Double skin facade

Double skin façades. Almost a self-explanatory name for façade systems consisting of two layers, usually glass, wherein air flows through the intermediate cavity. This space (which can vary from 20 cm to a few meters) acts as insulation against extreme temperatures, winds, and sound, improving the building's thermal efficiency for both high and low temperatures.
Credit :
Danish Pathan
Imran Inamdar
Qais Patel
Simran Patel
Tehlil Tamboli
Afshan Saudagar
Ubed Ali Sayyed
Omkar Salkar
Taher Ajmerwala
Danish Sheikh

1. GROUP MEMBERS Danish P (L) Imran Qais Simran Tahelil Afshan Omkar Ubed Taher A Danish S DOUBLE SKIN FRAMING SYTEM

2. INTRODUCTION- history, definition, purpose and components DOUBLE SKIN FRAMING SYTEM DEFINITION The Double Skin Facade is a system consisting of two glass skins placed in such a way that air flows in the intermediate cavity. The glass skins can be single or double glazing units with a distance from 200mm up to 2 meters. F or protection and heat extraction reasons during the cooling period, solar shading devices are placed inside the cavity. However, due to the additional skin, a thermal buffer zone is formed which reduces the heat losses and enables passive solar gains. HISTORY Double-skin facades started to emerge across Europe, Asia and the United States beginning in the 1980’s. Many of the early constructions were implemented in low-rise buildings, shortly followed by numerous high-rise applications in the early 1990’s. Many modern office buildings may have a lower energy use for heating, but on the other hand often have a higher use of electricity than older office buildings, due to a higher energy use for ventilation, cooling, lighting and office equipment. PURPOSE The purpose of the double skin facades, has often been to reduce the high temperatures in the building behind during the summer and to lower the heat losses during winter compared with a glazed single skin facade. Other improvements, which can be achieved are aesthetics, preheating of ventilation air, sound protection, night cooling etc. APPLICATION There has been and is a growing interest among clients to build and among architects to design office buildings  with glazed  double skin facades . 200 mm to 2m Double skin Façade with Louvers Sun shading Device COMPONENTS The following figure shows the components of a double skin facade. Exterior glazing. Interior glazing. Structural frame. Operable sun shade Sun shade canopy. Upper operable ventilation Maintenance catwalks

3. INTRODUCTION- system DOUBLE SKIN FRAMING SYTEM T he air buffer works as a barrier to heat loss. Sun-heated air contained in the cavity can heat spaces outside the glass, reducing the demand for indoor heating systems.  The cavity can be vented outside the building to mitigate solar gain and decrease the cooling load. Excess heat is drained through a process known as the chimney effect, where differences in air density create a circular motion that causes warmer air to escape. 

4. CLASSIFICATION DOUBLE SKIN FRAMING SYTEM CLASSIFICATION OF DOUBLE SKIN FACADE SYSTEMS There are different types of classification for double skin facades. Double skin facade has been used for several envelop function such as optimization of natural lighting and better ventilation system, and thermal and acoustic insulation . The classification figure out here is based on the mode of working of a facade presenting 3 categories which are independent on another. 1-THE TYPES OF VENTILATION It is related to the different types of driving forces ventilation of the cavity between two glass facades. The ventilation of the cavity can be natural, fan supported or mechanical . There are three kind of ventilation in double glass facade: Natural ventilation Mechanical ventilation Hybrid ventilation Hybrid ventilation includes both natural and mechanical ventilation in which we use mechanical ventilation when natural ventilation is not sufficient or it cannot work properly. 2-THE PARTITIONING OF THE FACADE The partitioning of the cavity shows that how the cavity between two glass facade situated is divided. Ventilated DSF consider as a dynamic part of the building which use different strategies to balanced best interior condition and environmental performance. 1.Juxtaposed Module 2.Corridor Type 3.Shaft box 4.Multi Storey 3-THE VENTILATION MODES OF FACADE The ventilation mode refers to the origin and the destination of the air circulating in the ventilated cavity. The ventilation mode is independent of the type of ventilation applied. There are 5 main ventilation modes:- 1.Outdoor Air Curtain 2.Indoor Air Curtain 3.Air Supply 4.Air Exhaust 5.Buffer Zone 6.Additional

