Supermarkets opt for SA’s cutting-edge green chill

Compiled by Eamonn Ryan

In an era where sustainability is paramount, supermarket chains are rewriting the playbook for refrigeration equipment.

Gone are the days of energy-guzzling, emissions-pumping cooling systems; instead, they’re embracing eco-friendly commercial refrigeration. From closed door freezers to smart sensors and natural refrigerants, forward-thinking stores are setting a new standard for environmentally responsible supermarket cooling. Check out this month’s project as an illustration.

CO₂ supermarket refrigeration cabinets had not been thought appropriate for hot climates like South Africa – but this country is developing into a centre of excellence for them, driven by leading retailers such as Woolworths which has been installing such systems for the past 15 years.

There are several types of refrigerators and cabinets that are commonly used in supermarkets. Here are some of the most common types and their uses:

Curved glass fridges: These fridges come in a variety of sizes and shapes and are particularly well-suited for storing deli meats. They give customers a full and unimpeded top and front view of products through the curved panels.

• Upright glass fridges: These fridges have sliding or static square glass fronts and can often be used as alternatives to curved glass ones. They serve extremely well at deli counters or butcheries.
• Baine Marie: This is a serve-over counter-type fridge, a variation on curved glass refrigerators. These are ideal for deli counters and the service of prepared foods. They feature stainless steel containers with lids, over a section filled with water. The water is held at a constant temperature to keep the foods warm or cold – whichever is applicable.
• Wall chillers: These are upright fridges that are designed to be placed against a wall. They are ideal for storing drinks and other items that need to be kept cool.
• Island fridges: These are large, open fridges that are designed to be placed in the middle of a supermarket floor. They are ideal for storing large quantities of items that need to be kept cool, such as fruits and vegetables.
• Low boys: These are low-height fridges that are designed to be placed under counters. They are ideal for storing items that need to be kept cool, such as drinks and dairy products.

The refrigeration and cooling equipment industry faces challenges in terms of energy efficiency and the use of natural refrigerants. However, there are opportunities to improve the efficiency of the equipment and to use new technologies such as magnetic bearings, graphene and aerogels.

Recommendations for proper supermarket refrigerator maintenance

Breakdowns to commercial refrigeration can be extremely costly to a supermarket. For this reason, it is vital that fridges be maintained carefully and consistently. Just Refrigeration shares its essential recommendations for good commercial refrigerator maintenance.

• Deep clean your fridges inside and outside: Your fridges will need a deep clean every few months. Remove all items from the interior and move them to another unit. Scrub the shelves and interior walls with a soft brush and a warm soap or vinegar solution. Remove the shelves and soak them before scrubbing them individually. Be sure to clean up any spills or stains. Wipe down the exterior of the fridges and remove any dirt that may have collected on the door seals.
• Clean the condenser coils: Every three months, you should clean your condenser unit. Dirt or dust that may collect on the unit can make it difficult for the fridge to maintain a consistent temperature. First, disconnect the power and use a stiff-bristled brush to clean away dust. You can also use a vacuum cleaner to remove dirt.
• Clean the evaporator coil: Keep the evaporator coil clean as well. It can be cleaned in much the same way as the condenser coils.
• Clean tubes and drain pans: These should be cleaned every month. Clean the pan using a vinegar solution or warm soap water and keep a careful lookout for any blockages in the tubes.
• Clean the door seals: They seem like such an insignificant component, but door seals are actually more important than you realise. They can be cleaned monthly, or even more frequently if the fridge is positioned in a kitchen where grease is regularly used.

Supermarket equipment sector adapts to energy efficiency and environmental friendliness

South African companies are at the forefront of innovation for rugged conditions, developing solutions tailored to local market needs and attracting swelling global interest, says Mark Howitt, sales director: HC Group.

There is a heavy reliance on local manufacturers for equipment and components in South Africa. While CO₂ technology has gained traction domestically, challenges have persisted in ensuring consistent supply and accessibility of parts.

HC Group itself is at the forefront of pioneering initiatives to meet growing demand for eco-friendly refrigeration solutions in the supermarket sector. By leveraging new technology, HC Group aims to set new standards for energy efficiency and environmental stewardship.

