What’s lurking behind our air conditioning and refrigerators?
In the context of climate change, producing cold air has become essential. As well as conserving and safeguarding the nutritional quality of the food we eat, it also contributes to our well-being, through air conditioning. However, the cooling fluids used in refrigeration and air conditioning units are powerful greenhouse gases.
Regulations are constantly being drawn up with the aim of protecting our environment. Read on for a summary of the major landmarks.
Description of cooling fluids
Cooling fluids, which are neither flammable, corrosive or toxic, are not harmful to humans. However, they do pose a risk of anoxia exposure, meaning they can be dangerous if they leak heavily in a confined or poorly ventilated space. For this reason, leak detection devices are recommended.
Also known as refrigerants, these fluids form the basis of a refrigeration cycle. Most air-cooled refrigeration systems use vapour compressing cycles and changes in fluid phases. They are chosen for their ability to absorb heat (calories) when they go from the liquid phase to the gas phase.
Generally speaking, the fluid in its liquid form absorbs heat (calories) from the place that needs to be cooled before being evacuated in another form released as a gas).
Cooling fluids classified according to category:
- Hydrocarbons: butane, pentane, propane, propylene, etc.
- CFCs (chlorofluorocarbons): R11, R12, R113, R115, R502
- HCFCs (hydrochlorofluorocarbons): R21, R22, R123, R124, R401a, R402a, R408a, R409a
- HFCs (hydrofluorocarbons): R32, R125, R134a, R15a, R143a, R152a, R404a, R407a, R410a, R507
- HFOs (hydro-fluoro-olefins): 1234yf, 1234ze, 1234zd
- So-called natural fluids: carbon dioxide, ammonia.
“F-Gas” regulation
Regulation (EU) No 517/2014 of the European Parliament and of the Council, known as F-Gas, provides for the phasing out of certain refrigerants used in refrigeration equipment. The goal is to cut global greenhouse gas emissions fivefold by 2030.
CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons) have been banned since 2015. They have been replaced by HFCs (hydrofluorocarbons), the gases mainly used as refrigerants in air conditioning and refrigeration systems. Despite their thermodynamic properties, they deplete the ozone layer and have a significant impact on global warming.
Note: they produce a very powerful greenhouse effect, up to 15,000 times more powerful than CO₂.
The regulations require a reduction in the average Global Warming Potential (GWP) of fluids, with the goal of achieving a decrease from 2,000 to 400 over 15 years. This is the part of the regulation that is set to have the strongest impact, because it prohibits the use of certain HFCs based on their GWP according to the following time frame:
All new equipment and systems are now designed to run with so-called natural, new-generation fluids such as ammonia (NH₃ or R717), carbon dioxide (CO₂ or R744) and hydrocarbons (propane and butane or R290) or other HFOs with low GWP such as R1234ze. They are trickier to handle but less harmful for the environment and more efficient from a thermodynamic point of view.
It will only be possible to perform maintenance on refrigeration equipment using pure fluids with GWP of less than 2,500. It will only be possible to use regenerated forms of R404a and R507 until 2030.
Which cooling fluids should you choose?
Most specialists are turning to cooling systems that run on carbon dioxide or R744, ammonia or R717, or HFOs with low GWP such as R1234ze.
Which cooling fluids should you choose?
La majorité des spécialistes se tournent vers des systèmes de froids alimentés par le dioxyde de carbone ou R744, par l'ammoniac ou R717 ou des HFO à faible GWP tels que le R1234ze.
Most specialists are turning to cooling systems that run on carbon dioxide or R744, ammonia or R717, or HFOs with low GWP such as R1234ze.
Ammonia: NH₃ or R717 has GWP close to 0 and a temperature range of -40°C to + 80°C.
For equipment and systems that require powerful refrigeration capacities, NH₃ is better suited, but this inorganic chemical compound is highly toxic and flammable. It can also become corrosive when in contact with some metals and alloys, or even explode in certain conditions.
In compliance with the load restrictions laid down in the F-Gas regulation, it is possible to use it in industrial refrigeration systems such as those found in the the food and chemical industries, ice rinks, ice production machines, systems designed to conserve processed food, and so on.
