On 26 August 2010 MSc Engineering Christian Anker Hviid from ALECTIA presented his PhD thesis entitled ‘Building integrated passive ventilation systems’. The research was carried out as a industrial PhD and has been implemented in ALECTIA and at DTU Civil Engineering.

The overall challenge of the PhD thesis concerns the fact that conventional ventilation technologies cannot fulfil future stringent requirements for indoor climate and energy consumption to the degree that the risk of global warming requires. A solution is predominantly to use passive ventilation as a replacement for active (mechanical) ventilation. Passive ventilation is a solution that uses natural forces and the physics of the building to maintain a sufficient indoor climate, without using electricity. This can be used particularly in temperate areas such as Denmark which has high wind speeds and large daily temperature fluctuations. Effective heat recirculation, filtration and low draught risks are important elements in making a passive ventilation system competitive.

In his thesis, Christian Anker Hviid develops special components for heat recycling and room air distribution, as well as a total hybrid ventilation concept with an equally good or better indoor climate than that provided by conventional mechanical ventilation systems. The concept is characterised by being a mechanical system, which actively takes advantage of wind and upward forces, so-called one-mode hybrid ventilation. The concept suggestion is supported by detailed simulations of energy and mass power in a test construction.

The results show that it is possible to maintain the required construction Energy Efficiency Class 2020 - with a decent margin.