The Global Cooling Prize, launched in 2018  to spur the development of a dramatically more efficient, climate-friendly residential air conditioning system with five-times less climate impact than conventional models, today announced two winners in an online ceremony: units developed by Japanese OEM Daikin and Chinese OEM Gree Electric Appliances.

The winning systems, chosen from eight finalists,  both exceeded the Global Cooling Prize’s five-times- lower-climate-impact criteria “but were too close for us to separate, being bounded by the testing uncertainty factors,” said Iain Campbell, senior fellow at the Rocky Mountain Institute (RMI), one of the main organizers of the Global Cooling Prize along with the Government of India.

The Global Cooling Prize comes with award of US$1 million.

The Daikin system employs HFO-1234ze, an A2L refrigerant with a 20-year GWP of four. The Gree system uses HFC-152a, an A2 refrigerant with a 100-year GWP of 120 and a 20-year GWP of 437. A2 and A2L are classified as having lower flammability (A2 higher than A2L).

A hydrocarbon system using propane (R290) from Indian OEM Godrej completed the testing phase of the competition, but “ultimately,  in my opinion, [Godrej was] materially hampered by the charge restrictions” on hydrocarbons in residential air conditioners, said Campbell.

The global standard IEC 60335-2-40 for room air conditioners (RACs) is being updated to allow a greater charge of hydrocarbons to be used. A final revised standard is expected to be published by the end of 2021.

The Daikin subsidiary involved in the competition –  Daikin Air Conditioning India Private Limited, with partners Daikin Industries Ltd and Nikken Sekkei Ltd. –  developed a vapor compression technology with “novel componentry,” according to Daikin. A multi-split method is used to connect three indoor units with one outdoor unit. In addition, an evaporative cooling method is used to improve the system efficiency by using heat of vaporization to lower the temperature of the air that outdoor unit takes in, said Daikin.

Gree Electric Appliances, based in Zhuhai, China, with partner Tsinghua University, developed a vapor compression technology integrated with evaporative cooling and solar PV. 

The Global Cooling Prize drew over 2,100 participant registrations from around the globe, including start-ups, research institutes, universities, and key industry manufacturers in more than 95 countries. Of the registered entities, 445 teams submitted preliminary ideas and 139 teams from 31 countries followed through with a full detailed technical application for the prize. 

The initiative was designed to address the impact of population growth, urbanization, and rising income levels, compounded by a warming planet, on demand for comfort cooling globally; room AC installations are expected to grow from 1.2 billion in 2018, to a projected 4.5 billion by 2050.

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