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Supermarket refrigerant leak solutions

Contributed by MSA Safety

This article looks at the issue of supermarket refrigerant leaks and offers a number of solutions to reduce emissions.

Grocery stores are energy-intensive environments, with refrigeration systems, lighting and HVAC units operating around the clock.
Grocery stores are energy-intensive environments, with refrigeration systems, lighting and HVAC units operating around the clock. Images supplied by MSA Safety

With South Africa’s aspirations to achieve a net zero carbon economy by 2050, rapidly finding and fixing refrigerant leaks in supermarkets may be one of many approaches to achieving this goal.

The average supermarket system contains thousands of pounds of refrigerant and, due to the size and complexity of their refrigeration system, is reported to leak approximately 25% of its refrigerant each year. This adds up to, “70 million metric tons of CO2 equivalent emissions each year just from supermarket refrigeration leaks. That is equivalent to the emissions from powering 12 million homes” 1. Furthermore, when refrigeration equipment operates with less-than-optimal amounts of refrigerant charge, system efficiency is decreased and additional energy consumption is required to maintain desired temperatures for food quality. This increased workload results in higher energy consumption, leading to inflated energy bills and increased carbon emissions.

South Africa’s commitment to a net zero carbon economy

South Africa ratified the Kigali Amendment to the Montreal Protocol in 2019 with the aim to reduce the consumption and production of hydrofluorocarbons (HFCs) and to simultaneously protect the ozone layer and help mitigate climate change. South Africa also signed the United Nations Framework Convention on Climate Change (UNFCCC) Paris Agreement in 2015. This aim was to fight against climate change, with a commitment to achieve a “peak, plateau and decline” greenhouse gas (GHG) trajectory. In 2021 revised target ranges of 398-510 Mt CO2-eq for 2025, and 398-440 Mt CO2-eq for 2030 were issued, as well as aspiring to reach a net zero carbon economy by 2050. These treaties address the impact of cooling products on the environment as they are the main source of HFC use in South Africa – and also consume a significant amount of electricity produced from emission intensive coal fired power plants.2

Supermarket energy use

Grocery stores are energy-intensive environments, with refrigeration systems, lighting and HVAC units operating around the clock. Supermarket energy consumption depends on many factors including in-store food preparation, preservation and display. Energy consumption varies widely from approximately 700kWh/m2 sales area in hypermarkets to over 2000kWh/m2 sales area in convenience stores. It is also reported that refrigeration systems account for between 30% and 60% of the electricity used, whereas lighting accounts for between 15% and 25%.3

Financial savings

In food retail, with a 2.3% net profit after taxes4, cutting any cost provides substantial equivalent earnings in grocery sales. Opportunities to cut costs in supermarket refrigeration are abundant, especially by reducing refrigerant emissions and minimising the associated costs. Most supermarket companies have millions of pounds of refrigerant in their stores’ refrigeration systems across the enterprise. Unfortunately, the average store leaks about 25% of that refrigerant every year. That refrigerant has to be replaced if it has leaked, and replacement refrigerant costs can rise rapidly. Additionally, various pieces of legislation around the globe have begun to place restrictions on the supply allowances for fluorinated refrigerants, which will continue to drive cost of refrigerants higher.

This leads to a cost line item every year in the millions for replacement refrigerant. Food retailers may have to sell hundreds of millions worth of goods just to break even on refrigerant replacement costs. That doesn’t count the corresponding costs for service technician time for repairs, energy efficiency losses due to leaks, refrigerated food inventory losses due to refrigeration outages, and the negative effect on food quality from improper case temperatures. For these reasons, there is an economic incentive in addition to the net zero carbon initiatives that drive the need to reduce refrigerant leaks from refrigeration systems.

Supermarket refrigerant leak solutions

As we’ve discussed, finding refrigerant leaks quickly is crucial for minimising environmental harm, ensuring regulatory compliance, enhancing energy efficiency, preserving goods, saving money and maintaining a positive reputation. Supermarkets that prioritise rapid leak detection can contribute to a more sustainable future while also benefiting their bottom line and customer relations. To support a rapid leak detection, notification and consequential repair to assist in minimising refrigerant emissions, there are a number of solutions from background monitoring and localised leak detection to connected and integrated IoT solutions.

