cool materials

Urban warming, commonly referred to as the ‘Urban Heat Island’ phenomenon (UHI), is a well-established effect that affects cities all over the world. This occurs due to urban physical characteristics such as urban canyon geometry and vegetation, but mainly to its typical materials. The thermal properties of the materials used for the external walls and roofs of buildings, as well as pavements, can have a major influence on the surface temperature. As a consequence of increased temperature, the UHI has an effect on energy consumption for heating and cooling urban buildings.

The materials that are used in outdoor spaces are of prime importance as they modulate the air temperature of the lowest layers of the urban canopy layer, they are central to the energy balance of the surface and they form the energy exchanges that affect the comfort conditions of city people. Paved surfaces contribute to sunlight’s heating of the air near the surface. Their ability to absorb, store and emit radiant energy has a substantial affect on urban microclimate.  

The raise of sustainability in the urban design is a key-factor for addressing the challenges in response to climate change, resource availability, environmental degradation and energy consumption. Urban planners need comprehensive microclimatic information in order to take decisions. This paper addresses the rehabilitation at the municipality of Acharnes, one of the largest municipalities of Attica, built at the southern foothills of Mt Parnitha, and 10 km north of Athens. The reintegration approach included field measurements of the thermal characteristics in the examined area.

Buildings account for 40% of Europe's energy use and a third of its greenhouse gas emissions. Building materials currently used in the construction of building have low solar reflectance, leading to an increase of surface temperature of the building. The aim of the present study is to develop various inorganic and colour change coatings for increasing the solar reflectance of buildings. A series of inorganic coatings are examined and tested.

In the last years there is a strong interest for application of bioclimatic techniques and practices in urban neighborhoods and open spaces. This paper presents a bioclimatic study of an open space in an urban area by the use of simulation tools giving emphasis on the replacement of conventional materials with cool materials. Routes linking traditional monuments in the Greek city of Florina are characterized of decreased human thermal comfort conditions during summer time.

Heat island phenomenon rises the temperature of cities, increases the energy demand for cooling and deteriorates comfort conditions in the urban environment. To counterbalance the impact of the phenomenon, important mitigation techniques have been proposed and developed. The use of cool pavements presenting substantially lower surface temperature and reduced sensible heat flux to the atmosphere, appears to be one of the most important proposed mitigation solutions. The present paper investigates and describes the actual state of the art on the field of cool pavements.

Rejection of solar gains is the aim of passive cooling strategies in any type of building and any climatic region. The extent of cool materials usefulness is dependent on the severity of external conditions and internal heat gains. The aim of the present paper is to underline the contribution of an innovative cool fluorocarbon coating in the reduction of energy demand for cooling in an industrial building with increased heat gains under temperate climatic conditions. The material is tested using accelerated weathering procedures and its optical properties, i.e.

The mitigation of the heat island effect can be achieved by the use of cool materials that arecharacterized by high solar reflectance and infrared emittance values. Several types of cool coatings,both commercially available and prototype ones have been tested. Their spectral reflectance, infraredemittance and surface temperature measurements reveal that these materials can be classified ascool materials with the ability to maintain lower surface temperatures. Cool materials can be used onbuildings (roofs and walls) and other surfaces of the urban environment.