LCCP, supermarket refrigeration, EnergyPlus, low GWP
Commercial refrigeration systems consumed 1.21 Quads of primary energy in 2010 and are known to be a major source for refrigerant charge leakage into the environment. Thus, it is important to study the environmental impact of commercial supermarket refrigeration systems and improve their design to minimize any adverse impacts. The system’s Life Cycle Climate Performance (LCCP) was presented as a comprehensive metric with the aim of calculating the equivalent mass of carbon dioxide released into the atmosphere throughout its lifetime, from construction to operation and destruction. In this paper, a new open source tool for the evaluation of the LCCP of different air-conditioning and refrigeration systems is presented. This LCCP tool is used to compare the environmental impact of three typical supermarket refrigeration systems (low temperature, medium temperature, and multiplex direct expansion systems). The environmental impact of these systems is compared based on three different refrigerants as follows: two hydrofluorocarbon (HFC) refrigerants (R404A, and R407F), and a low global warming potential (GWP) refrigerant (N40). The comparison is performed for 8 different US cities representing different climates. The hourly energy consumption of the display cases, required for the calculation of the indirect emissions, is calculated using a widely used building energy modeling tool (EnergyPlus). An uncertainty analysis is conducted on the three systems to determine the effect of the uncertainty of each input on total LCCP. A sensitivity analysis is performed on the three systems to determine the sensitivity of the LCCP results to changes in the charge of the system and power plant emission values used in the calculations. These studies help to determine the design factors, whether in general or for certain climates, which would require more attention when designing a refrigeration system in order to reduce its carbon emissions.