Cold Link Africa March | April 2024 | Page 31

INCORPORATING COLD CHAIN

TECHNICAL

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 .

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 CO 2 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 lessthan-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

CO 2

-eq for 2025 , and 398-440 Mt CO 2

-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 instore food preparation , preservation and display . Energy consumption varies widely from approximately 700kWh / m 2 sales area in hypermarkets to over 2000kWh / m 2 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 taxes 4 , cutting any cost provides substantial equivalent earnings in grocery sales .

Images supplied by MSA Safety

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

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 : Diffusionbased 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 .

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

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