Introduction: The increasing demand for air conditioning, particularly during extreme heat events like the 125-degree Fahrenheit heat index in Delhi, India, leads to power outages and exacerbates emissions. This creates a feedback loop where climate change drives more heat waves, necessitating more air conditioning use. In response, some innovators are exploring alternatives inspired by ancient cooling techniques, such as the use of terra-cotta, a material with a millennia-long history in hot climates.

In-Depth Analysis: Pranjal Maheshwari, an architect at Delhi-based Ant Studio, describes their terra-cotta cooling system, named CoolAnt, as a fusion of nature, traditional techniques, and modern technology. The fundamental principle behind CoolAnt is evaporative cooling, a process that leverages the natural property of terra-cotta’s porous, unglazed clay. This porosity allows a small amount of water to seep to the exterior surface, where its evaporation draws heat away from the material and the surrounding air. This ancient method is exemplified by traditional Indian terra-cotta pots used to cool water without refrigeration. CoolAnt applies this principle by allowing water to drip down a facade of terra-cotta tiles or pots, facilitating evaporation and thus cooling the ambient air. The system can also be integrated into windows, drawing inspiration from traditional Indian architectural elements like latticework, which provide both shade and ventilation. The first practical application of CoolAnt was in 2017 within a semiconductor factory experiencing heat issues from a diesel generator, providing a real-world test for the architects’ evaporative cooler design. Since this initial installation, Ant Studio has developed approximately 50 different CoolAnt systems, ranging from building envelopes to artistic installations. The designs incorporate variations inspired by natural processes, such as a beehive pattern to maximize surface area for evaporation, and leaf-shaped tiles that mimic the evaporative cooling mechanisms of trees. Some advanced systems are equipped with sensors that monitor temperature and activate a low-power pump to drip water onto the terra-cotta when temperatures rise. Water that does not evaporate is collected and recirculated, enhancing efficiency. The effectiveness of evaporative cooling is notably higher in hot, dry climates, where it can reduce temperatures by up to 18 degrees Fahrenheit. While its efficacy is diminished in humid conditions, the system still provides benefits through shade and ventilation. The primary role of CoolAnt, as described by Maheshwari, is not necessarily to completely replace conventional air conditioning but to significantly reduce its reliance and improve its efficiency. CoolAnt installations can pre-cool air before it enters traditional HVAC systems, thereby lowering the cooling load and enhancing the performance of existing air conditioners. Furthermore, these systems can be utilized in transitional spaces like lobbies and courtyards, and they enable the avoidance of air conditioning during periods of moderate heat or reduce the duration of AC use from an entire day to a few hours. This approach aligns with a broader trend of exploring passive cooling strategies, such as the use of ultra-white paint and new “supercool” cement, as a response to escalating global temperatures and the rapid growth in air conditioning adoption, with some Indian cities experiencing over 1,000% growth in cheap AC unit sales in the past year.

Pros and Cons: The CoolAnt system offers several advantages. Its primary benefit is its ability to reduce reliance on conventional air conditioning, thereby lowering energy consumption and associated emissions. The system’s effectiveness in reducing temperatures, particularly in dry climates, is significant, with potential drops of up to 18 degrees Fahrenheit. It also enhances the efficiency of existing HVAC systems by pre-cooling air. The use of terra-cotta, a natural and ancient material, aligns with sustainable design principles. The system’s adaptability is demonstrated by its application in various forms, from building envelopes to art installations, and its integration with sensors and water recirculation systems enhances its functionality. However, the system’s effectiveness is notably reduced in humid climates, although it still provides shade and ventilation. The source material indicates that on its own, it is often not sufficient to entirely replace air conditioning, suggesting it functions best as a complementary technology.

Key Takeaways:

• Modern air conditioning contributes to power outages and emissions, creating a feedback loop with climate change.
• CoolAnt, a terra-cotta cooling system developed by Ant Studio, draws inspiration from ancient evaporative cooling techniques.
• The system utilizes the porous nature of terra-cotta to facilitate water evaporation, which cools the surrounding air.
• CoolAnt can reduce temperatures by up to 18 degrees Fahrenheit in hot, dry climates and can improve the efficiency of conventional AC systems.
• While not always a complete replacement for AC, CoolAnt can significantly reduce its usage and is part of a broader trend towards passive cooling solutions.
• The technology has been implemented in various applications, including building envelopes and art installations, since its first use in 2017.

Call to Action: Readers interested in sustainable cooling solutions should consider the potential of passive cooling technologies like CoolAnt and explore how similar ancient techniques are being modernized to address contemporary environmental challenges. Investigating the performance of evaporative cooling systems in different climatic conditions and understanding their role in reducing energy consumption for cooling would be beneficial.

Annotations/Citations: The information regarding the heat index in Delhi, the problem of AC reliability during peak demand, the link between AC use and emissions, the concept of an escalating feedback loop, the inspiration from ancient cooling techniques, the use of terra-cotta, the description of CoolAnt by Pranjal Maheshwari, the functionality of terra-cotta in cooling water, the mechanism of CoolAnt’s operation, its installation in windows, the first installation in a semiconductor factory, the number of systems designed, design variations inspired by nature, the use of sensors and water recirculation, the temperature reduction potential in hot, dry climates, its reduced effectiveness in humid conditions, its role in pre-cooling air for HVAC systems, its use in transitional spaces, its ability to avoid or reduce AC use, its comparison to other passive cooling approaches, and the growth in AC sales in Indian cities are all derived from the provided source material (https://www.fastcompany.com/91392821/this-modern-ac-alternative-is-inspired-by-an-ancient-cooling-technique).