A reliable one-dimensional method applied to heat-transfer problems associated with insulated rectangular tanks in refrigeration systems

In this study, the heat-transfer characteristics of insulated cubes or rectangular tanks are analyzed by using the one-dimensional solid square-top wedge thermal resistance (SSWT) model and plate thermal resistance (PTR) model. It is found that, in cases of insulated tanks, the errors generated by the SSWT model are all positive and those generated by the PTR model are all negative. Thus, a combined PTR and SSWT (CPSWT) model, resulted by mixing SSWT and PTR models with the proportion factors of 0.6 vs. 0.4 (64-CPSWT model), can neutralize the positive and negative errors and obtain very accurate results in comparison with the three-dimensional numerical solutions. The errors returned by the 64-CPSWT model are within ±1% when applied to refrigeration systems with practical sizes and insulated thickness. Suggestions on how to obtain reliable heat-transfer results for an insulated rectangular tank in a refrigeration system are also presented.