Shading systems and sustainable design

Content Shading systems and sustainable design Randall Kohn Shade Factor Pty Ltd Australian agents for Warema Brief introduction of WAREMA Type 80 retractable external louvres Physical basics Slat and operation variants for exterior venetian blinds Controls Case study Bonn, Post Tower Discussion Sun. Light. WAREMA. 2 From family business to European market leader Company profile Established in 1955 (by Karl-Friedrich Wagner and Hans-Wilhelm Renkhoff) Three names WAgner REnkhoff MArktheidenfeld gave rise to a new word which was to become a hallmark for both a region and an entire industry: WAREMA. Headquarters Marktheidenfeld Sales revenue 2004 240 Mio Euro (app. 300Mio USD) Staff 2200 18 branches in Germany Angelique Renkhoff-Mücke entered her father's company in 1998 CEO and President of WAREMA Renkhoff Holding AG (Corp.) since 2001 3 4

5 Service Product range Tailor-made products (interior and exterior window shades, electronic controls) 6 WAREMA EXTERNAL VENETIAN BLINDS The Technical Catalogue. Type 80 Construction Construction of an external Venetian Blind. Example electric 80mm slat blind construction. Guide types. Blade profiles and their functions. Materials of manufacture. Mounting options. Built in recess. Weather cover options. Distance from mounting surface. Drive options. electric, crank, and linking. 1= 2= 3= 4= 5= 6= 7= 8= 9= cover panel headrail motor or crank-drive slats guiding-nipples guide-rails lifting-tape tilting-tape bottom-rail 8 3 1 7 4 2 5 6 Principals of solar protection Buildings and solar heat gain. Effect of blind curtains on solar heat gain. 9 Options to control internal daylight. 7 8

29 Minimum / maximum Dimensions Stack heights 30 Solar Parameters General demands of shading systems Energy Weather Warmth Light Time (day and night) Improve SHGC.(solar heat gain coefficient) or g factor in Europe. Energy saving (heating, cooling and artificial lighting) Increase of productivity and performance (High value building ) - Daylight using, visual comfort - Glare protection - Thermal comfort Adjustable to own needs Motorised and automated systems Seasons (spring, summer, winter, autumn) 31 32

33 Interaction of sun light Total energy conduction coefficient glazing Transmission τ Simplified display Reflection ρ Absorption α 100 % α e = 24 % Absorbsion of glassing τ e = 46 % ρ e = 30 % Direct reflection Direct solar transmittance. q a= 12 % Re-radiation of absorbed to outside q i= 12 % Re-radiation of absobed to inside. SHGC = 58 %(46+12) 34 Total energy conduction coefficient glazing Physical Principles of Solar Protection g Value Glazing + Solar Protection 100% (1000 W/m 2 ) (1 m 2 = 10,76 feet 2 ) α e =24% Radiation Transmission Radiation Reflection Radiation Absorption τ e ρ e α e IMPORTANT: The smaller the g, the smaller the τ e, and the darker! At 800 W/m 2 irradiation ρ e =30% τ e =46% + q o =12% q i =12% 96 W/m 2 approx. factor 5 glass pane q o secondary energy emission to outside q i secondary energy emission to inside SHGC= 58% (580 W/m 2 ) 35 heat insulating glazing + external venetian blind Compiled: Sep 2005 22 36

37 General demands of shading systems Physical Principles of Solar Protection Installation Type Improve SHGC Energy saving (heating and cooling) 1000W/m 2 100 % 1000W/m 2 100 % 20 % 800W/m 2 80 % 200W/m 2 F C = 0.09 g = 0.53 F C = 0.21 g = 0.53 F C = 0.60 g = 0.53 Adjustable SHGC-value! reduction of 600W/m 2 reduction of 75%? outside is 7 to 10 x more effective than inside? between the panes is 3 to 4 x better than inside Compiled: Sep 2005 38 35 Physical Principles of Solar Protection Inside Sun Protection Systems CONTROLLING DAYLIGHT. Work setting and daylight guidance. Reduction factor F C How can an F C value be estimated easily? black very dark dark beige/bright colours white/reflective Glazing g = 0.3; U g =1.1 W/m 2 K g = 0.45; U g =0.8 W/m 2 K g = 0.61; U g =1.4 W/m 2 K g = 0.7; U g =1.8 W/m 2 K g = 0.8; U g =3.0 W/m 2 K CONTROL OF LIGHT INTO THE INTERIOR BY THREE METHODS. A. Work setting. For external blinds B. Daylight guidance. For external blinds. C. Daylight transport. For internal blinds. Degree of radiation reflection for the sun protection system ρ e Compiled: Sep 2005 39 44 40

41 Shading Work systems setting. and sustainable For external design blinds. Venetian blinds with light guidance internal and external Reduce solar radiation, using daylight and provide glare protection. with external venetian blind with internal venetian blind 42 Venetian blinds with light guidance internal and external DAYLIGHT GUIDANCE. external double curtain wall internal internal Light guiding blind - lifted up. 43 44

45 DAYLIGHT GUIDANCE Light guiding blind - work station optimised Light guiding blind - without division 46 Venetian blind with light guidance internal Cost reduction - illumination costs Feedback signal Power supply One motor is used to tilt the upper part of the blind. Cost reduction (illumination costs). Through efficient and intelligent use of daylight, illumination costs of buildings can be reduced. By combining light-control systems with measurement and control technology,energy savings of up to 70% are possible. Feedback signal Power supply Motor control unit A pulse generator is providing a feedback signal in order to adjust the angle of the slats very exactly. The other motor is used to tilt the lower part of the blind and also to lift the whole blind. 47 48

49 Slats and perforation Controls - Why do we need them? The slats of the upper part are not perforated. Permanent increasing demands of comfort functions Safety (fire alarm) / protection against rain, ice, wind Energy consumption / reducing costs by using daylight Flexibility demands / changing of room division The slats of the lower part are half-side perforated in order to look through. Complexity of building / conventional control systems are not suitable for large buildings (e.g. low efficiency, fire protection, installation costs) Save installation and maintenance costs 50 Controls - Why do we need a network? Protection and comfort Information flow between all devices (e.g. weather data s) All information is available for the whole building Synergy of services / support of heating and cooling Visualisation of different values and information Enables diagnosis from a distance (online) Standard functions (photo automatic, wind-, rain-, ice monitoring) Calculation of azimuth and elevation Slat tracking as a function of azimuth and elevation Calculation /Evaluation the shadow and lightzones of a building in consideration of the buildings around Visualisation and remote control for maintenance Conventional control systems no communication Network systems communication between all network members (LONWorks = local operating network) 51 52

53 Slat tracking / slat guidance Slat tracking as a function of azimuth and elevation 54 Annual shading program Annual shading program This additional module for optimising deflection of light uses the contours of the building, the position relative to neighbouring buildings as well as its own geographical orientation to calculate the development of shadows which are typical for the day and the time of year. Like all other previous functions, these are stored as a data bank in the LON actuator and provide additional support for the daylight system technology. Calculation of each reference point / window. 55