5. CONCEPT AND WORKING OF DOUBLE SKIN FACADES DOUBLE SKIN FRAMING SYTEM THE INNER SKIN CAN BE OF BRICK, GLASS,ETC. THE DISTANCE BETWEEN THE TWO SKINS COULD BE FROM 0.2M TO 2M DEPENDING ON THE QUANTITY AND QUALITY OF AIR INSIDE THE CAVITY. THINNER THE CAVITY, HIGHER THE AIR TEMPERATURE INSIDE THE CAVITY. THE OUTER SKIN CAN BE OF GLASS, LOUVERS, ETC. INSULATED SURFACE IS PROVIDED IN HOT REGIONS TO REFLECT BACK THE HEAT AND SUNLIGHT. DAMPERS ARE PROVIDED TO CONTROL THE INLET AND OUTLET OF THE OUTSIDE AIR. CAN BE AT THE TOP LEVEL AND BOTTOM LEVEL OR AT EACH FLOOR LEVEL AND ARE MECHANICALLY CONTROLLED. FOR THE NATURALLY VENTILATED DOUBLE FAÇADE SYSTEM, THE AIR IS BROUGHT INTO THE CAVITY AND EXHAUSTED BY TWO MEANS: WIND PRESSURE AND/OR THE STACK EFFECT. THE MECHANICALLY ASSISTED VENTILATION SYSTEMS USUALLY USE AN UNDERFLOOR OR OVERHEAD VENTILATION SYSTEM TO SUPPLY OR EXHAUST THE CAVITY AIR TO ENSURE GOOD DISTRIBUTION OF THE FRESH AIR. SOMETIMES OPENINGS ARE PROVIDED AT THE INNER SKIN TO LET THE AIR INSIDE THE ROOM. THE AIR IS EXHAUSTED FROM THE ROOM THROUGH MECHANICAL SYSTEM. DONE SPECIALLY IN COLD REGIONS . SHADING DEVICES DUCH AS LOUVRES AND VENETIAN BLINDS ARE PROVIDED BETWEEN THE SKIN TO PROTECT FROM HEAT AND SUNLIGHT. CATWALKS ARE PROVIDED FOR MAINTENANCE AND CLEANING OF THE FACADES.

6. NATURAL LIGHTING IN DOUBLE SKIN FACADE DOUBLE SKIN FRAMING SYSTEM Lighting devices can also be placed in double envelope system. The double-skin façade reduces heat losses in the winter and heat gain in the summer through optical control of sunlight. Within one floor height, the double-skin façade can be divided into three sections. The upper section is made of insulating glass with integrated prismatic panels which automatically adjusts itself as a function of the altitude of the sun. This panel has two functions: reflecting sunlight toward the outside and admitting daylight into the interior space. The vision window is made of clear insulating glass and is manually operated by the occupant during the daytime. The lower level window is automatically controlled to stay closed when solar and thermal insulation are desired. LIGHTING DEVICES PRISMATIC PANEL WINDOW INSULATED PANEL INLET

7. TECHNICAL DATA DOUBLE SKIN FRAMING SYTEM DOUBLE SKIN FAÇADE CONSTRUCTION Façade systems comprise the structural elements that provide lateral and vertical resistance to wind and other actions, and the building envelope elements that provide the weather resistance and thermal, acoustic and fire resisting properties. The types of façade system that are used depends on the type and scale of the building and on local planning requirements that may affect the building’s appearance in relation to its neighbors. PRIMARY STRUCTURE: Typically this means columns, braces and beams in steel construction. In concrete add shear walls and slabs. In some super tall or non standards geometry buildings floor slabs are also "activated" meaning they provide diaphragm action, whereas in much other construction they merely rest on primary elements. PRIMARY STRUCTURE SECONDARY STRUCTURE: Secondary - everything that holds something up (provides "structure") but isn't crucial to the buildings structural integrity. Example of this is facade steel like mullions and transoms or other arrangements to hold cladding, or various structural elements that hold up secondary elements like canopies, ceilings and decorative screens etc. SECONDARY STRUCTURE

8. DOUBLE SKIN FRAMING SYTEM TECHNICAL DATA THE SECONDARY STRUCTURE CAN BE DIVIDED INTO THREE MAIN TYPES: CABLE SUSPENDED FACADES The facade brackets are available in two main categories. The first category of facade brackets are the ones that can be fixed on the edge of the slabs. This way the tensile loads from wind are transferred in to the end of the floor slab. The second category of facade brackets are the ones that are fixed on the top of the slab. This way the horizontal loads from wind and the vertical loads from dead load and the resultant loads are transferred in to the top of the floor slab Cable Suspended facades use high tensile cables or stainless steel rods to impose the loads of the facade on the main structure. This decreases the amount of solid structural elements visible on the project, therefore increasing the transparency of the facade. The two main types in the industry are tension rod facades and cable net walls. Panels are framed by mullions on the vertical edges and transoms on the horizontal edges. Mullions and transoms are thermally broken to prevent  through the element so that condensation does not occur. Unitized curtain walling is identifiable by the presence of split mullions and transoms on the panel perimeters PANEL FRAME FACADE CANTILIVER BRACKET STRUCTURE

