Controlled Mechanical Ventilation in Buildings: A Comparison between Energy Use and Primary Energy among Twenty Different Devices

Indoor air quality (IAQ) of buildings is a problem that affects both comfort for occupants and the energy consumption of the structure. Controlled mechanical ventilation systems (CMVs) make it possible to control the air exchange rate. When using CMV systems, it is interesting to investigate the relationship between the useful thermal energy requirements for ventilation and the energy consumption of these systems. This paper addresses whether there is a correlation between these two parameters. The methodology used in this work involves the application of equations of technical Italian regulations UNI/TS 11300 applied to a case study. The case study is represented by a 54 m3 room, which is assumed to have three CMV systems installed (extraction, insertion, insertion and extraction) for twenty different devices available on the market. Afterwards, simulations of useful thermal energy requirements QH,ve and primary energy EP,V were performed according to the electrical power of each fan W and the ventilation flow. The results show that the two values are not linearly correlated: it is not possible to clearly associate the operating cost for CMV systems according to building requirements. The study also shows that CMV systems are particularly efficient for high-performance buildings, where there is no leakage that can be ascribed to windows infiltrations.