An urban heat island (UHI) is a high-density urban area that is significantly warmer than its surrounding low density or rural areas. This phenomenon is a result of surface modification of its surroundings, i.e. use of highly absorptive urban materials, increased building density etc. The effect of UHI has been reported to cause an increase in air temperature of up to 15 °C and temperatures to remain high constantly as heat energy is trapped between buildings.
Conventional urban road and pavement materials have higher heat absorption capacities and will release the absorbed heat to the atmosphere after sunset. As these areas cover a significant percentage of urban surfaces, roads and pavements are major contributors to the increased ambient temperature. To mitigate the effect of UHI caused by heat absorption of urban roads and pavements, an alternative is to substitute these areas with a material that has low heat absorption capacity and put in place a cooling system to reduce heat absorbed.
The technology offered is an integrated solution that aims to decrease surface pavement temperature, and consequently, the ambient air temperature. It comprises of two components, a software tool that identifies hot spots in pavements and a pavement system that includes an underground liquid cooling system, pavement material and an intelligent control system. Overall, the solution will reduce the amount of thermal energy collected in urban roads and pavements and alleviate the effect of UHI.
Technology consists of 2 components
The software tool has been fully validated with laboratory experimental studies which confirmed a reduction of surface temperature up to 20°C. Identification of hot spots around urban areas also allows for a smaller cooling area as opposed to conventional cooling systems which require installation under the entire surface. Upon identification of the hot spots within an urban space and installation of the pavement system, the control system is utilized to manage the underground cooling system to ensure that it is activated only when high temperatures have been detected.
Data obtained from the proposed pavement system in a pilot test-site in the UK proved that the underground cooling system was able to absorb sufficient heat energy to melt snow and prevent ice accumulation. Development to incorporate binders derived from recycled sources for a new pavement material are currently underway and could provide a sustainable alternative for future pavements. The intelligent control system ensures that the pavement system’s performance is optimized and lowers the operational cost, depending on the conditions of the urban environment and the subsurface where the cooling technology is embedded.
The proposed technology could be employed in highly dense urban areas such as
It could also be marketed as a sustainable pavement or walkway system that helps to reduce the general use of heating or hot water consumption around and within the premises.
As the world’s population becomes more affluent, mass migration from rural areas to urban cities have prompted a surge in urban developments and infrastructure. The urban heat island phenomenon resulting from rapid urbanization remains a global concern. Cities have been driven to adopt smart solutions to reduce heat absorption from building materials in a bid to decrease the demand for indoor air-conditioning and consequently to lower energy consumption in buildings.
The integrated solution will provide the following benefits