CHAPTER: 2 LITERATURE REVIEW
2.1 INTRODUCTION TO SUSTAINABLE RETROFITTING
Any refurbishment of an existing building that intends to minimize carbon emissions and the building's environmental effect is referred to as a sustainable retrofit. Retrofitting plays a critical part in achieving the goal of sustainable development in the field of building renovation. Millions more buildings will need to be modified in the future years to increase their energy efficiency, reduce greenhouse gas emissions, and improve air quality, all of which contribute to improved health and the environment. Existing buildings must be retrofitted in order to help us achieve our net-zero carbon goals. The commercial and social benefits of changing and reusing old buildings are obvious, in addition to the environmental benefits. It is frequently significantly more cost-effective for clients than demolishing and reconstructing, creating unique spaces for occupants while preserving community heritage value.
2.2 LIGHTING RETROFITS
2 2.1 SIGNIFICANCE
Mostcommercialbuildingscanmakegoodeconomicsensefromenergy-efficientlighting upgrades. Replace old lighting components with advanced energy efficient lighting components to save up to 50% on lighting energy expenditures while maintaining or improving the visual quality of the workplace. In less than five years, most lighting upgrades pay for themselves through energy savings. Lighting improvements produce immediate benefits when occupant satisfaction and worker productivity are factored in the economic analysis.
2 2 2 WHEN LIGHTING RETROFITS?
When compared to other capital uses, lighting retrofits make financial sense anytime lighting energy can be saved while achieving a reasonable rate of return. This results in one or more of the following conditions existing in a building.
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1. Excessive Illuminance
2. Inefficient technology
3. Poor maintenance
4. Excessive hours of lighting operation
5. High Electricity charges/demand
6. Suboptimal Lighting conditions
2.2.3 BENEFITS
Lighting retrofits have numerous advantages for both the building owner and the building's occupants. Reduced electricity demand, energy savings, and lower building operating costs are all direct benefits. In some facilities, less quantifiable benefits such as improved lighting quality and potential productivity increases when existing lighting is poor or inadequate may be just as important.
2 2 4 BARRIERS
Despite the benefits and availability of energy efficient lighting technologies, significant barriers prevent businesses and building owners from adopting them. Customers frequently mistrust newer products due to a lack of understanding of the technology, changing electrical and energy codes, and the possibility of service interruptions. For the past two decades, electric utilityenergymanagement programmes havedemonstratedthat when customers are given accurate information and the promise of a good return on investment, they will move toward more energy efficient lighting solutions.
2.3 COMMERCIAL LIGHTING SYSTEMS
Lighting typically accounts for 20- 40% of total energy consumption in commercial buildings. Lighting is an area of almost any building, old or new, that offers many energy efficiency opportunities. A typical commercial building has a variety of lighting requirements, each with its own set of lighting efficiency options.
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The lighting systems used in office buildings, institutions, stores, schools, and all other non-industrial buildings are referred to as commercial lighting. Commercial lighting has a higher initial cost, a longer lifespan, better durability, higher maintenance and service costs, and better energy saving options when compared to other lighting.
In commercial buildings, lighting is a significant energy consumer. Electrical lighting generates a significant amount of heat, which contributes to the energy required to cool buildings. The ECBC specifies the amount of power that must be used for lighting, the types of lighting controls that must be used, and the situations in which daylighting must be used.
2.4 DAYLIGHTING IN EXISTING COMMERCIAL BUILDINGS
Daylighting has advantages that go beyond saving energy for electric lighting. The preference of occupants for daylight over electric lighting is widely acknowledged. The effects of daylight on stress, well-being, and mood are all positive. Furthermore, because of its high availability during the day, the strong blue component in its spectrum, and its excellent colour rendering qualities, it is effective in eliciting both visual and non-visual responses. Studies have shown that natural light can boost productivity, academic results, and user comfort, as well as improve people's visual abilities and reduce absenteeism and illness.
Although there are numerous opportunities for designing new buildings that utilize daylight,therearealsonumerousopportunitiesforrehabilitatingorretrofittinganexisting building for daylighting. Indeed, because of the large stock of existing commercial buildings, there may be more opportunities to retrofit existing buildings for daylighting than there are to design new buildings with natural light.
