Reliable simultaneous operation strategy in heat exchanger networks under variable heat loads. (25th February 2019)

• Record Type: Journal Article
• Authors: Chen, Qun; Zhang, Meng-Qi; Dong, En-Fu; Wang, Yi-Fei; Sui, Yu-Qiu
• Is Part Of: Applied thermal engineering. Volume 149(2019)
• Page Start: 1125
• Page End: 1133
• Publication Date: 2019-02-25
• Subjects: Energy conservation -- Heat exchanger network -- Operation strategy -- Heat load variation -- Pumps and valves; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2018.12.118
• Languages: English
• ISSNs: 1359-4311

Abstract

Highlights: Propose an optimal simultaneous operation strategy for VSPs and valves in HENs. Obtain the optimal operating parameters of VSPs and valves at variable heat loads. Optimized parameters benefit energy conservation on the premise of safe operation. Operation strategies influence the optimal operating parameters of HENs as well. Prescribed set-point temperatures cannot lead to the best performance of HENs. Abstract: The variation of heat loads challenges the operation strategy of heat exchanger networks (HENs). Previous individual valve control strategies enlarge the flow resistance, while the individual variable speed pump (VSP) control strategies might cause dangerous working conditions. This paper develops an optimal simultaneous operation strategy of both VSPs and valves in HENs under variable heat loads, which can avoid the extreme VSP operating frequencies and improve the performance of HEN on energy conservation. Optimization experiments with three different control strategies are operated on a practical multi-loop HEN to validate the effectiveness of new operation strategy. The results show that the new simultaneous operation strategy can achieve energy conservation on the premise of safe operation, about 90% power consumption reduction to individual valve control strategy at the heat load 800 W. What's more, besides boundary conditions, control strategies also influence the optimal operating parameters, which shows the limitation of traditional operation strategy with prescribed set-point temperatures.