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Daylighting and energy performance of a building for composite climate: An experimental study
Alexandria Engineering Journal (2016) xxx, xxx–xxx
H O S T E D BY
Alexandria University
Alexandria Engineering Journal www.elsevier.com/locate/aej www.sciencedirect.com
ORIGINAL ARTICLE
Daylighting and energy performance of a building for composite climate: An experimental study Madhu Sudan *, G.N. Tiwari Centre for Energy Studies, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India Received 20 May 2016; revised 28 July 2016; accepted 18 August 2016
KEYWORDS Daylighting; Energy saving; CO2 mitigation; Carbon credit; Energy matrices
Abstract The present study includes overall energy saving through thermal as well as daylighting for composite climate for the building known as SODHA BERS COMPLEX (SBC) situated at Varanasi, India. The building has been designed including all the passive concepts for thermal comfort as well daylighting to maximize the use of natural lighting for the occupants in day to day activities. This approach can be useful for multi-story building for rural and urban areas for both residential and commercial buildings. The energy saving potential and corresponding CO2 mitigation have been determined for different lifetimes of the building. The energy matrices namely energy payback time (EPBT), energy production factor (EPF) and life cycle conversion efficiency (LCCE) of the building have also been estimated by considering overall energy saving. An annual energy saving has been obtained as 3675.61 kW h due to daylight concept by considering different Zones in each floors of the building. Further, the EPBT has been determined as 49.25 years and 34.73 years for average 4 °C and 6 °C temperature difference between ambient and room, respectively. It has been found that when thermal heat gain increases in the building LCCE and EPF increase. Ó 2016 Faculty of Engineering, Alexandria University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
1. Introduction The energy is the integral part of the human life for almost all activities e.g. industrial, domestic, medical, transport. The world is facing a grim situation such as depletion of fossil fuel reserves, global warming and other environmental concerns, geopolitical and military conflicts and continuing fuel price rise if continuing the use of conventional energy sources [1–3]. Building of future has to take into account the tasks and the opportunities brought about by, environmental, societal and * Corresponding author. E-mail address: [email protected] (M. Sudan). Peer review under responsibility of Faculty of Engineering, Alexandria University.
technological changes [4]. Energy saving can be done not by bringing down the standard of living, but by utilizing more efficient technologies to produce the similar, or higher, levels of comfort and convenience, we have come to enjoy and appreciate [5]. Due to the environment and sustainable development issues, governments have increased their focus on energy saving technologies in the building and other sectors. For the commercial and residential building evaluation of energy efficiency is difficult to describe with precision as there is often a lot of vague information and various types of inaccurate assessment of data. The evaluation of energy saving in the building design selection has uncertainty and complexity. To select a suitable design, one needs to consider the use of function, technology, economics, and many other factors. The energy saving through the daylighting opening in the building
http://dx.doi.org/10.1016/j.aej.2016.08.014 1110-0168 Ó 2016 Faculty of Engineering, Alexandria University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article in press as: M. Sudan, G.N. Tiwari, Daylighting and energy performance of a building for composite climate: An experimental study, Alexandria Eng. J. (2016), http://dx.doi.org/10.1016/j.aej.2016.08.014
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M. Sudan, G.N. Tiwari
Nomenclature Af CW Ein Esol Eaout Ig
floor area (m2) of the room clerestory window embodied energy (kW h) annual solar radiation (kW h/m2) total annual energy saving (kW h) global solar radiation (W/m2)
is not only easy for quantitative calculation of the indicators, but also for qualitative description [6,7]. The energy efficient building design selection at the present time depends on the selector’s awareness about energy crisis and experience. In buildings, lighting systems are responsible for consuming large amount of energy all around the world [8,9]. Nowadays significant energy can be saved by creating cost-effective efficiency developments in the buildings and their equipment – which will reduce any nation’s energy consumption and GHG emissions which lead to significant economic savings to consumers [4]. It is reported that in the commercial sector around 25% of the total electricity is consumed by lighting systems [10,11]. The range of energy consumption varies greatly from country to country and is not only due to design and climatic conditions, but also to cultural habits. In USA, the lighting enduse in commercial building is 39% [11]; in the China, 15% [8]; in the Netherlands, 