Passive House components
essary not only from an energy point of view but also in terms of building physics (fig. 2.4, p. 10): • In order to a oid the thermal insulation of plane surfaces simply ending at junctions, it is necessary to make sure that all thermal bridges are prevented or at least minimised. • An airtight construction of the building envelope is necessary to eliminate draughts, leak-induced damage and ventilation heat loss. • The ind-tight construction of the building envelope avoids the thermal insulation from being wind-washed, i.e. air penetrating into and around the insulation, and thus reducing its effectiveness. Coordinated passive solar components High solar contributions to the heating can be made by using Passive Housesuitable windows and glazing systems. And this does not even require an excessively large solar aperture area, i.e. even a moderate window area can suffice. The size and number of glazed areas can be selected according to other aspects, such as daylight autonomy, the desired indoor/outdoor connection or designrelated considerations. The solar gain through windows can only provide a substantial contribution towards the space
heating if the heat loss of the window frames and window panes is kept to an absolute minimum. For summer conditions, it is essential, like in all buildings, to limit the solar aperture to the size necessary in terms of lighting and the connection to the exterior space, or to provide controllable shading de ices. Depending on the design of the building, different window quantities (e.g. window sizes) and qualities (U-value of the window and g-value of the glass) must be checked and assessed according to the impact they have on the performance both in summer and winter conditions. Alongside affecting the energy balance, these considerations have a significant impact on the appearance and the user friendliness of the building. High-performance ventilation unit Alongside the reduction of transmission heat loss, the minimization of ventilation heat loss, through the installation of a mechanical ventilation unit with a heat recovery system, is a key aspect of a Passive House building’s low space heat demand. All rooms within the thermal envelope of a Passive House are therefore provided with fresh air using a comfort ventilation system with heat recovery and a controlled supply and extraction of
air. The main aspect here is to ensure the air exchange necessary from a hygiene point of view. The effective heat supply rate of the mechanical ventilation unit should be at least 75 % in order to provide a suitable degree of efficiency and comfort. Adapted heating and cooling systems A Passive House requires heating and cooling systems that are suitable to match the low heating and cooling demands of the building. Generally speaking, any conventional type of heating system can be used. In many cases, though, Passive House buildings can be heated using the supply air only. Additional heating surfaces, if at all required, do not necessarily have to be placed beneath windows, which was previously the case. This has the effect of simplifying and reducing the installation work, which frees up the additional expenditure for the heat recovery system of the mechanical ventilation unit. These aspects have a considerable impact on the economic efficiency of the Passive House concept.
2.1 School for speech correction in Griesheim D 2011, Ramona Buxbaum Architekten. The new build includes three separate, compact pavilions built as timber frame structures.
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