2 4 1 DAYLIGHTING STRATEGIES
Few of the general strategies in incorporating daylight in lighting design are:
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lighting systems in commercial buildings
• Planthelayoutofinteriorspaces usethelayouttoallowdaylighttopenetrate far into the building.
• Orient the building to minimize building exposure to the east and west and maximize glazing on the south and north exposures.
• Follow ECBC Visible Light Transmittance (VLT) requirements [ECBC 4.3.3.1] for windows to maximize light and visual quality.
• Interior surfaces, and especially the ceiling, must be light colored. Consider light colored furnitureandroompartitions to optimizelight reflectance.Avoid furniture colors and placement that will interfere with light distribution. Keep ceilings and walls as bright as possible.
• Inability to control glare is the most common failure in incorporating daylighting and especially important where computer use is extensive. Glare control includes the use of adjustable blinds, interior light shelves, fixed translucent exterior shading devices, interior and exterior fins, and louvers.
• Install dimmers to take advantage of daylighting and where cost-effective;
• Combine time switching with daylighting using astronomical timeclocks
• Control exterior lighting with photocontrols where lighting can be turned off after a fixed interval.
2.4.2 DAYLIGHTING RETROFITTING TECHNIQUES
The addition of daylighting technology to an existing system can be used to retrofit it. These solutions are usually applied to the exterior of the building. The devices can reduce the cooling load of buildings in this way (23 percent - 89 percent, with the highest savings obtained for solutions with a low shading coefficient). External systems, on the other hand, must be robust and unaffected by weather conditions. These systems may require more maintenance, which is more difficult to accomplish when they are not directly accessible from the building. Internal systems are more cost-effective than external systems because they are protected from wind, rain, temperature changes, and snow, but they do not provide thermal benefits. Personal and glare control are possible with both solutions.
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A) SKYLIGHTS
Skylights have an impact on the building envelope when used as a retrofit solution. They are used to increase the amount of daylight that enters a room, thereby improving user comfort and lowering energy consumption. Prefabricated skylights are typically installed in an existing roof structure. Skylights are best used in areas where lighting level fluctuation isn't a significant issue.
B) LIGHT TUBES
Tubular daylighting systems, also known as light pipes or light tubes, have been developed to increase daylight contribution in places without windows, thereby improving lighting conditions while lowering energy consumption. Light tubes can be used in a variety of buildings, including industry plants, underground parking garages, supermarkets, and homes, and are most commonly used for roof applications.
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Figure 1: Skylights, source: archdaily
Figure 2: Skylights schematic section, source: archdaily
Figure 3: Light tubes, source: www.ecplaza.net
Figure 4: Light tubes schematic section, source: https://build.com.au
C) LAMELLA HELIOSTATS
Lamella heliostats are used in skylights and roofs to direct light into light wells and inner courtyards. The system, which consists of multiple, serially arranged highly specular deflecting blades, is designed to reflect sunlight vertically down into an adjacent room or light duct from any sun position.
D) LIGHT SHELVES
Light shelves are horizontal or nearly horizontal bales in the façade that shade and reject light at the same time. They improve user comfort by distributing daylight more evenly throughout rooms. Light shelves have an architectural impact on a building and require high rooms to function properly.
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Figure 5: Lamella heliostat, source: www.ecplaza.net Daylighting and electric lighting retrofit, a source book of IEA SHC task 50
Figure 6: Light shelves, source: www.ecplaza.net Daylighting and electric lighting retrofit, a source book of IEA SHC task 50
E) ENLARGEMENT OF WINDOW AREA
Theenlargementofwindowsinthefaçadecanbeconsideredas apossibleretrofitsolution to improve lighting quality and energy efficiency. Both thermal and lighting considerations must be taken into account in order to maximize energy efficiency.
F) ELECTROCHROMATIC GLAZING
A coating on the inside surface of the outer pane of an electrochromic (EC) window allows the glass to change transmittance in response to a small applied voltage (3-5V). Electrochromic coatings are reversible thin-film coatings that can change the appearance of glass or plastic from clear to a dark Prussian Blue tint. When solar heat gains must be reduced while allowing a view out and daylight contribution, electrochromic glazing should be used.
