25 June 2021
The Global Cooling Prize: An innovation challenge that shattered the performance ceiling for residential cooling

How can we implement the learnings from this global innovation challenge to shape the future of cooling?

Ankit Kalanki, Caroline Winslow, Iain Campbell (Rocky Mountain Institute) explain the outcomes and implications of this initiative.

In many parts of the world, access to affordable cooling is increasingly viewed as a necessity. Cooling supports positive health outcomes, higher productivity, and accelerated economic development. However, over 3 billion people in the world today are at some risk to their health and safety due to lack of access to coolth. Increasing population and rapid urbanization, coupled with a warming planet, are expected to drive the number of residential/room air conditioners (RACs) in service from 1.2 billion units today to 4.5 billion units by 2050 (Campbell et al., 2018). However, providing increased access to cooling using traditional approaches comes at an unaffordable environmental cost.

The Global Cooling Prize

To spur the development of a super-efficient, climate-friendly, and affordable cooling solution, an international coalition launched the Global Cooling Prize in November 2018. The coalition was initiated by Rocky Mountain Institute (RMI); the Department of Science & Technology (DST), Government of India; and Mission Innovation. The Prize called upon global innovators to develop a cooling solution with at least 5X lower climate impact than the standard RACs  sold in the market today, and at no more than 2X the cost of the standard AC unit when manufactured at a scale of 100,000 units per year.

In the two and half years of its journey, the Prize received an overwhelming response, not only from innovators, startups universities, and research labs, but also from AC manufacturers, as well as government institutions, industry associations, and global non-profit organizations. In April 2021, two teams – Daikin with partner Nikken Sekkei Ltd. and Gree Electric Appliances, Inc. of Zhuhai with partner Tsinghua University – were announced as the grand winners. The winners were determined following a successful completion of prototype testing in India, in an actual apartment building and simulated real-world conditions in the lab. Both teams achieved the five times lower climate impact criteria ‑ a reduction of more than 80% with reference to the baseline unit. (The reference baseline unit is a fixed-speed, mini-split type RAC unit with an Indian Seasonal Energy Efficiency Ratio (ISEER) of 3.5 W/W and using R22 refrigerant – representative of the most commonly sold RACs in the Indian market in 2017.) The climate impact reduction of the representative best available technology is determined by combining electricity reduction (based on simulated year-round performance in the lab) and refrigerant GWP using assigned weighting of 80:20 respectively, relative to the baseline unit.

To put these prototypes into perspective, the climate impact reduction of representative best-in-class RAC technology available in India today was assessed to be at about 45%. Furthermore, considering the operational savings due to the energy performance of the winning technologies, the total cost of ownership (i.e., cost to own and operate them over a 10-year period) was assessed to be about half that of the traditional ACs. Clearly, the winning technologies shattered the performance ceiling of what was previously believed to be technically possible for AC units, all while utilizing lower GWP refrigerants and saving consumers money.

How did the Prize succeed in catalyzing innovation?  

Around the world, improving energy efficiency in ACs has traditionally been driven by policymakers, pushing on the floor of performance through minimum energy performance standards (MEPS). And while there has been a 1.7% average increase in efficiency per year globally since 1990, it lags far behind what is technically possible and what is needed to offset the massive rise in cooling demand. But it is not just about policies, most consumers’ focus on first cost when making AC purchasing decisions, with little consideration given to efficiency and operating costs. This market demand for low first cost AC’s has driven the industry to focus on economies of scale and cost optimization, as opposed to technological innovation and efficiency. Industry has simply followed the market. It is this market failure that is the root cause behind the sluggish pace of innovation in this sector.

A prize was identified as an appropriate mechanism to spur innovation and overcome this market failure in the residential cooling sector. With a $3M prize purse and clearly defined outcome based technical criteria, together with the support of a large international coalition of over 30 organizations, the Global Cooling Prize was able to engage innovators from all over the world including AC industry players, universities and research labs, startups, and individuals. But in addition to receiving these innovative technology solutions, what was equally important was to be able to test the novel elements and specific attributes of these solutions. CEPT University, India – one of the four administering partners of the Prize – was instrumental in designing the Prize’s testing protocol and led the testing of the prototypes across three different protocols, with the primary testing protocol being undertaken at their state-of-the-art laboratory. This laboratory can simulate real-world weather conditions with high precision and controls, which was critical to establish the robust testing process and credibility of the prototypes’ performance.

Through the Prize we asked questions, framed within the prize criteria, of innovators, universities, and industry that the market and policymakers were not asking. This ultimately led to the successful identification and demonstration of 5X lower climate impact residential air conditioner technologies that have the potential to solve the cooling dilemma.

Reducing GHG impact of cooling

Considering the projected growth of residential cooling systems, the improvement of efficiency and climate impact of residential ACs can make a significant difference. But in our warming world, this is not enough. We also need better buildings that keep cooler through design and passive cooling strategies, so that we don’t need as much installed cooling capacity. Additionally, we need better sensing and control systems so that the cooling use is matched to the dynamic demand. The role of architects and building designers becomes even more critical as we seek to turn down the GHG impact of cooling and make our buildings more intelligent in how they manage the cooling needs. Further innovations in all these areas will be required to reduce the building sector’s massive energy and GHG footprint.

One phenomenon particularly associated with technological innovation, is the rebound effect, also known as Jevons’ paradox, which results in higher use of the more efficient technology due to lower operating costs. Although an important consideration, the innovative cooling solutions such as those developed by the winning teams dramatically lower the electricity use – by more than 75% – compared to typical ACs, such that the impact of the Jevons’ paradox can be absorbed. But in a warming world with rising global income levels and the ever-increasing demand for more cooling, we cannot be complacent and ultimately need to drive towards full decarbonization of our buildings.

What’s next?

The Global Cooling Prize has successfully identified, tested, and demonstrated the next generation of breakthrough cooling technologies. And although this is a critical step in the right direction to solving the cooling dilemma, it is by no means sufficient unless these technologies are commercialized and brought to market around the world. Rapid adoption and scaling of these technologies will now require a strong collaboration among multiple actors including innovators, manufacturers, investors, policymakers, and consumers.

We need to leverage the proven performance of these new technologies to inform current testing standards, such that future testing standards truly emulate real world conditions, or at least get a lot closer. We also need policymakers and regulators to undertake targeted actions to raise the baseline of minimum energy performance standards and stretch the performance rating systems to the level of these new ACs, to better inform consumers. With the right policies, consumers will have the knowledge to purchase ACs that will not only save them money over the unit’s lifecycle, and provide more comfortable indoor conditions, but also turn down the GHG impact of its use.


Campbell, I., Kalanki, A. and Sachar, S. (2018). Solving the Global Cooling Challenge: How to Counter the Climate Threat from Room Air Conditioners. Rocky Mountain Institute. http://rmi.org/wp-content/uploads/2018/11/Global_Cooling_Challenge_Report_2018.pdf


Source: https://www.buildingsandcities.org/insights/commentaries/global-cooling-prize.html

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