55% [11]; and in India more than 20% [12]; and in the UK it ranges from 30% to 60% [13]. Bansal and Minke (1988) has concluded that conventional energy resources are being exhausted through its limited resource and uncontrolled harnessing. To meet the energy requirements the world heavily relies on fossil fuels [14]. Almost 80% of the global energy demand is met by fossil fuels such as oil, gas and coal [15]. Presently renewable energy and nuclear power are contributing 13.5% and 6.5%, respectively of the total energy needs in the world. The enormous amount of energy being consumed across the world has led to adverse effects on the ecosystem of the planet [16]. According to recent studies, natural light not only improves students test score but also provides better physical health. Human beings also prefer to work in daylighting. It is an important component of the passive building. The interior of the buildings can be illuminated in several ways such as window, light well, clerestory [17], the laser cut penal [18], light shelf, light pipes [19,20], anidolic light-duct [21]. The use of the all these daylighting systems can save the artificial lighting in the buildings. These provisions are equipped to maintain coincidence to human visual response, attractive indoor environment, and allow people to maintain visual contact with the outside world [22–28]. Daylighting concept in building is an effective option of saving fossil fuels which ultimately leads to saving substantial amount of money and reducing emission of greenhouse gases [17]. In the present study, the complete energy and economics analysis has been determined by considering both thermal and daylighting concepts for the whole building, which is divided into different Zones in each floors. This paper presents monthly daylight performance of the building based on hourly
EPBT EPF SBC TLB LCCE LW
energy payback time (years) energy production factor SODHA BERS COMPLEX lifetime of the building (years) life cycle conversion efficiency light well
measured illuminance data under clear sky conditions. The paper evaluates the lighting energy saving and CO2 mitigation of the building. Further, the three energy matrices namely life cycle conversion efficiency (LCCE), energy payback time (EPBT), and energy production factor (EPF) of the building have also been determined by considering energy saving due to both thermal heat gain and daylighting. The embodied energy of the whole material has been taken to determine the energy matrices of the building. 2. Background information The building featured is located at Varanasi, Uttar Pradesh, India (latitude 25.28°N, longitude 82.95°E and altitude 76.8 m). It is four-storey building. 2.1. Building geometry The building was designed with wall windows, clerestory windows and light well, with the provision of natural ventilation through environmental conservation measures and sufficient daylight. Fig. 1a shows the photograph of the building. The SODHA BERS COMPLEX (SBC) has been built on land area of 236.91 m2. The covered area of the each floor is 152.42 m2 of the SBC. Each floor of the building is divided into three Zones. The brief discussion of basement, ground floor, first and second floor has been given in coming sections. 2.1.1. Basement Fig. 1b shows the top view of the basement which is made by using earth shelter concept for cooling and daylighting. For evaluation of energy saving, it is divided into three Zones. The daylighting and natural ventilation is provided by clerestory window and rooftop window through light well (LW304) which is located on the top of east (Zone 3) and south (Zone 1) for the basement, respectively. In the Zone 2 of the basement there is no special provision to provide daylight; this Zone illuminates through clerestory window and rooftop window. It is commonly used for community services. 2.1.2. Ground floor Fig. 1c shows the top view of the ground floor plan. It has facility of two light well in addition to sufficient crossventilation from north to south direction due to unique naturally made wind channel from east being a dead end of the road to cool the rest of whole building. The Zones 1–3 of the ground floor illuminate through east wall opening, light
Please cite this article in press as: M. Sudan, G.N. Tiwari, Daylighting and energy performance of a building for composite climate: An experimental study, Alexandria Eng. J. (2016), http://dx.doi.org/10.1016/j.aej.2016.08.014
Daylighting and energy performance of a building for composite climate
Figure 1a
Figure 1b
3
View of SODHA BERS COMPLEX (SBC).
Isometric typical view of the basement.
well (LW304) and light well (LW305). Further, in order to provide more daylight in Zone 1 south wall has also been opened. It is used for religious functions. It has no partition wall due to nature of its application which provides natural passage for first and second floor ventilations.
furnished daylight in Zone 3 (kitchen, toilet, bathroom, rooms and corridor). The south wall in Zone 3 has minimum exposed area (daylight opening) in comparison with east and west wall which minimizes the role of heat fraction from exposed south interior wall. The percentage of embodied energy of the material used in SBC has been shown in Fig. 2.
