Space Cooling

Although space cooling equipment performance is improving continuously and electricity production is becoming less carbon-intensive, indirect CO₂ emissions from space cooling are increasing rapidly – more than doubling to nearly 1 Gt between 1990 and 2021.

In the Net Zero Emissions by 2050 Scenario, indirect CO₂ emissions associated with space cooling demand by 2030 fall to about one-third of those in 2021, with a decrease in emissions intensity per unit six times faster than over the past decade.

Additional greenhouse gas emissions from space cooling are associated with refrigerant leakage (with a global warming potential [GWP] up to thousands of times higher than CO₂). The Kigali Amendment to the Montreal Protocol, adopted in 2016, regulates the use of hydrofluorocarbon (HFC) refrigerants to cut their consumption and production by more than 80% by 2047.

Energy demand for space cooling has risen at an average pace of 4% per year since 2000, twice as quickly as for lighting or water heating. The number of units in operation has more than doubled since 2000, reaching over 2.2 billion units in 2021. Higher energy consumption for space cooling particularly affects peak electricity demand, especially during hot days when equipment is used at full capacity.

Globally, space cooling energy demand rose over 6.5% in 2021, with growth close to 8-9% in Asia Pacific and Europe. Causes of growth vary across countries, but increased appliance ownership and rising temperatures are the main drivers.

The global average efficiency of air conditioners purchased by consumers has improved steadily in recent years. However, without moving towards the best available products, and improving the performance of the buildings in which they operate and their surroundings, electricity demand for space cooling in buildings could increase by as much as 40% globally by 2030.

To get on track with the Net Zero Scenario, the average efficiency rating of new air conditioners would need to increase at least 50% by 2030 in all markets. 

Buildings floor area has increased by more than 60% in the past two decades and is set to increase by another 20% over this decade, adding a total floor surface area of nearly 45 billion m². These floor area additions will mostly happen in regions that need space cooling. More than half of floor area additions are in regions with hot climates and mostly lack buildings energy codes covering the entire building sector.

Incorporating cooling-oriented design strategies into buildings energy codes and local planning, including passive and nature-based solutions, will be essential to reduce cooling needs and reduce the risk of heat islands in expanding urban areas while temperature rise. In the Net Zero Scenario, useful energy intensity (cooling service demand per square metre) declines by about 30% in 2030 compared with 2021. 

Heatwaves and other extreme weather events are increasingly frequent and severe. In June and early July 2022 record-breaking temperatures were seen in Europe, North Africa, the Middle East and Asia. In the United Kingdom 40°C was exceeded for the first time, and an intense heat wave was recorded in the United States in late July. 

Despite increasing deployment globally, the penetration of space cooling solutions and air-conditioning equipment is not equally distributed across the globe. In particular, the people needing space cooling the most are often the ones with less access to air conditioning or alternative space cooling solutions. For example, only around 5% of households in sub-Saharan Africa are equipped with an air-conditioning unit, roughly 10% in India and Indonesia, and around 30% in Mexico and Brazil. This compares with more than 85% in Japan, Korea and the United States respectively. Globally, one in seven people (1.2 billion in total) in poor rural and urban areas are estimated to be at high risk due to a lack of access to cooling.

Rising temperatures, together with a growing population, urbanisation and improved living standards, are driving a sharp increase in the adoption rate of air conditioning, which is expected to jump from 35% of the global population today to nearly 45% in 2030. Affordability and accessibility of sustainable cooling solutions (passive and active), in particular in the areas where it is needed, will be critical for human health and productivity and for reducing the impact of growing cooling demand. 

Data from air-conditioning product registries indicate that the units with the highest efficiency in some markets can be twice as efficient as the average unit sold – often at comparable prices, yet their deployment lags behind. Achieving the best available energy efficiency during partial-load operation is an important area of ongoing research.

In addition, advanced vapour compression cycles – currently under demonstration – have improved design by integrating refrigerant control systems, sensors, renewable energy sources and combining the technology with others (membranes, evaporative cooling). In addition, they operate with low-GWP refrigerants. Automated controls also enable the exploitation of cross-service synergies, such as recovering waste heat from cooling to heat water or, in the case of considerable loads, integrating the recovered heat into district energy networks.

Deployment of climate-friendly cooling equipment requires not only high-efficiency equipment, but also the use of natural refrigerants, or no refrigerant at all. Innovations are also emerging towards refrigerant-free units or solid-state cooling units. 

Renewable cooling technologies are also garnering more attention, particularly in countries where cooling demand is growing rapidly and the national electricity grid needs to be protected from overload, such as in China and India. In particular:

• Solar thermal cooling systems:##anchor1## The number of newly installed solar-driven systems is estimated to have surpassed more than 2 000 small units in 2021, up from 1 800 in 2018.
• Solar PV cooling can be realised in multiple system configurations, and PV-driven compression technologies in self-consumption mode are also beginning to penetrate the market, especially when solar radiation and cooling demand coincide, or by using integrated storage technologies. Direct current systems are also being tested in China.

District cooling can be an affordable solution to providing electricity grid flexibility in warm areas with high building density and free source/waste heat availability. It is still a developing sector, but progress in certain countries, such as China and Europe, has been significant in recent years. Progress in Europe is tracked on the Euroheat & Power website.

