Global Innovation Initiative
The aim of this project is to develop a better understanding of human thermal comfort in residential and commercial buildings across the globe, and to identify and exploit opportunities for natural ventilation, mixed-mode strategies and other low-energy techniques that provide air movement, such as evaporative cooling, to reduce energy demand. A combination of field measurements and computer modelling will enable us to better understand the unique transient and dynamic conditions in these low energy buildings and how we can simultaneously achieve reduced energy consumption with enhanced thermal comfort.
A growing body of evidence has established links between climate change and the carbon dioxide (CO2) emissions that arise from energy production and consumption. In 2010, annual CO2 emissions from the building sector were estimated to be 9500 Mt, equating to one-third of the world’s total CO2 emissions. The energy used for space cooling and heating accounts for the majority of CO2 emissions from buildings. Demand for this energy is driven by the basic human need for thermal comfort and good Indoor Air Quality (IAQ). With people typically spending 90% of their time indoors, the qualities of the indoor environment can have a significant impact on people’s health and well-being. But the current energy-intensive paradigms for conditioning the indoor environments, together with a changing global climate, have the potential to unleash an unprecedented growth in energy demand in the next few years. The combination of global warming and increase in purchasing power by growing economies bring forward a serious threat that air-conditioning will proliferate throughout the global residential sector, with potentially disastrous consequences for further energy demand and climate change.
Part of the solution for minimizing residential air-conditioning is likely to include encouraging higher levels of air movement at warmer temperatures, but it is not clear how best to incorporate this into the design and operation of residential buildings in order to reduce air-conditioning use. An important reason for this lack of understanding is the inherently dynamic qualities of indoor air motion and the human response to it, which have been difficult to quantify.
To date, global understanding of thermal comfort and IAQ is well developed for commercial buildings that use air-conditioning (the most energy intensive method of providing indoor comfort). Since the 1950s such buildings have predominantly had sealed envelopes and require continuous mechanical conditioning. Natural ventilation, in which operable windows allow occupants to harness the forces of wind and temperature difference to provide comfortable indoor conditions, can deliver significant energy savings for many types of buildings when operated in conjunction with properly controlled air-conditioning. This arrangement is known as mixed-mode. However, the building industry lacks information on how to design these buildings in a contemporary context so that they perform well.