International Journal of Advance Engineering and Research Development

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1 Scientific Journal of Impact Factor (SJIF): 4.72 International Journal of Advance Engineering and Research Development Volume 4, Issue 2, February e-issn (O): p-issn (P): Optimization of Energy Consumption in Buildings with Respect to Aspect and Orientation Vivek M Rathod 1, Sunil V Jaganiya 2 1 Civil Engineering, G.I.D.C Degree Engineering College 2 Civil Engineering, M. Tech (Structure) Abstract Daylight is rather a fact than a matter of discussion for many objectives as a source of lighting in buildings. The energy produced by various means is not sufficient to meet out the demands. The only proactive way for survival is to save energy. The daylight is a primary source of lighting in building to save electricity. In some typical buildings structures, lighting accounts for 25-40% energy consumption. During the last quarter of the 20th Century, designers have recognized the value and importance of introducing natural light in buildings. Most of the people appreciate natural sources of light. Good day-lighting designs result in energy savings and can shift to decreases the peak electrical demand during afternoon hours when daylight availability levels and utility rates are high. The main object of this paper is to develop a natural, scientific, engineering and economic integration of day-lighting concepts into the building design. This paper promotes daylight consciousness and importance of building design by saving energy through greater usage of natural light. Keywords- Solar energy, Day lighting, Green buildings, Architecture, Net zero energy, Building orientation, Technology. I. INTRODUCTION Daylighting is the use of light from the sun and sky to complement or replace electric light. Appropriate fenestration and lighting controls are used to modulate daylight admittance and to reduce electric lighting, while meeting the occupants lighting quality and quantity requirements. Energy efficiency of buildings can be improved by the planned use of natural light and thereby eliminating carbon emission and global warming. Introduction of innovative, advanced day-lighting strategies and systems can significantly improve the quality of light in an indoor environment. Working long hours exposed to artificial lighting (i.e. lighting electricity) is believed to be deleterious to health and working in daylight is believed to result in less stress and discomfort. Daylight provides the conditions for good vision, provides high illuminance and permits excellent colour discrimination. Appropriate, low cost, high performance daylight systems are required to integrate daylight planning in building design. In fact, using daylight (as opposed to electric light) to illuminate building interiors is a very old concept, older than the use of electric lighting. The common barriers that have hindered the integration of daylight in buildings in the past were: lack of knowledge regarding the performance of advanced day-lighting systems; lack of appropriate, user-friendly daylighting design tools, lack of evidence of the advantages of day-lighting in buildings, prevention of the architectural (aesthetic) factors. II. BENEFITS OF DAYLIGHTING Daylighting can significantly improve life-cycle cost, increase user productivity, reduce emissions, and reduce operating cost. Day-lighting can save considerable money which is utilized for purchasing resource, fixtures & controls for artificial lighting (electricity) and increases user comfort and satisfaction, leading to improved performance. Some of the commonly known benefits are given below: i. Daylight also reduces emission of greenhouse gases (GHGS), slows fossil fuel depletion and total energy costs by one third, then that of artificial lighting. ii. It can respond to changing weather conditions and connect occupants to the natural environment. iii. Passive solar buildings provide day lighting, which has been linked to increasing occupant satisfaction and productivity. iv. Reduced heating and cooling costs through natural heating/cooling cycles and using materials enhanced for penetrating, absorbing or releasing solar All rights Reserved 524