“Though market trends in refrigeration equipment have seen minimal changes over the past decade, HC Group subsidiary RRC (Refrigerated Retail Cabinets) differentiates itself through adherence to European standards and robust design tailored for the African market. Unlike European suppliers whose products may prioritise aesthetics over durability, we rather prioritise functionality and resilience to withstand the rigours of African conditions. Additionally, our efficient assembly process and extensive stock availability contribute to shorter lead times, providing customers with swift and reliable service, enabling the group to facilitate tailoring their refrigeration solutions to specific needs and preferences,” he adds.

RRC adopts a collaborative approach to manufacturing, sourcing standard cabinet components from Europe and customising them to suit African requirements. “By modifying the design to enhance durability and incorporating metal components in place of plastic, we can ensure that our refrigeration units are built to withstand the challenges of African transportation and usage.”

The context for HC Group’s innovation drive is a supermarket refrigeration equipment sector that faces increasing pressure to prioritise energy efficiency and environmentally friendly refrigeration and cooling equipment.

Another trend Howitt points to is the widespread transition from simplex refrigeration systems to more efficient multiplex systems. While this shift has been ongoing for years, it remains the central strategy for enhancing energy efficiency in supermarket operations. However, challenges persist in outlying areas, where technical expertise and availability of components may limit the adoption of advanced systems.

There is a heavy reliance on local manufacturers for equipment and components in South Africa. While CO₂ technology has gained traction domestically, challenges persist in ensuring consistent supply and accessibility of parts.

“Efforts to enhance energy efficiency extend beyond refrigeration systems to include innovations such as cabinet doors. The widespread adoption of glass or acrylic doors in supermarkets reflects a collective commitment to reducing energy consumption and optimising cooling efficiency. Moreover, advancements in compressor technology, such as variable speed drives, contribute to further energy savings and operational efficiency.

Transitioning to advanced refrigeration systems like CO₂ poses technical challenges, particularly in terms of maintenance and skill requirements. While multiplex systems offer greater efficiency, they also demand a deeper understanding of controls and operation. Overcoming these challenges requires ongoing training and education for maintenance personnel to ensure the seamless integration and optimal performance of new equipment, explains Howitt.

There has traditionally been a psychological barrier associated with installing doors on refrigeration units. “While there is a convenience in open display cases, the energy-saving benefits of enclosed units is trumping convenience. By preventing temperature fluctuations and minimising energy loss, refrigeration units with doors offer substantial efficiency gains, with potential energy savings ranging from 40% to 50%. Additionally, the longer shelf life of perishable goods stored in enclosed units contributes to reduced wastage, a significant consideration for retailers,” says Howitt.

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Shift in refrigerants

He notes that notwithstanding the global push towards natural refrigerants like CO₂, the adoption rate varies across different regions and supermarket chains. While major supermarket groups have long embraced CO₂ technology, others remain cautious due to concerns about technical complexity, rural skills shortages and gas availability. Additionally, regulatory hurdles and safety considerations surrounding flammable refrigerants like R290 pose challenges to widespread adoption, despite their environmental benefits.

Challenges arise in navigating safety concerns and regulatory frameworks as the industry moves away from hydrofluorocarbons (HFCs) and towards natural refrigerants. The transition to low-GWP (Global Warming Potential) alternatives presents both opportunities and complexities, particularly in ensuring compliance with evolving regulations and addressing safety considerations. While Europe leads the way in adopting sustainable refrigeration practices, other regions, including Africa and America, are more gradually embracing these innovations. However, significant disparities persist, with many supermarkets still reliant on traditional refrigerants.

“With regulations prohibiting the release of refrigerants into the atmosphere, the industry is shifting towards more sustainable practices, including the recovery and reuse of gases. While some companies offer services to evacuate and recover refrigerants, the focus is increasingly on adopting natural refrigerants like CO₂, which eliminate the need for evacuation and pose fewer environmental risks.”

In South Africa, regulatory frameworks regarding refrigeration standards and environmental sustainability are still evolving. While international agreements like the Kigali Amendment signal a global commitment to phasing out harmful refrigerants, implementation and enforcement vary across regions. While South Africa is a signatory, Howitt notes the absence of stringent local regulations compared to Europe, where compliance is more rigorously enforced. Despite efforts to raise awareness through workshops and conferences, regulatory deadlines remain ambiguous, reflecting a slower pace of change in the African market.

