Estimation of Energy Saving in Educational Building from Daylighting to Improve the Visual Comfort

Daylight is the occupied-range of light that is appropriate to the human visual response. Thus, it can contribute to human health, performance and productivity. Energy consumption can be reduced by improving in energy efficiency. The study emphaseson the design of lighting system that will be energy efficient. The basic purpose of this paper describes how to reduce the mounted lighting load and improve the illumination level as per international standards. A good lighting scheme should be based on more energy efficient & longer life and maintenance free equipment. In this research paper,a hypothetical study space is selected for the daylight analysis on the Ecotect and the Radiance software on summer solstice and winter solstice days under over cast sky condition. Ecotect software is used to determine lighting demand inside the selected study space and the obtained data is exported on Radiance for detailed and more accurate daylight analysis. It is pragmatic that illuminance level is varied with respect to date and time that are clearly expressed by the daily sun path and shadow range. It is also perceived that the installed artificial luminaries does not provide the required illuminance on the working plane and consume more energy. The major aim of this research is to reduce the lighting load by introducing energy efficient artificial luminaries into the room that provide the required illuminance level on the working plane. Lumen method is used to explain the energy saving which is carried out according to existing energy consumption compared with the proposed one. At the end cost comparison of energy consumption and payback period is alsocalculated. This study shows that overall cost saving in energy consumption is approximately 34.37% and the calculated payback period for the newly installed lights is comprising of approximately 11 months.


INTRODUCTION
S pending more time indoor may cause many psychological and physiological problems that may cause sickness due to inadequate light. The purpose of the study is optimizing the glare free natural light inside the building as to create the place with great visual quality [1].Humans are not only concerned about the visual performance of the lighting supply but also it is optimized use in the building industry [2]. Electrical energy constitutes almost 40% of the total energy consumed in commercial buildings.
surroundings, sky obstruction that is caused by the huge buildings causes the minimum daylight to reach the lower floors and interior spaces located deeply. Indoor lighting can be enhanced by using the available sunlight with the help of innovative day lighting schemes [6]. To get the perfect results simulation tools need a huge amount of iterations and time [7]. Expanding population and scarcity of natural resources demands the development and implementation of energy saving methods to meet the human needs without having an impact on future sustainability [8]. LEED (Leadership in Energy and Environmental Design) certification is a step to enhance the choice and use of efficient products [8][9].

DAYLIGHTING
Energy consumption cost is reduced up to numerous range by the entrance of the natural light in buildings. It has been investigated by Capeluto that in a well-deliberate building, daylightinglessens energy consumption costs, increases visual excellence [15], awareness, health and emotions of well-being [16][17] and deliversinnerrelaxation that are very hard and luxurious to produce with artificial lights [15]. It is necessary and useful methodology for achieving friendly growth of building, energy efficiency and visual comfort [16]. Day lighting or artificial lighting can enhance the visual comfort [18].

OBJECTIVES
The main objective of this paper is to reduce the installed lighting load and provide required illumination level on the working plane by adding energy efficient artificial luminaries. Energy consumption cost of existing and proposed artificial luminaries in study space is also evaluated.

METHODOLOGY
A hypothetical modeling approach is utilized to investigate potential energy savings due to daylight and artificial December at 12.00 pm for the selected theoretical case study having a dimensions of (50'-0''x30'-0''x15'). The long façade of the study space is south facing consisting of five large windows having dimensions of (4'-6"x7') and the sill height is (3') [19].

RESULTS AND DISCUSSION
All the illuminance values and energy saving estimation is obtained through daylight analysis and Lumen method.

Daylight Analysis
The study space has a dimension of (50'-0''x30'-0''x15') and its Architectural plan and another dimensions of the selected study space is shown in Fig. 2 and in Table 1.
An analysis grid is set that is located at a height of 3' above the floor level for the daylight analysis on Ecotect software. Ecotect Analysis parameters for simulation process are set towards precise values as shown in Table 2.

FIG. 2. ARCHITECTURAL PLAN OF STUDY SPACE
After setting all the simulation parameters and dimensions of the study space the daily sun path and shadow range in the month of June and December is shown in The existing electrical plan of Study space is shown in Fig. 5.
Existing design energy load calculation is shown in    Fig. 6(a-b).

TABLE 4. AVERAGE ILLUMINANCE AND VALUES OF DAYLIGHTING AND ELECTRIC LIGHT LEVEL OF THE SELECTED STUDY SPACE
Average Illuminance values that are obtained from the Radiance and Average values of daylighting and electric light level are estimated which is given in Table 4.
When the daylight analysis is completed, Lumen method is used to explain existing and proposed energy consumption results which are shown in Table 5. Authors The Proposed electrical plan of selected study space is shown in Fig. 7.
Estimation of energy saving is carried out according to existing energy consumption compared with the proposed one as per international standards. It is our major aim to reduce the lighting load by adding the daylighting into the room. Proposed design energy load calculation is shown in Table 4.

CONCLUSIONS
This paper is focused on reducing the installed lighting load as well as the glare and brightness issues associated