Energy impact of ventilation rates.

As heat exchanges through building envelopes and undesirable internal gains have been reduced in the last years due to energy conservation efforts, the importance of the energy needed to heat, cool and move outdoor air for ventilation has increased in relative tem1s. This study, developed within the European project TIP-VENT (JOULE) aims to study the impact of ventilation air flow rates upon the energy needs of typical buildings. Five real buildings were selected as case-studies: A hotel, an auditorium, an office building, a single-family residence and an apartment building. They were all simulated in a mild, a moderate and a cold climate. Several sensitivity studies were performed, among them: (1) impact of air flow rates stated by standards and regulations; (2) impact of building air tightness; (3) impact of ventilation control strategies, including variable ventilation, free-cooling and heat recovery. Conclusions clearly show that the different air flow rates demanded by different regulations & standards can have a large impact upon energy consumption. Opportunities for energy savings are also identified, namely in terms of the use of rational control strategies and active systems.