Around 80 countries had buildings energy codes in force in 2021. Codes are principally lacking in emerging and developing markets – typically in regions with high cooling needs. More than 80 countries already have minimum energy performance standards (MEPS) for air conditioners, with additional standards currently under development in over 20 countries. MEPS now cover more than 85% of global space cooling energy consumption in the residential sector, up from two-thirds in 2010. These standards vary considerably from one country to another, however, and are generally weakest or absent in hot and humid regions where rapid growth in demand for air conditioning is expected. Progress in MEPS adoption in emerging and developing economies is supported by the United for Efficiency (U4E) Model Regulation Guidelines for Air Conditioners.

As of June 2022, 136 countries have ratified the Kigali Amendment to the Montreal Protocol to phase down the usage of hydrofluorocarbons. Low-emission GWP refrigerants for space cooling are also mentioned in the nationally determined contributions (NDCs) of 43 countries.

In this year’s 7th IEA Global Conference on Energy Efficiency, co-organised by the Cool Coalition, cooling was highlighted as a human right. Consequently, actions are needed to bring about sustainable cold chains and raise the efficiency floor. International collaboration is leading progress towards sustainable cooling solutions. For example:

• From 2017 to 2021 the Kigali Cooling Efficiency Program helped to put space cooling on the global policy agenda, mobilising public and private finance, promoting MEPS and creating a significant network to drive change in the sector. This programme was succeeded in late 2021 by the Clean Cooling Collaborative.
• Since 2019 the Cool Coalition has actively focused on nine priority areas involving over 100 multi-stakeholder partners.
• The Green Cooling Initiative has implemented more than 240 projects in over 40 countries since 1995.
• The Fair Cooling Fund is an initiative that supports ambitious projects scaling up the impact of frontline fair cooling solutions.
• Since 2017 the Cooling for All programme has advocated greater action on access to sustainable cooling and generated evidence, partnerships, policy and tools to accelerate that action.

In addition, in 2022:

• UN-Habitat and the Atlantic Council’s Adrienne Arsht-Rockefeller Foundation Resilience Center announced the signing of a memorandum of understanding, which sets the foundation for collaboration to address extreme heat, especially in urban areas.
• EUROVENT and the Federation of Ibero-American Air Conditioning and Refrigeration Associations (FAIAR) signed a memorandum of understanding to foster Europe-Latin America collaboration on developing standards and best practices, as well as networking events, to promote sustainable and efficient HVAC systems.
• The Global Cooling Prize between 2018 and 2021 catalysed innovations to successfully demonstrate technologies with one-fifth of the climate impact of baseline equipment in hot and humid climates. Further work is currently underway in collaboration with the Clean Cooling Collaborative, LBNL and CEPT University to inform the development of future standards and metrics specific to this climate zone.

The private sector is also active in promoting sustainable space cooling; initiatives include:

• Business models: business models such as cooling as a service and on-bill or on-wage finance are helping deliver the most efficient options to consumers, reducing the price of energy-efficient products or financing the full cost.
• Sharing best practices: in France, Construction21 is a project that enables professionals in the building construction sector to share best practices in the construction of sustainable buildings.
• Equipment testing: the French CETIAT laboratory provides testing equipment for buildings and helps manufacturers to reach optimal design for system efficiency.

As the first measure to reduce the amount of energy needed for space cooling, proper building design can improve natural ventilation, thermal insulation, reduce air leakage and improve internal and external shading by incorporating advanced envelope components such as reflective roofs, as well as passive-building design elements, integrated storage and renewables. Building energy codes have proven to be a highly effective instrument to improve building energy performance. Behavioural measures (for instance, higher air-conditioning set points) and awareness measures also play a critical role in reducing space cooling consumption. Urban design, in particular the integration of green and blue areas, also contributes to reducing cooling demand.

Countries can support R&D efforts to foster innovative air-conditioning technologies, including those that use refrigerants with low GWP or that do not use refrigerants at all. Incentives and support for market-based measures can also create economies of scale to reduce the upfront costs of energy-efficient products. Plus, if the technologies are reversible, these benefits can be extended to the heating sector, since heat pumps are air conditioners that can run in reverse mode to provide heat.

Energy-efficient air-conditioning units can dampen the impact of rapidly rising cooling demand. Greater effort is therefore needed to expand and strengthen MEPS, with targets and requirements that progressively advance air-conditioning energy performance towards the level of best available technology and set a course for continuous improvement. Targeted policy programmes and financing mechanisms are needed to ensure the affordability of efficient space cooling technologies.

While efficient air conditioners will reduce the impact of cooling on electricity systems, more flexibility is needed to distribute electricity demand intelligently. Governments can promote innovative business models and demand response incentives to encourage the use of digital technologies such as smart thermostats and other improved controls that optimise the load distribution of energy demand for cooling.

Governments can work with the industry to devise renewable cooling solutions, involving stakeholders in long-term planning, particularly to reduce the installed costs of technology packages and to exploit technology synergies. Subsidies supporting renewable systems are effective at reducing their upfront costs.

With the growing number of net zero country pledges, both space cooling equipment users and manufacturers are looking to reduce their carbon footprint. Company net zero pledges can achieve success with short-term yearly targets until net zero emissions are achieved. Instruments to support the process are emerging, such as the Cool Calculator.

New business models, such as cooling as a service, are needed to reduce the upfront costs of the most-efficient technologies and accelerate their deployment. With proper support, manufacturers can deliver smarter and more responsive air-conditioning options (e.g. units with smart chips) to also provide electricity balancing services to the electricity grid.