Environmental sin Air conditioning – Air conditioning: Modern devices harm the environment less – knowledge

It got too hot for many people this summer, including in their homes. Dealers reported record sales of air conditioning systems. But: To what extent do the devices actually harm the environment? What are sustainable alternatives?

Stefan Reimann

Environmental scientists at Empa

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The environmental scientist Stefan Reimann conducts research at the Swiss Federal Laboratories for Materials Testing and Research (Empa) in Dübendorf. His research focus is on halogenated greenhouse gases (CFCs, HFCs).

These halogenated substances are continuously measured on the Jungfraujoch. The measurements are used to estimate the emissions over Switzerland, which come from leaky air conditioning systems, for example.

SRF knowledge: More and more air conditioning systems are being installed in Switzerland. What does this mean for the environment?

Stefan Reimann: On the one hand, these devices consume electricity. On the other hand, they contain coolants. If the systems are not completely sealed, these coolants escape into the atmosphere as greenhouses. Thus, the gases heat up the world.

Is there also an environmentally friendly variant for refrigerants?

That’s definitely where the development is headed. At the moment, the so-called HFOs in particular are being installed in the new air conditioning systems. Normal hydrocarbons are also increasingly used for cooling. However, there are still devices in use that contain environmentally harmful substances. And unfortunately they are still being produced.

Which environmentally harmful chemical compounds are you talking about?

The cooling of the devices is filled with fluorinated hydrocarbon. When these enter the atmosphere, they are effective as greenhouse gases. Such devices are also still available in Switzerland. Fortunately, however, the trend is towards more ecological coolants.



diethyl ether: Went down in history as the first “professional” refrigerant. However, the substance is highly flammable, toxic and harmful to the environment. For a time it was also used as an anesthetic. Ether has not been used as a coolant for decades.

Ammonia: Belongs to the natural coolants and is considered to be relatively environmentally friendly and cheap. However, the chemical combination of nitrogen and hydrogen in concentrated form can damage mucous membranes and lungs and irritate eyes and breathing.

Isobutane and Propane: Are environmentally friendly coolants that can be used in refrigerators and air conditioning systems.

Chlorofluorocarbons (CFCs for short): These synthetically manufactured coolants came onto the market in the 1930s. Your advantage: They are neither toxic nor particularly flammable. However, it was later proven that CFCs damage the ozone layer and play a key role in the greenhouse effect. World politics reacted to this and decided to ban the ozone-depleting substance in the Montreal Protocol.

Fluorinated hydrocarbons (HFCs for short): For this reason, these chlorinated hydrocarbons were replaced by fluorinated ones in the 1990s. These do not decompose the ozone. However, the HFCs are controversial with regard to their environmental compatibility, since they are strong greenhouse gases.

Hydrofluoroolefins (HFO for short): The latest generation of synthetic coolants are the so-called fluorinated olefins, which, unlike their predecessors, only remain in the atmosphere for a short time and are only very weak greenhouse gases.

Carbon dioxide: CO2 is a non-flammable and environmentally friendly refrigerant, but has been little used for a period of time. Today, the substance is experiencing a revival because it hardly contributes to the greenhouse effect. CO2 is currently used, for example, for industrial and commercial cooling.

Are these devices more expensive than the conventional ones?

A new development always entails a small price increase at the beginning. But in principle, the coolant that is in it is much cheaper and about as efficient. For example, propane is cheaper than HFOs. I’m sure that the new devices will cost about the same over time.

What would be the impact of air conditioning systems if they were not further developed?

If we continue at this rate, the climate will warm by about 0.1 degrees by 2100, in addition to what we otherwise expect. These calculations make it clear that the greenhouse effect of these plants is considerable.

Do the new devices also consume less electricity?

Yes, because there is more efficient technology behind it. This automatically leads to a reduction in power consumption and the energy that is put into it.

But the great revolution is probably not to be expected.

As always, it’s a little slower than we’d like. The fact that the fluorinated hydrocarbons can be largely replaced by normal hydrocarbons is certainly a very good development.

The interview was conducted by Daniel Theis.

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