Who Has Never Taken Refuge in an Unexpected Space in Summer, Overwhelmed by the Heat? Air conditioning is often seen as a blessing for bodies exhausted by high temperatures. According to ADEME, 40% of businesses were equipped with an air conditioner in 2020.

While this solution is beneficial to humans in the short term, it raises a real environmental question in the long term. In France, air conditioning in the tertiary sector represented a consumption of 10.6 TWh in 2020.

Including the residential sector and the impact of refrigerants, it generated around 3.5 million tons of CO2 per year. And these numbers are constantly increasing.

In the context of global warming, The IEA (International Energy Agency) Estimates that the global stock of air conditioners could double by 2050, weighing heavily on electricity consumption and emissions of Greenhouse Gases.

But how can you air-condition your business and ensure the comfort of your employees, without affecting the planet? Reasonable and sustainable air conditioning solutions exist.

Discover these less energy-consuming alternatives to air conditioning that reduce your carbon footprint, but also your energy consumption and your Electricity Bill.

Classic Air Conditioning: An Environmental and Energy Challenge

Air conditioning systems are all based on the same principle: Cool the Ambient Air by Transferring Heat from the Inside to the Outside, thanks to a refrigerant fluid.

While this technology is effective, its energy consumption and greenhouse gas emissions raise questions in a world threatened by global warming.

What are the current air conditioning methods?

Air conditioning consists of rejecting heat outside and injecting fresh air inside. In a closed circuit, the refrigerant Calories absorbed inside the building.

Transformed into a gaseous and condensed state, the fluid increases in temperature. Expulsion of heat to the outside lowers its pressure and temperature. Cooled, the gas refreshes the ambient air, diffused into the building by a fan.

The air conditioning market is full of solutions adapted to each need. Some of the most common include:

• The reversible air conditioner : reversible air conditioning heats the indoor air in winter and cools it in summer. While it guarantees thermal comfort all year round, its purchase cost is higher than conventional air conditioning. However, it consumes less energy than a heating system.
• The Mobile Air Conditioner : the mobile air conditioner offers a powerful, compact and simple solution for cooling small spaces. Most often on wheels, it can be moved easily as needed.
• The wall-mounted air conditioner : wall-mounted air conditioning requires more ambitious work to install the indoor and outdoor units and connect them through a duct. But this system has proven its efficiency and reliability. With their increasingly aesthetic modules, wall-mounted air conditioners adapt to all spaces and surfaces.
• The Cassette Air Conditioner : The Cassette Air Conditioner is built into the ceiling for more discretion. It blows fresh air downwards to ensure a homogeneous air conditioning of the room.

Air conditioning: what is the impact on the environment?

If they are effective, conventional air conditioning systems are Expensive and Not Very Virtuous for the Environment.

According to CNRS researchers, air conditioning maintains a Vicious Circle. By rejecting heat outside buildings, it Would reinforce the urban heat island phenomenon. Studies showed in 2012 that the temperature in the streets of Paris would have increased by 0.5°C under the effect of air conditioning, making it even more necessary.

Energy-intensive, the use of air conditioning is also accompanied by Peaks in electricity consumption in summer. In 2020, the International Energy Agency (IEA) estimated that all the world's air conditioners and fans represented around 10% of global electricity consumption, mainly produced by fossil fuels and which emit greenhouse gases.

Refrigerant is the main black spot in air conditioning. Hydrofluorocarbons (HFCs) used for cooling and refrigeration have a Global Warming Power (GWP) of the order of 120 to 14,800 times that of CO2.

If the synthetic gas R32 should replace the gas R410A which is very harmful to the environment, its global warming power (GWP) of 675 kg eq. CO2 remains above the European target of 400 kg eq. Maximum CO2 in 2030.

What are the traditional alternatives to conventional air conditioning?

Humans have always invented techniques to ventilate their homes and freshen the atmosphere. The episodes of Heat wave Invite you to rediscover these Natural air conditioners Low tech, requiring no fossil fuels, electricity, or other energy sources.

The Canadian and Provençal climate sink

The Canadian well and the Provencal well are natural ventilation and aeration systems. Already used in Roman times, These geothermal devices use the differences in temperatures between the outside air and the ground To warm or cool the atmosphere of a building.

The principle is simple: it involves capturing the outside air, heating or cooling it by circulating it into the ground via buried pipes, then diffusing it inside the building.

This system of Geothermal energy Is called Canadian Well When It Comes to Heating a Building With cold outside air warmed up in contact with the warm ground. He is called Provencal Well When It Comes to Refreshing a Building With hot outside air cooled in contact with the cool ground.

Ecological and efficient, Canadian and Provençal Wells exploit air and land, their own, local, inexhaustible and free resources. They Can Allow Gain around 10°C less.

On the other hand, their installation represents a High Budget of a few thousand euros to finance earthworks and equipment (ducts, air intake terminal, ventilation system, etc.). This device must be thought of as early as the design of the building.

Through ventilation

Through ventilation consists in artificially creating a natural phenomenon known to all: the Air current.

Thanks to wind pressure, Outdoor Air Enters the Building and Expels Hot and Polluted Air. To be effective, the openings for the air intakes must be arranged facing the dominant wind and the air outlets opposite.

If this system creates a feeling of refreshment and renews the indoor air, it is not Not an air conditioning system. During a heatwave, it diffused hot air. Its performance also depends on weather conditions and wind strength.