2 v. Daylight helps in thermal massing to reduce temperature swings and produce a higher degree of temperature stability and thermal comfort. III. DAYLIGHT FEASIBILITY The main aim of daylight Feasibility is to determine how much daylight you can use in various areas of your building, Daylight Feasibility depends on: i) the availability of natural light (based on latitude and longitude of the building site and environmental surrounding conditions of the building area); ii) orientation of buildings; iii) Climatic factor. Because daylight is not used simply to illuminate an interior space (e.g., view, outdoor connection, ventilation, egress), the issue is not whether or not to use a window, but whether one can capitalize on it to increase occupant comfort, satisfaction, and perhaps productivity. In fact, to the geographic orientation, high latitudes have different summer and winter conditions, whereas, the seasonal variation of daylight is less apparent at the low latitudes. Hence building designers should aim for maximum daylight penetration in buildings in winter seasons, at the high latitudes. In tropical region, as the daylight levels are high throughout the year, designers should prevent overheating by restricting the amount of daylight entering in to the building. Therefore, the designer has to calculate the availability of daylight under different climatic conditions and fix the orientation of building, which leads to permit the maximum daylight to penetrate throughout the building without producing the overheating effect. The feasibility of day light further can be understood from figure 1. Figure 1. Passive Solar design according to Sun path diagram for winter and summer 3.1 Rapid Feasibility Study Calculation to Estimate Potential Lighting Energy Savings Step 1: Calculate the planned window-to-wall ratio (WWR) for a typical office space or bay. For unknown, estimate for your building style; for example, using 0.35 for a typical, moderately strip-glaze building. For larger windows or curtain wall, use For smaller punched windows, use Step 2: Estimate the obstruction factor (OF) from figure 2. Net glazing area / Gross interior wall area = WWR <50% obstructed, OF = 1 50% obstructed, OF = % obstructed OF = 0.65 Figure 2. Determination of obstruction All rights Reserved 525

3 Step 3: Make a preliminary glazing selection and note the visible transmittance (VT) factor which is an optical property that indicates the fraction of the visible light transmitted through the window. Some of the common examples are shown in figure 3. Figure 3. WWR = 0.30 WWR = 0.50 WWR = 0.70 HIGH VT = 0.88 MEDIUM VT = 0.53 LOW VT = 0.38 Clear Tinted Heavily Tinted (Reflective) Determination of Visible Transmittance Step 4: Calculate the daylight feasibility factor. If it is 0.25, then day lighting has the potential for the significant energy savings for the building zone. If it is < 0.25, then consider removing the obstructions or increasing window area. Window-to-Wall Ratio [WWR] x Obstruction factor [OF] x Visible transmittance [VT] = Feasibility Factor IV. GENERAL DAY LIGHTING PRINCIPLES i. Increase perimeter daylight zones extend the perimeter footprint to maximize the usable day lighting area. Avoid direct beam of sunlight on critical areas. Direct sunlight in non-task areas can be helpful because it provides building occupants with information about outside weather conditions and the time of day. But in critical task areas it leads to excess the inner surrounding temperature. However, also when a critical task is being performed in direct sunlight, the light can cause unacceptable contrast ratios, disability glare, or direct reflection. ii. Bounce daylight off of surrounding surfaces. In general, the larger and softer the light source which leads to the better the visual quality, hence reduces the resulting eye strain, as easier to function. iii. Reflect daylight within a space to increase room brightness. iv. Slope ceilings to direct more light into a space. Sloping the ceiling away from the fenestration area will help increase the surface brightness of the ceiling further into a space. v. Allow daylight penetration high in a space. Windows located high reduces the likelihood of excessive brightness. These can be done by following ways shown in figure 4 given below. Shed roof Equal vertical moniter Saw tooth roof with sloping glazing Saw tooth roof with vertical glazing Unequal vertical moniter Twin- slope moniter Figure 4. Different ways for day lighting All rights Reserved 526

