The thermal comfort and IAQ of recent Dutch energy efficient office buildings with thermal activate building systems

The need for more energy efficient Heating Ventilation and Air Conditioning systems led to a search for new systems for heating, cooling and ventilation of buildings. Strong reduction of energy consumption within the built environment is necessary because of the growing effects of depletion of fossil fuel and global warming. This lead to a almost standard concept of energy efficient office buildings in the Netherlands. That concept exists of heat pumps and  LTES aquifers combined with thermally activated building systems (TABS). Though there are many studies about TABS behaviour they are mainly based on simulations and only a very few actual field studies have been performed on the ventilation performance, draft and the perceived comfort of the ventilation in combination with TABS. Therefore  measurements were done and questionnaires held to determine the perceived comfort and IAQ in three recently completed office buildings with the energy efficient TABS concept. The results showed that in one office the percentage of predicted satisfied persons would be more than 40% and the others respectively around 20% and around10%.  The results of the held questionnaires also showed that the three buildings score on average 4 on a scale from 1 to 7 for the aspects of perceived indoor comfort, so the occupants were slightly more dissatisfied with the performance of the TABS.