2.1.3. First and second floor The layout planes of the first and second floors have been shown in Fig. 1d. The Zone 1 accommodates typical room, LW304, LW305, kitchen, conference and computer with open corridor for east and north side. The room is illuminating east or north window and clearstory window. Daylighting provided through the east window (or clearstory window) and west clearstory window, illuminates the conference room and computer room. The Zone 2 has been illuminated through light well (LW305). The light well (LW304) and south wall opening
3. Energy saving The energy saving potential from daylight has been determined by using the following equations. 3.1. Luminous flux The hourly luminous flux, /ðlumenÞ of the daylighting inside the room can be calculated [29,30] as follows:
Please cite this article in press as: M. Sudan, G.N. Tiwari, Daylighting and energy performance of a building for composite climate: An experimental study, Alexandria Eng. J. (2016), http://dx.doi.org/10.1016/j.aej.2016.08.014
4
M. Sudan, G.N. Tiwari
Figure 1c
Figure 1d
/ ¼ ðEia Af Þ
Isometric typical view of the ground floor plane.
Isomeric typical view of first and second floor.
ð1Þ
3.3. Daily artificial energy saving, E (kW h)
where Eia ðlxÞ is the hourly average daylight illuminance inside the working surface and Af (m2) is the horizontal working surface area.
The daily lighting energy saving potential, E (kW h) can be expressed [31,32] as
3.2. Lighting power, Pi (W)
E¼
N X Pi
ð3Þ
i¼1
The hourly lighting power, Pi (W) can be determined [31,32] as / Pi ¼ ð2Þ BF ee
where N (h/day) is sunshine hour for a typical day.
where ee (lm/W) is the luminous efficacy of the artificial light source and BF is the efficiency of ballast (or ballast factor).
The annual mitigation of CO2 can be determined by using the relation as follows [31,32]:
3.4. Mitigation of CO2
Please cite this article in press as: M. Sudan, G.N. Tiwari, Daylighting and energy performance of a building for composite climate: An experimental study, Alexandria Eng. J. (2016), http://dx.doi.org/10.1016/j.aej.2016.08.014
Daylighting and energy performance of a building for composite climate Bricks/tiles
Reinforcement
Cement
Other
21%
Activities/process
4.2. Energy production factor (EPF) The overall performance of the building can be predicted with help of the energy production factor. The ratio of these two quantities is referred as the energy production factor (va ). It is based on the lifetime of the building and can be expressed as Eaout ð7Þ va ¼ TLB Ein
21%
18%
5
19%
where TLB is the lifetime of the building. 21%
Figure 2 SBC.
4.3. Life cycle conversion efficiency (LCCE)
Percentage embodied energy of the material used in
1 CO2 mitigation ¼ ðE TLB Ein Þ 1 La 1 0:98 kg 1 Ltd
/ðtÞ ¼
ð4Þ
3.5. Carbon credit earned The carbon credit earned from the mitigation of CO2 (in tons/ year) can be calculated as follows [31,32]: Carbon credit earned ¼ CO2 mitigation ðtonsÞ ð5Þ
4. Energy matrices The performance of the building is evaluated by using three fundamental energy matrices: namely the energy payback time (EPBT), energy production factor (EPF) and life cycle conversion efficiency (LCCE) [33,34]. 4.1. Energy payback time (EPBT) Energy payback time (EPBT) is the total time period required to recover the total energy consumed to prepare the materials (embodied energy) used for construction of the building. It is one of the main parameters for analysing the energy sustainability of the building which can be expressed as EPBT ¼
embodied energy ðEin Þ Years annual energy saving ðEaout Þ
ðEaout TLB Þ Ein ðEsol TLB Þ
ð8Þ
where Esol is the annual solar radiation.
where EðkW h=yearÞ is an annual lighting energy saving by daylighting, La ð%Þ is the loss due to poor electrical lighting and Ltd ð%Þ is transmission and distribution loss. TLB ðyearÞ is lifetime of the building, Ein is the embodied energy of materials used in the building.
