Components for natural ventilation

In recent years, the use of natural ventilation in e.g. schools and office buildings has increased. One reason among others is that mechanical ventilation has often been held responsible for the poor indoor climate in many buildings. Furthermore, investigations have shown that natural ventilation can compete with mechanical ventilation - both with regard to primary energy use and environmental impacts. In several situations natural ventilation is even better than mechanical ventilation. However, the use/application of natural ventilation is somewhat restricted due to the lack of components with the same (high) level of development/standard as for mechanical ventilation. Inlets directly in the facade, e.g. cracks in the building envelope, trickle ventilators or windows/doors often lead to problems with comfort and excessive ventilation heat losses.One objective of the project is to investigate the possibilities of developing controlled facade inlets at floor-height for natural ventilation by displacement ventilation, which does not result in problems with thermal comfort. The second objective is to develop an air-to-fluid heat exchanger with a low pressure-drop and thereby enable heat recovery in natural ventilated buildings. At the same time the heat exchanger enables pre-heating of the supply air and thus reduces the comfort risks