BUILDING ENCLOSURE COUNCIL

Transcription

1 4/28/2014 BUILDING ENCLOSURE COUNCIL 2014 Lecture Series Glass Enclosure Design DAYLIGHTING STRATEGIES: WHEN THE WHOLE WINDOW IS A WALL March 24, 2014 By: Kera Lagois & Keith Yancey LAM PARTNERS BEC Boston is a committee of the Boston Society of Architects BSA/AIA, part of a national network of Building Enclosure Councils, cooperating with the National Institute of Building Sciences Building Enclosure and Thermal Environment Council (BETEC). 1

2 DAYLIGHTING STRATEGIES: When the Whole Wall is a Window Kera Lagios Keith Yancey This presentation is protected by US and International Copyright laws. Reproduction, distribution, display and use of the presentation without written permission of the speakers is prohibited.

3 This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to constitute approval, sponsorship or endorsement by the AIA of any method, product, service, enterprise or organization. The statements expressed by speakers, panelists, and other participants reflect their own views and do not necessarily reflect the views or positions of The American Institute of Architects or of AIA components, or those of their respective officers, directors, members, employees, or other organizations, groups or individuals associated with them. Questions related to specific products, publications, and services may be addressed at the conclusion of this presentation. AIA/CES Quality Statement Why daylight in the first place? What are the issues associated with daylighting quality? Understanding the different types of daylighting metrics What tools are most effective for evaluating daylight? Shading studies Examples of dealing with glass facades Learning Objectives and Tonight s Agenda

4 Commercial Bulding Electricity Use (2005) Source: Information from a modeling study by S. Treado, R. Mistrick et. al. at Penn State University Energy Performance vs. WWR

5 Why Daylight? An ample and pleasant view was consistently found to be associated with better office worker performance Heschong Mahone Group Why Daylight?

6 Studies have shown that workers in call centers process calls 6% to 12% faster when they have the best possible views versus no view. Heschong Mahone Group Why Daylight? Maintenance 1% Rent 14% Energy 1% Salaries & Benefits 84% Annual Office Costs

7 Pie I have eaten Pie I have not yet eaten Pie Lighting for Humans

8 Why Daylight? In studies, the greater the glare potential from primary view windows, the worse the office worker performance, decreasing by 15% to 21%. Heschong Mahone Group Why Daylight?

9 Views! Views!

10 Daylight and Views Illuminance Daylight Factor Daylight Zone Daylight Autonomy Spatial Daylight Autonomy Continuous Daylight Autonomy Useful Daylight Illuminance Daylight Glare Probability Daylight Saturation Percentage Defining Daylight

11 Exterior Overhangs Light Shelves Fixed Louvers Automatic Louvers Glazings Tinted Glass Fritted Glass Dynamic Glass Interior Manual Shades Automatic Shades Light Shelves Automatic Blinds or Louvers Shading and Redirecting Techniques

12 What do we do when the whole window is a wall?

13 THERE S TOO MUCH DAYLIGHT SHADING REQUIRED

14 Exterior Overhangs Light Shelves Fixed Louvers Automatic Louvers Glazings Tinted Glass Fritted Glass Dynamic Glass Interior Manual Shades Automatic Shades Light Shelves Automatic Blinds or Louvers Shading and Redirecting Techniques Exterior Overhangs Light Shelves Fixed Louvers Automatic Louvers Glazings Tinted Glass Fritted Glass Dynamic Glass Interior Manual Shades Automatic Shades Light Shelves Automatic Blinds or Louvers Shading and Redirecting Techniques Our Focus

15 Which work the best? & How do we know? Most daylight Least direct sun Most view Least glare Which work the best?

16 New simulation techniques How do we know? 1. Annual or Climate-Based Metrics 2. Dynamic shading analysis 3. Glare analysis New simulation techniques

17 Illuminance Daylight Factor Daylight Zone Daylight Autonomy Spatial Daylight Autonomy Continuous Daylight Autonomy Useful Daylight Illuminance Daylight Glare Probability Daylight Saturation Percentage New simulation metrics Illuminance metrics These metrics tell us how much light there is in a room at one point-in-time (one date, one time). Measured in footcandles (fc), or lux Daylighting simulations traditional metrics

18 Annual or climate-based metrics Illuminance-based metrics that are performed for the whole year. Annual daylighting simulations Daylight Autonomy The percentage of occupied time during the year when a point receives a specified threshold level of illuminance. Example 1: The point has a DA of 40 at 30fc. 40 percent of the year, that point will get 30fc or more of illumination. Example 2: The space has a mean DA of 76 at 30fc. On average, 76 percent of the year the space will have 30fc of illumination. Annual daylighting simulations

19 Annual or climate-based metrics family Daylight Autonomy (DA) Continuous Daylight Autonomy (CDA) Useful Daylight Illuminance (UDI) Spatial Daylight Autonomy (sda) DA max Annual daylighting simulations types Differences between annual metrics and traditional metrics a) They are annual simulations b) They use climate-specific weather data c) Results are expressed as a percentage of time d) You can account for shading behavior over the year Annual daylighting simulations

20 Reading Daylight Autonomy Grids Understanding Daylight Autonomy Glare metrics Rule of thumb contrast ratios Luminance calculations Simulation metrics (UGI, DGR, etc.) Glare Simulations Traditional Methods and Metrics

