Buildings Guide

Space Cooling

Key Message

Space cooling constitutes 15% - 40% of the total energy consumption in a typical commercial building located in hot-arid and hot-humid climates (Itron, Inc., 2006; Eia.gov, 2015). In the USA, a mature air conditioning market, space cooling accounts for around 8% of residential and 13% of commercial elec-tricity consumption and 2% in the EU (IEA, 2010). Many high GDP growth regions of the world fall in cli-mates that require cooling, and the markets there are far from saturation (McNeil & Letschert, 2007). In such a baseline scenario, energy consumption due to air conditioning is only expected to rise signifi-cantly in the coming years, and the search for avenues for efficient cooling mechanisms will become indispensible (GEA, 2012). However, energy-efficient design, components, strengthened by strong poli-cy measures may save 12% (2,105.9 TWh(/yr) of energy on space cooling (including ventilation) in the building sector (IEA, 2011) in the year 2050.


Cooling demand in buildings is caused by external as well as internal factors. External factors include solar activity and weather conditions outside. Besides external heat gains, internal factors such as heat gains from people, lighting, various appliances and equipment are responsible for significantly adding to the building’s internal heat gains. Significant cooling load on the buildings can be reduced by following passive building technologies on the building shell, through the use of energy-efficient lighting and appliances and also through optimizing user behaviour and energy management systems. The remaining cooling demand to meet comfort conditions within the space can be met using various cooling technologies as described in this section.


What causes cooling demand in builidngs?

What causes cooling demand in builidngs?

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Various configurations of air conditioning systems are used for space cooling in modern day buildings. The following section gives a brief overview of energy consumption for space cooling in different building sectors.


The market value of refrigeration in 2010 was worth €46 billion (US$63 billion) and rose to about €64.3 billion ($88.4 billion) in 2012 (BSRIA, 2012). Packaged equipment for residential and commercial use accounts for two thirds of that value. The remainder is from commercial equipment for central systems, including chillers, rooftop units, VRF (variable refrigerant flow) systems, rooftop units and fan coil units (BSRIA, 2012).


There are two basic methods of space cooling technology available for commercial and residential air conditioning equipment in buildings. One method is the ‘vapour compression refrigeration cycle’. The second method is based on the ‘vapour sorption/desorption technique’. While the vapour compression cycle is driven by electricity, sorption/desorption cooling uses heat, which can also be solar heat as primary source of energy. The following list thereafter gives more information on various kinds of cooling equipment and cooling distribution systems available.

Comparison of COP (typical average Vs. highest efficiency: BAT) of various types of cooling equipment
Source: Data from various product catalogues and ARMINES, VHK, BRE (2012) study

Note: The higher the COP, the more energy-efficient is a technology. The COP of a sorption chiller appears low but it can use free heat (such as waste heat, solar energy). All other technologies require electricity, which requires primary energy input of at least a factor 2.5 higher to generate.


Each of the key components of air conditioners have technology solutions that can significantly improve the efficiency compared to average typical units. In some markets most, or all of these, are necessary features to achieve the local regulatory minimum energy performance standards (MEPS) (e.g. in Japan) and are typically seen in high efficiency products in many other markets. Each technology is summarised below and in the following table, along with the indicative energy savings they can achieve if applied on their own to a basic low efficiency unit. Note that the different technologies interact and savings overlap, so savings from each cannot be added together to estimate overall potential.


Michael Taylor
Sriraj Gokarakonda
Christopher Moore


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  • Eia.gov, (2015). Energy Information Administration (EIA)- About the Commercial Buildings Energy Consumption Survey (CBECS). [online] Available at: http://www.eia.gov/consumption/commercial/about.cfm [Accessed 28 Jun. 2015].
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  • IEA, (2010). ENERGY TECHNOLOGY PERSPECTIVES 2010 - Scenarios & Strategies to 2050. [online] Paris Cedex: International Energy Agency. Available at: https://www.iea.org/publications/freepublications/publication/etp2010.pdf [Accessed 2 Nov. 2012].
  • IEA, (2011). Technology Roadmap. Energy-efficient Buildings: Heating and Cooling Equipment. [online] Paris Cedex: International Energy Agency. Available at: https://www.iea.org/publications/freepublications/publication/buildings_roadmap.pdf [Accessed 2 Mar. 2013].
  • Itron, Inc., (2006). California Commercial End-Use Survey Report. [online] California: California Energy Commis-sion. Available at: https://www.google.de/search?q=CALIFORNIA+COMMERCIAL+END-USE+SURVEY&ie=utf-8&oe=utf-8&gws_rd=cr&ei=z403Vq6yMYfxUqWDqPAH [Accessed 2 Feb. 2013].
  • McNeil, M. and Letschert, V. (2007). Future air conditioning energy consumption in developing countries and what can be done about it: the potential of effi ciency in the residential sector. In: eceee 2007 Summer Study. [online] Stockholm: ECEEE, pp.1311-1322. Available at: http://www.eceee.org/library/conference_proceedings/eceee_Summer_Studies/2007/Panel_6/6.306/paper [Accessed 2 Nov. 2012].

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