By Jason Ayres
From the April 2019 Issue
As the cost of refrigerant has increased dramatically during the past several years, leak detection and prevention and reducing refrigerant emissions have become high priorities for supermarkets, large chilling plants, food processing plants, cold storage facilities, and large air conditioning installations. In order to do this, refrigerant management through effective leak detection and refrigerant tracking is essential.
Since 2017, the cost of hydrofluorocarbon (HFC) refrigerants has increased between 275-700%, especially in Europe with the FGas (fluorinated gas) regulations based on the global warming potential (GWP) of these gases. Older refrigerants with a high GWP are being gradually phased out in favor of newer compounds with a lower GWP. These newer compounds carry a CO2 equivalent much lower than the compounds they replace. As a result, refrigerant prices have skyrocketed over the past year—an upward trend expected to continue.
With these ongoing price increases, the cost of replacing refrigerant far outweighs the cost of the technician’s time to locate and repair these leaks. That doesn’t even take into account the cost of lost inventory, increased utility consumption, damaged or overworked equipment, and potential fines from regulators. Dramatic price increases along with a heightened concern for the environment has motivated a significant change in operations strategy. The goal of a refrigerant leak detection program becomes to find small leaks before they become big and costly problems.
Where do leaks typically occur? The first question is where do leaks typically occur in a commercial refrigeration system? Leaks often occur in mechanisms where there are changes in temperature, pressure, and vibration. Valves, pipe joints, and compressors are often the location where leaks can occur. Leaks can also be caused by poor installation or maintenances procedures that are aggravated by these changes. Any device that is poorly restrained or supported within the system can also cause leakage. In some instances, leaks can also be caused by unintentional damage by a third party such as cleaning machines, trucks, or forklifts.
It is important to note that the majority of refrigerant loss is due to a number of small leaks that often exist for a very long time, making them more difficult to detect. In a study of several million leak events, it was discovered that leakage from mechanical joints tends to be progressive, starting small and developing into full-blown events. Leakage of refrigerant is often caused by a breakdown or failure of the equipment due to aging, resulting in failure of mechanical joints and seals. Aggravated by changes in temperature, pressure, and vibration, some leaks come and go, making them very difficult to find.
Implementing a comprehensive leak detection program. With revised EPA Section 608 rules now in effect, it is also important to use a permanent leak detection system that ensures compliance with the latest regulations—or risk fines for failure to comply. Refrigerant leaks are not only costly, but can also be hazardous under certain conditions. ASHRAE Section 188.8.131.52 deals with safety of personnel who may be inadvertently exposed to harmful gases from a leak. These developments have put a new focus on a comprehensive refrigerant management strategy incorporating low level leak detection.
While most applications have some form of leak detection, the question is whether the system is adequate. Proactive leak management should include the correct type of leak detection technology coupled with a remote monitoring and refrigerant tracking system in order to detect and notify as early as possible. Each event can also be weighted by its status: Alert, Alarm, or Critical.
There is refrigerant management software that can track events to determine patterns of which asset is typically the cause of the leak. The availability of this data can impact overall effectiveness. The leak index acts as an early warning for a pending increased usage of refrigerant, while the leak rate defines long-term performance.
With the high cost of refrigerant, a proactive leak detection program has a significant impact on the bottom line. The average refrigerant leak rate for a grocery store is estimated to be about 25% per year. A best practices implementation can reduce that rate to 7% per year.
Selecting the right monitoring system. Choosing the right monitor for the installation is a critical first step. These include infrared, semiconductor, electrochemical, and catalytic bead options. The most sensitive and reliable type of monitor is infrared that can detect refrigerant gas leaks at 1 ppm. These can also be recalibrated to detect new gases as old ones are phased out and new refrigerants are introduced. For permanent monitoring, aspirated multi-point leak detection systems can continuously monitor multiple locations across the refrigeration system, and for larger installations monitors can be networked.
As prices rise and new regulations are introduced, long-term success calls for a proactive refrigerant management program that lowers costs, reduces utility consumption, and helps protect the environment.
Ayres is an application support engineer at Parasense, a Bacharach Company, a provider of cleantech solutions for gas and refrigerant leak detection and identification. Ayres has 25 years of experience delivering Parasense hardware and software solutions covering refrigerant gas detection, refrigerant reduction strategies, energy monitoring, and energy reduction programs.
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