Home >

Refrigeration

2005-02-28
Refrigerated food is a luxury which we now take for granted. Most households have fridges, freezers or both and most diets include items, like dairy products, fast foods and ice cream, which would perish at normal room temperature. But while we may see fridges as benign tools quietly doing their job, like most electrical appliances there is an environmental price to pay for the service they provide.

By 1986 a quarter of all global chloroflourocarbon (CFC) production was being used for refrigeration. Although CFC gas production is banned in European Union countries, manufacturers can still sell old stocks of fridges which contain CFCs. Even with curbs on new production present levels of CFCs will continue to destroy ozone in the upper atmosphere for up to one hundred years. Likewise, hydrochlorofluorocarbons (HCFCs), used as a coolant and in the foam insulation of domestic fridges, are banned because they are ozone depleting. Hydrofluorocarbons (HFCs) are now being promoted to replace these other chemicals for the coolant and the foam insulation as they do not harm the ozone layer. They are, however, powerful greenhouse gases - at least 1,200 times more powerful than carbon dioxide (CO2). ICI estimates that 25% of the CFC market will be taken by HFCs by the year 2000. If HFCs replace CFCs without restriction, global HFC emissions would increase to the equivalent of 1,931 million tonnes of CO2. If they are also used as substitutes for HCFCs, the emissions could rise to the equivalent of 4,665 million tonnes of carbon dioxide equivalent by 2035, which will have a significant effect on global warming.

Fridges containing HFCs or HCFCs can be labelled 'CFC free', even though they are environmentally damaging. The 'natural' refrigerant hydrocarbon is less harmful. Before CFCs were developed in the 1930s, HCs were widely used in refrigeration. They have no effect on the ozone layer, less impact on global warming (3-4 times more powerful than CO2 but nothing like HFCs – which are 1,200 times more powerful as a greenhouse gas), are cheaper than CFCs and HCFCs and are non-toxic. Calor Gas have produced four specialist hydrocarbon refrigerants: CARE 10 (isobutane), CARE 30 and 40 (propane) and CARE 50. Prices of HC fridges are competitive with HCFC and HFC fridges or, at most, around £50 extra. If the most energy-efficient appliance is bought rather than the least, the lower running cost will payback the price difference within eighteen months.

According to the Energy Savings Trust a power station annually emits up to 0.5 tonnes of CO2 to power an average sized fridge. Refrigeration also accounts for 36% of electricity consumed by all domestic appliances. Energy efficient refrigeration can use up to 70% less energy than existing, less efficient models. The most energy efficient unit is completely CFC and HFC free and has an energy consumption of 0.1kW/h/100l/24h, which is the equivalent energy consumption of a 15 watt light bulb. Friends of the Earth recommend buying fridges that run on less than 150kW/h annually and freezers or fridge/freezers which run on 350kW/h or less annually. This amounts to savings of 160kg and 320 kg on CO2 emissions, respectively.

Annual energy consumption rates are now displayed on all new models. The label must provide information on the appliance's noise emissions and give an energy rating. The most energy-efficient appliance will have an 'A' grade and the least efficient will have a 'G' grade, these standards being set by the manufacturer.

Several easy steps can be taken to ensure the best performance from your fridge or freezer.

When buying a new appliance, do not buy one that is bigger than your needs.
Free standing appliances positioned in a cool place perform best.
Keep the coils at the back dust free as accumulation of dust on condenser coils can increase energy consumption by up to 30%.
DIY insulation around the sides of the appliance saves energy consumption.
Do not fill more than ¾ full to allow for circulation of cold air.
Always defrost regularly.
Check door seals for leaks.
Cool and cover foods before placing into the fridge or freezer.
A thermometer is a useful instrument to have in your appliance so that the temperature can be kept constant (3°C to 5°C for fridges and -18°C for freezers).

Around 2000 tonnes of CFCs are contained in the three million fridges scrapped in the UK each year. The CFC coolant can be removed - this is compulsory in Sweden, Germany and The Netherlands but not in the UK (only 15% coolant is currently recovered), although most local authorities offer this service. Even if CFCs in coolants were recovered from all scrapped fridges, 80% of CFCs used in refrigeration could still be emitted into the atmosphere as the UK currently has no facilities for reclaiming CFCs present in the insulation foam, which is released when the machine is shredded. A Danish company has developed a process to recover 85% of the CFCs in the insulation foam by crushing the fridge/freezer under water and collecting the CFCs given off.

Some manufacturers and retailers offer trade-ins and recovery of CFC coolant. Repairs can be difficult as manufacturers do not readily supply spare parts, but the German companies Siemens and Bosch have excellent spare parts policies which Liebherr and AEG are beginning to emulate. The industry is making recycling easier and AEG, Liebherr and Bosch code all their plastic components to simplify sorting and recycling. Siemens already have their old appliances returned to them for recycling. Calor Gas has a reclaim policy for its hydrocarbon refrigerants and will reprocess or incinerate depending on their state.