Heat Transfer Reduction Across the Walls of Refrigerated Van Trailers by the Application of Phase Change Material

Abstract

The purpose of this thesis is to present the results obtained by incorporating phase change materials (PCMs) into the conventional insulated walls of commercial refrigerated van trailers (herein referred to as "refrigerated trucks"). The idea was to apply a building insulation technology (inclusion of PCMs) that was developed previously, at the University of Kansas, in the walls of refrigerated trucks. Although the technology had been applied to buildings, the concept is a novel one within the automotive industry. Although transportation experiences more dynamic challenges compared to its building counterpart, this analysis can open an interesting window for an innovative solution to an area of energy used in the transportation sector. In this research endeavor, two similar van trailer simulators were constructed and used to test the proposed technology under stationary environmental conditions. Both simulators were outfitted with the same number of measurement devices in the exact same locations. The technology was tested in similar days in terms of temperature and solar insolation. The relevant variables that were monitored were the heat flux across the walls of the simulators and temperatures, including surface and indoor air temperatures. Other relevant data, such as weather parameters (e.g., insolation) were also measured and recorded. The primary observation was how the peak heat flux and the total heat flow responded for the two simulators. The results obtained suggested that the van trailer simulator outfitted with PCMs had lower peak heat transfer rates by approximately 42.4% and total heat flow over a period of time one day by as much as 27.7%. Month-long results suggested that the reductions produced by the proposed technology were 43.8% for peak heat transfer rate and 26.3% for total heat transfer. The refrigeration units that cool the insides of refrigerated trucks do so by burning fossil fuel, usually diesel. Any decrease in the refrigeration load requirements would eventually result in lower fuel consumption. The reduction in heat transfer rate (i.e., peak load) would assist in reducing the size of the cooling equipment, which could also result in cost savings.