Investigation of heat transfer Exergy loss number and its application in optimization for the shell and helically coiled tube heat exchanger

In this study, the Exergy analysis of the shell and helically coiled tube heat exchanger (SHCTHX) were investigated. The heat transfer Exergy loss of the SHCTHX implemented by MATLAB software was developed, where the dimensionless number named heat transfer Exergy loss number (xi HT) was proposed. The effect of parameters (core tube diameter (DC), space between the shell and the core tube (Delta DBC), inner diameter of coiled tube (di), thickness of the coiled tube (dt) and mass flow rate (Mshell)) on the effectiveness (epsilon), heat transfer Exergy loss number (xi HT) and number of transfer unit (NTU) were investigated. Moreover, the optimization of the SHCTHX was studied. When the design parameters are set as DC, Delta DBC, di, and dt, there is coincidently opposite variation trend for xi HT and epsilon, the optimization results of which are identical. When the design parameters are set as DC, Delta DBC, di, dt and Mshell, the effectiveness (epsilon) of optimization results with xi HT is 30% larger than that without xi HT; while the heat transfer area, the overall heat transfer coefficient, the needed mass flow rate and the heat transfer irreversible loss of optimization results with xi HT have reduction of 30%, 15%, 30% and 10% than those without xi HT.