G) MICRO LAMELLAE
Micro lamellae are stainless steel strips that are mounted in the cavity of low-E glazing and have a large number of small perforations. Low-angle sunlight passes relatively unhindered, while higher-angle sunlight is blocked. This daylighting system improves visual and thermal comfort while lowering energy usage. Micro lamellae should be used for high-rise buildings, roofs, and large glass facades where strong solar shading is required and no maintenance is required.
H) PRISMATIC ELEMENTS
Prismatic elements are thin, planar saw tooth devices made of clear acrylic that redirect or reflect sunlight. They are used in fixed or sun-tracking arrangements, and can be used in façades and skylights, depending on their optical properties. On all façade orientations and in glazed roof areas, prismatic elements are used for sun shading. Improved thermal behavior and lighting distribution are the main reasons for the increased energy efficiency.
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The schematic shows a mix of top lighting, side lighting, light shelves, high reflectance ceilings and wall diffusion to provide fairly uniform deep plan daylighting without the glare of direct sunlight.
2.5 LIGHTING SYSTEMS FOR RETROFITTING
2.5.1 LAMP, BALLAST & LUMINAIRE REPLACEMENT
The majority of existing lighting installations, according to studies on energy-efficient lighting retrofit, are fluorescent lighting (with conventional ballasts). Due to increases in new construction baselines and decreases in the number of existing very inefficient lighting systems, energy savings are generally decreasing over time.
Traditional options to consider in Lamp, ballast and luminaire replacement:
1. Relamp and reballast;
2. Delamp and reballast;
3. One-for-one fixture replacement;
4. Complete redesign.
5. Retrofit with LED Lamps
Options 3 and 4 represent a higher investment since entry into the plenum is required-a key factor affecting the cost of retrofitting-but they also present a higher saving potential.
A new generation of lighting retrofit kits is available in energy efficient LED options. These kits enable component parts to be installed in 15 minutes or less into the housing of old fixtures, provide better quality and better-looking fixtures and involve minimal disruption because they are installed below the ceiling.
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Figure 7: Mix of daylighting strategies
2.5.2 LIGHTING CONTROL SYSTEMS
The use of electric lighting control systems - in order to provide light exactly at the right time, to the right level and in the right place - can significantly contribute to reduce the consumption of electricity for lighting.
A) OCCUPANCY SENSORS
For everyone else, there are occupancy sensors Commercial units have become very sophisticated, with such features as methods of detection that eliminate false triggering, vandal resistance, automatic adjustment of time delays for maximum savings, and a choice of auto-on or manual on operation. Choose manual-on, also known as vacancy sensor, settings for rooms that have windows and may not always require light when occupied
Residential grade sensors are not intended for heavier commercial use and may actually increase electrical use by keeping lights on in daylit rooms. Many commercial sensors include a small photosensor that can prevent this Occupancy sensors can yield excellent energy savings when used with incandescent systems, considering the total switched load-controlled.
B) DIMMING
Dimming for functional and aesthetic purposes continues to stand in the way of adoption of some efficient lighting technologies. Use of automatic dimming, and in some cases manually dimmed lighting, can be shown to improve the efficiency of incandescent and halogen sources. This is most often true in rooms with very low-level lighting requirements or multi-function spaces where both high and low-level lighting are needed. Many incandescent luminaires, especially in hotel meeting rooms and conference facilities, operate on dimming systems required to handle a range of functions.
C) DAY-LIGHT LINKED CONTROL SYSTEMS
Daylight-linked controls (DLCs) are based on daylight exploitation. These systems control illuminance levels thanks to photosensors and algorithms that convert signals sensed by photocells in actions (a switching condition or a specific dimming level) actuated by the lighting equipment. DLCs use is rather limited because of different
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factors: difficulties in design, installation and calibration, problems connected to the evaluation of achievable energy savings, users' reluctance in accepting them.
D) DEMAND DRIVEN LIGHTING CONTROL
Demand driven lighting control is a system that combines an electric lighting solution with a control strategy to achieve a high level of lighting quality while lowering energy consumption. When lighting quality and personalization are critical, a control strategy and electric lighting solution should be used. Demand-driven control solutions can reduce lighting system energy consumption while maintaining high visual comfort for occupants. The goal is to only provide the amount of light that is required in the room. Illuminance can be reduced in areas that are out of sight. The amount of light required is determined by the number of people present, their position, and their current task. Demand-driven lighting systems are made up of several luminaires that can be controlled independently. Furthermore, precise detection of the occupant's location using presence detection systems (PIR or camera-based) is required.