“However, the long-term benefits of natural refrigerants like CO₂, including lower maintenance costs and reduced environmental impact, make them increasingly attractive despite the initial capital investment.”

He highlights the importance of considering lifecycle costs over upfront investments, particularly for large retailing groups. “While upfront capital expenditure may be higher for eco-friendly refrigeration solutions, the lower maintenance costs and enhanced sustainability align with the companies’ environmental commitments and long-term objectives. Moreover, the push towards carbon neutrality and sustainability goals further incentivises investment in green technologies, driving demand for energy-efficient and environmentally friendly refrigeration systems.”

Beyond regulatory compliance and cost considerations, there is a broader cultural shift towards quality control and food preservation. “By maintaining consistent temperatures throughout the supply chain—from manufacturing to distribution to retail—companies can enhance food quality and reduce waste. This holistic approach underscores the importance of temperature control as a critical factor in ensuring product integrity and consumer satisfaction.”

While regulatory challenges and market dynamics present obstacles to widespread adoption of eco-friendly refrigeration solutions, there’s a clear momentum towards sustainability and environmental responsibility. By addressing regulatory uncertainties, promoting technological innovation, and aligning incentives with long-term sustainability goals, the refrigeration industry can pave the way for a greener, more efficient future.

 

CO₂ installations set to revolutionise supermarket refrigeration

The world is looking closely at CO₂ systems in South Africa because it had not been thought that CO₂ systems were suited to hot climates – yet they perform well in hot South Africa when designed in more robust forms.

Richard Drinkrow, MD of Mainstream Refrigeration, says CO₂ installations have rapidly gained popularity among supermarkets in recent years. “For at least the past 15 years,” he explains, “supermarkets have been on a journey to save energy, convert to non-greenhouse gases, and move away from ozone-depleting freons.” This journey, rooted in both environmental responsibility and business pragmatism, has yielded substantial energy savings for supermarkets over time.

One of the pivotal moments in the evolution of CO₂ installations was the advent of advanced technologies designed to enhance energy efficiency. Drinkrow recounts a groundbreaking project initiated some years ago, which aimed to test the efficacy of various energy-saving technologies in refrigeration systems.

“We implemented electronic expansion valves, high-speed EC fans, variable speed drives on compressors, and other innovative solutions, the team achieving significant energy savings of over 45%. This success laid the benchmark for subsequent endeavours focused on further reducing energy consumption in refrigeration systems,” he says.

Industry focus then shifted to alternatives to traditional refrigerants with high global warming potential, such as R404a. Two main options emerged: CO₂ and hydrocarbons. Drinkrow emphasises the superiority of CO₂ due to its minimal environmental impact and non-flammable properties.

“While hydrocarbons pose lower pressure risks,” he noted, “the safety and environmental benefits of CO₂ make it the preferred choice for most supermarkets.” This shift towards CO₂ installations has proven highly successful, with energy savings exceeding expectations.

Today, approximately 95% of the new refrigeration systems installed in projects Mainstream Refrigeration is involved in utilise CO₂ technology, underscoring the industry’s commitment to sustainability and their efficacy in achieving both environmental and economic goals.

“Initially, one of the primary challenges encountered with CO₂ installations was the scarcity of equipment capable of handling the high pressures associated with this refrigerant. However, the market has since evolved, with a plethora of products specifically designed for CO₂ refrigeration now readily available. Furthermore, in the beginning the premium paid for CO₂ plants could range from 30 to 35%. However, as the market matured this margin has significantly decreased to around 5 to 10%.” This reduction in cost differential highlights the increasing affordability and viability of CO₂ installations for supermarkets.

However, notwithstanding the clear advantages of CO₂ technology, Drinkrow says not all supermarket chains have embraced it uniformly, highlighted varying philosophies among companies regarding equipment investment and maintenance practices.

“Some supermarket groups prioritise long-term efficiency and reliability. They invest in high-quality equipment designed to operate efficiently for over 15 years before considering upgrades. In contrast, others adopt a more short-term approach, opting for cheaper systems with shorter lifespans,” he adds.

