Study of Lightshelves

Page 1

STUDY OF LIGHT SHELF AND RESULTING ILLUMINATION LEVEL INSIDE SPACE FOR MALDIVES AND MOSCOW REGION

BACKGROUND

INTRODUCTION

The objective of this paper is to understand and highlight the effectiveness of light shelves in different geographical region and their effect in illuminance level inside the space. Daylight simulations were performed for a custom light shelves (plastic material) for a typical space in two different location - 1) Moscow, Russia and 2) Male Hulelu, Maldives. Moscow, in Russia, is located at 55.7 degree latitude and Male Hulelu, in Maldives, is located at 4.2 degree latitude. Simulations were performed using Ecotect and Radiance and weather data for both the space were taken from U.S Department of Energy website. Simulation readings were taken both for sunny as well as overcast sky, during 21st of March, June and September. For Maldives, readings are taken at 9 AM, 12 PM and 3 PM of day and for Moscow, readings were taken at 9 AM, 12 PM and 5 PM. Along with variation in day and time, reading were also taken having variation in location of light shelf - both side of wall (inside and outside), only exterior side of wall and only interior side of wall and compared with same situation of day and time without light shelf. The space taken for study was a small room with dimensions of 4.5 M x 6 M with height of 3 M. The smaller faced with width of 4.5 M faces south and has a opening and light shelf. No opening are there on other sides - East, West and North. Height of light shelf is 2.1 M from ground and is 0.6 M in width both inside and outside the wall. Length of light shelf is 3.9 M and is centrally placed on the facade of 4.5 M leaving wall edges of 0.3 M both the sides. Illumination range inside the space is not tried to be maintained in specific range of comfort. It is used in pure form as obtained by the conditions available. Analysis grid for the space is divided into grid of 21 x 17 units with 21 units at facade of 4.5 M width. Analysis of results is based only for the central grid and not any other portion of the grid, and hence space.

The light shelf is a classical daylighting system, to control and distribute sunlight and skylight, reduce glare, and improve the interior illuminance in side-lit rooms. (Christoffersen 1995, littlefair 1996). Light shelves are the horizontal devices which help to reflect light from window towards the ceiling and penetrate little deep in the space. Light shelves are designed to shade and reduce sunlight and skylight near the window, and reflect light from its top onto the ceiling. They have high reflective top surface to enhance the reflection of light towards the ceiling. Light shelves are typically used in big bulky buildings where it is difficult for light to penetrate deep inside or places where sky is over casted most of the time. IMPORTANT: LIGHT SELF BOUNCE LIGHT FROM SHELF TO CEILING WHICH THEN GETS BOUNCE TO THE PERIMETER ZONE ONLY AND NOT AT THE BACK WALL.

APPLICATION

Illuminance Level, Light shelves, Sunny Sky, Overcast Sky, With Light Shelf, Without Light Shelf.

• Light shelves require direct sunlight. The windows should face the sun for a larger fraction of time that the space is occupied. As a result, they are more advantages to place on windows facing equator. • They are generally mounted with window having large area of glazing over the height of 2.1 m (7 ft.). • The glazing that directs light on the light shelves is required to be clear glass, in order to receive sufficient light to reflect. Tinted or Colored glass reduces the intensity of income light. More smoother the surface, more will be the reflection. • Depending on quality of light required, finishing layer of light shelves and the ceiling can either be smooth or rough.

STUDY MODEL

LIMITATIONS

KEYWORDS

• The extension of light shelves inside the room may result in interface with sprinkler system. In Canada, they cannot exceed 1200 mm (4 ft.) in width if sprinklers are present or the design will require integration with sprinkler system to cover the floor area under the light shelf. • The illumination range and level inside the space depends both on time of day and year and also on sky conditions. • Light shelves needs regular maintenances in terms of cleaning in order to have proper and sufficient reflection of light off the shelf to the ceiling.

ELEMENTS INVOLVED • • • •

ARCHITECTURE 632 006 - DAYLIGHTING

Light Shelf - Reflector Window Ceiling Shading device(s)

SCHOOL OF DESIGN

UNIVERSITY OF PENNSYLVANIA


Turn static files into dynamic content formats.

Create a flipbook
Issuu converts static files into: digital portfolios, online yearbooks, online catalogs, digital photo albums and more. Sign up and create your flipbook.