12ð€=ton of CO2 Þ
It is the net energy productivity with respect to the solar input exposed different faces over the lifetime of the building and can be expressed as
ð6Þ
where Ein ðkW hÞ is the embodied energy of the total materials used in the building and Eaout ðkW hÞ is the annual energy saving by the daylighting and thermal heat gain.
5. Methodology The data of solar radiation, outside and inside illuminance have been taken at SBC, Varanasi, India, in the duration of January-December 2014. The following methodology has been adopted to calculate energy saving and energy matrices of the building. Step 1: The hourly experimental observation has been taken at working surface in the SODHA BERS COMPLEX (SBC), Varanasi, India. Step 2: The hourly luminous flux, /ðlumenÞ on the working surface inside the building was calculated using Eq. (1). The value of horizontal working surface area (Af) is given in Figs. 1b–1d. Step 3: The hourly lighting power, Pi (W) and daily energy saving potential, E (kW h) were determined by using Eqs. (2) and (3), respectively. The value of ee ðlm=WÞ and BF is taken 70 lm/W and 0.90 respectively. Step 4: Daily energy saving potential has been determined by summing the hourly energy saving. Step 5: Monthly energy saving has been calculated by summing daily energy saving for each month. Step 6: The energy saving in each month is summed to get annual energy saving potential by the daylight. Step 7: The mitigation of CO2 and carbon credit earn has been determined by using Eqs. (4) and (5), respectively. The value of the loss due to poor electrical lighting, La ð%Þ and the transmission and distribution loss, Ltd ð%Þ has been taken is 20% and 40%, respectively. Step 8: The embodied energy (Table 1) of used materials in building and annual thermal heat gain (Table 2) has been taken [34]. Step 9: Total energy saving has been determined by summing the energy saving by the daylight and thermal heat gain. Step 10: The analysis of three fundamental matrices namely, The energy payback time (EPBT), energy production factor (EPF) and life cycle conversion efficiency
Please cite this article in press as: M. Sudan, G.N. Tiwari, Daylighting and energy performance of a building for composite climate: An experimental study, Alexandria Eng. J. (2016), http://dx.doi.org/10.1016/j.aej.2016.08.014
6
M. Sudan, G.N. Tiwari Breakup of embodied energy of materials used in SODHA BERS COMPLEX (SBC) [32,34].
Table 1 Serial
Material/name of work
Total embodied energy (kW h)
1 Cement 186770.83 2 Bricks/tiles 234677.08 3 Stone ballast 14919.67 4 Sand 12171.08 5 Lime/Pop/Putty 3268.33 6 Reinforcement 221977.67 7 Aluminium 1463.89 8 Glass 5200.00 9 Plywood 45625.00 10 Wood 19361.11 Total embodied energy 1120753.83 kW h
Table 2
Serial
Material/name of work
Total embodied energy (kW h)
11 12 13 14 15 16 17 18 19 20
PVC/plastic Paint (oil bound) Paint (water bound) Marvel/Makrana stone Ceramic tiles/sanitary ware Iron Copper Brass Activities/process Transportation
3593.33 3966.67 16562.50 291.67 24761.11 30958.33 2100.00 1833.33 241017.78 50234.44
Total annual energy saving by thermal heat gain and daylighting in SBC [34].
Total embodied energy (kW h)
Average temperature difference (DT) between room air and ambient air temperature (°C)
Total annual thermal heat gain for complete building (kW h)
Annual Energy by daylighting for complete building (kW h)
The total annual energy saving for SBC (Eaout) (kW h)
1120753.83
4 6
19079.28 28592.64
3675.61 3675.61
22754.89 32268.25
Annual solar radiation incident (KW h/m2)
Area (m2)
Horizontal East South West North Total
750 428 465 435 405 2463
152.42 327.60 126.72 329.40 80.40 1016.54
Total annual solar energy (Esol) 114315.00 140212.80 58924.80 143289.00 32562.00 2503738.02
Solar radiation
illuminance
90000
800
80000
700
70000
600
60000
500
50000
400
40000
300
30000
200
20000
100
10000
0
Illuminance (Lux)
Exposer part of the Building
900
Solar radiation (W/m2)
Table 3 Calculation for annual solar radiation incident different exposes of the building.
