Computationally Efficient Modeling Approach for Evaporator Performance under Frost Conditions

Growth of a frost layer on an evaporator surface due to low evaporator temperature as well as moisture contained in surrounding air deteriorates performance of a refrigeration system significantly and requires significant energy for defrost. Many studies have been performed to model the heat and mass transfer phenomena in an attempt to have insight and accurate prediction. However, many models form nonlinear algebraic differential equations and thereby it is computationally demanding to include them into a typical building energy simulation environment for a cooler or freezer consisting of an enclosure, refrigeration equipment, defrost elements, and controls. Computationally efficient but reasonably accurate models are needed in order to evaluate overall system performance. The objective of this paper is to introduce a modeling approach to overcome the problem. A numerical solution strategy based on an enthalpy-based reformulation and linearization method will be presented. Comparisons of a proposed and detailed model results are provided