Driven by multinational retailer interest in CO₂, the technology is expanding beyond the borders of South Africa, as far as Dubai, with local manufacturers like Mainstream Refrigeration leveraging word-of-mouth referrals and inquiries to secure projects globally. “Word of mouth plays a significant role. Potential clients seek information, leading to discussions and eventual collaborations. African nations like Namibia are spearheading initiatives to transition to eco-friendly refrigerants, presenting opportunities for local manufacturers to export their expertise and products.

“Beyond Africa, global interest in CO₂ technology extends to regions like the Middle East, where extreme temperatures and power challenges necessitate resilient refrigeration solutions.” Despite competition from international players, South African companies are poised to capitalise on their reputation for quality and reliability.”

As to why such systems are generating interest as far afield as Dubai, Drinkrow attributes the success of CO₂ installations in challenging environments, such as hot climates and regions prone to power outages, to their reliability and durability. “This is due to the robustness of the software linked to them – while imitators can copy parts – the software is a differentiator that is stimulating interest in South African CO₂ systems. “Surviving frequent power disruptions and adapting to extreme conditions demonstrate the robustness of our CO₂ technology in real-world scenarios,” he adds.

Drinkrow reinforces the critical role of software controls in optimising CO₂ refrigeration systems. Drawing parallels with automotive advancements, he highlights how electronics and engine management systems have revolutionised energy efficiency in refrigeration. With precise control over variables such as fan speed, compressor operation and energy consumption, CO₂ systems are continually evolving to deliver greater efficiency and performance.

Addressing concerns about skills shortages, particularly in South Africa, Drinkrow emphasises the resilience and adaptability of modern refrigeration systems. Advanced controls and remote monitoring capabilities empower technicians to troubleshoot and maintain CO₂ plants effectively, even with limited on-site resources.

“A commitment to research and development underpins the industry’s quest for continuous improvement. Companies are constantly exploring new technologies and methodologies to enhance system efficiency and reliability. While not every endeavour yields success, the willingness to experiment and innovate ensures that CO₂ refrigeration remains at the forefront of sustainable cooling solutions.”

While CO₂ systems offer numerous advantages, integrating them with existing infrastructure can pose challenges. Drinkrow cautions against using components designed for conventional refrigerants, as the higher pressures of CO₂ systems require specialised equipment. Safety remains paramount, with precautions necessary to prevent pressure-related incidents and ensure proper system functionality.

R744 booster systems in commercial refrigeration

By Oliver Javerschek, application engineering and product performance, and Tobias Fuhrer, product manager reciprocating compressors, BITZER.

In recent years, transcritical CO₂ systems have largely become standard practice in commercial refrigeration, such as in supermarkets and medium-sized cold stores. The systems are increasingly becoming integrated system solutions for low and medium temperature applications as well as air conditioning and heating. Co-ordinated interplay and control of the individual system components pave the way for a stable, reliable operation mode for the entire year.

BITZER analyses countless systems in close co-operation with customers and partners. Building on tests in its laboratory and demonstration systems, BITZER supports its customers from planning and building new commercial refrigeration systems to retrofitting pre-existing ones. By equipping compressors with VARISTEP mechanical capacity control, it becomes possible to build efficient refrigeration systems with excellent capacity graduation in the smallest of spaces, as demonstrated by a few case studies below.

The challenges of refrigeration in supermarkets

Supermarkets are characterised by their highly changeable need for refrigeration depending on the time of day or customer footfall. Besides the well-known basic requirements such as observing the permissible operating conditions and ensuring functional oil management, the capacity control must be tailored to the application for compressors to operate smoothly. The purpose of capacity control in parallel compounding is to cover minimum loads in order to minimise on-off cycles, especially in the lead compressor, and achieve a high control accuracy (CF) with minimal capacity changes per step, so as to lower operating costs and increase the reliability of the system.

