Refrigerant Monitoring


The first synthetic refrigerants hit the market in the 1950s. Unlike their predecessors, they were non-flammable and non-toxic, which made them much more popular to use.

On May 16, 1985, scientists Joe Farman, Brian Gardiner and Jonathan Shanklin published their findings on the discovery of the first hole in the ozone layer over Antarctica. Around the same time, people became aware of the climate-damaging potential of refrigerants. In the Montreal Protocol of 1987, all 197 member states of the United Nations finally committed themselves to reducing the number of substances that are harmful to the climate. Among other things, they agreed to halve production and consumption of the refrigerant CFC within 13 years. Today's regulations go much further, banning previously widely used refrigerants and switching to more climate-friendly ones.

From the Montreal Protocol to the new F-Gas Regulation

The Montreal Protocol decided to abolish all ozone-depleting substances containing chlorine or bromine. CFCs (Chlorofluorocarbons), which were used almost everywhere at the time, fell under this category and were being replaced by other refrigerants. But the substitutes were based on fluorine compounds and turned out to be problematic as well. HCFCs (Hydrochlorofluorocarbons) and HFCs (Hydrofluorocarbons) have an extremely high global warming potential (GWP) and are considered to be harmful to the climate. In 2016 at a conference in Rwanda, these substances were added to the Montreal Protocol. The reduction of fluorinated greenhouse gases is based on country-specific regulations. For example, the F-Gas Regulation in the European economic area. In addition to the reduction of refrigerants with a GWP > 1000, the continuous monitoring or frequent preventive inspection of refrigeration systems play a decisive role.

Shifting Regulations for Refrigerant Systems

Many existing refrigerant systems run with charges well above 3 kg. New regulations have led to an artificial shortage of refrigerants, causing enormous price increases.


This is to prevent parasites from entering the country. However, these gases are often harmful not only to microorganisms or insects, but also to humans. When the containers are unloaded at their destination, these gases come into contact with people. Many of these gases can hardly or not at all be smelled. Especially when these gases are present in workplaces, there is often a long-lasting exposure. This can lead to illness or organ damage - even decades later. In order to counteract this invisible danger, personal measuring devices are indispensable for occupational safety. Besides measurement techniques based on infrared spectroscopy, other techniques such as electrochemical sensors are also used for this purpose. These devices need frequent maintenance or replacement due to a changing detection limit based on physical reasons. NDIR technology, equipped with long-life infrared sources such as those from Axetris, is often more reliable and requires significantly less maintenance.

The Challenge in Monitoring

With newly regulated refrigerants on the market and shortened monitoring cycles, this raises the question of well-suited technologies to detect or monitor refrigerant emissions. Ideally, this technique covers a broad spectrum of detectable substances and enables good target gas selectivity. Widely used sensors based on the electrochemical principle are often only able to meet these requirements to a limited extent. One of the main problems is the frequency of calibrations, without which the measurement accuracy is no longer reliable. The measurement principles based on infrared (IR) spectroscopy fully meet these requirements. Not only for the new refrigerants, but also for the gases that are still used in the transition period or in special applications.


The Advantages with the IRS from Axetris

Axetris' Infrared Sources cover the entire spectrum from 2 to 14 µm. Non-dispersive IR spectroscopy (NDIR) and photoacoustic spectroscopy (PAS) are two measurement principles that use sources like this.


Both principles are significantly higher in their acquisition costs than conventional sensor solutions. They redeem themselves through a long service life of over 7 years and longer calibration and maintenance cycles. HFO, a refrigerant forced by the new regulations, can only be measured with semiconductor sensors (MOS) in addition to IR measurement technology. However, MOS as an inexpensive alternative measurement technology looks at shortcomings with a limited service life and short calibration cycles which don't manage to outweigh the cost-of-ownership comparison.