A A Solver-TOPSIS technique for multi-objective optimisation of innovative multi-stage VCR systems by using Microsoft Excel

Multi-objective optimisation analyses using Microsoft Excel

Abstract

This paper describes a method for multi-objective optimisation analyses of multistage vapour-compression refrigeration (VCR) systems by utilising the single-objective solver of Microsoft Excel and the TOPSIS decision-making method. The paper illustrates the Solver-TOPSIS method by analysing an innovative two-stage VCR system that adds a heat-recovery intercooler to the conventional system after the first-stage compressor. The Excel-aided model developed for the system calculates its coefficient of performance (COP), exergetic efficiency, total cost rate, and total equivalent warming impact (TEWI). Four design parameters are treated as variables which are the evaporator and condenser temperatures, the isentropic efficiency of the compressor, and the flow rate of the cooling water. Comparing the values of the four performance indicators as optimised by the proposed method with those optimised by the MIDACO solver shows that the method yields higher values of the system’s COP and exergetic efficiency and lower TEWI at the expense of slightly increasing the total cost rate. The total rate of exergy destruction in the system optimised by method is also lower than in the one optimised by MIDACO.