9. Technical data DOUBLE SKIN FRAMING SYTEM

10. Technical data DOUBLE SKIN FRAMING SYTEM Opening principles The air velocity and the type of flow inside the cavity depend on: • The depth of the cavity (both for mechanical and natural ventilation) • The type of the interior openings (both for mechanical and natural ventilation) • The type of the exterior openings (for natural ventilation) General When choosing the materials used for the construction of the Double Skin Façade, caution should be paid to the pane type and the shading device. Selection of Glass For the internal skin (façade): thermal insulating double or triple pane. The panes are usually toughened orunhardened float glass. The gaps between the panes are filled with air, argon or krypton. For the external skin (façade) toughened (tempered) single pane. Sometimes it can be a laminated glass instead. Thickness of glass Outer pane – 8mm thk glass Intermediate – 4mm to 6 mmthk Internal pane - 4mm thk

11. DOUBLE SKIN FRAMING SYTEM COMMERZBANK HEADQUARTERS It is a Highrise building in Frankfurt, Germany. It was built in 1991-1997. It was designed by Fosters and Partners, Energy consultant was Roger Preston. It became Europe’s tallest building just 300m, with high antenna of 40m on the top. BRIEF The aim was to create a building which is capable of expressing current values, where the environment friendliness is as important as function of the building CLIMATE The climate of Frankfurt in 'continental' , summers are warm and winters are colder. Hence the building has adopted double skin facade system to deal with the climatic conditions as the system is prominent for this type of climate CASESTUDY 1- COMMERZBANK HEADQUATERS, GERMANY Single skin facade on the garden side SUNPATH Double skin facade on the offices side

12. 225 mm DOUBLE SKIN FRAMING SYTEM THE INTELLIGENT FACTOR The inner skin of external windows and the atrium have motor driven sashes that is controlled by building management system, or by occupants using wall mounted switches. During undesired conditions windows are closed by the BMS and air conditioning gets activated. ENERGY STRATERGY The building is designed to utilize the natural ventilation for a large proportion of operating cycle. Natural ventilation and lighting is achieved by open able windows which are controlled by central computers CASESTUDY 1- COMMERZBANK HEADQUATERS, GERMANY Ventilation with closed and open windows Ventilation happens in the building through Chimney Effect Frankfurt Commerzbank facade system details

13. DOUBLE SKIN FRAMING SYTEM COMMERZBANK HEADQUARTERS It is a high rise office building designed by RENZO PIANO BUILDING WORKSHOP, Energy consultant for ARUP GMBH for the Diamler Benz inter services. BRIEF The building required to house the headquarters, financial services, information technology, telecommunications and media services. The project was symbol of the companies commitment to a united Germany and rebuilding historic capital. INTELLIGENT FEATURES Building management system Learning facility Weather data Responsive lights Sun tracking facility Occupant override Self-generation – CHP/PV/WIND Night cooling Solar water heating CLIMATE The climate is continental, summers are warmer and winters are colder than UK. In winters the temperature drops to -25 degree Celsius and is summer it rises to 32 degree Celsius. CASESTUDY 2 – OFFICE BUILDING IN PLOTSDAMMER PLATZ,BERLIN, GERMANY SUNPATH GLASS PANEL GLASS LOUVRES

14. DOUBLE SKIN FRAMING SYTEM CASESTUDY 2 – OFFICE BUILDING IN PLOTSDAMMER PLATZ,BERLIN, GERMANY 700mm LOUVRES AT THE OUTER SKIN 700MM CAVITY CONVENTIONAL WINDOWS WITH MASONRY WALL The east, south, west elevations have the highest exposure to solar gain which incorporates a glass wall 700mm outside the main window wall. This outer wall consists of glass panels which open to 70 degree by sensors for natural ventilation in warm climate. In cold climate, they close to create an insulation layer. The inner façade consists of lower and upper panels of insulated glazing, at night in warm weather, the upper window opens automatically, to ventilate the inner spaces and to emit the heat built up during the day. UPPER WINDOW OPENING AUTOMATICALLY