With the increasing urgency of addressing climate change and meeting net zero targets, coupled with the rising cost of energy, it’s no surprise that discussions around reducing energy consumption are centre-stage across most industries.
In the refrigeration sector, one proposed solution is to raise the standard storage temperature of frozen foods from -18°C to -15°C. Proponents argue that this shift could save substantial energy, but there are many challenges that make it a far from straightforward solution. Here, Steve Shipp, Managing Director of Ultra Refrigeration, explores why the move to -15°C may not deliver the promised benefits, and could even create new problems for both businesses and consumers.
The Assumed Benefits vs. The Complex Reality
The main argument in favour of raising frozen storage temperatures centres on energy savings. Running refrigeration equipment at -15°C instead of -18°C is believed to reduce energy consumption significantly, as maintaining colder temperatures requires more power. This notion appeals to those looking to make quick and easy sustainability wins in the cold storage and food retail sectors.
However, the reality is much more complex. Changing temperatures in frozen storage isn’t as simple as turning a dial. The existing cold storage infrastructure has been carefully optimised for -18°C over decades. Simply raising temperatures to -15°C without modifying equipment, settings and controls can result in inefficiencies. Depending on their flexibility, refrigeration packs may become less stable, with once fine-tuned compressors that are now too large for the application ‘hunting’ rather than finding a steady point. This can lead to reduced system stability, inefficiency and increased maintenance costs; all of which defeat the original intention.
Cold Chain Integrity, and Food Quality and Safety
Maintaining a consistent temperature throughout the cold chain is crucial to food quality and safety. When food products are stored at -18°C, there is an important safety buffer; if there’s a temporary rise in temperature during transport or storage, the product is less likely to reach unsafe or quality-compromising temperatures.
However, with a storage target of -15°C, this safety buffer shrinks. Any exposure to ambient temperatures risks pushing the product above -15°C, potentially leading to partial thawing. And if the next stage of the cold chain is also set to -15°C, there is little or no temperature differential (TD) to pull the temperature back down. The reality is that minor variations are inevitable during cold chain transportation and unloading. For example, items are sometimes left on loading docks temporarily or placed in retail storage areas where temperature control may be inconsistent. Without the safety buffer at -18°C, any temperature increase is likely to cause visible thawing, which can compromise the product’s texture and quality before it even reaches consumers.
Consumer Experience and Perception
The impact of this temperature change will extend to consumers’ experiences and perceptions of product quality. When consumers purchase frozen goods stored at a higher temperature, the time spent out of refrigeration during transport from store to home is much more likely to be enough to cause partial thawing.
Many frozen foods are fragile and will noticeably soften or structurally deteriorate even if they remain technically within the ‘safe’ zone at -15°C. By the time the consumer unpacks their groceries at home, products like ice cream may have lost their firmness and other frozen items may begin to show signs of thawing.
This could adversely impact on consumer trust. When items consistently fail to meet expected quality, shoppers are likely to lose confidence in a brand or store, even if they’re unaware of the reasons behind the shift.
We’re aware that a major UK supermarket is currently trialling the move to -15°C and it will be interesting to note the impact not just on energy use and emissions, but also on consumer perception of food quality.
Transferring the Energy Burden to the Consumer
Interestingly, the proposed shift to -15°C won’t necessarily reduce the total energy required for the cold chain; rather, it redistributes it. By reducing the energy demand on commercial storage facilities, the need to restore items to their optimal temperature simply shifts to consumers. Most household freezers are not designed to handle frequent refreezing, and they tend to be less efficient than commercial systems. Because partially thawed products will be entering home freezers, consumers will inadvertently bear the cost of re-freezing—both in terms of energy consumption and product quality.
The cost implications are twofold: while businesses save on operational expenses, consumers are left with increased energy bills. This shift could also increase the collective energy demand on a national scale, placing additional pressure on the electrical grid. In an era of energy sensitivity, moving the problem down the chain to consumers could undermine sustainability goals rather than support them.
Food Quality and Shelf-life Concerns
The argument for shifting storage temperatures often overlooks the intricate relationship between temperature and food quality, particularly in frozen goods. Although -15°C may seem sufficient for most foods, it’s arguably a borderline threshold for maintaining quality over extended periods. In addition, products like ice cream require lower temperatures (down to -24°C) to prevent changes in texture and taste. Even marginal temperature increases can lead to a degradation in quality, particularly in items stored for longer periods or with high moisture content.
The shelf-life of frozen foods depends on stable, low temperatures, and raising the temperature to -15°C may result in shorter shelf-life or inferior quality particularly, as we’ve seen, minor temperature fluctuations are inevitable in the cold chain. For retailers, this shift could lead to an unwanted cost in terms of higher rates of food spoilage and waste.
Ice Cream – a Special Case
As we’ve mentioned, ice cream requires a much lower than standard storage temperature, typically down to -24°C. This requires it to be stored separately, at a lower temperature, especially if other products are held at -15°C. This requirement complicates in-store operations, as retailers will need separate ice cream freezer display cabinets or risk compromising product quality. This will limit the opportunities for moving product categories around and reduce flexibility for shop floor merchandising. And for businesses with limited backroom space, the cost and logistical challenges of adding additional separate overflow freezer space for ice cream could be prohibitive. The alternative is to run all backroom storage at -24°C to satisfy the needs of ice cream, but over-freezing all other products (and wasting energy).
An Alternative Path: Smarter Control and Energy Efficiency
Instead of making a blanket change to storage temperatures, we would advocate a more intelligent approach to refrigeration management. Rather than setting a uniform -15°C, businesses could optimise their energy use through dynamic, intuitive controls. This approach involves adjusting air and product temperatures more strategically within each storage environment to balance efficiency with quality.
For example, storage could be designed to maintain product temperatures around -15°C while briefly lowering the air temperature to -18°C when needed. This method would preserve the quality of frozen products without imposing the same energy demand as constant -18°C storage. Such dynamic systems can be integrated with sensors and software that track ambient temperature trends and adjust cooling cycles accordingly, allowing for closer control and reducing energy usage over time.
Conclusion
While the concept of shifting to -15°C for frozen storage may sound appealing to those seeking quick, cost-cutting solutions, as we’ve seen it’s not the universal panacea it’s portrayed to be. The move oversimplifies the complexities of cold storage and risks transferring costs down the chain to consumers, potentially compromising food quality and creating inefficiencies in other areas.
We believe a more effective way to balance energy efficiency with food safety and quality is to leverage advanced refrigeration technology that allows for smarter, dynamic control over storage conditions. As the push for sustainability continues, it’s essential to take a holistic approach that addresses all aspects of the cold chain, rather than relying on simplistic solutions that might ultimately not deliver the promised benefits.
This ‘one-size-fits-all’ solution could end up harming both product quality and customer satisfaction, while failing to deliver the promised reduction in carbon emissions and energy costs. It’s potentially causing us to take our ‘eye off the ball’ in terms of seeking tangible refrigeration engineering solutions. It seems we’re pushing the limit and hoping for the best. As always, the devil is in the detail.
If you would like to discuss aspects of your existing refrigeration equipment, or want to talk about a new project, please get in touch by emailing us today at info@ultraref.co.uk or calling us on +44 (0) 330 2232404.
