Comparison of three residential ventilation systems in practical operation

Three mechanical ventilation systems widely used in Swiss apartment buildings were investigated experimentally. The first system is the Central Bidirectional ventilation (CBi), where each dwelling is equipped with an AHU, supply air in bedrooms and extract air in wet rooms. In the second one, the Centralized Unidirectional ventilation (CUn), each dwelling isequipped with a unidirectional ventilation unit, extract air in wet rooms and outdoor air transfer devices in bedrooms. In third system bedrooms and living rooms are equipped with non-ducted Decentralized Ventilation Units (DVU), additional the wet rooms are served by independent extract air fans. The three ventilation systems were investigated in a total of 33flats in 17 apartment buildings, with a total of 98 supply air rooms and 86 extract air rooms. Multiple products were represented in all systems. The cleanliness of the ventilation systems was assessed visually and the frequency of filter changes was queried.With few exceptions, the hygienic condition was good to satisfactory. In 80% of the CBi systems and DVU's, filters were changed at least once a year. In the CUn systems, this was done only half as often. The air flows were measured in all rooms as found. Then the filters were changed and the ventilation components were cleaned. Finally, all airflows were measured again. The values in the as-found and clean condition were compared with the requirements of the Swiss standards. Overall, the CBi systems proved to work quite stable and robust. The supply air flow rate was 6% lower in the as-found conditionthan after cleaning. For the other two systems, significant reductions in supply air flow rates dueto clogged filters and devices were observed as well as significant imbalances. One conclusion is that CUn and DVU systems would require significantly more filter changes and cleaning to ensure the same reliable operation conditions as the CBi system. For the CBi, the specific electric power input was determined and compared with measurements in projects carried out 9 and 12 years earlier. The SPI was about one third lower than in the older projects, which was interpreted as product improvements.+ ID der Publikation: hslu_91779 + Art des Beitrages: Präsentation Konferenzpapier/Tagungsbeitrag + Veranstalter: REHVA + Sprache: Englisch + Letzte Aktualisierung: 2022-08-12 13:21:5