20120328 Technical Seminar on Daylighting Environment in Hong Kong
Upcoming SlideShare
Loading in...5
×
 

20120328 Technical Seminar on Daylighting Environment in Hong Kong

on

  • 240 views

 

Statistics

Views

Total Views
240
Views on SlideShare
231
Embed Views
9

Actions

Likes
0
Downloads
1
Comments
0

1 Embed 9

http://www.linkedin.com 9

Accessibility

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

20120328 Technical Seminar on Daylighting Environment in Hong Kong 20120328 Technical Seminar on Daylighting Environment in Hong Kong Presentation Transcript

  • + Daylighting Environment in Hong Kong By Dr Ernest K W TSANG Sustainability Consultant, Parsons Brinckerhoff
  • + 2AgendaWhy Daylight?Parameters affecting Indoor Daylighting EnvironmentDaylighting Performances of Commercial Building in Hong KongDaylighting Assessment Criteria for Green Buildings
  • +  Improves Circadian Photobiological Activation  Prevents Sick Building Syndrome  Enhances the Phase Synchronising Ability of Light  Has Positive Effects on Sociability and Hormone Patterns  Provides Energy Saving OpportunitiesWhy Daylight?“On studying the Causes and Motivesof Nature, the Observer isFascinated, above all, by Light.” –Leonardo da VINCI
  • + Parameters affecting Indoor Daylighting Environment A Snap Shot Study on 35 Buildings from 1960s to mid 2000. 4
  • + 5 Key Parameters  Building Area and Orientation  Glass Type  Window Area  Shading  External Obstruction
  • 6+ Building Area and Orientation Effect – Increasing Internal Area reduces the Daylight Factor (DF) Building Area varies No Strong Orientation Effect
  • 7+ Glass Type Effect – Visible Transmittance of Glass affects the DF directly Major Glazing include Clear, Tinted, Reflective and Low-e Trend is observed for the Selection of Glazing during the Past Five decades
  • + 8 Glass Type
  • + 9 Window Area  Effect Glazing Type WWR  Amount of Natural Light Clear 36.4% admits into Building Directly Tinted 42.0% Proportional to Window Area Reflective 44.0%  Window Area are expressed in Low-E 46.5% Window to Wall Ratio (WWR)
  • + Shading were found for Buildings completed before mid-80s and after late 90s Shading Shade Window from Direct Sunlight Penetration but allows Diffuse Skylight to admit 10
  • + 11 External Obstruction  Effect Obstruction Percentage  Obstructs Part of Sky Angle (θb) (%)  Reflects Skylight and Sunlight θb≤30° 25 30° <θb ≤ 60° 45 60°<θb ≤ 80°  Most of the External Finishing 30 are with Light to Medium Colour
  • Daylighting Performances of+ Commercial Building in Hong Kong A study of Two Commercial Buildings by Simulation 12
  • +  Two Buildings were selected for Detail 13 Analysis  Daylighting Analysis was Conducted using RADIANCE  The CIE Standard Overcast Sky was selected for Simulation StudyDaylightingPerformances of  The following three performances wereCommercial Building in analysisHong Kong  Indoor Illuminance  Daylight Glare Index  Annual Lighting Energy Projection 13
  • + 14 The CIE Standard Overcast Sky  General Equation of Overcast sky is shown as below:  The Luminance at Zenith is 3 Times of That for the Horizon  Independent with Solar Position
  • + 15 Daylight Glare Index (DGI)  Glare from Windows can arise from Excessive Contrast between the Luminance of the Visible Sky and the Luminance of the Internal Surfaces within the Field of View.  Threshold DGI of 22
  • + 16 Building A Plan of Building Model Details
  • + 17 Building A - South-facing
  • + 18 Building A - West-facing
  • + 19 Building A - North-facing
  • + 20 Building A – DGI Orientation Daylight Glare Index Lowest Floor Middle Floor Highest Floor North 14.0 16.3 19.1 South 13.8 18.5 19.0 West 10.9 16.4 17.0
  • + 21 Building B Plan of Building Model Details
  • + 22 Building B - Northeast-facing
  • + 23 Building B - Southeast-facing
  • + 24 Building B - Southwest-facing
  • + 25 Building B - Northwest-facing
  • + 26 Building B – DGI Orientation Daylight Glare Index Lowest Floor Middle Floor Highest Floor Northeast 19.6 18.6 19.4 Southeast 16.1 16.7 17.8 Southwest 17.6 15.9 17.5
