Optimization of Triple Effect Vapor Absorption Refrigeration System: A Statistical Approach

Abstract

The present paper optimized the first and second law performance of the triple-effect vapor absorption refrigeration systems (TE-VARS) using statistical techniques like Taguchi, Taguchi-based gray relational analysis (GRA), and response surface methodology (RSM)-based GRA methods, which provide the most accurate and optimized results. Liquified petroleum gas (LPG) and compressed natural gas (CNG) are considered as the source of energy to operate TE-VARS, as the system requires significantly higher generator temperature. Also, volume flowrate of these gases along with the annual operating cost to drive the system have been presented. A thermodynamic model was first formulated using engineering equation solver (ees) software for the computation of the coefficient of performance (COP) and exergetic efficiency (ECOP). The most influential parameters like temperature in the main generator, concentration, and pressure at different components are studied and determined using analysis of variance (ANOVA) and Taguchi methods. The optimum parameters were determined based on the mean effect plot of S/N ratios for COP and ECOP. It has been found that the maximum COP and ECOP were calculated to be 1.915 and 0.15, respectively, under the Taguchi method. Furthermore, Taguchi-GRA was used for the simultaneous optimization of the operating parameters and performance of the system. It is observed that the absorber temperature is the most influential parameter for affecting COP and ECOP. Moreover, a RSM-based GRA method was also applied and developed regression models that yield most optimum COP and ECOP as 1.963 and 0.1606, respectively. Comparison shows that the RSM-based GRA method provides the most optimum conditions, which is one of the key finding of the present study. Also, rate of exergy destruction at each component of TE-VARS has been plotted under optimized operating conditions. The optimum volume flowrate for LPG and CNG comes out to be 0.057 and 0.177 m3/s, while the minimum operating cost (yearly) are 299.827$ and 183.293$, respectively.