In terms of thermal insulation the double envelope is known as This means that The shading device within the double envelope absorbs the solar gain and re-radiates it in the cavity
As we hav mention double envelobe are used to maxmize daylight while controling solar gains which is tipical in office blding \ And int his pictures these operable shading devices
Since the double envelope reduces the temp of the interior skin, it reduces the overall mechanical intervention (cooling equipment) in turn lessens energy use Night time ventilation: During the hot summer days, the interior spaces can easily be overheated. In this case, it may be energy saving to pre-cool the offices during the night using natural ventilation. The indoor temperatures will then be lower during the early morning hours providing thermal comfort and improved air quality for the occupants.
Box windows: self contained with air intake and exhaust ports for cavity ventilation. (natural convection) , punched in , great for privacy and high noise level
the surface temperature of the inner glass is kept close to room temperature, leading to increased occupant comfort in the perimeter zone, near the facade. This type of facade is recommended for cold climates, because of the increased comfort during the cold season and the possible recovery of solar energy.
Done to maximize usable floor area The outer glass leaf is suspended beyond the edge of the primary structure. Fire escape: The glazed space of a Double Skin Facade may be used as a fire escape.
Cavity is ventilated through large openings at the base and parapet. (natural convection) Lighter as opposed to heavy 80’s shading systems
Architects should keep in mind the points that they can get for implementing green strategies These are the three main categories, double envelope strategies can achieve in
We should keep in mind the maintenance requirements of the double envelope: In utilization we must be aware that the…. Other maintenance requirements include Maintaining ventilation controls Cleaning inside the cavity
If this operable glass can provide access to each façade unit, the depth can be greatly reduced for efficient maintenance and material considerations. North America: fixed insulating glass on the outer leaf with a hinged plate of glass added to create a thin double envelope. Heat absorbed is removed by drawing out the stale air.
Large-scale vs significant floor area underutilized: Cost comparisons must take into account the maintenance factor Acoustic insulation: In view of some authors the sound insulation can be one of the most important reasons to use a Double Skin Façade Effective double envelope applications are sometimes actually Poor energy performers
Corridor multi-story Transparency/ architectural design: In almost all the literature, the desire of the architects to use larger glazed facades is mentioned.
Vent/smoke extract (2) Height-adjustable façade suspension (5) Use of double glazing (8) Convector (12) Cover fresh air intake (15)
GreenStudio - Chapter 4 1 4 Double Envelopes
Design Envelopes An Overview Dana al-Hasan - Dalal al-Shatti Design IV - Dr. Yasser Mahgoub
Building and facade orientation Double envelopes: Are multiple leaf wall assemblies used in the transparent or largely transparent portions of a building façade Outer leaf Intermediate space Inner facade
Design Intent <ul><li>Maximize daylighting while controlling solar gain </li></ul><ul><li>Reducing the need for mechanical cooling </li></ul><ul><li>Increase the use of natural ventilation </li></ul><ul><li>Increase acoustic isolation, especially in urban areas. </li></ul>
aesthetic Relationship of glazing to overall facade The glass wrapped facade used the glass panels as shingles on the building exterior. Glazed balconies in Venice, Italy
Thermal insulation Relationship of glazing to overall facade Outer glazing covers the entire surface of the façade at the Arup offices in London A “double skin glazed thermal buffer” curtain wall addresses solar heat gain as the project’s critical factor. Simply put, a shading device within the double skin absorbs solar gain and re-radiates it as heat trapped in the cavity
climate control Performance goals at the transparencies most double envelopes are designed to maximize daylight while controlling solar gain – a condition typical of office buildings dominated by internal heat gain . The interstitial space is used as a protected enclosure for operable shading devices that might otherwise suffer from wind damage and weather exposure.
active heating and cooling Performance goals at the transparencies Double envelope mitigate the surface temperature of the interior glass, reducing the mechanical intervention required to provide comfortable conditions under both and cooling modes The double envelope facade of Bayerische Vereinsbank Building in Germany has operable leaf glass louvers
Configurations: 4 main types Construction Strategies Box window Corridor facade Multi-story facade Shaft-box
Box windows Pre-fabricated curtain wall system Construction Strategies Kofmehl Building (Switzerland) Architect: SSM Architekten’s
Corridor facade Construction Strategies City Gate (Dusseldorf) Architect: Petzinka, Pink & Partners Pre-fabricated curtain wall system
Effective with regard to ventilation Incorporate service walkways of metal grating Construction Strategies Corridor Multi-story Victoria Ensemble (Koln) Architect: Thomas Van Den Valentyn
Shaft box Construction Strategies ARAG Turm, Dusseldorf Architect: Norman Foster
LEED Rating Energy and Atmosphere (35 points) Fundamental Commissioning of Building Energy Systems Minimum Energy Performance Fundamental Refrigerant Management Indoor Environmental Quality (15 points) Minimum Indoor Air Quality Performance Environmental Tobacco Smoke (ETS) Control Innovation and Design Process (6 points) Construction Strategies
Utilization Maintenance Requirements Efficiency of the façade can only be assessed in the context of the climate conditions of the site Each double façade must be tailored to the occupant’s function
Europe: Operable inner glazing leaf Control over outdoor air in the workspace North America: Interior hinge plate glass “ exhaust window” Maintenance Requirements
<ul><li>Factors to consider include: </li></ul><ul><li>Facade cost </li></ul><ul><li>Floor space available </li></ul><ul><li>Compatible structural system </li></ul><ul><li>Total building energy flows </li></ul><ul><li>Size and complexity of mechanical plant </li></ul><ul><li>Cost of long-term maintenance </li></ul>Double envelopes should be considered along with another strategy Considerations
Case Study Client: Archiepiscopal Ordinariat, Munich, Building Directorate Competition Architects: Karin Hengher, Olga Ritter Project Architects: Karin Hengher (Project Manager), Michael Frank, Annette Gall, Susanne Rath Competition 1996, 1st Prize Completed 2000 <ul><li>Objectives of using the double envelope strategy </li></ul><ul><li>different colors and intensities of light shine into the church </li></ul><ul><li>opaque glazing prevents views into the chancel from the outside </li></ul>
Any Questions? If you are interested in this strategy you might want to consider the following literature: On the Typology, Costs, Energy Performance, Environmental Quality and Operational Characteristics of Double Skin Facades in European Buildings. Available: http://www.earthscan.co.uk/Portals/0/Files/Sample%20Chapters/9781844073894.pdf Double Skin Facades, Maria Wall Available: http://www2.ebd.lth.se/ebdhome/avd_ebd/main/personal/Harris/main/Double%20Skin %20Facades.htm Case Studies: Double FaçadeAvailable: http://www.architecture.uwaterloo.ca/ faculty_projects/terri/sustain_casestudies/ut4.pdf Case Studies: Double Facades in Germany Available: http://www.bbri.be/activefacad es/new/index.cfm?cat=5_example_building&sub=8_germany