0 8.00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18.00
Time (h)
(LCCE) has been computed using Eqs. (6)–(8), respectively. The value of the annual solar radiation (Esol ) has been given in Table 3.
Figure 3 Hourly variation of solar radiation and outside illuminance for Varanasi climate conditions in the month of May.
6. Results and discussion The illuminance level of daylighting was measured at daytime when all the lights were off and occupants do our commercial activity in the building. The illuminance levels along the corridor, rooms, T1, T2, B1, B2, were measured for each Zone. The illuminance was measured at one hour intervals, weekly, from 8 am to 6 pm between January and December 2014. Fig. 3 shows the variation of solar radiation and outside illuminance corresponding to the clear sky conditions at the horizontal surface in the month of May 2014. Fig. 4 shows the hourly variation of illuminance level in the basement for Zone 1–3. It displays the respective hourly averages illuminance beings to increases in the early in the morning, reaches maximum value at around noon and gradually decreases towards the evening for Zones 1 and 2. The key reason behind this, the Zones 1 and 2 illuminate through light well and south daylight
Illuminance (Lux)
450
Zone1
Zone2
Zone3
400 350 300 250 200 150 100 50 0 8.00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18.00
Time (h)
Figure 4 Hourly variation of inside illuminance in the basement in the month of May.
opening. In Zone 3 daylight enters through the east opening due to this illuminance decreases from morning to evening. The minimum illuminance was 30 lux in Zone 2 at 6 pm while
Please cite this article in press as: M. Sudan, G.N. Tiwari, Daylighting and energy performance of a building for composite climate: An experimental study, Alexandria Eng. J. (2016), http://dx.doi.org/10.1016/j.aej.2016.08.014
Daylighting and energy performance of a building for composite climate
700
7
Kitchen
T1
T2
B1
B2
Open
Zone2
zone3
Illuminance (Lux)
600 500 400 300 200 100 0 8.00
9:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18.00
Time (h)
Hourly variation of inside illuminance for ground floor in the month of May.
Figure 5
450
Kitchen
T1
T2
B1
B2
Open
400
Illuminance (Lux)
350 300 250 200 150 100 50 0
8.00
Figure 6a
9:00
10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18.00 Time (h)
Hourly variation of inside illuminance in the Zone 1 (first and second floor).
1600
R301
R302
R304
R305
LW305
Corridor
Illuminance (Lux)
1400 1200 1000 800 600 400 200 0 8.00
9:00
10:00
11 :00
12 :00
13:00
14:00
15 :00
16:00
17:00
18.00
Time (h)
Figure 6b
Hourly variation of inside illuminance in Zone 2 (first and second floor).
Please cite this article in press as: M. Sudan, G.N. Tiwari, Daylighting and energy performance of a building for composite climate: An experimental study, Alexandria Eng. J. (2016), http://dx.doi.org/10.1016/j.aej.2016.08.014
8
M. Sudan, G.N. Tiwari R304
1600
R307
R308
Illuminance (Lux)
1400 1200 1000 800 600 400 200 0 8.00
9:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18.00
Time (h)
Figure 6c
Hourly variation of inside illuminance Zone 3 (First and second floor).
the maximum was 400 lux in Zone 3 at 8 am. Fig. 5 represents the variation of illuminance level inside the Zones 1–3 for ground floor. The ground floor follows same trend of variation illuminance as the basement is maximum in Zone 3 and minimum was Zone 2. The range of illuminance has been found in kitchen as, T1–2 or B1–2 as 30–80 lux in Zone 1. The illuminance level in Zones 2 and 3 is varies in the range of 40–112 and 80–650 lux, respectively that is the sufficient, and no need artificial light in the daytime. Figs. 6a–6c, display
Zone1
Zone2
the distribution of the illuminance level in first or second floor for Zones 1–3. It is clear from Fig. 6a; illuminance level inside the kitchen (first or second floor) is approximately 3–4 times higher than the ground floor kitchen. The main reason behind this result is of daylighting opening and the distance of the working surface from the daylight source. The illuminance level maximum has been found 1500 for LW305 at 12 pm in Zone 2 and minimum was 35 lux for R301 at 6 pm in Zone 2. It is clear from Figs. 6a–6c; maximum illuminance has been
Zone1
Zone3
Energy Saving (kWh)
Energy Saving (kWh)
60 50 40 30 20 10
Jan
0 Jan
Feb Mar Apr May Jun
Jul
Aug Sep
Zone2
Zone3
100 90 80 70 60 50 40 30 20 10 0 Feb Mar Apr May Jun
Jul
Aug Sep Oct Nov Dec
Months
Oct Nov Dec
Months
Figure 7a basement.
