Potential life cycle carbon savings with low emissivity packaging for refrigerated food on display

► Use of low emissivity food packaging in refrigerated display cases investigated. ► Emissivities measured for a range of materials and some selected for trials. ► Selected packaging used in freezer display cases greatly reduced radiant heat load. ► Potential savings of 30% in energy and carbon shown to be available. ► Significant reductions in life cycle emissions were demonstrated. The retail of food produces a large amount of carbon, both directly through embodied energy in the food and its packaging, and indirectly through energy use. Supermarkets are large consumers of energy in the UK, accounting for up to 5% of the UK’s total consumption. A large proportion of this energy, up to 50%, is used in refrigeration of food and much of this is used to cool open type display cabinets. However, work at Unilever Research Laboratory in the 1970s indicated that the input energy required for cooling open display refrigerated cabinets could be substantially reduced by applying low emissivity (i.e. high reflectance) materials in food packaging, causing the cabinet heat load and the temperatures of stored foods to be reduced. One drawback was that it was difficult to print on the surface of these materials without reducing their reflective properties. However, subsequent developments in packaging technology and the use of modern manufacturing processes have overcome the earlier disadvantages of these materials, permitting printing onto the external surfaces of low emissivity packaging, while still retaining its reflective properties. This paper presents an update of the Unilever study, in terms of the potential of modern, low emissivity food packaging materials for improving refrigeration system efficiency. The results of the new study indicate that some types of packaging will allow an increase in refrigerator operating temperature of up to 10K, with no loss of refrigeration performance with respect to the food. This is expected to result in improved refrigeration system efficiency, with reductions of up to 30% in both energy consumption and carbon emissions and a likely significant increase in shelf life for stored foods. In addition, the embodied carbon for the packaging and the life cycle impact of its use, have been evaluated. Packaging having low embodied energy content has been identified, and it has been predicted that significant net savings in both carbon and energy are possible over the life cycle.