Publication date: Available online 10 April 2013
Source:Building and Environment
The potential systemic differences in performance of natural, exhaust and mechanical ventilation in dwellings is the object of relentless debate among scientists, industry and policy makers, although comparisons found in literature often fail to compare the different systems on an equal basis. Presenting the results from a multi zone simulation based optimization study of residential ventilation design flow rates and sizing of the system components, this paper aims to provide a benchmark for achievable performance for the different systems for moderate climate regions (eg. Western Europe), as well as point to possible sizing strategies for future standards. The results clearly demonstrate that, considering average occupant exposure to metabolic carbon dioxide, there are small differences in the optimal performance for the 3 system approaches, with an increase of about 13% in ventilation heat loss for equal exposure for the natural ventilation system compared to the mechanical ventilation system. These differences are more marked (up to 26%) when peak exposure is considered. For typically household activity related sources, the mechanical and exhaust ventilation systems provide substantially better optimal performance, while building tighter improved the performance of all 3 system approaches. Exhaust ventilation benefits from small trickle ventilators and large transfer devices. The latter also improves the performance of natural ventilation systems, while slightly higher supply flow rates provide the best results for mechanical ventilation.
Source:Building and Environment