English

This document aims to present the progress and the outcome of the research on double skin façades that is being carried out within the European ‘BESTFACADE’ project. Double skin facades have become an important architectural element in office buildings over the last 15 years. The demand for natural and hybrid ventilation in commercial buildings is increasing due to growing environmental consciousness while at the same time energy consumption for buildings has to be reduced.

In hot and arid climates, evaporative cooling appears to have significant potential to provide thermal comfort and reduce the energy loads of summer season. These regions used wind towers as means to reduce energy consumption of air conditioning systems.However, the cooling potential of wind towers techniquewas investigated in real exiting building in Ouarglacity of Algeria (hot and arid climate); Measurements have been performed under two conditions with and without evaporative potential.A mathematical model of wind tower has been developed and validated using the measured data.

Presently the assessment of the thermal behaviour and the energy efficiency of naturally ventilated double skin facades (DSF) is only possible by using complex simulationtools, which allow inter-connections between fluid dynamics, energy balances and optical transport mechanisms. The performance assessment of mechanicallyventilated DSF is slightly easier but still requires simulation tools.

This study documented that houses in the southeastern United States built on typical wall ventedcrawl spaces possess the following characteristics: 1) liquid water, water vapor and associatedmoisture issues, 2) mold spores, 3) measured holes between the crawl space and living space, 4)measured transmission of mold spores from the crawl space to the living space.

This paper outlines the Australian Standard 1668.2: 2002 ETSHI risk methodology and extends it to give a means of calculating the numerical death risk from exposure of specific age/gender groups to defined Environmental Tobacco Smoke, (ETS) exposures.Acceptable risk exposure is discussed (with numbers) and actual mortality statistics are presented for comparison.A smoking permitted office situation is analysed and some conclusions are drawn.This paper (and the underlying research) was not funded by pro or anti tobacco interests.

For the prototype of the local air conditioning of the working places named PERMICS(Personal Microclimate System) the air velocity and turbulence intensity at horizontal air inlets were analyzed. The velocity field was visualized with smoke. Based on findings from visualization the measurements were made with new technology of the hot-wire anemometer named HW3D-ED. Experimental analysis has been supplemented by a numerical simulation of the velocity field on the air terminal device and in the breathing zone using a commercial CFD package, software PHOENICS.

The Single Coil Twin Fan (SCTF) system is a newly developed air-conditioning and air distribution system that aims to deliver enhanced IAQ as well as save energy. The fundamental principle of this system is based on demand ventilation and demand cooling, which is achieved in the individual occupied zones through localized temperature and carbon dioxide sensors positioned in the respective return grilles. The conditioning of the two air streams is achieved by a single compartmented cooling coil, which provides ease of control of the chilled water flow through the coil.

The present communication forms part of the conclusions to emerge from the research project-Development of a methodology for the estimation of ventilation efficiency in residentialhouses- financed jointly by the Spanish Ministry of Education and Science and by ERDF, andcarried out from 2003 to early 2006.The aim is to present the results obtained for ventilation efficiency in systems of hybrid ventilation for houses, which is about to be implemented in Spanish legislation.

For the approximation of the internal loads of humidity, too high values are often chosen inSwiss low energy houses. Later on in reality, the occupation and the presence in the dwellingsare significantly lower. These leads to high specific air volume rates and consequently to lowhumidity levels. Humidification by vapour generators, humidity recovery and optimized air volume rates are currently applied. Engineers can now calculate the internal humidity loads without humidity storage in walls etc.

This paper describes steady-state energy and exergy analyses on an instantaneous and on adaily basis for dwelling ventilation systems and domestic hot water DHW production systems. The ventilation uses mechanical exhaust with environmental air supply without heat recovery or balanced ventilation with heat recovery. The exhaust ventilation air is used to preheat DHW, using a heat exchanger or a heat pump. Energy and exergy demands in winter days for De bilt, the Netherlands, are presented at the component level, in terms of heat and electricity, for the systems.