Outline of HybVent

In well thermally insulated office buildings, which are more and more frequent in lEA countries, ventilation (and cooling) account for more than 50% of the energy requirement, and a well-controlled and energy-efficient ventilation system is a prerequisite to low energy consumption. Natural ventilation and passive cooling are sustainable, energy-efficient and clean technologies as far as they cah be controlled, (that is if well modelled and understood). They are well accepted by occupants and should therefore be encouraged wherever possible. Unfortunately, the design of energy-efficient ventilation systems in office buildings is often turned into a question of using either natural ventilation and passive cooling or mechanical ventilation and cooling. This prevents a widespread use of sustainable _ technologies because a certain performance cannot be guaranteed under all conditions. In fact in the large majority of the cases a combination of systems, hybrid ventilation, would be beneficial depending on outdoor climate, building design, building use, and the main purpose of the ventilation system