As the cost of refrigerant has increased during the past several years, detecting and preventing leaks, and reducing refrigerant emissions, have become high priorities for large chilling plants, food processing plants and cold-storage facilities, among others. 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 to 700 percent. The changes have been particularly felt in Europe with the F Gas regulations based on the global-warming potential (GWP) of these gases. Older refrigerants with a high GWP are being phased out gradually in favor of 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 risen steeply over the past year. This upward trend is expected to continue worldwide.
Given refrigerant pricing trends, the cost of replacing refrigerant can be expected to outweigh the cost of the technician’s time to locate and repair leaks for some time. Aside from the hard MRO and labor costs, locating and repairing refrigerant leaks also mitigates hidden or potential expenses such as lost inventory, increased utility consumption, damaged or overworked equipment, and fines from regulators. An effective refrigerant leak detection program can help processors find small leaks before they become bigger and more costly problems.
For permanent monitoring, aspirated multi-point leak detection systems can continuously monitor up to 16 locations across the refrigeration system. For larger installations, monitors can be networked.
Where Do Leaks Typically Occur?
In order to find leaks in a facility, one must first understand where leaks typically occur in a refrigeration system. Leaks often occur in mechanisms where there are changes in temperature, pressure and vibration. Valves, pipe joints and compressors are common culprits. Leaks also can be caused by poor installation techniques or maintenance procedures. Any device that is poorly restrained or supported within the system also can cause leakage. Finally, in some instances, leaks can 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 losses are due to the presence of a number of small leaks that often exist for a long time. Such leaks are difficult to detect. In a study of several million leak events, it was discovered that leakage from mechanical joints tends to be progressive. They begin as small leaks and degrade over time into a full-blown event. Refrigerant leakage also can be caused by a breakdown or failure of the aging equipment that results in the failure of mechanical joints and seals. Aggravated by changes in temperature, pressure and vibration, some leaks come and go, making them difficult and time-consuming to find.
Valves, pipe joints and compressors are locations where leaks can occur.
Implementing a Comprehensive Leak Detection Program
With revised EPA Section 608 rules now in effect, it is important to use a permanent leak detection system that ensures compliance with the latest regulations. Failure to follow such regulations risks fines for lack of compliance.
Aside from their effects on the bottom line, refrigerant leaks can be hazardous under certain conditions. ASHRAE Section 188.8.131.52 deals with the safety of personnel who may be exposed inadvertently to harmful gases from a refrigerant leak. A comprehensive refrigerant management strategy to stay in compliance also incorporates low level leak detection.
ASHRAE Section 184.108.40.206 deals with the safety of personnel who may be exposed inadvertently to harmful gases from a refrigerant leak.
While most applications have some form of leak detection, given evolving regulations, it is important to ask whether the current system is adequate. A proactive leak management program should include the correct type of leak detection technology, comprehensive remote monitoring, and a refrigerant tracking system in order to detect and notify you of leaks as early as possible. Each event can be weighted by its status such as alert, alarm or critical.
Modern systems include continuous monitoring with multi-party alerts that can be accessed remotely. Some refrigerant-management software can track events to determine patterns and identify whether specific assets are typically the source of leaks. Having this data can help improve the overall energy efficiency and effectiveness of the refrigeration system. For instance, the leak index acts as an early warning for a pending increased usage of refrigerant. Likewise, the leak rate defines the long-term system performance. The goal is to achieve and maintain a low leak rate — and to respond to leak events detected quickly and effectively.
In process and even commercial refrigeration applications, a proactive leak detection program can improve the bottom line. For example, the average refrigerant leak rate for a grocery store is estimated to be about 25 percent per year. A best practices implementation can reduce that rate to 7 percent per year.
The goal of a refrigerant leak detection program is to find small leaks before they become bigger problems.
Selecting the Right Monitoring System
With various types of monitors available, selecting the right monitor for the installation is a critical first step. Options include infrared, semiconductor, electrochemical and catalytic bead. Infrared is the most sensitive, and it can detect refrigerant gas leaks at 1 ppm. Infrared detectors can be recalibrated to detect new gases or refrigerants as old ones are phased out.
For permanent monitoring, aspirated multi-point leak detection systems can continuously monitor up to 16 different locations across the refrigeration system. For larger installations, these monitors can be networked.
As market forces and standards develop continue to influence the development industrial process refrigeration installations, a proactive refrigerant management program is a prudent step toward lower costs, reduced utility consumption and environmental stewardship. PC