4 vi. vii. Filter the daylight. Trees, plants, draperies, screens, translucent shades, and light-scattering glazing diffuse and distribute light while reducing its intensity. Understand that different building orientations will benefit from different day lighting strategies. V. BUILDING ORIENTATION In terms to building orientation for daylight utilization passive solar system plays a key role, as it is the best way to utilize into a building during the initial design. Passive solar systems utilize the basic concepts for the architectural design of the building. They usually consist of: i. Rectangular floor plans elongated perpendicular to east-west axis. ii. Glazed inner facing walls for proper reflection of light. iii. Thermal storage medium exposed to the solar radiation. iv. In north and south light shelves/overhangs or other shading devices shade the elevation from the summer sun; thus elevation overhangs should be horizontal while east and west elevations usually require both horizontal and vertical overhangs. 5.1 Orientation of building as per Solar Aperture The natural benefits of sun can be used for supplying the maximum buildings heating and daytime lighting needs by designing a building s orientation, proportions, and fenestration to take the advantage of the sun s path. However, it is important to note that windows which admit daylight also admit solar heat, and though heat from the sun is welcome in buildings in cold climates, in excess it can make buildings uncomfortably hot in summers. It is therefore, important to be able to assess the trade-off between the natural daylight and unwanted heat gain. VI. ASPECT The challenge is in providing daylight by effective use of windows is to allow adequate amounts of daylight. A designer can control window area, location type, glazing properties, shading systems, ceiling parameters, and interior design features to achieve these goals. The following sections below provide some guidance on the importance of each of the design parameters related to day light effectiveness: i. The amount of daylight in the building depends on the source of light which directly leads to effect on aspect of dimension to which natural light is to be refracted inside the building area. Here below figure indicates that the depth [H] of window is equal to twice width [2h] of work plane. Total daylight Area = 2H X [W+2T] Section Plan Figure 5. Aspect ratio for amount of day light in work plane ii. Strip windows provide more uniform daylight. The easiest way to provide adequate, even day lighting is with a nearly continuous strip windows. Punched windows are acceptable, but the breaks between windows can create contrasts of light and dark All rights Reserved 527

5 Figure 6. Strip and punched windows iii. Effective SHGC is the cumulative Solar Heat Gain Coefficient which can be reduced by shading devices and type of glass used. It can be clarified from figure 7. Figure 7. Indication of SHGC (Thermal Image view) VII. CONCLUSION This paper shows some effective ways for conservation of energy in buildings with respect to some modifications and point to be kept in mind during construction on the basis of aspect and orientation of the building. As nowadays there is dramatic increase in usage of natural resources and factor of pollution levels. Energy use has increased drastically. Today, buildings use approximately 40% of all energy consumed in the world. If we continue on this path of energy use in conjunction with population growth projections, with few new sources of fossil fuels, we could deplete all natural resources within few years. The buildings sector has major opportunity to reduce environmental impact by incorporating energy efficient technologies in design, construction and operation of both new and existing buildings. Net zero energy buildings are more effective and advantageous, making up applications likely to expand and permitting better and more sustainable energy systems. VIII. REFERENCES [1] Clay Nesler, Vice Precident of Global Energy and Sustainability, Anne Shudy Palmer, Senior Research Associate, Johnson Conrols, Inc. [2] Sharma AK, Bansal NK, Sodha MS, Gupta V (1989), wall for cooling/heating of buildings in composite climate. International Journal of Energy Research, Volume 13, Issue 6, pp [3] A White paper on Net Zero Energy Commercial Buildings- an inspiring vision for today. [4] The Green Building manual, Piyush Goenka, Archipidia press, edition [5] Net Zero Energy Buildings: A Classification system based on Renewable Energy Supply options, National Renewable Energy Laboratory, June [6] Natural Lighting in Green Buildings, D Sandanasamy. / International Journal of Engineering Science and Technology (IJEST). [7] Natural Light in Architecture, Derek Phillips with a foreword by Carl Gardner, first published [8] Environmental Design & Construction (EDC), Daylighting Today and Tomorrow, All rights Reserved 528

6 [9] Miller, David M, Daylighting Innovation Creates Smarter Solutions for Energy Savings, Aesthetic Appeal, Interior Comfort, New York Real Estate Journal, September [10] CIBSE, Energy Efficiency in Buildings: CIBSE Guide F, 2nd edition, Chartered Institution of Building Services Engineers (CIBSE), London. [11] US Green Building Council, "LEED-NC (Leadership in Energy and Environmental Design) Version 2.1," last accessed in February [12] "Prime Minister Inaugurates "Indira Paryavaran Bhawan". It is India s First on Site Net Zero Building" Information Bureau, Government of India. 25 February Retrieved 23 May All rights Reserved 529