Please read through the gas guide to find out more: Ammonia
Carbon dioxide: CO₂ or R744 has GWP close to 0 and a temperature range of -54°C to 10°C.
For small- and medium-scale equipment and systems, CO₂ is the recommended solution. There is no limit in terms of load. Only a small amount of cooling fluid is required in refrigeration systems which, at the same time, boost their energy performance. It also has the advantage of being widely available and affordable. R744 is neither toxic nor flammable, but in high concentrations (0.5% and above, or 5,000ppm), it is a silent, deadly gas.
R744 is suitable for a range of industrial and commercial refrigeration applications such as the chillers used by food outlets, industrial cold rooms, heat pumps and so on.
Please read through the gas guide to find out more: Carbon dioxide
R1234ze: GWP close to 0 and a temperature range of 20°C to + 110°C
Solstice® ze is an ultra-low GWP hydro-fluoro-olefin (HFO) gas intended for refrigeration and air conditioning applications. It is used for equipment and systems that are of a size compatible with this fluid, such as chillers and heat pumps, including high-temperature PAC systems.
Recent studies have shown that the use of R1234ze results in a Coefficient of Performance (COP) that outperforms ammonia-based systems by 25%.
The advantages of gas detection
In addition to the safety aspect, leak testing also has significant benefits in terms of budget:
> LIMIT THE LOSS OF COOLING FLUIDS
Some fluids such as R404a are set to be phased out, leading to an inevitable rise in prices, as manufacturers adjust their rates in response to the upcoming shortage of these fluids. By detecting leaks of these refrigerant gases as quickly as possible, we help keep costs down.
> REDUCE THE FREQUENCY OF LEAK TESTS
Reducing the number of leak tests performed on your equipment saves time (downtime for staff and unproductive use of money. Any equipment item with an HFC load of more than 5 CO₂ TEQ is subject to a leak test performed by a qualified person.
We are seeing more and more gas detectors in facilities installed on sites requiring refrigeration.
Source: Légifrance
Good practices for fixed gas detection systems
All gas installations pose a risk. This is why it is so important to monitor any potential leaks, to protect staff and equipment from the risk of explosion, poisoning and asphyxiation. The rules depend on the configuration of each installation, but it is essential to take into consideration the density of the gases and the air flows when deciding where to install the detectors.
For a refrigerant system using ammonia:
The sensors are placed high up to ensure the protection of staff (machinery room, technical gallery).
- Zones to be monitored: compressor, condenser and valves (where there is a risk of leakage)
- Type of sensor: electrochemical
- Cable to be used: 9/10 pair armoured cable (use of a third cable if the sensor has a display)
For a system using cooling fluids or HFO:
The sensors are placed near to floor level due to the density of the Freon, usually in the machinery rooms and technical galleries.
- Zones to be monitored: compressor, condenser and valves (where there is a risk of leakage)
- Type of sensor: Semi-conductor or Infrared
- Cable to be used: 3 x 1mm² armoured cable
Do not overlook your personal protective equipment
Some refrigerants are toxic and pose a fire hazard. If you need to work on these installations from time to time and for short periods, you need to have the right personal
EYE PROTECTION
To offset the risk of splashes caused by fluid leaks or the opening of a pressurised circuit, you need to wear adequate eye protection to protect yourself from projections and ice burns.
Safety goggles, face covering, face shield, etc.
SKIN PROTECTION
To offset the risk of splashes caused by fluid leaks or the opening of a pressurised circuit, you need to wear adequate skin protection to avoid burns.
Protective clothing, gloves to protect your hands from the cold.
RESPIRATORY PROTECTION
If the concentration of refrigerant gas is unknown or high due to a leak, there is a risk of anoxia.
You can check the oxygen concentration using an oxygen meter before you enter the zone. In such cases, you must without fail be equipped with self-contained breathing apparatus (SCBA).
Cooling fluids are not usually toxic, but certain types require specific protection. Find the right filter for your fluid in the table opposite.