In recent years, rationalisations in systems and installations have, in practice, often led to conflicting requirements in terms of high efficiency, low system complexity and low investment costs. Common consequences include unfavourable system performance and poorer operating reliability, such as due to:

• a reduced number of compressors and/or excessively large compressors per suction group
• active liquid injection with regular subsequent injections in lieu of an external desuperheater for the low temperature stage
• low temperature capacity control with on-off cycles instead of capacity control with a frequency inverter
• even stricter heat recovery requirements
• heat recovery systems without storage tanks on the hot water side
• less time needed for production, installation and commissioning
• a reduced number of filter and oil changes

The discharge gas temperature illustrates the effects on the lead compressor. A standard compound control system monitors the following variables independently of one another and features a safety cut-out for the high pressure, discharge gas temperature, suction gas superheat, oil level and motor temperature. The permitted discharge gas temperature in particular depends on the pressure ratio, suction gas superheat, operating frequency, operating time and dynamics of the operation. A lower operating frequency and higher suction gas superheat affect the thermal load of the compressor and lower its application limit.

• Highly unfavourable operating conditions for the lead compressor in the medium temperature stage are characterised by:
• Daytime operation with lots of on-off cycles in the lag compressors and unstable (fluctuating) operating conditions brought about by low control accuracy
• Night-time operation with low operating frequency and regular pump-down cycles with a high-pressure ratio and high suction gas temperatures
• Night-time operation with low operating frequency and a high number of on-off cycles, characterised by an active liquid injection before the lead compressor was shut down causing an excess of liquid refrigerant on the suction side during the restart delay
• The conditions shown as examples indirectly affect the tribology of the compressor drive gear and can result in increased wear on the bearings.
• An excessively low control range and significant load or capacity changes result in instability in the overall system, especially when the control range of the lead compressor is unable to compensate for the drops in capacity caused by other compressors switching on and off. Control accuracy is used to describe this relationship. It is the difference between the capacity of the lead compressor at maximum and minimum frequency, divided by the capacity of the subsequent compressor (source: ASERCOM, see also www.bitzer.de/shared_media/html/kt-600/)

Five Global Trends and how to respond

Supplied by Danfoss

Right now, things are changing like never before. Mega trends like electrification, digital communications, and the fight against climate change are creating both opportunities and challenges for the food sector worldwide.

Danfoss sees that first-hand working with hundreds of food retail chains in more than 60 countries. In particular, it reports five big, overlapping changes that are combining to shape today’s workload for supermarkets’ teams… and five key ways to respond.

• Intense pressure on operating margins makes cost savings essential: The average profit margin for a large food retailer currently stands at just 1.7%. This puts every operating cost under scrutiny – because it has a direct impact on competitiveness and profitability. What this means in practice: supermarket teams need creative ways to save operating costs – including new technology and partnerships. They might also need to implement the technology for new revenue streams.
• Increasing food safety and reducing food loss are more important than ever: According to the UN Food and Agriculture Organization (FAO), food wastage accounts for 3.3 gigatonnes of greenhouse gas emissions. Avoiding food loss has always been essential to limit costs; it’s now part of sustainability too. What this means in practice: retailers will need to keep their focus on maintaining safe refrigeration temperatures – and avoiding equipment breakdowns that waste time, money and food.
• Climate change regulation makes refrigerant choice critical: Initiatives like Europe’s F-gas regulations and US Climate Alliance are having a direct impact on refrigerant availability and cost worldwide. Choosing an alternative with low global warming potential has growing advantages. What this means in practice: choosing the right refrigerant brings advantages in cost, regulation, availability, environmental impact and sometimes tax.
• Utilising waste heat as a resource: More than half the world’s population now lives in cities, and the United Nations predicts that it will climb to 68% by 2050. This means urban neighbourhoods will need new ways of meeting energy challenges – such as China’s district heating systems. This can put retailers at the heart of the energy revolution. What this means in practice: in some Nordic countries, retail stores divert around 30% of their excess capacity into heating homes in the surrounding area. This is a potential source of revenue.
• Electrification is a challenge… and an opportunity: Bloomberg estimates 57% of all new cars worldwide will be electric-powered within the next 20 years, and many retailers are already providing charging facilities. But there are also significant opportunities to benefit from energy arbitrage. What this means in practice: as well as infrastructure, retailers need to find ways to prevent expensive short-term spikes in energy use as vehicles charge. But those who can find flexibility in their energy demand may be able to proactively cut costs.

These five trends influence each other. For example, says Danfoss, the opportunity to reduce energy tariffs by optimising electricity demand is all the more compelling because of the need to find cost savings wherever possible. In the same way, the changing food retail energy landscape needs a co-ordinated approach. We’ve identified five technical strategies which, when combined, will help supermarkets to stay ahead of—and in some cases benefit from—society’s emerging demands.

