Display cases are widely used in supermarkets to demonstrate commercial goods for customers, like milk, frozen food, ice-cream, etc. There are two types of display case: open case and closed case. The goods inside display cases need to stay within a stable temperature range to meet the quality standards. However, due to variety of faults (e.g., leaving door opening), it is hard to maintain a stable temperature. The associated energy consumption from display cases is extremely high due to faults. There is a need for a dynamic energy model to accurately predict the good temperature and energy consumption under faults. A dynamic model is developed based on operation data collected through field tests in a low global warming potential (GWP) refrigeration system, at Oak Ridge National Laboratory.