Refrigerant Leak Detection
Refrigerant Regulations and Refrigerant Gas Sensors
Concerns over climate change are leading to new laws restricting the use of refrigerants common in air-conditioning systems. Emerging government regulations at the state, national, and international levels want to phase-out refrigerants with high Global Warming Potential (GWP). Such refrigerants are thousands of times more polluting than carbon dioxide.
These new regulations have emerged within the last year, with a short time window to achieve compliance. This poses a variety of challenges for residential and commercial HVAC equipment manufacturers. This is an issue because firstly, manufacturers are being mandated to develop new and environmentally friendly, Low Global Warming (LGW) refrigerants and cooling systems.
Secondly, they must be able to react to and conduct refrigerant leak detection (per, e.g., ASHRAE Standard 15 and UL 60335-2-40) with refrigerant gas sensors. This is because next-generation refrigerants such as R32, R454b are flammable (ASHRAE safety classification 2L or A2L) at certain concentrations in the air.
Refrigerant leak detection with the refrigerant gas sensor is therefore a matter of both safety and environmental protection—one that has made refrigerant gas sensors a rapidly emerging global market.
Environmentally-Induced Refrigerant Leaks
The inner workings of an AC unit can experience wide humidity and temperature swings. Most of the refrigerant gas sensors on the market today have difficulty maintaining effectiveness in such conditions for extended periods of time. Meanwhile, consumers have come to expect high reliability—the AC should “just work” all the time.
Downtime due to faulty refrigerant gas sensors, requiring visits from technicians, is a non-starter. Of immediate need is a sensor developed by IoT infrastructure companies that are capable of dependable and accurate gas sensing in a harsh environment.
MPS™ Refrigerant Gas Sensor
NevadaNano’s MPS™ A2L Refrigerant Gas Sensor has been configured to provide just what this emerging market needs: a robust, refrigerant-dedicated sensing solution like that can reliably recognize leaks over a long field life, in real-world environments, without frequent servicing.
NevadaNano’s Molecular Property Spectrometer™ (MPS™) Refrigerant Gas Sensor provides accurate and reliable detection of mildly flammable (A2L) R-32, R-454b blends, R-1234yf and other low global warming refrigerant gases such as (A1) R744 as well as (A3) R290 and R600 common in HVAC applications.
With a 15+ year calibration interval and lifetime, the MPS A2L Refrigerant Gas Sensor delivers industry-leading performance and the lowest total cost of ownership.
Operating Principle
The Molecular Property Spectrometer™ (MPS™) A2L Refrigerant Gas Sensors transducer is a micro-machined membrane with an embedded Joule heater and resistance thermometer. The MEMS transducer is mounted onto a PCB and open to ambient air.
The presence of a flammable refrigerant gas causes changes in the thermodynamic properties of the air/gas mixture that are measured by the transducer. Sensor data are processed by patent-pending algorithms to report an accurate concentration.
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MPS™ Refrigerant Gas Sensor Features:
• Meets UL 60335-2-40 & ASHRAE 15 requirements
• Wide environmental operating range with no cross-sensitivity to rapid T & RH changes
• No false positives
• Extremely fast response time
• Immune to poisoning
• 15+ year calibration interval
• 15+ year lifetime
• Built-in self-test for fail-safe operation
• Industrial and residential packaging options
• Third-party tested
• Available now for integration
For More Information
In the video below, watch our demonstration of the basic performance characteristics of the MPS™ A2L Refrigerant Gas Mini Sensor
Refrigerant Gas Sensor Technologies
Refrigerant gas sensors are used to detect different types of refrigerant gases and alert users when a gas is present. These sensors utilize various technologies such as infrared, electrochemical, and photoionization detectors. In this article, we will compare these sensor technologies and their advantages and disadvantages.
Infrared Refrigerant Gas Sensors
Infrared refrigerant gas sensors detect the specific wavelengths of light that are absorbed by different refrigerant gases. These sensors use an infrared light source that emits a beam of light at a specific wavelength. When the light hits a gas molecule, it is absorbed, and the sensor detects the reduction in the intensity of the light beam.
Infrared refrigerant gas sensors are highly selective and can distinguish between different refrigerant gases.
They are fast and accurate in detecting gases and can provide real-time monitoring of gas levels.
However, infrared sensors are relatively expensive compared to other types of sensors. They require regular calibration to maintain accuracy. They may also be affected by dust or other particles in the air, which can interfere with the light beam. Moreover, they are heavily affected by changes in temperature or humidity, making them unreliable in changing environments.
Electrochemical Refrigerant Gas Sensors
Electrochemical refrigerant gas sensors work by detecting changes in the electrical conductivity of the air when certain gases are present.
These sensors have a reactive electrode that is exposed to the air and a reference electrode that is not exposed to the air. When a gas is present, it reacts with the reactive electrode, causing a change in the electrical conductivity between the two electrodes.
Electrochemical refrigerant gas sensors are relatively inexpensive and easy to use. They can detect a wide range of gases and are sensitive to low gas concentrations.
Moreover, they are durable and can withstand harsh environments. However, electrochemical sensors are not as selective as other types of sensors and may respond to other gases. They require regular calibration to maintain accuracy and may be affected by changes in temperature or humidity.
Photoionization Refrigerant Gas Sensors
Photoionization refrigerant gas sensors detect the ionization of gas molecules when they are exposed to high-energy ultraviolet light. These sensors use a light source that emits a beam of ultraviolet light at a specific wavelength. When the light hits a gas molecule, it ionizes the gas, and the sensor detects the resulting current.
Photoionization refrigerant gas sensors are highly sensitive and can detect low gas concentrations. They are fast and accurate in detecting gases and can provide real-time monitoring of gas levels. Additionally, they can detect a wide range of gases, including volatile organic compounds (VOCs).
However, photoionization refrigerant gas sensors are relatively expensive compared to other types of sensors. They may be affected by changes in temperature or humidity and require regular calibration to maintain accuracy.
Choosing the best refrigerant gas sensor for a particular application requires careful consideration of the specific requirements and limitations of the system. Infrared sensors are a great option when the detection of a specific gas is required, and cost is not an issue.
Electrochemical sensors are more affordable and are ideal for detecting a wide range of gases. On the other hand, photoionization sensors are highly sensitive and can detect low gas concentrations, making them suitable for detecting VOCs.
Overall, each type of refrigerant gas sensor technology has its own advantages and disadvantages. The decision to choose the appropriate sensor technology is ultimately based on the requirements and constraints of the application.
While infrared sensors are highly selective and reliable, electrochemical sensors are affordable and durable, and photoionization sensors are highly sensitive and versatile. It is important to weigh the pros and cons of each type of refrigerant gas sensor to choose the best fit for a specific application.
