Factors affecting energy consumptions and carbon footprint in refrigerated road transport: A brief review of recent advances in technology, materials and methods

In this paper some research related to the thermal insulation of the body, the energy consumption and the environmental impact of the cooling units are presented. The use of new materials such as the aerogels (both at ambient pressure and under vacuum conditions) is considered as an option and discussed in terms of performance, reliability and costs. Concerning usual solutions for the insulating walls based on polyurethane foams, the actual thermophysical properties of the blowing agents used in insulating walls are discussed in the view of the new regulations for the use of F-GAS refrigerants. The methods to calculate the air infiltration rate and radiative properties of the walls are commented. The ageing of the material used for the insulation body is discussed with the relative issues related to the appropriate prediction of the life of in-service units. Concerning the energy consumptions and environmental impact results from works related to the classic option of vapor compression cycles is compared to new ones such as cryogenic units in terms of total environmental impact, running costs and feasibility. Finally, works discussing new alternatives for refrigerants in vapor compression systems are presented.