Experiences regarding draught effects for ventilative cooling in cold climate

New buildings have to satisfy stricter standards regarding energy efficiency and consumption. This results in higher insulation levels and lower air leakages that reduce heating demands. However, together with the heating demands reductions, higher temperatures in summer and particularly shoulder season are more frequent even at moderate to cold climates. In order to ensure acceptable indoor environment quality, removal of excess heat becomes unavoidable. Using mechanical cooling in residential buildings is considered incompatible with achieving zero energy buildings (ZEB). Using ventilative cooling (VC) one can combine mechanical ventilation to supply minimum hygienic airflow rates and windows opening to supply cooling. The ZEB's ventilation systems gain larger importance as they can ensure minimum air quality, provide heating and in summer months remove excess heat.
The Living Lab in Trondheim (Norway) is built as zero emission building. In Norway, 100 % of the cooling needs can be covered by ventilative cooling, either by mechanical or natural ventilation. The ventilative cooling potential depends on many variables; the internal gains, solar gains, use of solar shading, windows g and U values, heat loss coefficient of the building, ventilation flow rate, indoor and outdoor temperatures, etc. One additional consideration for cold climates is over cooling; this is an extra limitation on the use of window opening for cooling. Over cooling is related to thermal discomfort and extra energy use for heating.
The Living Lab has six motorized windows that enable for cross and buoyancy driven ventilation. In addition, three sliding doors can be used for cooling purposes with the restriction that their opening can only happen during occupied hours.
The goal of this paper is to develop a control system based on measurements. The control has to ensure sufficient cooling and hygienic airflow rates. This control ought to ensure thermal comfort without incurring increased energy use. The control is applied to the building in shoulder seasons and the measurements of the performance are presented.