New MEMS thermal conductivity sensors for A2L refrigerant leaks

Posifa Technologies has launched a new sensor solution for detecting A2L refrigerant leaks in residential and commercial air conditioning systems, heat pumps, and refrigeration equipment. The new PGS6000 sensors accurately detect A2L refrigerant concentration in the air by measuring the change in thermal conductivity of the gas mixture inside the cabinet. This technology improves safety and efficiency by allowing early detection of leaks while providing long-term reliability of 15 years or more in harsh environments.

"Despite being environmentally friendly and energy-efficient, A2L refrigerants are mildly flammable, making them a potential risk if not managed effectively in HVAC/R systems," said Peng Tu, president and CEO of Posifa Technologies. "Early detection of leaks not only prevents the escalation of potential fire hazards but also protects against possible health risks and saves valuable energy by ensuring efficient operation. With their fast response time, high reliability, and high detection precision, our PGS6000 series sensors are critical components in these systems."

The series uses the company's second-generation MEMS thermal conductivity sensing element. It provides a patented heat transfer cavity that delivers highly sensitive and repeatable thermal conductivity measurement by removing possible occurrences of natural convection inside the cavity. As thermal conductivity measurement is achieved completely inside the sensor chip, maximum miniaturisation can be realised at the device level – a critical capability for HVAC equipment manufacturers who must retrofit the sensors into existing designs.

The detectors are developed with a relative humidity sensor and a barometric pressure sensor. This strategic inclusion allows the detectors to compensate for thermal conductivity changes influenced by humidity and barometric pressure variations, improving the accuracy of A2L refrigerant concentration measurement. The series detects R32 and R454B refrigerants and supports RS485 MODBUS RTU output.

Key features of the series incorporate a fast response time of <250ms and compensation for humidity and pressure, ensuring accurate functioning in harsh environments. Notably, the sensor has no lamps or delicate optical paths to break and is non-reactive to 'poisons' or contaminants, guaranteeing long-term stability and reliable performance.