Essay Window and Set Daylight Factor

Submitted By Peiyao-Liu
Words: 3417
Pages: 14
Open Document
version: 3/16/2009

A Design Sequence for Diffuse Daylighting

‘DAYLIGHTING
RULES OF THUMB’

Tiffany ff Otis
O | Christoph
C
Reinhart
Harvard Graduate School of Design

version: 3/16/2009

WHAT IS IT?
- This document presents a sequence of simple equations (rules of thumb) which can be used to identify potentially daylit zones in a building and to assign them dimensions and glazing areas. areas - The sequence is meant to be applied during the preliminary phases of building design (initial massing and programming).
- Its ease of application means that a daylighting concept can be formed for g while it is still being g designed g and that the building’s g an entire building daylighting scheme can be quickly re-evaluated as the design evolves.

INFO
The design sequence is based on a recent paper which compares design sequence predictions to more advanced daylight simulations using Radiance. It can be read under www.gsd.harvard.edu/people/faculty/reinhart/documents/DiffuseDaylightingDesignSequence.pdf version: 3/16/2009

WHEN?
- The method presented in this guide has been developed for buildings that are either located in a climate with mostly overcast (cloudy) sky conditions or in an urban environment whose spaces primarily receive diffuse daylight. - It must be stressed that the repercussions of direct sunlight are effectively ignored by the design sequence. I.e. the resulting spaces should be adequately lit under overcast sky conditions, but may be ‘overlit’, overheated and/or ‘glary’ in the presence of direct sunlight.

INFO

It is recommended that you carry out an initial evaluation of your site to using a sun path diagram and local climate file to quantify the importance of direct versus diffuse radiation for your site.

version: 3/16/2009

DESIGN SEQUENCE
(1) How much daylight is the space receiving?
Calculate effective sky angle.
(2) H
How much h lilight ht d does th the space need? d? Set target mean daylight factor desired for the space.
((3)) Can the target level be achieved?
Calculate the window to wall ratio required to achieve the set daylight factor and choose to continue or abandon daylighting of the space. space (Daylight Feasibility Test)
(4) What dimensional constraints does the target level impose?
Calculate suitable room depths p and surface reflectances.
(5) What quantity of openings are required to achieve the target level in a space with these dimensions?
D t
Determine
i th the required i d glazing l i area.

version: 3/16/2009

SKY ANGLE
(1) How much daylight is the space receiving?
Calculate effective sky angle.

version: 3/16/2009

SKY ANGLE
(1) How much daylight is the space receiving?
Sky angle (θ) = 90º – arctan(y’/x) – arctan(y/d)

INFO
In case you do not know yet where to place your window just pick the center of the face for your sky angle calculation. Please note that more complex obstruction conditions can be analyzed using a 3D model and a raytracer.

version: 3/16/2009

DAYLIGHT FACTOR
(2) How much light does the space need?
Set target mean daylight factor desired for the space.
- The daylight factor (DF) is a metric used to quantify the amount of diffuse daylight in a space. (Diffuse daylight is light that has been scattered in the atmosphere before reaching the Earth’s surface).
- It is usually measured at the height of the workplane (i.e. a desktop), under a standardized CIE overcast sky. It is defined as the ratio of the illuminance of a point in a building and the illuminance at an unshaded outside point facing upwards:
DF = (Ein / Eext ) × 100
Ein : Interior illuminance at a fixed point on the workplane.
Eext : Exterior illuminance under an overcast sky.
- The
Th ‘mean
‘
daylight d li ht ffactor’ t ’ off a room is i th the average d daylight li ht ffactor t value l off a grid of sensors at work plane height that extends across the room.

version: 3/16/2009

DAYLIGHT FACTOR
(2) How much light does the space need?
Daylight factor calculation diagram:

version: 3/16/2009

DAYLIGHT
Show More

Related Documents: Essay Window and Set Daylight Factor

Essay On Daylight Saving Time

Has the clock struck midnight for Daylight Savings Time? If something wasteful was costing you money would you want to continue doing it? What if it was bad for your Health? Each year millions of dollars are thrown out the window due to Daylight Savings Time. For the last 50 years we have had to move our clocks forward one hour during the spring, and push them back one hour during the fall. This process is called Daylight Savings Time, a concept that I along with many others feel is no longer practical…

