The chilled and frozen food industry has weathered a series of significant changes over the past several years. Regulations enacted under the American Innovation and Manufacturing (AIM) Act, the Significant New Alternatives Policy (SNAP) program, and both state and municipal rulings, have placed stringent guidelines on the use of hydrofluorocarbon (HFC) substances and acceptable refrigerant substitutes. In addition, the use of higher global warming potential (GWP) refrigerants in new equipment will be phased out as early as January 1, depending on the equipment type and application.
As regulations continue to unfold, owners and operators in the food service industry need straightforward, streamlined solutions to remain compliant without risking downtime or disruptions. Advancements in refrigerant sensors and controls can help to deliver these benefits as the industry adapts to the use of low-GWP A2L and natural refrigerants (e.g., R744/CO2 and R290/Propane).
Changes to Refrigerant Leak guidelines
Some refrigerant leak detectors use sensors to detect a loss of pressure. Typically, a four-pound loss will trigger an alert in most permanently installed applications. Advanced sensors that are calibrated for a specific A2L refrigerant can detect the concentration of refrigerant gas in and around the sensor. In the event the concentration of refrigerant gas exceeds a set threshold, the sensor will send an output to the accompanying controller, which is configured to initiate the mitigation process. The refrigerant leak detector and its firmware are considered part of a Protective Electronic Circuit.
The RLDS can be factory-installed or installed in the field. Each scenario requires several steps that must be completed to ensure compliance and reliability. These include A2L refrigerant sensor placement, proof of long-term reliability testing and compliance with refrigerant mitigation protocols. Because of this, it is important to work with trusted manufacturers that are listed by nationally recognized certification agencies such as Underwriter Laboratories (UL) for the specific equipment in which the RLDS will be installed.
Refrigerant Leak Mitigation Requirements
In addition to A2L refrigerant sensors, the RLDS must also be equipped with control logic to activate mitigation protocols that reduce the concentration of leaked refrigerant within the occupied space. Mitigation sequences will deploy under two conditions: if the concentration of leaked A2L refrigerant exceeds the pre-set LFL (Lower Flammability Level) or if one or more of the A2L sensor has failed. Mitigation may look different depending on the application, but typically it involves using isolation valves to limit the amount of refrigerant released, as well as activating evaporator fans and/or exhaust fans to quickly disperse the leaked refrigerant.
In the event of an A2L refrigerant leak, mitigation strategies must be deployed within 30 seconds to mitigate flammability and health risks. To be deemed safe, the concentration of leaked A2L refrigerant must be reduced to a level that is at or below the specific refrigerant’s 25% LFL.
A2L refrigerant sensors have an expected life of 10 to 15 years. In addition to determining if the sensing is operating correctly, it’s also important to warn service technicians when one or more A2L sensors are approaching end-of-life. This can be done by using a communication protocol, such as Modbus between the A2L sensor and controller. Modbus communications can provide additional information, such as which A2L sensor caused the system to go into mitigation, the number of operating days, A2L refrigerant type and more.
Integrated Controls
While the addition of A2L refrigerant leak detection and mitigation may sound like an additional layer of operational overhead, advancements in electronic control technology are enabling a simplified and more robust experience. These cutting-edge controllers integrate A2L refrigerant leak detection and mitigation with temperature, humidity and pressure control. Delivering full-system insight, next-generation controls help improve up-time and streamline troubleshooting and maintenance.
In addition to monitoring operating conditions, advanced A2L refrigerant sensors use various technologies to detect the presence of refrigerant gas. The A2L sensor must utilize self-test protocols, ensuring proper operation. In the event of a failed A2L sensor, the system will go into mitigation and stay in mitigation until the failed refrigerant sensor is replaced.
Today’s advanced controls also leverage cloud connectivity, allowing operators and technicians to monitor systems anytime and from anywhere – whether that’s on-site or via a mobile device. Controllers that are equipped with web-enabled technology are easier to configure, and controllers at multiple locations can be aggregated into a single dashboard to provide a streamlined way to monitor equipment.
Preparing for Refrigerant Changes Now
As the cold chain continues to remain in a state of influx, it is important that all involved parties understand compliance requirements and best safety practices. Change is inevitable, but it doesn’t have to disrupt operations or diminish performance. Consulting with equipment manufacturers before low-GWP refrigerants are implemented within an operation can help develop a strategy that will better meet the demands and requirements of the specific application.
For example, when replacing or installing a new walk-in cooler or freezer, there is a good chance that the refrigeration system will use an A2L refrigerant. This will require the use of A2L refrigerant sensors, and the integration of controls that can provide refrigerant mitigation functionality. To quickly alert service technicians of a refrigerant leak, operators can benefit by specifying a control system that provides cloud-based remote connectivity. In addition to receiving alerts related to refrigerant leaks, most cloud-based controls also allow technicians to monitor and receive alerts and warnings when refrigeration systems aren’t maintaining the required space temperature and/or humidity. Trend data also assists service technicians in diagnosing potential problems before a critical condition causes the refrigeration system to shut down, resulting in product loss.
As new equipment is specified, ask manufacturers what refrigerant leak detection and mitigation systems are in place and confirm these components have been safety agency approved. Although some manufacturers may offer standard options, adding advanced control capabilities will often deliver stronger ROI over the equipment life span.
