Reducing costs though energy efficiency

As energy bills hit new heights, the cost of running refrigeration systems becomes even more critical. The energy used by refrigeration systems in the food and beverage industries is often a significant part of the operational costs.

In particular, the food service sector has faced significant challenges. The sector not only had to deal with shutdowns and low customer numbers through the covid pandemic, but now has to recover while energy costs are increasing. Utilising the best and most efficient equipment is vital to be able to minimise the costs of energy. Evidence shows that the energy used by similar food service equipment can be very variable. Electricity consumption data collected by Mudie et al. (2016)[1] in a sample of fourteen UK public house-restaurants (gastro pubs) showed that refrigeration represented the largest consumption in each of the study kitchens, using 41% of the electricity (13% walk in freezer, 5% walk in fridge and 23% other refrigeration). This was 28% of the total energy consumption (including gas) of the kitchen, with the kitchen using 63% of the energy consumption of the whole business area. SKM Enviros (2011)[2] estimated for 2010 that 14.8 TWh of electrical consumption was used in the UK for food service, of which 4.16 TWh was for refrigeration (28%). Based on a 2010 price of 20p /kWh, this equated to £832 million pounds per year spent by the food service industry on refrigeration. Obviously, this would be far greater today with energy costing at least 50% more.

Obviously, there is no substitute to buying the best performing equipment in the first place. For example, energy labelling of beverage coolers has indicated that there is a huge difference between purchasing the best cabinet and one that just achieves the minimum energy performance standards. For a typical 200 litre, 2-door back bar cooler operating at the K1 classification (average temperature equal to or less than 3.5°C) in climate class 1 (25°C, 60% RH according to BS EN ISO 22044:2022) a ‘G’ label cabinet consumes 10 times more energy than an ‘A’ labelled cabinet. Realistically ‘A’ rated, and ‘G’ rated cabinets are not common. Moving from a more common ‘E’ or ‘F’ rated cabinet to an available ‘B’ rated cabinet often incurs no extra cost and saves between £208-278 per year (based on the reported national average price of £0.34/kWh as reported for October 2022 by the Energy Saving Trust). As many food service outlets have multiple refrigerated appliances, this can add up to thousands of pounds per year for no greater initial cost.

Overall, there are many opportunities to save energy through use of energy efficient technologies or strategies. There are also options with some equipment to raise temperatures at certain times of day if the food stored is non-perishable. For example, beverage coolers can be turned off when not being used, and as long as the off period is long enough, there is an overall saving in energy even though energy is expended to re-cool the products after the off period.

There are also options to reduce cost though application of strategies such as demand side response. This is only relevant where users are paid to go off grid at certain times of day or have a flexible tariff than enables them to switch off systems during periods of high energy cost and then use energy during periods of low energy cost. This tariff shifting is a means to save money and not energy but has financial benefits for the operator and benefits for the grid as higher carbon energy generation sources do not need to be utilised during the peak tariff times.

At RD&T we provide independent expertise on design and operation of refrigeration systems. If you would like to discuss how to reduce energy demand in any sector of the food cold chain, please contact Judith Evans (j.a.evans@rdandt.co.uk) or Alan Foster (alan.foster@rdandt.co.uk) at RD&T.

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