English

A large opening has first been defined as "an opening where the flow is not fully unidirectional". Then an experimental setup has been installed to conduct wind tunnel measurements on several models of a circular disk, in order to characterize the pressure distribution on simple objects provided both with and without openings.

This paper reports experiments carried out in a scale model, about possibilities to use buoyancy forces to distribute air and heat through horizontal openings. Water and saline water have been used as operating fluids. This study focuses on the effect of a staircase on the fluid exchange through the horizontal opening. This research is planned to be carried on in a full scale 2 storey-building.

One of the main objectives of this pilot study in a Swedish school was to evaluate the hybrid ventilation system with respect to ventilation, IAQ, thermal comfort, use of electricity for ventilation. The monitoring phase, lasting 2 years, included continuous measurements of outdoor environment, indoor environment, energy use. The monitoring system was integrated with the building energy management system. The reduction in energy use for space heating in the buildings was important and the reduction in use of electricity for ventilation too.

This paper presents the European Research project RESHYVENT with its structure (partners and different work packages) , and its objectives : to develop demand controlled hybrid ventilation systems, including the development of four prototypes of hybrid ventilation systems for specific climates.

The performance of various kinds of ventilation systems (mechanical supply, mechanical exhaust, mechanical supply and exhaust, crawl space supply and hybrid exhaust) was evaluated in a full-scale test house during heating period. The concentration method (SF6 tracer gas) was used to measure the ventilation air flow rates to each roomntilation. Results of experiments are presented, showing the air distribution between floors and rooms.

This paper presents a numerical study of hybrid ventilation in densely populated multi-storey urban apartment units. Seven cases are presented with variation of parameters such as outdoor air temperature, apartment floor heat source and built-in fan power : 3 cases with natural ventilation and 4 with hybrid ventilation. An analysis of thermal comfort and pollutant transport is made from the calculation results.

Results of IEA ECBCS annex 35 Hybvent case studies about the control strategy used in buildings with hybrid ventilation are summed up in this paper : it is easy to design a suitable control strategy for hybrid ventilated cellular offices, but it is much more difficult for the landscapes offices mainly due to automatic central control of windows.

The use of a hybrid cooling system using radiant cooling panels with wind-induced cross ventilation is described in this paper. Its performance is compared to the hybrid system using underfloor air-cooling. The radiant cooling panels system appears more energy efficient and brings more thermal comfort than the under-floor air cooling system.

This study was undertaken in IEA ECBCS Annex 35 to model a hybrid-ventilated room and to implement control strategies. An experimental cell was designed and simulations were performed after having adjusted the thermal models to experiments. The hybrid ventilation proved more performant than traditional ventilation systems.

This paper gives the results of a field study in Danish office spaces with displacement ventilation systems. Draught was identified as a serious problem. Half of the 227 occupants were not satisfied with indoor air quality. Occupants counteract draught discomfort in blocking air supply diffusers or asking the maintenance staff to increase the supply air temperature. So a very careful design for displacement ventilation is required in order to perform satisfactorily in practice.