2.5.3 TASK AMBIENT LIGHTING DESIGN
Task-ambient lighting is an alternative lighting solution that replaces general lighting by separating the illumination of (a) task area(s) with a higher lighting level from the illumination of the remaining ambient area with a lower lighting level. Task – ambient lighting will be used to save energy while increasing productivity. In an existing lighting situation, a new lighting design, or a lighting condition that does not achieve the required lighting levels throughout the room, personal control is required.
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2.6 ENERGY ANALYSIS OF LIGHTING RETROFITS
The energy analysis is most efficiently done through the use of lighting retrofit spread sheets that compare prior fixture energy use and time schedules with post retrofit energy and schedules. Lighting measures are, in most cases, evaluated on a room-by room basis, and matched to schedules of lighting use.
Lighting retrofit analysis involves simple arithmetic calculations. What is complicated is the wide assortment of available options, and criteria for determining the appropriate solution. The process of energy analysis is as follows.
1. Aiding in the collection of necessary data
2. Organizing fixture data in a format that can transfer directly to the analysis tool
3. Including limited of lighting retrofit option data that can be customized and expanded by the user
4. Allowing energy saving comparison for lighting retrofit options
5. Tallying simple utility cost savings based on average electrical cost per kWh
6. Providing quick financial reports for customization.
2.7 ECONOMIC EVALUATION OF LIGHTING RETROFITS
2 7 1 SIMPLE PAYBACK PERIOD
The most common measure of economic performance used by many energy management companies and lighting retrofit providers is the simple payback period-the period of time it takes for the savings in operating and maintenance costs to equal the initial investment. Simply replacing the existing lamps and ballasts without any improvement in energy efficiency has an infinite payback period there are no savings. Replacing them with lamps and ballasts that are more energy efficient will yield a payback. The length of payback period becomes shorter when the energy and lamp replacement cost savings are proportionally higher in relation to the initial costs. Pay back is popular for its simplicity and because in most cases the rate of payback is the primary indicator of opportunity.
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While the payback calculation can be easily adjusted to consider utility rebates and annualized maintenance costs, more detailed economic analysis based on rate of return or lifecycle cost is recommended for most lighting retrofits
2.8 LIGHTING QUALITY AND QUANTITY EVALUATION IN . RETROFITS
One should evaluate the quantity and quality of light before undertaking a retrofit. In doing so, the lighting professional may be able to identify one or more options for the retrofit or replacement of each type of targeted luminaire.
Determined if the existing quantity of light (illuminance as measured in foot candles) and light quality is appropriate for the space. Light quality is not as easily quantified as light quantity, although several key issues are readily identifiable. If both are acceptable, retrofitting light sources orlamps andballasts withlower-wattageoptions with equivalent lumens is appropriate.
2.8.1 LIGHTING QUANTITY
Lighting quantity or average illuminance can be measured or calculated for each space and compared to the recommendations of NBC or ECBC. If a space is over lighted, there an opportunity to reduce or tune the light level to what is needed. This will save end and operating costs, and if the full cost of retrofit is acceptable, the cost will be paid for through the energy savings.
2.8.1 LIGHTING QUALIITY
Lighting quality can be recognized but remains hard to define. High-quality illumination can result from good design using modest lighting equipment, yet the use of expensive lighting equipment does not guarantee good lighting quality. When lighting. is retrofitted, it presents an opportunity to improve the quality of the lighting as well as the energy efficiency. If one is not careful about applying retrofit technologies such as high efficiency reflectors appropriately, lighting quality can also suffer.
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CHAPTER: 3 CASE STUDIES
3.1 CASE STUDY 1: 435 INDIO WAY, CALIFORNIA
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and lighting
in commercial buildings
Location Sunnyvale, California Geographical coordinates 37.8° N, 122.4W Occupancy Type Commercial Typology Retrofit Climate Type Dry-summer subtropical Project Area 31759 ft2 EPI 42.6 kWh/m2/yr Installed PV capacity 113.2 kW
Figure 8: 435 Indio way entrance
435 Indio Way is an over 50-year-old single-story tilt-up in Sunnyvale, California, that was renovated to achieve net-zero energy. The building incorporates innovative design strategies for climate-response as well as occupant wellness while reducing costs by as much as $100.83/sq.ft as compared to similar minimum-code buildings. The energyefficient building in fact exceeds its design goals and supplies energy back to the grid.
