Refrigeration systems are one of the biggest energy users for businesses — making them a key area for cost and energy savings. On this page you’ll find tips for running your system efficiently, and considerations for installing new systems or upgrades.  

Smarter refrigeration systems

In 2023, refrigeration was the third largest user of electricity in New Zealand — after hot water cylinders and electric furnaces.* So, running your system efficiently doesn’t just lower your bills, it can help ease the demand on New Zealand’s electricity supply. 

Whether it's small tweaks to your maintenance routine or investing in upgrades to your current technology, optimising your system can deliver real benefits — including better protection of your products.  

On this page

Maintenance of refrigeration systems 

Well-maintained refrigeration systems operate more efficiently, last longer, and reduce product spoilage — saving on your business costs.  

  • Inspect and repair door seals — poor door seals let warm, humid air into refrigerated areas, increasing the temperature and frequency of evaporator defrosting. Keeping door seals in good condition can save 1-5% of your refrigeration costs, typically covering the repair or replacement costs in under 1 year. 
  • Inspect and repair insulation — poor insulation increases heat gain and refrigeration costs. You can use thermal imaging surveys to find areas of poor or failed insulation.
  • Clean condenser coils — dirty condenser coils raise the condenser temperature and pressure, reducing the efficiency of your refrigerator. Keeping coils clean can save 2-3% of your refrigeration costs for every 1°C reduction in condenser temperature, savings usually cover any costs in just a few months. 
  • Train staff to spot issues — knowing the warning signs of an underperforming refrigerated space, and fixing problems early, helps avoid bigger issues later. 

Find the right technician

When you’re maintaining, installing or upgrading your equipment, always seek advice from a qualified engineer. Ensure anyone servicing your system holds the right certifications and follows the IRHACE Code of Practice. This helps ensure your system is safe, compliant, and running at peak efficiency. 

Optimise performance of your refrigeration system

Ensuring your refrigerator is performing well at optimum settings can avoid wasted energy — saving on energy costs.

  • Use defrost sensors

    Sensors automate defrosting so that it only occurs when needed — saving energy. This can save 5-10% of your refrigeration costs — usually paying off your sensors in under 3 years.  

  • Reduce peak time usage

    Cool stores hold temperature well, especially in winter, so refrigeration can often be turned off during peak demand times. This can cut peak charges by up to 50% in wintertime, depending on your electricity tariff structure.   

  • Optimise multiple compressor control

    Run large screw compressors at full load and using the smaller screw or reciprocating compressor to trim capacity. This can save 5–15% of the energy needed, usually paying off the extra controls in less than a year. 

  • Increase suction pressures

    Increasing the suction temperature and pressure reduces the compressor work for a given amount of cooling. This can save 1-5% of your refrigeration costs and the changes required usually have a payback of under 1 year. 

  • Lower the head pressure

    Reduce pressure and energy use by lowering the condenser temperature with some simple setup changes. This can save up to 30% of your refrigeration costs, often with a payback period of just a few months.

  • Use cooling tower controls

    A constant fan speed can cause excessive cooling. A temperature switch or a variable speed drive can turn the fan off or down when not needed. This can save 20–80% of fan energy use, with a payback period of 1-2 years. 

Upgrade or install a refrigeration system

When designing a new refrigeration system, or upgrading your current one, make sure any new features are the right size for your needs. Smart design choices that optimise your equipment can save thousands on running costs. 

  • Use good insulation and automatic doors 

Using correct insulation panelling and installing rapid roller doors in the design phase will minimise heat gain and reduce long-term operating costs.

Rapid roller doors reduce air interchange, lowering heat gain and slowing evaporator frosting. They can be used in conjunction with well-maintained strip curtains. Each of these could save you thousands of dollars in energy costs each year.  

  • Choose a low GWP refrigerant 

When equipment such as walk-in chillers and refrigeration cabinets have refrigerant leaks, more energy is used to keep it running, and refrigerant gas is lost to the atmosphere, increasing the emissions of harmful hydrofluorocarbons (HFCs).  

Replace systems with a high Global Warming Potential (GWP) refrigerant with low GWP gases such as CO, propane and ammonia. Ensure that any remaining high GWP systems are well maintained and checked regularly for leaks.

  • Install variable speed drives (VSD) on fan motors 

A constant fan speed causes excessive cooling at times. A VSD can be used on evaporator fans, and cooling tower fans, slowing the fan when possible, saving power and ensuring more stable temperatures. A fan at half-speed uses less than 20% of the energy a fan at full-speed uses. 

  • Capture and reuse waste heat

Refrigeration systems generate heat and release it into the surrounding air. This heat energy is valuable, and with the right setup can be captured and reused for other purposes. Consider installing heat recovery technology to repurpose waste heat for water heating or space heating.  This helps reduce your energy bills and makes use of energy you’ve already paid for. A desuperheater (heat exchanger) could save you the hot water equivalent of around 50% of your refrigeration energy use, with a payback period of just a few years. 

Learn about heat recovery systems(external link) 

Know the regulations 

EECA (the agency that backs Gen Less) regulates some types of refrigeration units. This ensures that only those that meet specific efficiency and performance requirements are sold in New Zealand.  

  • Refrigerated display cabinets — have glass fronts and are often seen in cafes and supermarkets. 
  • Refrigerated storage cabinets — look like a household fridge or freezer and are used in commercial kitchens. 
  • Ice cream freezers, and scooping cabinets — often seen in cafes and convenience stores.

There is a voluntary star rating system for these regulated refrigerators which can help you compare specific models. 

 

Search the database(external link)

Additional resources

Further information, free tools and resources to improve energy efficiency of refrigeration systems and dispose of refrigerants safely.

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