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, highlighting the unreliability of modern AC when demand is highest. This surge in AC use also contributes to emissions, creating a feedback loop where climate change drives more heat waves, necessitating more AC use. In response, some startups are exploring alternatives inspired by ancient cooling techniques, such as the use of terra-cotta, a material with a long history of application in hot climates.

In-Depth Analysis: The terra-cotta cooling system, named CoolAnt and developed by Delhi-based design firm Ant Studio, draws inspiration from nature, traditional techniques, and modern technology, according to architect Pranjal Maheshwari. The fundamental principle behind CoolAnt is evaporative cooling, a process that utilizes the porous nature of unglazed clay, or terra-cotta. This ancient technique is exemplified by traditional Indian terra-cotta pots, which cool water through evaporation. Tiny pores in the terra-cotta allow a small amount of water to seep to the exterior, where its evaporation draws heat away from the water inside. CoolAnt applies this principle by allowing water to drip down a facade of terra-cotta tiles or pots, facilitating evaporation and thus cooling the surrounding air. The system can also be integrated into windows, mimicking the shading and ventilation provided by traditional Indian latticework. The first practical application of CoolAnt was in 2017 within a semiconductor factory experiencing heat issues from a diesel generator, providing an opportunity to test the concept beyond theoretical design. Since then, Ant Studio has developed approximately 50 different CoolAnt systems, ranging from building envelopes to art installations. Variations of the design incorporate natural inspirations, such as a beehive pattern to maximize surface area or leaf-shaped tiles that emulate the evaporative cooling process in trees. Some systems are equipped with sensors that 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 most pronounced 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. CoolAnt is not typically a complete replacement for air conditioning but serves as a complementary system. Maheshwari explains that CoolAnt installations can pre-cool outdoor air before it enters conventional HVAC systems, thereby reducing the cooling load on traditional air conditioners and improving their overall efficiency. These systems can also be implemented in transitional spaces like lobbies or courtyards. Furthermore, CoolAnt can enable the avoidance of air conditioning during moderately hot weather or reduce the duration of AC usage from an entire day to a few hours. This approach aligns with other passive cooling strategies, such as the use of ultra-white paint or new “supercool” cement, as a response to extreme heat. The increasing reliance on air conditioning globally, with AC unit sales in some Indian cities growing by over 1,000% in the past year, underscores the rationale for rethinking this dependency.

Pros and Cons: The primary advantage of the CoolAnt system is its ability to reduce ambient temperatures through evaporative cooling, potentially lowering temperatures by up to 18 degrees Fahrenheit in hot, dry climates. It also offers shade and ventilation, contributing to a more comfortable environment even when its cooling capacity is reduced in humid conditions. By pre-cooling air before it enters conventional HVAC systems, CoolAnt can decrease the energy demand on traditional air conditioners and improve their efficiency, potentially leading to reduced electricity consumption and associated emissions. The system’s design, inspired by nature and traditional techniques, offers an alternative to energy-intensive AC units and can enable reduced AC usage during moderately hot periods or shorten the overall duration of AC operation. The recirculation of water also contributes to resource efficiency. However, the effectiveness of evaporative cooling is significantly reduced in humid climates, limiting its cooling potential on such days. While it can reduce AC use, it is generally not sufficient on its own to replace air conditioning entirely in all scenarios. The source material does not detail any significant drawbacks beyond the climate-dependent efficacy.

Key Takeaways:

• Modern air conditioning faces challenges with reliability during peak demand and contributes to emissions, creating a feedback loop with climate change.
• CoolAnt, a terra-cotta cooling system developed by Ant Studio, utilizes ancient evaporative cooling techniques inspired by nature and traditional Indian architecture.
• The system works by allowing water to evaporate from terra-cotta surfaces, thereby cooling the surrounding air, and can be integrated into building facades or windows.
• In hot, dry climates, CoolAnt can reduce temperatures by up to 18 degrees Fahrenheit, and it can improve the efficiency of conventional HVAC systems by pre-cooling air.
• While not a complete replacement for air conditioning, CoolAnt can reduce AC usage and is part of a broader trend towards passive cooling solutions.
• The increasing global reliance on air conditioning necessitates rethinking cooling strategies, especially in regions experiencing rapid AC adoption.

Call to Action: Readers interested in sustainable cooling solutions should consider exploring the principles of evaporative cooling and its potential applications in various climates. Investigating other passive cooling techniques, such as those mentioned in the article like ultra-white paint and “supercool” cement, would also be beneficial for understanding a holistic approach to reducing reliance on conventional air conditioning.

Annotations/Citations: The information regarding the heat index in Delhi, the unreliability of AC during high demand, the link between AC use and emissions, and the escalating feedback loop with climate change is derived from the provided source material (https://www.fastcompany.com/91392821/this-modern-ac-alternative-is-inspired-by-an-ancient-cooling-technique). The description of CoolAnt, its inspiration from nature, traditional techniques, and modern technology, as well as the role of Pranjal Maheshwari, is also from the same source. The explanation of terra-cotta’s cooling properties, its use in traditional Indian pots, and the mechanism of evaporation are detailed in the source. The first installation of CoolAnt in a semiconductor factory and the subsequent development of around 50 systems are cited from the source. The variations in design, including beehive patterns and leaf-shaped tiles, along with the use of sensors and water recirculation, are all described in the provided material. The potential temperature reduction of up to 18 degrees Fahrenheit in hot, dry climates, and the reduced effectiveness in humid conditions, are stated in the source. Maheshwari’s explanation of how CoolAnt precools air for HVAC systems, improves efficiency, and can be used in transitional spaces is also from the source. The comparison to other passive cooling approaches and the statistics on AC sales growth in Indian cities are attributed to the source material (https://www.fastcompany.com/91392821/this-modern-ac-alternative-is-inspired-by-an-ancient-cooling-technique).