How Micro-Hybrid’s NDIR Technology Redefines Refrigerant Gas Detection

Monitoring refrigerant gases in industrial cooling is critical for personnel safety and plant efficiency. While optical infrared sensing is well established for modern fluorinated refrigerants (HFCs, HFOs), ammonia (NH₃) has long been one of the most challenging gases to measure using compact infrared technology. As a result, much of the market has relied on electrochemical sensing.

Electrochemical sensors became widely adopted due to their availability and familiarity. However, their limitations are well known. Operation depends on electrodes, membranes, and ongoing chemical reactions, making them inherently sensitive to aging, humidity, contamination, poisoning, and cross-gas interference. Cross-sensitivity, in particular, is difficult to eliminate completely and must often be managed through compensation strategies.

Micro-Hybrid addresses these limitations through an advanced multiple-reflection optical design. This approach significantly increases the effective optical path length within a compact form factor. The resulting signal enhancement enables reliable detection across refrigerant-specific absorption bands - including the difficult 10.5 µm NH₃ region - without relying on chemical reactions, high operating temperatures, or large sensor housings.

Beyond ammonia, Micro-Hybrid NDIR technology supports the measurement of a broad range of refrigerant gases used in commercial and industrial cooling systems. This includes common fluorinated refrigerants such as HFCs and HFOs, as well as natural refrigerants including CO₂ and hydrocarbons. Each gas has characteristic infrared absorption bands, enabling targeted optical measurement with the appropriate emitter, optical path, filter configuration, and detector. This gives system developers a flexible foundation for building leak-detection and process-monitoring solutions across multiple refrigeration platforms.

The resulting NDIR sensor platform delivers performance characteristics that are difficult to achieve with electrochemical technologies:

• Wide measurement range: 0–30,000 ppm, supporting trace detection and high-concentration industrial environments.
• High sensitivity: detection limit ≤ 30 ppm at zero point.
• Fast response: T90 < 30 seconds for real-time monitoring.
• Fine resolution: 1 ppm digital resolution.
• Strong focus on accuracy: high measurement precision is critical for gas detection systems, where dependable alarm behavior matters more than simply maximizing operating lifetime.
• Excellent stability: long-term drift ≤ ±450 ppm per year.
• Strong linearity: ≤ ±300 ppm across the measurement range.
• Reliable repeatability: ≤ ±150 ppm.

Selecting a refrigerant sensor affects far more than the measurement range. In refrigeration and industrial safety systems - whether monitoring synthetic blends, hydrocarbons, CO₂, or ammonia - sensor technology influences alarm reliability, maintenance requirements, environmental robustness, and the long-term consistency of measured values.

Electrochemical sensors are established and widely used for toxic refrigerants like NH₃. They measure gas through chemical reactions involving electrodes, electrolyte, membranes, and gas diffusion structures. This can provide a familiar and cost-effective solution, but the signal depends on the condition of the sensor’s internal chemistry.

Over time, aging, humidity, contamination, and exposure to high gas concentrations can influence sensor behavior. Cross-sensitivity to other gases may also require compensation measures. In safety-related applications, this can make regular verification, calibration, and replacement planning particularly important.

Micro-Hybrid’s NDIR gas sensors take a different approach. They measure refrigerant gases optically through infrared absorption at gas-specific wavelengths, without relying on consumable sensing chemistry. The multiple-reflection optical design increases the effective optical path inside a compact housing, enabling a sufficiently strong signal even in the challenging NH₃ absorption region near 10.5 µm.

The sensor is engineered for durability in demanding environments. Service life can reach up to 10 years, with a typical lifetime exceeding 7 years. Operation does not rely on consumable chemistry, reducing common degradation mechanisms.

Resistance to overloading and automatic fault detection support reliable operation under challenging conditions. Stable performance is maintained across a wide environmental range:

• Temperature: -40 to +60 °C
• Pressure: 700 to 1200 hPa
• Humidity: up to 95% RH, non-condensing

NDIR measures gas concentration through infrared absorption at gas-specific optical wavelengths rather than chemical reactions. This approach provides intrinsic selectivity across various refrigerant molecules, eases cross-sensitivity risks, and supports stable measurement performance without consumable materials.

Micro-Hybrid’s optical sensing technology enables high-performance refrigerant detection including difficult target gases like ammonia with capabilities that are difficult to achieve with traditional technologies. It represents a shift toward stable, high-precision gas sensing for demanding industrial environments and refrigeration safety applications.

Moving beyond consumable electrochemical sensors gives developers access to a stable optical measurement principle, dependable accuracy, analog and digital integration options, and consistent long-term performance. Whether an application requires trace-level leak detection, high-concentration monitoring, or reliable alarm handling across industrial refrigeration systems, the Micro-Hybrid NDIR platform provides a robust foundation designed for precision and practical system integration.