Researchers study more efficient refrigeration techniques
researchers at the University ofBristol have launched a
government-funded project to come up with more efficient
Initial figures produced by the two-month-old project suggest that the dairy industry is likely to be the highest user ofrefrigeration, the researchers say in publishing a description of the project on their Internetsite. In the UK an estimated 1,500 to 2,000 food and drink manufacturing sites are major users of refrigeration, accounting for over 4,500 GWh of electrical energy consumption.The figure represents about half of their total energy consumption, say researchers at theuniversity's Food Refrigeration and Process Engineering Research Centre (FRPERC). Food and drink accounts for 14 per cent of the total energy used by UK businesses. The sector hasto reduce its energy use to 899.6 kWh per tonne of throughput by 2010, under rules set by theDepartment for Environment, Food and Rural Affairs (Defra). FRPERC is lead coordinator of the project, which also involves researchers at Brunel, London South Bank and SunderlandUniversities. Defra has taked them with identifying, developing and fostering the development of more energy efficient refrigeration technologies and business practices for use throughout the food chain. The research programme will focus on estimating energy use throughout the different parts of thefood supply chain. They will then identify the most promising technologies, systems and business practicesbefore undertaking feasibility studies. The mapping exercise, which is underway, aims to identify and rank the top 10 processes in terms of the potential to achieve the greatest totallowering improvement in energy usage. Researchers are working on completing an energy efficiencyranking for each of the major food categories and processes. To make the estimate researchers are conducting a survey of the published data available from collaboratingorganisations. The researchers will use industry production figures and household consumptionstatistics to determine the largest commodity sectors that use refrigeration. Their initial figures suggest that the dairy industry is likely to be the highest user of refrigeration.UK milk production totalled 6,762,000 tonnes in 2005. Using the assumption that all milk is chilled down to 4ºC from 37ºCthey calculate energy usage has to be reduced by about 240 GWh each year. The second largest user of refrigeration is probably the meat industry, they estimate. With annual UK slaughtered production totalling 1,721,000tonnes and assuming that all this meat is chilled from 37ºC down to 4ºC, they calculate energy usehas to fall by about 60 GWh per year. It has become very clear in the first month of the project that there is a dearth of measured real data on energy consumption of refrigeration systems in theood manufacturing industry," said the researchers. "Most of the available data are estimates based on an educated guess of the proportion of energy used within a factory on refrigeration. Far more detailed data is required to identify the critical 10 areas with the highest potential to make major energy savings." Identifying other major food sectors is more difficult, the researchers say, pointing out thatwhile many fruits and vegetables are being refrigerated, much of the primary cooling is carried out before the product reaches the UK. Once the main refrigeration sectors of use have been established, the more challenging task willbe to complete an assessment of energy use along the food chain. "It is necessary to identify the proportion of product that is frozen, or heated and re-cooled, stored, transportedetc.," the researchers say. "Data for specific processes and measured energy consumption is scarce. At this point, more focused surveys and measurements are planned to obtain the missing data. It is already evident that there is a major difference between the theoretical energy required to change product temperature and the actual energy consumption for refrigeration." The researchers say estimates indicate that refrigeration systems use as much as 15 percent of the total energy consumed worldwide. The UK's plans to cut greenhouse gas emissions is part of an EU programme to progressively put the brakes on industry's production carbon dioxide (CO2) , linked to causing a general rise in the temperatures worldwide. Each member state must detail its programme to reduce CO2 in a National Allocation Plan (NAP). The plan makes allocations to specific industries and then individual plants. Industry must then invest in ways to cut emissions to meet the targets or buy credits under the bloc's Emissions Trading Scheme (ETS). The food processing industry is a major energy consumer and discharger of greenhouse gas through its reliance on cooking, refrigeration, freezing and air compressor systems. The increased investments needed to meet the targets have added to the costs companies must pay to stay in business.