Environmentally friendly, economical and maintenance free, pass-through ventilation is a Complementary aeration system Which is seldom self-sufficient.

The Use of Wet Terracotta Pots

Terracotta pots are an ancient way to freshen up a room. This system uses the natural properties of terracotta, a porous material.

Continuously soaked in water, the pots sweat. Water vapor absorbs heat, which lowers the room temperature.

This ecological air conditioning system was widely used in ancient times, especially in Egypt. It also inspired the Palestinian Jara. Suspended from the ceiling, this terracotta tank stores water by cooling the room.

The greening of buildings

The installation of fences on walls for climbing plants, the greening of terraces or plant arches are not new solutions. The Hanging Gardens of Babylon built in ancient times are proof of this.

Provided you choose the right plants, greening acts like a thermal insulator for the building. By creating shade, she reduces heat storage and contributes to the control of temperatures in urban heat islands. It also protects surrounding buildings from the reflection of sunlight.

Building design, orientation and layout

As effective as they are, these traditional systems do not compensate for poor building design. Our ancestors knew that instinctively. Who has never enjoyed the freshness of old stone houses, protected from the heat by thick walls?

Bioclimatic design brings up to date simple and sustainable principles, with one objective: to make the most of the sun in winter and to protect yourself from it in summer. Taking into account the climate and the environment, bioclimatic construction and renovation pay particular attention to:

• The surface and orientation of facades and glass openings.
• The integration into the building of sun protection (sun caps, sunshades, shutters, awnings...)
• The choice of building materials and their color to maintain warmth in winter and freshness in summer inside (stone, brick, wood...)
• THEthermal insulation and the thickness of the walls and roof.
• THEintegration of vegetation to regulate temperatures and create a microclimate in summer (green roofs and walls, garden, bamboo fence...)

Modern methods of air conditioning

Traditional systems may not be sufficient to cover cooling needs. Of numerous modern, ecological and efficient alternative solutions have enriched the air conditioning market in recent years.

Bio-air conditioning or Evaporative Air Freshener (RAE)

Also known by the acronym of RAE (Evaporative Air Cooler), bio-air conditioning is a mobile cooling system. It is based on the same Principle ofhydrocooling than terracotta pots. The ambient air is captured and then cooled by passing through a filter composed of organic matter and maintained in a humid state. Fresh air is released into the room by a fan.

With low electricity consumption and the absence of refrigerant gas, bio-air conditioning is a compact, economical and ecological device, easy to install and move.

Ideal for lowering the temperature of an office by up to 5°C, its range is nevertheless limited. Not suitable for confined and/or humid spaces, the RAE must be placed near an ajar window to promote air renewal.

Son accessible cost varies from 100 to 500 euros depending on the capacity of the tank, the power of the device, the air flow and the options chosen (purifier, programming...).

The use of renewable energies

Although they raise the question of refrigerant, conventional air conditioning systems using renewable energies nevertheless make it possible to reduce energy consumption and the carbon impact of air conditioning.

The air-to-air heat pump

La Reversible air-to-air heat pump works like Canadian and Provencal wells. Elle captures outside air to heat the building in winter and cool it in summer. The only downside is the mandatory use of refrigerant to ensure heat exchanges.

Solar air conditioning

While still confidential, new innovative air conditioning systems use photovoltaic electricity to cool buildings:

• Solar air conditioning by adsorption or absorption : these techniques consist in producing cold from Sun heat. The cooling effect is created by the evaporation of a refrigerant (such as water) in reaction to heat. The refreshed air is diffused into the building by a fan coil.
• Solar air conditioning by desiccation : this technique consists in cooling the outside air using desiccating materials that absorb its moisture. Once dry, the hot air is cooled by evaporating the water and then diffused into the building.
• Aerovoltaics : this technique consists in capturing the freshness retained under the photovoltaic panels to cool the building.

Smart windows and solar films

Protecting a building from the sun's heat is a basic principle for cooling a building. Beyond simple actions such as installing sunshades, shutters or green walls, innovative technologies offer reinforced protection:

• Electrochemical glazing windows : an intelligent system, electrochemical glazing allows you to customize the level of luminosity and heat. Composed of crystals and an electrolyte, glass changes color under the effect of an electric current and a chemical reaction. When the electricity is switched on, the glazing turns bluish to allow light but not heat to pass through. The increase in electric current makes the glass opaque. However, these windows are still not very accessible, with a cost of up to 600 euros per square meter.
• Solar films and coatings : thanks to their metallized composition, anti-heat solar films reject up to 80% of solar energy, without reducing visibility to the outside. They limit the phenomenon of overheating in the event of high outside temperatures, resulting in better comfort for building occupants and reduced energy consumption.
• Reflective materials and roofs : on the principle of Cool Roofing, reflective materials and roofs reflect sunlight to keep surfaces cool and improve the thermal comfort of buildings. Thanks to light colors and mineral pigments, these materials reinforce the albedo effect, i.e. the reflective power of the surface.

Alternatives to conventional air conditioning make it possible to save energy, to reduce the cost of air conditioning on the bill, to limit the environmental impact of greenhouse gases, to improve thermal comfort and to reduce maintenance and maintenance costs.

More expensive, technologies based on geothermal energy, renewable energies and bioclimatic design offer a global and efficient solution for buildings. More modest, ventilation, window protection or bio-air conditioning are emerging as ecological and effective alternatives that are more accessible.

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