1. Use smart refrigeration case control to reduce operating costs
2. Connect to the internet to eliminate food waste and cut service costs
3. Treat refrigerant selection as a long-term decision
4. Integrate each store’s systems to gain economies of scale
5. Reduce energy prices by optimising demand

This isn’t the future – it’s happening right now. Between them, these five approaches can help retailers cut costs, minimise environmental impact, and find a competitive advantage, while safeguarding food safety.

They’re best used in combination, according to Danfoss; for example, heat recovery is much easier with a CO₂ system, and smart case controllers maximise the benefit of monitoring online.

Danfoss calls this joined-up approach Smart Store. Food retailers around the world are already using it to improve efficiency, find new opportunities, and meet the sector’s current challenges head on.

New ‘smart store’ paves the way for 21st century supermarkets

A new ‘smart store’ will work as Danfoss’ test centre for energy efficiency technology. It is expected to be approximately 50% more energy efficient, compared to a typical supermarket with a first-generation CO₂ refrigeration system.

As the world’s population continues on its course to reach 10 billion people by 2050, investments in sustainable food retail and storage are urgently needed to ensure that we are able to feed the growing number of people on the planet. The pressure is growing, both on energy demand and costs, and on the need to cut down on food loss. If food waste was a country, it would be the third largest emitter behind the US and China, contributing to up to 10% of the world’s greenhouse gases.

To address these problems directly, Danfoss has announced the opening of a new, flagship supermarket which is expected to be approximately 50% more energy efficient compared to a typical supermarket with a first-generation CO₂ refrigeration system and no energy efficiency solutions. It is also expected to be approximately 20–30% more efficient than an equivalent local store already fitted with multiple energy efficiency solutions.

Climate-friendly, super-efficient and loaded with automation solutions, the new smart store is providing inspiration for food retailers in a world of rising energy costs, emissions and worsening food losses.

Commenting on the launch, Jürgen Fischer, president of Danfoss Climate Solutions, said: “We have developed this new smart store supermarket with partners and customers to demonstrate that it is possible to build a climate friendly and super-efficient facility, using world-class heating and cooling technology.”

While supermarkets and retail food stores are an integral part of communities around the world, they are also big energy consumers. The average profit margin for a large food retailer is just 1.7%, which puts every operating cost under scrutiny. Energy is an area where significant savings can be achieved with relatively low investment and good payback times. In fact, the US EPA estimates that one US dollar in energy savings is equivalent to increasing sales by USD59.

The range of new solutions in the smart store demonstrates the significant savings that can be achieved in supermarkets, with a typical payback time of three to four years. Roy Naidoo, Danfoss Climate Solutions, sales director at Sub-Saharan Africa mentioned that: “Due to the high importance of energy saving in South Africa and other African countries, we have noticed a trend towards adopting smart store solutions. Customers require real-time monitoring and management of their stores, particularly to regulate and manage their energy consumption. By having a physical concept, we can demonstrate to the market what we can offer.”

Solar power is the supermarket’s primary energy source with 100kW solar panels on the building’s roof providing green energy to support the supermarket operations. Heat capture and reuse is also key to the energy efficiency of the supermarket with up to 90% reduction in supermarket heating costs expected. Excess heat is the world’s largest untapped source of energy. The smart store is fitted with state-of-the-art heat recovery units, designed to recover the waste heat from all the refrigeration systems. The recovered heat is reused to heat up the store and produce domestic hot water, with any additional heat shared with residents of the surrounding town through a district energy network.

Other initiatives such as installing doors on refrigerator and freezer cases will save around a third on energy use, while the choice of LED lighting uses up to 85% less electricity than incandescent bulbs.

Jürgen Fischer added: “Danfoss has reimagined what food retail stores could look like in the 21st century. For the first time, all of Danfoss’ most cutting-edge technology and energy efficient food retail solutions are being brought together into one retail site. But the new smart store supermarket is only the beginning. Because it will also serve as an application development centre, a ‘live’ testing site for new technologies, which we hope will inspire food retailers around the world to move towards zero emissions supermarkets – while making economic sense.”

References: Danfoss, BITZER, Just Refrigeration, Mainstream Refrigeration

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