Energy consumption in the UK food chill chain – primary chilling

There is increasing pressure on governments and industries to make significant reductions in carbon emissions. In the UK, 11% of electricity is consumed by the food industry and in some sectors a substantial portion of site energy, up to 90%, is consumed by refrigeration systems. The aim of this work was to: identify the major primary chilling energy requirements in the UK; calculate or make a best estimate of their efficiency; and determine which chilling processes have the highest energy saving potential. In terms of the heat energy to be extracted during the primary chilling process, the six most important categories in rank order were milk (532 GWh/year), meat (114 GWh/year), potatoes (59 GWh/year), other vegetables (36 GWh/year), fish (6.5 GWh/ year) and fruit (5.9 GWh/year). There is little published data on the measured energy consumption of commercial primary chilling processes in the UK or that is directly applicable to the UK. From the data that is available, the energy efficiency (useful heat extracted from material/measured electrical energy used) varies from 0.138 to 5.337, with cooling of milk being far more efficient than that of the next two most important categories, meat and potatoes. Using the best of existing technologies it is estimated that 154 GWh could be saved per year in potato cooling, 128 GWh in milk and between 51 and 80 GWh in the cooling of carcass meat. Savings in other commodity areas are likely to be more than an order of magnitude less.