English

As a consequence of the energy and environmental issues, it is necessary to reduce the energy consumption of buildings. So, the air tightness of building envelopes is being improved and the air change rate due to infiltration is decreasing. It is then even more important than in the past that the buildings are equipped with well designed and working ventilation systems in order that the air renewal within buildings is ensured. In this context, the market of balanced ventilation systems with heat recovery for dwellings is growing. 

Roofs are the envelope component more severely hit by solar radiation in summer (1470 kWh/m2 on average in Italy), hence one may expect that using cool materials on the finishing layer of a roof should provide a significant reduction in the heat flow entering the building, with sensible relief in terms of building cooling load.  In this paper a case study is presented, based on the dynamic simulation of an existing office building in Catania (Southern Italy).

The PerFluorocarbon Tracer (PFT) method is a low-cost method commonly used for measuring air exchange in buildings.  This is a specific instance of the more general  Continuous-Injection, Long-Term Sampling (CILTS)  approach for using tracer gasses. The technique  is widely used but there has been little work on understanding the uncertainties (both precision and bias) associated with its use, particularly given that it is typically deployed by untrained or lightly trained people to minimize experimental costs.

This paper describes part of the research that is being done on the prediction of the performance of light pipes and the ways to optimize their design, in order to house artificial lighting, able to supplement daylight in a space.

There is a growing consensus that the climate is changing faster than at any time in the past millennium. This is likely to have major effects upon many aspects of the built environment. UK Climate Impact Projections 09 indicate significant increases in Summer Mean Temperatures. This may suggest a requirement for cooler buildings during the summer months. In consequence, that would likely lead to an increase in demand for mechanical ventilation and comfort cooling.

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.  

In order to improve the quality of ventilation systems, assessments are widely used. In this paper, 3 main assessment levels are distinguished based on the number of ventilation systems to be assessed and the assessment objective.

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.

Highly reflective building envelope materials are widely identified as an effective design option to limit the peak surface temperatures of roofs in summer conditions, thus mitigating the urban microclimates and the energy demand for cooling. However, especially surfaces having high solar reflectance are subject to soiling (i.e. deposition of soot and other airborne particles), in addition to ageing, and biological growth. All these processes reduce the reflectance of bright surfaces (and increase the reflectance of surfaces having reflectance lower than roughly 0.20).

French authorities have launched an extensive thermal renovation program aiming at retrofitting 4M dwellings over 10 years, with priority given to the most energy consuming ones. Without specific focus on airtightness, retrofitting does not achieve very low airtightness levels, which means numerous leaks in the envelope. Added to the possibility of fungus development at the junction between ancient and new wall, the possibility of airflow conveying pollutants emitted in walls into indoor air is a major concern for public health.