In commercial and industrial refrigeration, one common hidden problem can affect safety, harm the environment, and cost you money— refrigerant leaks.
While no refrigeration system is ever completely leak-proof, the goal is to detect and fix leaks as early as possible. That’s where refrigerant leak monitoring systems come in — not as luxury add-ons, but as essential safeguards.
Who Need a Refrigerant Leak Monitoring System?
Every refrigeration machine room and every refrigerated room needs a refrigerant monitor, especially, if the system to be monitored contains more than 23 kg of refrigerant. There are several good reasons to install a gas monitoring system.The main reasons are personnel safety and environmental concerns in line with
current legislation. It is also financially profitable to have reliable facilities with as
leak-free systems as possible. There are three main reasons to install refrigerant monitoring systems:
• For personnel health & safety
• For environmental care
• For financial reasons
For personnel health & safety
Several of the gases in refrigeration plants are dangerous to humans. In lesser concentrations, ammonia can cause irritation to the respiratory tract and eyes, and in higher concentrations may lead to severe injuries and eventually death .HFC (HCFC) refrigerants and carbon dioxide displace oxygen from the air and may ultimately bring about suffocation .HCs such as propane and isobutene are hydrocarbon compound, containing only carbon and hydrogen. These compounds cause no damage to the environment, but are flammable. So, measures to minimise risk need to be taken. HCs may also cause suffocation.
For environmental care
Most of the gases in refrigeration plants have adverse environmental effects. The so-called F gases, the fluorinated greenhouse gases, are discussed the most. Some older gases with chlorine compounds are now totally banned within the EC and may only be used in recycled form.
HCFC
HCFCs like HCFC 123 and HCFC 22 are halogenated hydrocarbon compounds with chlorine that affect ozone depletion. These refrigerants are governed by Montreal Protocol and under phase out schedule in India.
HFC
HFCs like HFC 134a and HFC 410A are halogenated compounds that do not contain chlorine and thus do not affect the ozone layer. However, HFCs have a significant impact on global warming so emissions must be minimised. The uses of HFCs are regulated by the Kyoto Protocol and recently being included in Montreal protocol as well. It thus is in our common interest to keep refrigerants in systems that are as free of leaks as possible.
For financial Reasons
The refrigeration systems are, especially, prone to leaks: Vibration expansion and contraction in lines, breaks in capillary tubes, poorly connected flare connections all contribute to repeat service calls and early compressor failure. Statistically every refrigeration system loses its complete charge three times intent years. There is a direct relationship between refrigerant loss and compressor failure in a refrigeration system where failure can be traced back to inadequate refrigerant gas due to leaks. Approximately 50% of supermarkets electric cost services the refrigeration system. And slow leak will gradually reduce a compressors capacity, and directly affect efficiency, causing the compressor to run more frequent and longer run times. This will directly reduce compressor life. Refrigerant blends (400 Series) can leak the component with the highest saturation pressure first, leaving the blend in the system short of the chemical.
Choosing the Right System
A gas detection system consists of a chain – from discovery of the risk to the corrective action. It is important to think through the measures to be taken at each level of alert, and to plan for the appropriate staff to be informed, such as the plant manager and maintenance contractor.
1. What is the purpose of the alarm?
2. Which gas(es) are to be detected?
3. What detection principles are the most appropriate? How many sensors are needed, where and how should they be placed?
4. What rules and regulations apply for the refrigerant in use?
5. What is the refrigerant’s density relative to air?
6. How does the ventilation affect the detected area?
7. What steps are to be taken when an alarm occurs?
The function of different alarm levels
Alarms can typically be divided into Level 1, 2 and 3 alarms, also named low level alarm, main level alarm and high level alarm. Each different alarm level calls for different measures: Normal (0 to 10 PPM): This PPM range is based on normal background readings of most refrigeration and comfort air applications. This level is considered safe for equipment and AEL recommendations Low Level (25 PPM): Alarm for maintenance staff, this indicates possible leak. Repeated low alarms indicate a probable leak that should be identified and repaired for conservation purposes. The purpose of low level Alarm is to indicate that a possible leak exists and to provide early warning before the leak grows. Main Level (50 PPM): Urgent alarm for maintenance staff, flashing light activated. This indicates a significant and growing leak. The probable leak should be identified and repaired as soon as practical, if not immediately. The purpose of main alarm is to indicate that a substantial or growing leak exists and minimize the refrigerant loss before it reaches a point which might affect personal and building operations. The building ventilations should not be
started as this would hamper the ability to find leak. High Level (150 PPM for R123 and 500 PPM for others): Emergency alarm as the main level alarm, with siren activated and alarm sent to the rescue services, refrigeration plant is shut down (powersupply as well). This indicates that significant leak or possibly a catastrophic spill has occurred. For R123, the level has exceeded the short term exposure level (STEL) of 150 PPM. The high speed exhaust ventilations should be turned on to reduce the level of below acceptable level exposure level of 50 PPM. For other refrigerants, the level may have approached the AEL of 1000ppm. High speed exhaust ventilation should be turned on to reduce the level to below 50 ppm. The purpose of high alarm is to indicate a major leak. In addition to ventilation, a remote area supervisor should be notified that a possible large leak has occurred and proper personal protective equipment might be needed in order to enter the space.
Conclusion
Refrigerant monitors system offers two important benefits: refrigerant conservation and safety. With the decreasing availability of refrigerants, coupled with rising cost, it is important to have a refrigerant monitor in the equipment room to provide early warning of refrigerant loss. As a leak-sensing device, a refrigerant monitor constantly measures the amount of specific refrigerants in the surrounding air. It's capable of initiating alarms, activating building ventilating systems, and integrating with building automation systems. Refrigerant monitors are also strongly recommended for all existing chiller rooms or refrigerant storage
facilities.