The aim of this workshop organised by BBRI was to identify recent developments in ventilation systems/strategies and to analyse how such innovative systems are at present treated in regulations and how they could be better treated in the future.
Sixteen countries world wide have participated to this international programme (IEA ECBCS Annx 35) running from 1998 to 2002 about "Hybrid ventilation in new and retrofitted office buildings" . All results of the project are published in a booklet and a CD ROM. They have also be published onthe AIVC CD (see AIRBASE recording number 14923).
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.
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.
The concentration of fungal spores is higher in the crawl space than inside houses. Domestic mechanical exhaust ventilation systems may create air flow between crawl space and base floor through leaks. This study used data from eight buildings to develop a model providing relation between indoor and crawl space fungal spores concentrations. Results show that the correlation between the fungal spores in the crawl spaces and indoors depends on the size range of microbe species.