435 Indio Way’s most outstanding feature is that it’s cooled only by passive strategies, with a backup HVAC system that is 22% smaller than conventional systems.
STRATEGIES TO IMPROVE DAYLIGHTING AND LIGHTING SYSTEMS INCORPORATED:
Active strategies:
• The building remains daylit for approx. 80% of the occupancy hours.
• The roof has been fitted with 43 skylights that are tilted southwards to bring diffused daylight into the building.
• The windows have been fit with self-tinting or electrochromic glass
• Light fixtures used are LED and are wired to occupancy motion and infrared sensors
• Acoustic fabric ceiling ensures an even distribution of light inside the building
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lighting
buildings
Figure 9: skylights of 435 Indio way
Figure 10: Window louver detail
Passive strategies:
• An omni-controller monitors the performance of passive strategies
• Actuators operate the skylights and windows to automatically open and close for the night ventilation
• Occupants who work late nights were identified and their workspaces were mapped. This helped determine which windows needed to be opened to facilitate night purge without causing discomfort to the late-night occupants.
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Figure 11: Retrofitting strategies
3.2 CASE STUDY 2: STATER BROS SUPERMARKET, CALIFORNIA
Concerned about rolling blackouts caused by California’s energy crisis in 2001, Stater Bros. retrofitted six stores with tubular skylights from Solar tube to provide backup lighting. Recognizing the energy-saving benefits, the company later installed 164 light pipes in a new 43,000-square-foot supermarket in Chino Hills, California. During most daylight hours, this free lighting source replaces nearly all of the artificial lighting in the store. Integrated photosensitive controls modulate supplementary artificial lighting in zones throughout the store relative to natural light from the light pipes. This daylighting system is estimated to cut the store’s lighting energy costs in half.
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lighting systems
buildings
Location Chino Hills, California Geographical coordinates 33.9° N, 117.7W
Type Commercial
Retrofit
Type Mediterranean Project Area 43,000sq. ft
Occupancy
Typology
Climate
Figure 12: Stater bros supermarket
CHAPTER: 4 ANALYSIS
4.1 STEPS OF ANALYSIS AND EVALUATION
An existing commercial building is taken into account, existing daylighting and lighting systems are analyzed. Based upon the analysis methods for improving the lighting quality and energy consumptions is suggested. The steps for carrying out the analysis is as follows:
Step 1: Selection of a suitable commercial building, preferably a retail store or supermarket.
Step 2: Supermarket in the locality has been identified (Supreme supermarket, karicode, Kollam) and its building plan (only ground floor is taken into account) is generated.
Step 3: The plan is divided into even grids (1m X 1m), daylight factor of each grid at one point is calculated using lux level meter.
Step 4: The obtained daylight factor is analyzed and compared with standard illuminance as per national building code.
Step 5: Areas with adequate daylight is identified in the existing building and areas with insufficient daylighting is marked. The energy usage of lighting in both sufficient and insufficient daylighting areas are identified, analysis is done based on whether the provided lighting is necessary in the space.
Step 6: Lighting retrofit methods for improving lighting quality as well as to save energy is suggested for the supermarket based on the analysis.
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Figure 13: Chosen supermarket, supreme kollam
4.2 STANDARDS OF LIGHTING LEVELS
4.2.1 STANDARDS OF ILLUMINANCE LEVEL AS PER NATIONAL ……..BUILDING CODE 2010
The chosen commercial building falls under Supermarkets and Hypermarkets, so the required illuminance level ranges from 300-500-750 Lux per square meter of the illuminated area.
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Table 1: Standard Illuminance level for different types of interior activity
4.3 EXISTING LIGHTING LAYOUT
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4.4 OBTAINED RESULTS OF DAYLIGHT FACTOR
Daylight factor, DF = (Ei / Eo) x 100%
Where,
Ei = illuminance due to daylight at a point on the indoors working plane, Eo = simultaneous outdoor illuminance on a horizontal plane from an unobstructed hemisphere of overcast sky.
