Development of Gas Sensor for Highly Flammable Refrigerant (R290), Ensuring Safe and Accurate Refrigerant Leak Detection in HVAC Systems

Environmental regulations are driving the European HVAC industry to switch from synthetic to natural refrigerants, such as R290. To ensure safe operation with this highly flammable refrigerant, Senseair, a Swedish subsidiary of Asahi Kasei Microdevices (AKM), has developed "Sunlight R290," a gas sensor featuring high measurement accuracy and operating range, while minimizing heat generation, packaging space, and power consumption. High-volume shipments of Sunlight R290 are scheduled to begin in September 2024.

Existing and upcoming regulations in regard to PFAS (per- and polyfluoroalkyl substances, also called “forever chemicals”) and F-gases (fluorinated greenhouse gases) are severely restricting the use of conventional synthetic refrigerants in air conditioning, heat pumps, and other HVAC systems. The natural refrigerant R290 is propane gas, which is considered to be a more sustainable alternative to conventional solutions. However, due to its high flammability, reliable and highly accurate leakage detection measures are required to ensure safe operation.

Senseair’s newly developed gas sensor Sunlight R290 employs the latest NDIR (non-dispersive infrared) technology, utilizing LED light sources and photodiode sensors. Due to its minimal heat generation, the sensor can be safely operated with R290. Additionally, due to the characteristics of the NDIR method, the detection is less affected by vibrations or interfering gases, enabling robust and reliable measurements that meet the stringent leak detection requirements of the IEC 60335-2-40 safety standard for electric heat pumps, sanitary hot water heat pumps, and air conditioners.

With a measurement range of 0-100% LFL (lower flammable limit) - the concentration of a combustible material in air below which ignition will not occur - the sensor features a high measurement accuracy of +/- 2.5% LFL.