COP28: How Sustainable Cooling Can Combat Climate Change And Promote Circularity

Climate change induced heatwaves are among the modern anathemas threatening the way we live, work and breathe. A report by the University of Cambridge in 2022 estimated that lethal heatwaves will impact 300 million Indians by 2050, increasing exposure to diseases, health risks, food shortages and higher mortality rates. This is poised to trigger a surge in demand for air conditioning, which could lead to rise in emissions as much as 120 million metric tonnes by 2050 in India, setting back our journey towards sustainable development as well.

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As Net Zero goals inch closer, we are at a critical juncture when the call to action for energy transition and circular economy has grown stronger, prompting nations around the world to look at sustainable cooling solutions. This is evidenced in India as well, with the pledge to drive Resource Efficiency and Circular Economy during its G20 presidency.

How does District Cooling tap into the principles of circularity?

While there¡¯s no one-stop approach to sustainable cooling, District Cooling (DC) is emerging as a viable model to reduce, reuse and recycle wastewater and heat. Through an insulated closed loop, industrial-grade pipe network, district cooling provides chilled water for indoor cooling to industrial, commercial, and residential buildings. Cold supply water enters the building and flows through a heat exchanger absorbing heat from the building space, thereby providing energy-efficient cooling. The warm water then recirculates back to the central plant through a closed loop return line.

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Unlike traditional cooling, the key lies in harnessing the waste heat from industries and power plants, which can be repurposed as an energy source for the cooling process. Hence, a district cooling system reduces dependency on electricity grids and can achieve up to ten times the efficiency of a regular cooling system.

The immense scale of DC systems also makes it possible to use lake, ocean, and recovered greywater and treated sewage effluents instead of potable water, thereby improving resource efficiency. With aggregation of cooling demand through district cooling-as-a-service, it is possible to achieve economies of scale improve energy efficiency, and yield more socio-health-economic benefits for the populace. It can also reduce the carbon footprint by mitigating the impact of 100 million tonnes of CO2 released every year by traditional cooling systems.

From circular cities to a circular economy

Globally, district energy with district cooling/heating as a primary subset, is being used to build circular cities, which, in turn, become the foundation for a circular nation. Scandinavian countries, including Denmark, Sweden, and Finland, have been at the forefront of implementing DC/DH systems that utilize low-grade industrial residual waste heat from energy-intensive, industrial processes. In Helsinki, more than 80% of energy used in district cooling is obtained from unutilized energy sources, such as surplus heat from data centres, business premises, residential complexes, industrial processes etc. It is a prime example of instituting principles of circularity successfully.

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Closer home, India Cooling Action Plan (ICAP) advocated the adoption of technologies like DC as it requires 15% less capacity than conventional distributed cooling systems for the same cooling loads, due to load diversity and flexibility in capacity design and installation. The DC system in Gujarat International Finance Tech City is touted as India¡¯s first, where the requirement of 270,000 TR is met with 180,000 TR of chillers. With steady reuse of waste heat, the ecosystem can achieve a sustainable and symbiotic relationship between cooling infrastructure and local industries.

Creating self-sustained virtuous cycles of sustainable growth

As a circular strategy, DC¡¯s benefits spill over to energy-savings and cost savings as well. Cost-saving is a major plus with DC systems, as they consume less energy and require low maintenance. Sunk costs and operational costs associated with oversized individual chiller plants are avoided. With large-scale, central water-cooled chiller plants, it consumes less energy than on-site cooling systems, whilst stabilizing electric loads as well. DC systems can free up a lot of space on large campuses, which can be utilised for various other purposes. The freed-up space can be used for greening, such as community gardens or parks, which can go a long way in minimising the heat island effects. Another significant advantage is that empty spaces can be even converted into solar canopies, reducing grid dependency, energy consumption, electrical costs and carbon emissions.

Circular economy is not just a buzzword anymore, with developing and developed nations across the making tangible efforts to make this a reality. Are we ready to move beyond age-old dependency on traditional systems and take bold steps towards a more sustainable future?

About the Author: Sudheer Perla is the Managing Director, Tabreed Asia. All views/opinions expressed in the article are of the author.