domingo, 20 de mayo de 2012

Wood-Panel Facades – Eco-Refurbishment of Multi-storey -Buildings

Arthur Schankula established the architecture firm Schankula Architekten/Diplomingenieure in 2003. In addition to his design work, he develops wood-construction systems for refurbishment and new construction.

Eco-refurbishment of existing buildings is one of the most important measures to reduce energy consumption, and correspondingly, carbon dioxide emissions. In practice, however, this often involves additional work coordinating the subcontractors, both for fabrication and installation of the new multiple-layer facade, and for potential ventilation systems with air ducts and electrical connections. In order to alleviate these problems, we developed a novel facade system that integrates cladding, insulation, and ventilation (including supply air pre-conditioned via a solar collector) in prefabricated wood panels. The entire refurbishment can be implemented on the building exterior – without significantly inconveniencing the users.

Stage 1/Passive facade: This is the basic version, to which the ventilating facade and solar collectors are added. The storey-high elements -timber-stud constructions- make it possible to insulate the exterior wall and renovate the cladding and windows in one pass. The width of the elements corresponds to the width of the dwelling unit and its typically 7 to 8m. The maximum width is 12m. Due to construction tolerances in the existing building, there may be air spaces behind the new modules: these should be filled with batt insulation. In addition, the climatic concept requires that the edges and joints between the individual elements have an airtight seal. The material closing the gaps around the windows must meet fire-protection and acoustic standards.
Stage 2/Ventilating facade: Building on stage 1, in this version ventilating system with heat recovery is introduced in each element. Ideally the window is at the centre of the element; the ventilator is at the side of the window, facilitating maintainance. The supply air intake is in the jamb; the air is pre-conditioned, then distributed to a duct in the lower part of the element and blown into the room through an opening behind the heating element. The eshaust air is expelled through openings in the masonry. After the heat is recovered it exits the system via the jamb. When opening the windows for ventilation is an option, the system is turned off in summer.
Stage 3/Solar-collector facade: employs the method used in the ventilating facade -but instead of using the heat extracted form the exhaust air, utilizes solar energy. In order to heat the air -"working air"- a layer of transparent glass is set in front of the wood elements. Except for a slit, the gap between the two layers is airtight. The insulation (wood shavings) is sandwiched between perforated hardboard. An additional air space between the isulation and the building is closed in three sides; at top it is linked to the main duct, where the ventilator creates suction. This allows the air behind the glass panel, which has been heated with solar energy, to be directed via the insulation to the heat exchanger. Here the heat in the working air is transferred to the supply air. Then the working air is expelled through the jamb.
Depending on the season, the heat stored in the insulation and the masonry wall is available to pre-condition the air in the late afternoon or early evening. If the building massing allows, the system can also support cross-ventilation. In this instance a ventilating facade can also be employed on the opposite surface, because excess heat from south-facing rooms flows into those facing awat from the sun. then, in addition to the air taken in on the north, the exhaust air ventilator transports the air from the south side through the apartment to the exterior. The cross-ventilation causes the north facade to expel twice as much air as is taken in. Thus, the fresh air taken in is heated more than in a pure heat recovery process.






















Source: Details Magazine

1 comentario:

  1. Your blog is awesome and really helpful for readers. The Eco Refurbishment is a Passivhaus builders London based environmental construction company.

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