  • + Daylighting Assessment Criteria for Green Buildings Different Daylight Assessment Criteria 27
  • Green Buildings+ 28 Commonly used Assessment Criteria  PNAP  LEED  BEAM Plus
  • + 29 PNAP APP-130 Lighting and Ventilation Requirements – Performance-based Approach  Vertical Daylight factor: 8% for Habitable Room; 4% for Kitchen  Assume the window area is 10% of the usable floor area.  Under the standard CIE Overcast sky condition
  • + 30 BEAM Plus  1 Credit where at least 80% of Floor Area in all Normally Occupied Spaces is adequately lit with an Average Daylight Factor of 2% or more.  1 Credit where provision of Suitable Daylight Glare Control and Maintaining the Average Daylight Factor of 2%.  -> the CIE standard Overcast Sky
  • + 31 LEED 2.2  Option 1 – Glazing factor Calculation  Achieve a min Glazing Factor of 2% in a minimum of 75% of all Regularly Occupied Areas.  Option 2 – Daylight Simulation Model  Min Daylight Illuminance level of 25fc achieved in a min 75 %of all Regularly Occupied Areas.  The CIE Standard Clear Sky in noon of Equinox  Option 3 – Daylight Measurement  Option 4 - Prescriptive
  • + 32 LEED 2009  Option 1 – Simulation  75% or more regularly Occupied Space achieve daylight illuminance levels of a min. of 25 fc and a max 500fc in a clear sky condition on 21 September 9:00 and 15:00  Option 2 – Prescriptive  Option 3 – Measurement  Option 4 – Combination
  • + 33 LEED 2012 (based on draft 3)  Provide manual or automatic glare devices for all regularly occupied spaces  Option 1 – through Annual Computer Simulations, achieve Daylight Autonomy value of 55% (2 points) or 75% (3 points) regularly occupied spaces.  Option 2 – Using a model, achieve required illuminance levels for 75% (1 point) or 90% (2 points) regularly occupied spaces  Option 3 – Using direct measurements, achieve required illuminance levels for 75% (1 point) regularly occupied spaces
  • 34+ Are We Ready for the New Version? Parsons Brinckerhoff’s Approach
  • + 35 Which Option are we recommended?  Option 2 is recommended.  Only two different sets ofSimulation  Similar to LEED 2009 Option 1 with followingRefinements:  1. Standardise outdoor illuminance levels from Typical Meteorological Year (TMY)  The AVERAGE of the Two Time Slots  Reflectance (Ceiling 0.8; Floor 0.2; Wall 0.5)  No Furniture layout is required  What are still unclear?  How to calculate Illuminance for Sun and Sky Components?
  • + 36Option 1Terms and Criteria
  • + 37 Spatial Daylight Autonomy “The % of Aggregate Floor Area of Regularly Occupied Spaces which achieves a minimum highly Illuminance value of 300 lux at task level for at least 50% of the hours between 8am to 6pm, Local Clock Time, after accounting for Typical Weather Conditions, Exterior Obstructions, Attached Furniture Systems and after Blinds have been operated hourly to block direct sun predicted to enter the space that would fall on more than 2% of the calculation grid.”
  • + 38 Criteria  achieve Daylight Autonomy value of 55% (2 points) or 75% (3 points) regularly occupied spaces.  No more than 10% of any qualifying daylight space could receive direct sunlight for more than 250 hours per year at task level before operable blinds or shades are deployed and after accounting for exterior obstruction, typical weather, and attached furniture system
  • + 39 Problems Ahead  Weather Data  TMY does not include any Illuminance Information  No Sky Distribution Pattern is Defined  Simulation Time  Over 3,650 sets Simulation  How to predict Direct Sun/Shadowing?
  • + 40 Weather Data  Sun and Sky Illuminance values  Illuminance Data would be calculated from Irradiance Data of TMY  Sky Luminance Distribution Data  Based on ASRC-CIE Model/Perez’s sky Model  Based on the latest the CIE Standard Skies
  • + 41 Daylight Coefficient Approach
  • + 42 Simulation method Indirect Sun Component Direct Sky (145 or 580 Component sets (aimed ray) simulation) Direct Sun Indirect Sky Component (by Component neglectable (145 or 580 time for sets simulation) Overall simulation) Illuminance Level
  • + 43 Questions & Answer Thank you 28th March 2012