Methodology: Illuminance levels of the interiors were obtained using Lux level meters at every point in a 1m grid of the plan. Simultaneous daylight factor for each grid is calculated and zoned.
The experiment was carried out during 9:00AM (15th December 2021) in the morning with only the illumination of daylight, all the artificial lighting was turned off. The outdoor illuminance, Eo was 13500 Lux.
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4.5 TOTAL ILLUMINANCE AND POWER USAGE …..CALCULATION
Billing counters:
The billing counter area is illuminated by 42 nos. of 600 lumen output 7w downlighters and natural daylighting.
Total Illuminance due to artificial lighting alone = (42 x 600) = 25,200 Lumens.
Total Illuminance due to natural lighting alone = 40 Lumens (Taking average of obtained readings)
Therefore,
Total Illuminance = 25,200 + 40 = 25,240 Lumens
Illuminance per square meter = 485 Lux.
Total power usage by artificial lighting = 294 W
Shopping area:
The shopping area is lighted using 21w 2000Lumen output LED tubes, aligned in 5 rows with each rows having 15 LED tubes, also in the back side a row of 7 LED tubes with same lumen output and power usage is mounted horizontally.
Total Illuminance due to artificial lighting alone = [(15 x 5) + 7] x 2000 = 1,64,000.
Total Illuminance due to natural lighting alone = 3 Lumens (Taking average of obtained readings)
Therefore,
Total Illuminance = 1,64,000 + 3
Illuminance per square meter = 600 Lux.
Total power usage by artificial lighting = 1722 W
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4.5 ANALYSIS AND INFERENCES ON EXISTING …..LIGHTING LAYOUT
Analyzing the building interiors, it is observed that the existing illuminance is much greater than the required illuminance as suggested in national lighting code. Thus, considering this we can reduce the no. of artificial lighting systems installed as a lighting retrofit strategy.
Also, Near the billing counter area, it is observed that the amount of daylight is abundant so retrofitting strategies to incorporate daylight during morning hours can be utilized and minimize the use of artificial lighting. The illuminance level can be reduced up to 300 Lux from 485 Lux, hence reducing power usage by existing extra lighting system.
The shopping area is very less illuminated by daylighting and abundantly lighted by artificial lighting. The illuminance level can be reduced up to 100 Lux from 600 Lux to reduce energy consumption and as a retrofit strategy.
The service area of the building is less utilized and user flow is very less, so strategies likeoccupant sensors etc can bemadeusein this areaofthe building to reducethe energy consumption and make the building more sustainable.
4.6 RETROFITTING STRATEGIES AND ENERGY SAVINGS
Billing counters:
6.5W, 600Lumen output LED downlighters are provided as a retrofit strategy along with dimmers and daylight linked control system.
The no. of lights required to replace is calculated as follows,
Minimum Required illuminance per sq.m of area as per NBC = 300 Lux
Maximum illuminance that can be achieved in the billing area = 15,600 Lumens
Therefore, No. of lights required to achieve maximum permissible illuminance
=Maximum permissible / Illuminance of lighting provided =15,600/600 = 26
Considering the lighting quality and aesthetics this can be rounded off to 28 and 7 rows of 4 downlighters each in a row can be provided
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Total energy savings is 98W per hour in the billing area, since all the 40 nos of 7W lights are replaced with 28 nos of ,6.5W LED tubes
Shopping area: 21W, 2000 Lumen output LED Batterns are mounted on track lighting as a retrofit strategy.
The no. of lights required is calculated as follows,
Minimum Required illuminance per sq.m of area as per NBC = 100 Lux
Maximum illuminance that can be achieved in the billing area = 27,300 Lumens
Therefore, No. of lights required to achieve maximum permissible illuminance
=Maximum permissible / Illuminance of lighting provided =27,300/2000 = 14
Considering the lighting quality, functionality and spatial requirements this can be 40 nos in 5 rows of 7 LED each in a track and 1 row horizontally with 5 LED each can be provided.
Total energy savings is 882W per hour in the Shopping area, since all the 82 nos.of LED Tubes are replaced with 40 nos of ,21W LED batterns.
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