1. Climate change, overheating buildings, and energy-hungry air conditioning: the vicious cycle
Rising temperatures and completely obsolete air conditioning systems
Climate change in the coming decades will bring extended periods of intense heat and heatwaves, driving building overheating and increased summer energy consumption. In 2019, ADEME reported that 22% of households had one or more cooling systems, up from 14% in 2016—a 50% increase in just three years. By 2050, ADEME projects that one in two homes will rely on air conditioning. Already today, the European air conditioning market represents 8 million units sold annually, worth €5 billion.
While the principle of an air conditioner is to blow cold air, it actually does so by absorbing warm air from a space and expelling it outside. Conventional air conditioning systems are therefore an unsatisfactory solution, given their massive carbon footprint: they're energy-intensive, rely on refrigerant gases with high global warming potential, and release heat into the environment. Today, air conditioners worldwide have the same carbon impact as Japan. Worse still: by 2050, they'll consume as much electricity as China does today. This is a vicious cycle with severe consequences—one that Caeli Énergie has made it its mission to break.
The challenge primarily concerns multi-family residential buildings. More commonly equipped with air conditioning systems than single-family homes, these buildings are also more prevalent in urban areas, making them more exposed to Urban Heat Islands (UHI). A study conducted by the Centre National de Recherches Météorologiques, published last July, examined the widespread use of air conditioning in the Paris region. The findings are unequivocal: locally, temperatures increase by up to 3°C due to hot air expelled by air conditioning systems.
Addressing this challenge, accelerated by the regulatory framework
Since the heatwave that struck France in 2003, cooling has become mandatory: Following the 2003 heatwave that caused more than 15,000 deaths in France, the government issued the Decree of August 13, 2004, amending the Decree of April 26, 1999, which set out the specifications for the multi-year agreement provided for in Article 5-1 of Law No. 75-535 of June 30, 1975 on social and medical-social institutions. This ensured that all nursing homes would have cooled rooms. The same approach was proposed for healthcare facilities.
It has therefore become urgent to protect vulnerable populations during heat waves—particularly in nursing homes and hospitals—as well as critical equipment and examination or competition halls.
To this is added the Law of March 30, 2023: a five-year exemption regime from public procurement law has been established to massively scale the energy renovation of public buildings. 400 million square meters of public real estate (300 million square meters for local authorities) must be renovated.
Incentives and subsidies will be provided to projects that choose companies compliant with this law, rather than outdated air conditioning systems. These new standards will therefore drive the expansion of new solutions that are far more environmentally friendly.
The need for disruptive innovation in the existing air conditioning market
Over the next thirty years, an average of four air conditioners could be sold every second, according to the International Energy Agency. Air conditioning is becoming a genuine climate disaster: it's time for a new model.
The most urgent measure to implement would be ensuring that all new air conditioners are far more energy-efficient. Not all units are created equal—some are up to 25% more efficient than others. But is that enough? The need for projects championing the "air conditioning of the future" is becoming increasingly pressing.
Caeli is one of them.
2. Replacing imported polluting air conditioning units with low-carbon cooling systems manufactured in France
High energy efficiency refrigeration systems with a low environmental footprint
Caeli's mission is to offer a sustainable alternative to conventional air conditioning. The company, based in Isère, designs and manufactures cooling systems with a low environmental footprint: they consume 5 times less energy than conventional air conditioners and operate without refrigerants. Additionally, they don't release heat outdoors and don't contribute to the urban heat island effect.
This innovative, patented solution, developed at CNRS, harnesses the phase-change energy of water as it evaporates. In practice, this process is naturally enhanced to produce air that's colder than any other evaporative system on the market.
At the heart of the Caeli project: innovation, performance and reshoring
i) Technological innovation
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The major advantage of this technology lies in its apparent simplicity: the only moving parts are fans, and the functional core requires neither chemicals nor rare metals to operate—just water and air. Only a handful of companies worldwide have mastered this cycle, and Caeli Énergie currently delivers the best performance in this field.
ii) Energy performance
Caeli's cooling systems deliver a remarkable improvement in energy and thermal performance compared to conventional air conditioning. Their coefficient of performance (COP) exceeds 17—four times higher than that of standard AC units.
iii) Industrial reshoring
Beyond the CO2 challenge, Caeli is pursuing another objective: relocalizing air conditioning system production. Their workshops, located in Grenoble, handle 100% of their manufacturing.
To achieve this, they rely on two main approaches:
simple and proven technologies, a network of strong local expertise
Behind the project, a skilled team driven by long-term ambition
At the origin of the project are Rémi Pérony (CEO), deeply involved in the company's strategy and growth, and Stéphane Lips, a former researcher at the Centre d'énergétique et de thermique de Lyon (CETHIL), who created the Caeli product. He leads the R&D side of the project.
The Caeli Energie team is made up of people who share a strong commitment to the climate cause, driven by values of efficiency, care, and fairness.
3. A sustainable solution to the recurring problem of summer overheating
Caeli's technology: revolutionary air conditioners with zero heat emissions
The technology developed by Caeli is based on indirect dew-point evaporative cooling. The dew point is the temperature to which air must be cooled to reach saturation and begin condensing. This cooling solution is based on the Maisotsenko cycle and can cool an air mass below its wet-bulb temperature.
To optimize the Maisotsenko cycle, Caeli Energie's R&D teams developed a patented process that maximizes the heat exchange surface between air and wet surfaces, enabling high compactness and unique performance.
Proven results in environmental impact
Caeli's value proposition aims to transform and improve our living spaces with the lowest possible environmental impact. This is achieved through 2 objectives:
First objective: drastically reduce the environmental footprint of air conditioning
Turning on a Caeli product means reducing your CO2 emissions by 85%. Within a few years, that translates to 250,000 tons of CO2 kept out of the atmosphere.
Caeli cooling systems:
do not use refrigerant fluids, and therefore have zero environmental impact on the greenhouse effectuse 5 times less energy than conventional air conditioningoperate without an external cooling unit, making integration easier and preventing any hot air discharge outside
Concrete, measurable results:
To quantify this environmental benefit, a comparative life cycle assessment (LCA) was conducted using the OPEN LCA tool. The results speak for themselves: deploying the solution across Europe would reduce air conditioning-related carbon emissions by a factor of 3 to 6.
Second objective: boosting efficiency for ever-greater environmental performance
Thanks to its unique technology, the Caeli air conditioning system's energy efficiency actually increases as the temperature difference between indoors and outdoors grows.
This solution therefore offers:
1/ High energy efficiency: for equivalent use, compared to conventional air conditioning, a Caeli system consumes 5 times less electricity.
2/ Water savings: thanks to its energy efficiency, Caeli's technology requires very little water compared to a conventional air conditioner
3/ No impact on humidity levels: conventional air conditioning dries out the ambient air, but Caeli does not affect the absolute humidity (water content) in the room
For all these reasons, we are very proud to support Caeli Énergie in financing the creation of a pilot production line to scale up its manufacturing capacity, fund system production operations, and make strategic hires.
The Caeli project as told by its co-founders:
The press is talking about it:
Caeli Energie wants to deploy its low-carbon cooling systems, Les Échos
Caeli Energie raises €10 million to deploy its "green" air conditioning, Maddyness