Ventilation system has to be design in order to strike a balance between indoor air quality and energy requirements.So, the ventilation efficiency can be considered as a major issue to deal with this objective. In order to assess the efficiency of pollutant elimination from a room, a methodological approach using CPD has been developed. It is based both on local and global indexes. These indexes take into account the distribution of pollutant concentration inside room and the mean concentration at the exhaust with respect to the occupant location.

54 fume hoods in three laboratory buildings in Norway were tested for containment using two tracer methods based on European and American standards, in addition to face velocity measurements. In the first method, an abridged version of Nordtest VVS 095, tracer gas was measured at one point in the sash opening, in front of a mannequin placed at the fume hood with a sash height of 30 cm. In the second method, based on ASHRAE 110-1995, tracer was measured in the breathing zone of the mannequin for a 67 cm sash height.

The evaluation of the ventilation effectiveness and thermal comfort for various industrial ventilation schemes has been carried out by 1:4 scale model experimentation. Measurements of air speed, temperature, and contaminant concentration allowed the contaminant removal and thermal comfort to be quantified using ventilation effectiveness and thermal comfort indices, respectively. Archimedes number scaling was used to convert the small scale measurements to full scale conditions. The ventilation efficiency generally increased when the heat load was increased and/or the flow rate decreased.

The effect on ventilation effectiveness parameters of the recirculation of air is investigated. The results of work with respect to air change effectiveness parameters is explained and extended to the effect of recirculation on the contaminant removal effectiveness parameter of local air quality index. It is demonstrated, first with respect to a simple system with one supply and exhaust and then by extension to a system with multiple exhausts, that it is possible to calculate the effect of recirculation by means of a simple algebraic expression.

As heat exchanges through building envelopes and undesirable internal gains have been reduced in the last years due to energy conservation efforts, the importance of the energy needed to heat, cool and move outdoor air for ventilation has increased in relative tem1s. This study, developed within the European project TIP-VENT (JOULE) aims to study the impact of ventilation air flow rates upon the energy needs of typical buildings. Five real buildings were selected as case-studies: A hotel, an auditorium, an office building, a single-family residence and an apartment building.

We calculate the influence of thermal mass and night ventilation on the maximum indoor temperature in summer. The results for different locations in the hot humid climate of Israel are presented and analyzed. We find that the maximum obtained indoor temperature depends linearly on the temperature difference between day and night at the site. The fit can be applied as a tool to predict from the temperature swing of the location the maximum indoor temperature decrease due to the thermal mass and night ventilation.

Night-time cooling of buildings is a recognized way of reducing the use of air conditioning, and hence energy consumption. The paper describes the construction and testing of a latent heat storage system, which uses a novel combination of night cooling, heat pipes and phase change materials (PCMs) and has the distinct advantage that it is suitable for fitting to existing buildings. The design of the heal pipe/PCM heat storage unit is briefly discussed.