Words 1744 - Pages 7

My Profile Essay

Energy and Buildings 38 (2006) 824–835 www.elsevier.com/locate/enbuild Findings from a survey on the current use of daylight simulations in building design Christoph Reinhart *, Annegret Fitz Institute for Research in Construction, National Research Council Canada, Ottawa, Canada K1A 0R6 Abstract This paper presents findings from a web-based survey on the current use of daylight simulations in building design. The survey was administered from December 2nd 2003 to January 19th 2004. One hundred…

Words 8561 - Pages 35

Essay on Temperature and Air

Webliography 8 Images 9 – 12 Human Comfort There are several basic factors that will affect human comfort in an internal environment, these include, heat, air quality, light and sound. Each variable has certain levels at which they are acceptable and comfortable in an enclosure and must be controlled in order to maintain…

Words 4045 - Pages 17

Essay on My Story =)

between different parts of the same fluid. Density currents flow along ocean and lake bottoms, because the water entering is colder, saltier, or contains more suspended sediment and thus is denser than the surrounding water. Density currents are a factor in water pollution, as the industrial discharge of large amounts of polluted or heated water can generate density currents that affect neighboring human or animal communities. 3. Describe 2 ways in which mountains affect the climate. - The temperature…

Words 1231 - Pages 5

Research Paper On Qt 5

#1172931) - error in template code (LP: #1178257) - undefined template function in vecmath (LP: #1178391) - Setting Startup date and time (Other:) sets time to UTC, not my local (EDT) time (LP: #1198570) - Debug messages don't completely convert paths to local directory separator (LP: #682633) - Garbled text hovering over time/date (LP: #1176424) - Set time to now (Icon not illuminated) (LP: #1178498) -…

Words 7610 - Pages 31

Trigonometry and Unit Circle Essay

Trigonometry and the Unit Circle Lesson One: Angles and Angle Measures Specific Outcome 1: Demonstrate an understanding of angles in standard position, expressed in degrees and radians. Achievement Indicators: 1.1 Sketch, in standard position, an angle (positive or negative) when the measure is given in degrees. 1.2 Describe the relationship among different systems of angle measurement, with emphasis on radians and degrees. 1.3 Sketch, in standard position, an angle with a measure of 1 radian…

Words 7260 - Pages 30

Research Paper On The Hunger Games

The Hunger Games By:Melissa 8KH The movie The Hunger Games was one of the most talked about movies of this year. As you may already know this newly released movie is based on a book, actually a series of three books The Hunger Games, Catching Fire and Mocking Jay. There will be 3 movies in total, just like the books. In this movie two tributes are chosen from each district to battle to the death in a competition of brains and skills. From my research I learned that the author of these books Suzanne…

Words 8353 - Pages 34

Genette: Left-wing Politics and Picture Essay

Michel Foucault, THE ORDER OF THINGS An Archeology of the Human Sciences A translation of Les Mots et les choses (1966) PART 1 CHAPTER I Las Meninas 1 The painter is standing a little back from his canvas [1]. He is glancing at his model; perhaps he is considering whether to add some finishing touch, though it is also possible that the first stroke has not yet been made. The arm holding the brush is bent to the left, towards the palette; it is motionless, for an instant, between canvas and paints…

Words 6807 - Pages 28

Essay on Final Exam Study Guide

research. -biopsychosocial approach: an integrated approach that incorporates biological, psychological, and social cultural levels of analysis. -three important components of the scientific method: Theory: an explanation using integrated set of principles that organizes observations and predicts behaviors or events. - a good theory should organize observed facts. - and it should imply hypotheses that offer testable predictions and, sometimes, practical applications. 2. Hypothesis:…

Words 4850 - Pages 20

Business Essay

References…………………………………………………………………………………….11 Education for All Lowering Tuition Costs Report summary To lower the costs of tuition we first had to understand why the costs are so high and what ways that are available to lower them. Through our research we found that the main factors of…

Words 5945 - Pages 24