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Refrigeration

Energy efficiency and refrigeration
Refrigeration case study
Refrigeration tips

Energy efficiency and refrigeration

Refrigeration systems are a critical element of any business needing to preserve perishable items or cool non-perishable products for sale. Your selection of equipment and the way in which you operate it can have a big impact on your energy bill.

Like lighting, refrigeration is an often overlooked source of energy saving. In fact, in some businesses, refrigeration is the largest component of energy costs.

A key point to remember when looking at reducing refrigeration energy is that the aim is to save energy without compromising the quality of the product. Poor temperature control of food is a major cause of food poisoning. It is vital that your business has a good understanding of the health and safety requirements for the types of food you deal with. For more information regarding food safety, contact your Local Government Environmental Health Officer.

Refrigeration case study

Cafe saves energy and improves quality

A regional Western Australian cafe adjusted its refrigeration system to save energy and improve product quality.

The cafe has a large refrigerated walk-in cool room for the storage of drinks and food. The unit has six large glass doors for displaying drinks and is cooled by a system that includes an outdoor compressor unit and an evaporator mounted in the cool room.

The evaporator is mounted at one end of the rectangular cool room on a short wall opposite the entry door. The glass doors and storage shelves are arranged along a long wall of the room (see figure below).

Figure 1: Cool room layout

This cool room design led to a few problems. In order to keep the drinks at the access door end cold, the temperature control thermostat had to be set very low. Because the cold air did not circulate effectively through the cool room, food and drinks near the middle and evaporator-end of the room were freezing. To overcome this problem, foodstuffs such as lettuce (which freezes very quickly) could only be stored near the access door.

So excess energy was being used because the compressor was working harder than necessary, and food quality was suffering.

The solution? The owners installed a small fan in the room to circulate the air and stacked their stock in a configuration which promoted good airflow. This meant the thermostat could be set at a higher temperature – 4°C as compared with the previous temperature of almost 0°C.

The results – improved product quality and lower energy usage.

The cost of installing and running the fan was more than offset by the improved energy efficiency and product quality. The cafe estimated that the payback for the fan installation would be less than two years.

This case demonstrates that it is possible to decrease energy usage and improve product quality at the same time.

Summary

Note: Whilst care has been taken in the preparation of this material, it is intended to provide a general idea about what can be achieved in a particular situation. Quantitative indicators may vary with time and changing circumstances. Each situation is different, requiring its own evaluation; and therefore the results given above should not be taken as being directly transferable to other circumstances. Names and addresses have been withheld for privacy reasons.
 

Refrigeration tips

Reduce the cooling load

Reducing the amount of cooling required from your refrigeration system means the system doesn’t have to work as hard. To achieve this you could try changing your temperature settings, switching off display or internal lighting and controlling anti-sweat heaters.

Reduce the heat intrusion

Stop warm air from getting in, and cold air from getting out, by managing your system to limit door openings, covering open fridges and maintaining your door seals.

Improve cooling efficiency

Strategies to reduce the energy needed to maintain a cool environment include improving internal air circulation and keeping evaporators clean and ice-free.

Improve the heat transfer efficiency

Help your system operate more efficiently and reduce energy costs by improving air circulation over the condensers, keeping the condensers clean and locating them in the coolest location.

Managing the use of the refrigeration system

The way you use your refrigeration system can have a big effect on running costs. You can improve performance by managing stock levels and consolidating stock, loading stock in batches (perhaps even at night), turning off refrigeration systems when not required, only cooling what's needed (non-perishables) and regularly monitoring the system.

Buying the correct system

The best time to save energy is when you are purchasing new equipment. Selecting the right refrigeration system for the job saves energy, and money. Consider your size and temperature requirements, door/access type, insulation, equipment location, controls and monitoring.

Further information

Find out how to reduce your energy costs, by contacting Synergy's Energy Consultants. Just email us at  energyreview@synergyenergy.com.au or call 1300 859 333.

For more information on energy efficiency in your business visit the Sustainable Energy Development Office at http://www1.sedo.energy.wa.gov.au