Active monitoring

Active monitoring solutions for detecting refrigerant leaks in supermarkets involve continuous, automated systems that operate in the background, ensuring ongoing surveillance of refrigeration systems. Diffusion and aspirated systems are commonly used for supermarkets. Diffusion monitoring systems operate by allowing gases to passively diffuse into sensors, while aspirated monitoring systems actively draw air samples through a network of sample lines directly to sensors for detection.

Diffusion-based detectors: Diffusion-based detection systems provide simplicity, cost-effectiveness, and require moderate maintenance: Overall, diffusion-based detectors are relatively simple devices. They operate by allowing refrigerant gas to diffuse through the greater occupied space into a membrane to reach the sensing element. When the gas concentration reaches a certain level accumulated in the space, an alarm is triggered by the detector. Diffusion detectors are often more affordable than networked aspirated systems, making them a cost-effective choice, especially for smaller supermarkets with budget constraints. Moderate maintenance costs for diffusion-based detectors are generally equated because of fewer moving parts and do not rely on pumps or aspirators, reducing the need for regular servicing beyond required annual calibration. Because of their principles of operation and the sensing technologies incorporated into the devices, diffusion detectors primarily fill the purpose of safety compliance for the occupied space. Substantial reduction of leaks and emission rates can be achieved with pumped systems using low-level detection technology.

Aspirated monitoring systems: Aspirated systems, also known as active air sampling systems, can detect even very low concentrations of refrigerant gases. They use a pump to continuously aspirate air samples, ensuring high sensitivity and quick response to leaks. Aspirated systems are designed to cover larger areas. They use a network of sampling points, allowing them to monitor extensive spaces and cover larger refrigeration systems’ common leak areas effectively. This feature makes them suitable for large supermarkets with complex refrigeration systems. Aspirated systems can sample air from various locations, which is particularly useful in supermarkets where refrigeration units might be dispersed across different sections of the store.

Diffusion or aspirated background detection?

For smaller supermarkets with limited space and straightforward refrigeration setups, diffusion-based detectors could be a suitable and cost-effective choice. However, for larger supermarkets with complex refrigeration systems and a need for comprehensive coverage and high sensitivity, aspirated monitoring systems are the preferred option despite their higher initial cost and installation complexity. Higher rates of emissions reduction can be achieved with more sensitive detection technology that can locate sample points in close proximity to likely leak sources. The choice between these systems ultimately depends on the specific requirements, budget and size of the supermarket.

Active monitoring solutions for detecting refrigerant leaks in supermarkets involve continuous, automated systems.
Active monitoring solutions for detecting refrigerant leaks in supermarkets involve continuous, automated systems.

Localised leak detection

Once a refrigerant leak is detected using the adopted refrigerant monitoring solution, it’s important to then pin-point the leak itself so an effective repair can be made. Portable electronic devices and ultrasonic detectors are commonly used to achieve this end.

Portable electronic leak detectors: Portable, handheld electronic leak detectors can detect a wide range of gases, including refrigerants. Technicians can move these devices close to potential leak points, and the detector will alarm when it detects gas concentrations above a certain threshold, effectively locating the source of the leak. They are commonly used in commercial HVAC and refrigeration systems.

Ultrasonic leak detectors: Ultrasonic leak detectors can also be used to detect the sound generated by a leak. They convert the ultrasonic sound waves into audible signals, helping technicians pinpoint the exact location of the leak. These detectors are beneficial in detecting leaks in compressed air systems and vacuum systems.

Integrated IoT solutions

Cloud-based monitoring solutions collect data from sensors and devices installed in the supermarket’s refrigeration systems or external monitors and consolidate and visualise it for trend analysis across multiple locations. These solutions offer remote access, allowing authorised personnel to monitor the system’s status from anywhere. Cloud platforms often come with analytics tools that provide insights into system performance and trends.

BMS software can integrate refrigerant monitoring as part of its functions. BMS continuously monitors various building systems, including refrigeration. It provides real-time data and can be configured to send alerts via email, SMS or in-app notifications when leaks are detected.

Conclusion

As supermarkets in South Africa navigate the complexities of environmental responsibility and compliance, investing in advanced refrigerant leak detection solutions is not just a choice but a necessity. By adopting eco-friendly refrigerants and leveraging cutting-edge detection technology, supermarkets can improve both environmental preservation and operational efficiency. Moreover, staying compliant with global regulations not only helps secure the future of our planet but also fosters a positive image for the supermarket industry as a whole. Embracing these changes today can pave the way for a sustainable tomorrow.

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