COOLING | RESEARCH Outdoor unit Schematic of a low-cost hybrid AC design Featuring in Annex 53 is a low-cost hybrid AC design based on a prototype that won the 2021 Global Cooling Prize (courtesy of Prof Baolong Wang) Condenser Rotary compressor Controller Axial fan Water supply pipe Electronic expansion valve Ventilation fan Outdoor Indoor unit Wet-membrane humidifier Indoor Cross-flow fan COOLINGS RACE AGAINST TIME Evaporator In response to anticipated rapid growth in demand for air conditioning by 2050, the International Energy Agency has released a report on the latest technology developments in the AC and heat pump sector, as the executive summary explains A ir conditioning (AC) and refrigeration systems account for a large share of current global energy consumption, and this demand is expected to increase sharply over the next 50 years unless actions are taken to ameliorate the increase. In response, the International Energy Agency (IEA) initiated a project, Annex 53, to look at the development of high-efficiency and low-global warming potential (GWP) AC, refrigeration, and heat pump technologies. The final report for the project was published last month. Titled Advanced cooling/refrigeration technologies development, it was produced through the IEA Technology Collaboration Programme on Heat Pumping Technologies (HPT TCP). The technical scope of Annex 53 was very broad by design. It is unlikely there will be only one, or even a few, so-called right solutions to the challenge. Therefore, the participants were free to investigate a wide range of possible technology solutions. Research, development and demonstration (RD&D) efforts focused on advanced, higher-efficiency technology solutions for future AC and refrigeration systems. The adoption of AC in developed countries increased rapidly in the 20th century, and the 21st century is expected to see increased adoption in developing countries especially those with hotter climates and large, growing populations, such as India, China, Brazil, and Middle Eastern and African nations. The IEA predicts that, by 2050, AC energy consumption levels will increase by 4.3 times the 2010 levels for non-Organisation for Economic Co-operation and Development (OECD) countries, as opposed to only 1.5 times for OECD countries1. The demand for refrigeration is expected to increase at similar rates, driven primarily by food-preservation and storage needs; food demand is expected to increase 70% by 2050 relative to 20102. India, for example, has the largest refrigerated warehouse capacity of any country in the world, and this is expected to reach GLOBAL RESEARCH An IEA Annex is a collaborative research project undertaken by the IEA to address specific challenges and opportunities in different energy-related fields. These projects bring together experts from various countries and organisations to conduct research, share knowledge, and develop solutions. Participants are typically research institutions, universities, and companies from multiple IEA member countries. Each Annex has a well-defined theme or research area, such as building energy efficiency, renewable energy integration, or advanced cooling technologies. Annexes typically last for three to five years and culminate in a final report, technical papers, and other resources freely accessible to the public. The findings and technologies developed through Annexes contribute to the IEAs overall mission of secure and sustainable energy supplies. For more Annexes produced by the IEA Technology Collaboration Programme on Heat Pumping Technologies, visit heatpumpingtechnologies.org. Also see Critical juncture, CIBSE Journal, February 2023. www.cibsejournal.com March 2024 39 CIBSE March 2024 pp39-40 Annex 58 Refrigerants Report.indd 39 23/02/2024 16:56