, two-stage and cascade HTHP systems in detail. The results show that the dual-pressure condensation HTHP system is superior to traditional HTHP system from the perspective of energy efficiency and exergetic performance. A maximum COP is obtained at the optimum intermediate water temperature. The COP of dual-pressure condensation water-cooled saturated system (DWSAS) is the highest of 4.16, and 3.37–9.34% higher than the traditional HTHPs. R1234ze(Z) shows much higher energy efficiency over the other refrigerants for the applications of HTHP, and the COP is 2.62–4.47% larger than using R600a at the outlet temperature of heat source of 15–35 °C. The exergy destruction is also significantly reduced by using dual-pressure condensation HTHPs due to the improvement of thermal matching in the condensers. DWSAS shows the lowest exergy destruction, which is 4.28–19.35% lower than traditional HTHPs. DWSAS by using R1234ze(Z) is recommended due to its outstanding energetic and exergetic performance.