Evaporative Cooling: A Current Alternative Towards Sustainable Air Conditioning

In a world urgently seeking sustainable solutions to combat climate change and preserve our resources, the technology behind evaporative cooling emerges as a beacon of hope. This is demonstrated by the technical analysis of the results obtained from its application in a positive impact project carried out by our company during the transformation of an old theater in Madrid into a sustainable gastronomic space. It shows how evaporative cooling, based on an ancient physical principle, can revolutionize the way we keep our spaces cool and comfortable without compromising the planet's sustainability.

The Fundamental Principle: Latent Heat of Evaporation

At the core of this innovation lies the latent heat of evaporation, a simple yet powerful concept. When water changes from a liquid to vapor state, it absorbs energy and, as a result, cools the surrounding environment. This forms the basis for the operation of evaporative cooling systems, which harness this process in two distinct ways.

Dual Function of Porous Terracotta Walls

Firstly, porous terracotta walls are saturated with water. As the water evaporates from these surfaces, it cools the air around them, creating a refreshing effect inside the space.

Secondly, hot and dry air enters the system and encounters these terracotta walls. In this encounter, the dry air absorbs water vapor, which cools and humidifies it. In summary, this system provides a dual cooling effect, both through the direct evaporation of water and the air humidification process.

Optimal Operating Conditions

Evaporative cooling achieves its peak performance in warm and dry conditions. To illustrate this, let's take an example of an average day in July or August in a city like Madrid. At a temperature of 32°C and a relative humidity of 40%, the air enters the system (point A in the chart bellow).

At the system's outlet, the air has been humidified to 80%, and its temperature has decreased to 24.2°C. This is achieved without adding additional energy, solely through the processes of evaporation and humidification. The result is a much cooler and comfortable environment.

Astounding Energy Efficiency

One of the most remarkable features of evaporative cooling is its energy efficiency. Our detailed analysis revealed that for an air flow rate of 1,500 m³/h, the system absorbs 5,088 grams of water in an hour. This translates to 11,499 kJ of absorbed energy, which is divided into an instantaneous power of 3.19 kW. However, it's important to note that the system only uses the fan approximately 20% of the time, reducing the effective power to 2.55 kW.

Compared to the best air conditioning systems, which have an Energy Efficiency Ratio (EER) close to 4, evaporative cooling shines with a Coefficient of Performance (COP) of 31.87. In other words, it is eight times more efficient than the best air conditioning.

Health and Environmental Benefits

In addition to its impressive efficiency, evaporative cooling brings additional benefits. This system increases indoor humidity, highly recommended in our dry climate. Furthermore, it promotes air renewal, enhancing indoor air quality. These aspects are not only comfortable but also beneficial for health.

We will continue betting on sustainable solutions like this!!

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