PR2013

Increasing roof reflectance reduces absorption of solar radiation, roof surface temperatures, and heat flux in the building interior. At the building level this leads to savings in air-conditioning energy consumption and increase in indoor comfort. At the macro level it helps in mitigating Urban Heat Island effect and reduces net solar radiation absorbed by the earth, lowering local air temperature and pollutant formation, and reducing global warming. Various studies have demonstrated energy savings in buildings using cool roofs.

The urban climate of high-density areas is often affected by an increase of the air temperature known as Urban Heat Island (UHI) phenomenon. 
UHI is strongly influenced by the solar reflectance of conventional materials used for building envelope and urban coatings, i.e. streets and square pavings. 
The present work proposes an original method to predict the temperature of both facades and local air mass on urban scenarios. The effect of changes on coatings may also be estimated.  

The indoor environment and occupants’ health of approximately 5,000 residential buildings were investigated by a questionnaire covering entire Japan. The purpose of this survey is to clarify the association between indoor air pollution and adverse health effect, and to study effective ways of keeping indoor air clear with ventilation systems in house. Questionnaires were distributed to 7,812 occupants living in a house with a mechanical ventilation system across 47 Prefectures in Japan on February 2012 using internet survey web site.

The need to improve the energy performance of buildings, both new but also, and in particular, existing ones, is more imperative than ever. The “traditional” approach of thermal insulation is quite satisfactory for the reduction of thermal heating losses and loads, but it is not enough for coping with the problem of increased cooling loads, that are evolving to the single most influential problem, mainly for buildings in the densely built urban environment in Mediterranean and Southern European countries. 

Cool roof is a well-documented passive cooling strategy for buildings in several climate conditions. The mechanism consists of the reduction of the heat load entering the roof, which is characterized by high solar reflectance and high thermal emittance. The purpose of this paper is to study the coupled effect produced by such a technology. First, the passive cooling contribution is quantified, then, the “active” contribution is investigated.

A strategy to reduce global warming is to increase the reflectance and thermal emittance of the built environment (Akbari, Menon, e Rosenfeld 2008). The urban heat islands usually increase the temperature by more than 10ºC (Santamouris et al. 2001).  A cool roof can reduce the temperature up to 3.3ºC (Synnefa, Santamouris, e Akbari 2007) and improve indoor thermal comfort and reduce energy consumption.

Solar reflectance is the key performance parameter of cool roof and cool pavement materials. For its assessment, the measured spectral reflectivity of the sample is weighted by a reference spectrum of solar irradiance. Several standard and non-standard spectra are however available, taking into account different climate conditions, angle of incidence of the solar beam, contribution of the diffuse radiation content.  

The tourism industry is responding to the widespread concern over the future of the global climate. However, little quantitative work has been done on carbon dioxide emissions associated with tourism destinations. This paper proposes a framework illustrating how this can be done. The tourist carbon footprint (TCF) is a result of tourists’ personal consumption, transportation, activity, and accommodation costs. In this study we evaluate the tourist carbon footprint associated with tourist transportation to and in the vicinity of the prefecture of Attica, Greece.

Much of the on-going discussion on urban heat island mitigation and proposed measures for cooling is based on case-studies taken at a specific scale and settings; the evaluation of the effectiveness of proposed cooling measures is therefore made using performance criteria derived for that specific scenario.  The transferability of this knowledge to other sites and climatologies is not ensured.

Our recent study has shown that the acrylic silicon polymer is useful to formulate self-cleaning topcoat which may maintain the thermal insulation effect of cool roof effectively. 
A 2K self-cleaning topcoat was formulated with a water-borne type acrylic silicon polymer. Its effect to maintain high solar reflectance was confirmed by outdoor exposure test in comparison with coatings having no self-cleaning function. The solar reflectance performance was well maintained regardless of installation angle, lightness of colour or pigment type.