However, the increasing use of individual ACs will also significantly increase the country's energy demand, putting pressure on electricity grids and driving up emissions.

District Energy in Cities Initiative, National District Cooling Potential Study for India, a 2021 UNEP report, mentions the scale of India's cooling challenge.

According to the report, urbanisation and economic growth will increase the commercial floor area in India by 2.5-3 times, and the number of urban households will double over the next two decades (2018-2038).

Altogether, demand for space cooling in India is expected to increase 11 times over the same period. In addition, rapid increases in demand for cooling in the cold chain, transportation and refrigeration are also projected.

While building efficiency and design, passive cooling, nature-based solutions, fans, and coolers from an environmental perspective should all be promoted before air conditioning, India Cooling Action Plan (ICAP), the UNEP report notes, also advocate a shift to "district cooling, trigeneration and thermal storage".

What is a district cooling system?

A district cooling system (DCS) is a modern, efficient way to air condition a network of buildings in cities or campuses, erasing the need for individual ACs. DCS distributes (supplies and collects back) cooling energy in the form of chilled water from a central district cooling plant to multiple buildings through a distribution network of insulated, underground pipes for space and process cooling. Individual users purchase chilled water for their building from the operator of the DCS and do not need to install their chillers or cooling towers.

Many of the energy efficiency advantages of DCS result from combining many diverse load profiles, allowing the district cooling plant equipment to operate at high load factors with resulting higher levels of efficiency. This demand aggregation also provides the economies of scale that allow district cooling systems to cost-effectively utilise high-efficiency and sustainable technologies that are less economically and technically feasible for an individual building.

"A DCS can serve a wide variety of loads such as commercial offices, hotels, residential, industry units, data centres, cold chain, sports arenas, malls, schools, institutional buildings and hospitals," explained Sudheer Perla, country head, Tabreed India, a Dubai-based utility that provides energy-efficient and environmentally friendly district cooling solutions. Perla was one of the panellists at one of the sessions at IEW, The road to a cleaner grid: Decarbonisation and energy diversification for the power and utilities industry.

Additionally, DCS offers a massive benefit to building owners of not procuring, installing, operating, and maintaining air conditioning plants. It also offers them extra rooftop and basement space for commercial activities, capital and operational cost savings, and enjoy the luxury of having reliable, uninterrupted, and economical cooling as a service. Finally, the centralised approach of district cooling allows the safe and controlled use of environmentally friendly refrigerants that are not appropriate or available at the individual building level.

"At present, most air conditioning loads in India are met by on-site cooling technologies consisting of either window or room air conditioners or central air-cooled or water-cooled chillers powered by the electricity grid. The efficiency and refrigerant consumption of on-site cooling equipment varies significantly depending on the product, building and cooling system design, operation and maintenance, and even the building's ownership structure. In general, in dense urban areas, energy and refrigerant use for air conditioning is far lower if clusters of buildings and even whole townships are connected to a DCS," Perla explained.

"With urbanisation at its peak, Tabreed looked at high numbers with regards to the growing energy demand forecast for the next three decades in context to the ICAP. Hypothetically speaking, if all of India's incremental cooling demand is met through district cooling, then it is possible to shave up to 100 Gigawatts of power demand," Perla said at IEW.

Cooling as a service, added Perla, is very much in line with providing utilities like water/gas through piped networks to aid aggregate demand centrally, which would lead to a drastic decrease in the quantum of cooling devices and equipment.

In India, large central cooling plants have already been used in the commercial building segment for many years. In addition, consumers like airports, IT campuses etc., often provide space cooling by setting up large centralised air conditioning plants, which are captive systems by nature, i.e. will not expand beyond the development. However, the large-scale adoption of DCS is still nascent in India and requires concerted policymakers and industry attention.

“District cooling using electric chillers can typically reduce annual electricity consumption by 25% over individual water-cooled central plant. In many cases, this reduction can be higher, reaching 30-40%. When technologies such as CHP and/or free cooling are used, electricity reductions can be up over 80%,” says the UNEP report.

According to the UNEP report, district cooling systems are a proven technology that has been deployed for many years in many cities worldwide.

Countries like Sweden, UAE, Singapore, China, Colombia, France, Malaysia, and Egypt have started meeting their air conditioning demand with DCS.

Policy shifts needed for DCS

Starting India's market for district cooling is not simple – the pace of real estate in cities, the novelty of this technology and the diverse barriers that exist make shifting the cities, industry and the country to district cooling all the harder.

DCS should be conceptualised in the master planning stage of urban development for it to be a major driver of urban sustainability, as it has been in numerous countries. Roles and responsibilities of municipalities and DISCOMs are vital to promoting DCS for large green field commercial developments in India.

“There is a need for a District Cooling Code for the country which prescribes legal, administrative, leasing and contracting guidelines for real estate developers, district cooling service providers, government departments and financial institutes,” recommends the UNEP report.

GIFT CITY DCS

Gujarat International Finance Tech-City, or GIFT City, is India’s first merchant DCS developed by the Government of Gujarat. GIFT City has been developed on 886 acres of land with a planned total built-up area of 5.76 Mn Sqm, and includes commercial buildings, residential buildings, social buildings such as hotels, clubs and malls, and a hospital.

With DCS, the total requirement of 270,000TR of air-conditioning shall be met with just 180,000TR of chillers. Each plant has been designed with a chilled water-based stratified thermal energy storage tank, which can be charged during the off-peak period and discharged during the peak period, thus reducing the electrical demand from 240MW to 135 MW only.

The views expressed are personal