Exergetic optimization of basic system components for maximizing exergetic efficiency of solar combisystems by using response surface methodology

In this study "design parameters" and efficiency effect of basic system components on exergetic efficiency of "Solar Combisystems (SCS)" which can be named as a new generation space heating systems are investigated in order to determine the optimum operating values of system components. The effects of four variables, instantaneous exergetic efficiency of solar collector (ηExcoll), heat exchanger-1 (ηExhe-1), heat exchanger-2 (ηExhe-2) and heating system (ηExHS) on the overall exergetic efficiency of SCS are investigated based on central composite design (CCD) and quadratic models are developed to correlate the variables to overall system net and gross exergetic efficiency. From the analysis of variance (ANOVA), the most influential factor on each experimental design response is identified. It is found that, (ηExcoll), (ηExhe-1), (ηExhe-2) and (ηExHS) are statistically significant for net and (ηExcoll), (ηExhe-1) and (ηExHS) are statistically significant for gross exergetic efficiency of overall system. Binary interaction effect of independent variables are investigated and it is found that (ηExcoll) and (ηExhe-1) is the most important couple that effects the net exergetic efficiency of the system. Net and gross exergetic efficiency of overall system reach to 12% and14.6% individually, within the optimum values of the variables. © 2015 Elsevier B.V. All rights reserved