Cool energy saving: how to cut energy waste from refrigeration and chilling
With an ongoing focus on energy and carbon management and cutting costs, the FMCG sector has a need to achieve energy savings, and refrigeration and chilling is the perfect place to focus.
Whether it be manufacturing processes, food storage in distribution centres, or the operation of supermarket displays, industry producers, distributors and retailers can often expect around 50% of their site’s electricity costs to be from the use of refrigeration technology. In food transportation, the use of on-board refrigeration can account for 25–40% of a vehicle’s total fuel consumption.
Naturally, any savings in energy will hugely improve bottom-line operating costs, as well as enhancing environmental impact through reduced CO2 emissions.
Where to focus
It may be the case that existing equipment is old and operating inefficiently and, therefore, requires financial investment to upgrade or replace it with modern systems, for example by using high-efficiency chillers, pump motors and controls, or display cabinets.
There are some relatively straightforward and low cost changes that can be made, such as modifying refrigeration process temperatures that have been set too low. Overcooling by 1°C can increase energy consumption by 2–3%, according to the Carbon Trust, which states that raising the temperature of a frozen food store room set at to -25°C to -20°C could save 10 to 15% of the refrigeration energy.
Some more easily identifiable solutions will help cut energy costs by up to 20%. Most are simply good housekeeping and usually require minimal investment.
Lighting in cold stores/chill rooms and retail display cabinets should be switched off when not required. Where doors are fitted, they need to be checked to ensure that they close properly and are then kept closed whenever possible. The Carbon Trust estimates that open doors can add £2 per hour to energy costs for chill rooms and £6 per hour for freezers. Door seals also need to be checked to ensure that they are not damaged and that chilled air is not escaping. This might be clearly evident in supermarkets if the customer aisles leave customers shivering.
Store areas and refrigerator cabinets should not be overstocked such that the chilled airflow is blocked or restricted. But space that is underused will also result in a reduced level of overall economy. Placing polystyrene boxes to fill the empty spaces will minimise the total volume of air that requires chilling and reduce the amount of energy required for refrigeration and freezer equipment.
Ice build-up reduces heat transfer efficiencies, and consequently freezers use more energy. So, it is important to keep freezers free from ice.
Efficiency innovation
Other more current solutions may be used to eliminate inefficient energy losses from supermarket refrigerator display cabinets, as well as reduce retail food waste. This includes the trialling of fitted glass doors, or alternatively, airflow management systems within multi-deck refrigerator cabinets which can provide energy savings of “more than 25% compared with conventional open front display cabinets” (FMCG news).
It might also be worth careful consideration of more elaborate options such as free cooling at low ambient temperatures during colder months of the year and the application of heat energy recovered and recycled from refrigeration systems for use in other building services, such as domestic hot water systems
Improving maintenance
Unfortunately, there are symptoms of other operating inefficiencies that will not be as easy to recognise and diagnose unless the equipment’s performance is frequently monitored, and inspections and maintenance activities periodically completed.
Performance monitoring not only ensures that refrigeration equipment is kept at optimum output, but also helps identify potential problems that could cause unwanted breakdowns. As expected, monitoring will require accurate measurement of specific operating parameters, and if this is not possible from instrumentation fitted to the equipment as standard, then monitoring will need to become part of the overall maintenance regime.
Poorly maintained refrigeration equipment will notably increase energy consumption, in some instances by up to 10%. Regular maintenance should check for any unusual operating problems. Do refrigeration pumps sound noisy? Is the refrigerant level satisfactory and/or is there any evidence of refrigerant leaks? Also, check that refrigerant pipework insulation is intact, and that condenser and evaporator circuits are not damaged and are clean and not blocked.
As you can see, there is plenty of scope to cut energy waste by increasing efficient operation of refrigeration and chilling equipment – providing impressive potential for reducing running costs and your carbon footprint.
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