Optimization of Solution Flow Rate and Heat Transfer Area Allocation in the Two-stage Absorption Heat Exchanger System Based on a Complete Heat and Mass Transfer Simulation Model

Abstract The absorption heat exchanger (AHE) system utilized in district heating can expand the heating scale and reduce energy consumption. Recently, the AHE system is widely applied in northern China. The optimized process system, including the multi-section and multi-stage system, has arisen to improve the performance. But there is no theoretical basis for the optimization design of internal parameters. This paper considers the total dissipation of the system, including the heat and mass transfer of internal solution for the first time. And a complete simulation model for the operation of the AHE system is first proposed based on the one-dimensional three-fluid heat transfer model. Compared with the existing sensible heat transfer model, this model can simulate the actual operating parameters of the AHE system more accurately and carefully. The relationship between the optimum condition with the minimum outlet water temperature of primary network and the state of minimum thermal resistance is studied under different circumstances. Besides, the optimization of solution flow rate and heat transfer area allocation is studied in this paper. The result guides the design of internal parameters and improves the energy saving in district heating.