Login
A new school building block in Passivehouse standard near Kortrijk (Belgium) is in use since spring 2013. The urban development regulations required that this new building did not influence the incidence of daylight in the adjacent dwellings. This results in an open corridor on the first floor and classrooms with a front door. Draught and increased energy losses are expected. This design choice is contradictory to the basic idea of a passive school that aims to be very airtight and to have very low energy use and excellent thermal comfort.
The aim of this paper is to evaluate the impact of the use of the front door on the thermal comfort in the classroom in this passive school in winter season. The requisite heating capacity at the time the door is opened is also determined and compared to the installed capacity.
This evaluation is based on a survey of pupils and teachers and on measurements in the classroom in winter 2014. The survey studies the experiences of the users. The measurements determine the use of the front door, i.e. the duration and frequency of opening, during one week. In addition, operative temperatures are measured on several positions and heights in the classroom. Finally, the airflow through the door is determined by tracer gas measurements.
The survey concluded that every respondent experiences cold draught and almost all users are annoyed by this draught. Monitoring showed that less than half the openings were expected based on the timetable of the classroom. The most occurring opening durations are 6 and 20s. The airflow was determined by tracer gas measurements for these opening durations. A significant temperature decrease was found close the door. Impact factors on the magnitude of decrease are opening duration, indoor-outdoor temperature difference, wind speed and direction, successive openings. The effect on the temperature is not evenly spread in the classroom. The temperature decrease significantly reduces as the distance to the front door increases. Temperature decrease is more pronounced close to the floor.
Survey and monitoring showed that a the use of the front door influences thermal comfort and increases infiltration losses in this classroom in this passive school. It is advised to consider this effect in the design of heating system in and the assessment of energy performance of future Passive House projects including rooms with front doors.