21 Glare metrics Daylight Glare Probability (DGP) The probability that a person working in a space will find the conditions glary. < 35% Imperceptible Glare > 35% - < 40% Perceptible Glare > 40% - < 45% Disturbing Glare > 45% Intolerable Glare Glare Simulations New Methods and Metrics Testing different shading conditions

22 Example office Example office

23 9-0 Example office Material Finishes Floors 20% Walls 50% Ceilings 80% Ground 20% External Light Shelf 80% Glazing 63% Transmission Roller Shades 50% Transmission/20% specular transmission Example office

24 BASE NO SHADING EXTERNAL LIGHT SHELF LOUVERS Three shading conditions How do they each compare in effectiveness? What are the pros and cons of each? Three shading conditions

25 OVERALL LIGHT LEVELS Mean DA 89 On average, 89% of the occupied time there is 30 fc Mean DA 95 On average, 95% of the occupied time there is 30 fc Daylight autonomy

26 Mean DA 87 On average, 87% of the occupied time there is 30 fc 2% REDUCTION Mean DA 94 On average, 94% of the occupied time there is 30 fc Daylight autonomy Mean DA 82 On average, 82% of the occupied time there is 30 fc 8% REDUCTION Mean DA 94 On average, 94% of the occupied time there is 30 fc Daylight autonomy

27 BASE NO SHADING EXTERNAL LIGHT SHELF LOUVERS Three shading conditions USEFUL LIGHT LEVELS

28 How much of that daylight is useful? How much of it falls between 10 and 200 fc? Three shading conditions UDI >50% 47 47% of the space that has a UDI greater than 50. That means that 47 percent of the area has light levels between 10 and 200 fc (100 and 2000 lux) over the course of the year. Useful daylight illuminance

29 UDI >50% 49 49% of the space that has a UDI greater than 50. That means that 49 percent of the area has light levels between 10 and 200 fc (100 and 2000 lux) over the course of the year. 4% INCREASE Useful daylight illuminance UDI >50% 75 75% of the space that has a UDI greater than 50. That means that 75 percent of the area has light levels between 10 and 200 fc (100 and 2000 lux) over the course of the year. 66% INCREASE Useful daylight illuminance

30 BASE NO SHADING EXTERNAL LIGHT SHELF LOUVERS Three shading conditions DIRECT SUN HOURS

31 Mean DA 14 On average, 14% of the occupied time there is direct sun Mean DA 15 On average, 15% of the occupied time there is direct sun Direct sun analysis Mean DA 10 On average, 10% of the occupied time there is direct sun 28% REDUCTION Mean DA 14 On average, 14% of the occupied time there is direct sun Direct sun analysis

32 Mean DA 6 On average, 6% of the occupied time there is direct sun 57% REDUCTION Mean DA 11 On average, 11% of the occupied time there is direct sun Direct sun analysis BASE NO SHADING EXTERNAL LIGHT SHELF LOUVERS Three shading conditions

33 VIEW AND SKY VIEW Mean DF 6 View and daylight factor

34 Mean DF 5 View and daylight factor Mean DF 3 View and daylight factor

35 BASE NO SHADING EXTERNAL LIGHT SHELF LOUVERS Three shading conditions GLARE

36 Glare analysis point in time Month: January - December Time: Morning - Night Glare analysis point in time

37 Glare 22.2% 22.2% of the occupied time there are glary conditions Annual glare analysis Glare 18.3% 18.3% of the occupied time there are glary conditions 18% REDUCTION Annual glare analysis

38 Glare 10.9% 10.9% of the occupied time there are glary conditions 51% REDUCTION Annual glare analysis BASE NO SHADING EXTERNAL LIGHT SHELF LOUVERS Three shading conditions

39 OVERALL LIGHT LEVELS WITH INTERNAL ROLLER SHADES Mean DA 47 On average, 47% of the occupied time there is 30 fc Mean DA 89 On average, 89% of the occupied time there is 30 fc Daylight autonomy with internal shading

40 No Internal Shading Mean DA 90% UDI > 50 45% Internal Shading Mean DA 47% UDI > 50 91% Daylight autonomy with(out) internal shading Mean DA 45 On average, 45% of the occupied time there is 30 fc 4% REDUCTION Mean DA 85 On average, 85% of the occupied time there is 30 fc Daylight autonomy with internal shading

41 Mean DA 55 On average, 55% of the occupied time there is 30 fc 17% INCREASE Mean DA 85 On average, 85% of the occupied time there is 30 fc Daylight autonomy with internal shading SHADES OPEN 27% 27% of the occupied time of the year the shades are open Operable shading analysis

42 SHADES OPEN 30% 30% of the occupied time of the year the shades are open 11% INCREASE Operable shading analysis SHADES OPEN 55% 55% of the occupied time of the year the shades are open 1O1% INCREASE Operable shading analysis

43 BASE NO SHADING EXTERNAL LIGHT SHELF LOUVERS Three shading conditions Conculsions?

44 BASE NO SHADING EXTERNAL LIGHT SHELF LOUVERS LOUVERS Summary

45 Some Examples

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49 Use narrow floor plates to maximize DZ to overall floor area Keep floor to ceiling heights generous Bring light in high Redirect light Space plan accordingly Keep access to windows for everyone Use automatic lighting controls in daylight zones Balance daylight with electric light Keep finishes light Daylightng Strategies Summary

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