Demand controlled ventilation: A case study for existing Swedish multifamily buildings

The aim of the work accounted for in this paper has been to investigate a demand controlled ventilation (DCV) system for a typical Swedish multifamily building with exhaust ventilation. Another aim has been to apply and evaluate the IDA Indoor Climate and Energy (ICE) simulation software in this application. The work has been related to a renovation project of a large number of apartments with exhaust ventilation systems recently carried out by a Swedish municipal housing association. A typical apartment, chosen among 1000 existing apartments, has been modelled using IDA Climate and Energy simulation software. Four exhaust ventilation system concepts have been evaluated:1. reference system with constant air volume flow;2. demand controlled ventilation system: carbon dioxide control, variable air flow;3. demand controlled ventilation system: humidity control, variable air flow;4. demand controlled ventilation system: occupancy control, variable air flow. The simulations show that it would be possible to achieve energy savings using occupancy and/or humidity controlled ventilation to reduce the average ventilation flow rate while keeping an acceptable indoor climate. Based on the simulation results a demand controlled ventilation system is developed and implemented in occupied apartments in order to investigate the performance. A measurement based validation of the simulation program indicates that it can be applied reliably.