Comprehensive investigation of transport refrigeration life cycle climate performance

This paper presents the comprehensive investigations for the total lifetime CO2-equivalent emissions for food transport refrigeration system under various influencing factors. The new R404A alternative refrigerant-R452A, is investigated to provide an improved environmental performance. With a lower global warming potential (GWP = 1945), which is around half GWP of the currently existing R404A, R452A can make a 5-15% emission reduction for the food transport refrigeration system. In the R452A system, reducing the ambient temperature from 90 °F (32 °C) to 60 °F (15.5 °C) can produce up to 60% emission reduction for the fresh product case while 39% reduction for the frozen. Decreasing the annual leak rate from 25% to 10% can give a 13% emission reduction for the R452A fresh product case while 4% reduction for the frozen. Increasing the food product refrigerating temperature (evaporating temperature) set-point from −10 °F (−23 °C) to 50 °F (10 °C) can lead to more than 80% emission reduction. In addition, a 15% annual insulation degrade rate can provide a 13% emission reduction for the fresh and 14% for the frozen. Moreover, the Cycle Sentry running mode can result in a 14-21% emission saving than the Continuous. Furthermore, the sunny/cloudy conditions, system efficiency improvement rate, and alternative transport refrigeration technologies other than the conventional hydrofluorocarbon (HFC) based vapour compression refrigeration systems, are also investigated to explore the possibility to minimize environmental impacts.