Monthly energy saving of the different Zones for
Zone1
Zone2
Figure 7c Monthly energy saving in each Zone for first and second floor.
900
Zone3
Basement
Ground Floor
First Floor
Second Floor
800
Energy Saving (kWh)
Energy Saving (kWh)
60 50 40 30 20 10
700 600 500 400 300 200 100
0 Jan
Feb Mar Apr May Jun
Jul
Aug Sep
Oct Nov Dec
0
Zone1
Zone2
Zone3
Months
Figure 7b
Monthly energy saving in each Zone for ground floor.
Figure 8 the SBC.
Annual energy saving potential for different floors of
Please cite this article in press as: M. Sudan, G.N. Tiwari, Daylighting and energy performance of a building for composite climate: An experimental study, Alexandria Eng. J. (2016), http://dx.doi.org/10.1016/j.aej.2016.08.014
Daylighting and energy performance of a building for composite climate Table 4
9
Net CO2 mitigation and carbon credit earned for the different lifetimes of the buildings.
Average temperature difference (DT) (°C)
For L = 100 Year Net CO2 mitigation (Tons)
Carbon credit earned (US$)
Net CO2 mitigation (Tons)
Carbon credit earned (US$)
Net CO2 mitigation (Tons)
Carbon credit earned (US$)
4 6
2355.66 4296.39
28267.92 51556.68
6997.66 10879.11
83971.92 130549.32
11639.65 1761.83
139675.8 21141.96
Table 5
For L = 200 Year
For L = 300 Year
The energy payback time of SODHA BERS CONPLEX (SBC).
Average temperature difference (DT) between room air and ambient air temperature (°C)
The total annual energy saving for SBC (Eaout) (kW h)
The energy payback time (Years)
4 6
22754.89 32268.25
49.25 34.73
Table 6
Calculation for Energy Production Factor (EPF) for different lifetimes of SBC.
Average temperature difference (DT) between room air and ambient air temperature (°C)
The total annual energy saving for SBC (Eaout) (kW h)
EPF for L = 100 Years
EPF for L = 200 Years
EPF for L = 300 Years
4 6
22754.89 32268.25
2.03 2.08
4.06 5.75
6.09 8.64
Table 7
Life Cycle Conversion Efficiency (LCCE) for different lifetimes of SBC.
Temperature difference (DT) between room air and ambient air temperature (°C)
Total annual average energy saving for SBC (Eaout) (kW h)
LCCE for L = 100 Years
LCCE for L = 200 Years
LCCE for L = 300 Years
4 6
22754.89 32268.25
0.0046 0.0048
0.0068 0.0106
0.0076 0.0113
received in Zone 3 and minimum in Zone 2 for all floors. In Zone 2 of the first or second floor, LW305 provides the illuminance inside the room and corridor. In the daytime, no required artificial light excludes R301. In the building maximum illuminance received in Zone 3 for first or second floor and minimum was in the Zone 2 for basement. Figs. 7a–7c represent the monthly variation of energy saving of the Basement, ground, first and second floor (Zone 1–3). Zone 3 scored greater energy saving than Zones 1 and 2 of all floors. It is clear from these figures the monthly energy saving in Zone 1–3 for each floor increases from January to May and decreases from July to December. The key reason behind this Jun to August increased frequency of rain in comparison with April to May. Fig. 8 represents the total annual energy saving by the daylighting for each Zone for each floor of the building. The annual energy saving potential in the basement, ground, first and second floor was estimated as 452.17, 815.70, 1411.11 and 1411.11 kW h, respectively for the clear sky conditions. However, for the full cloudy day daylight does not perform better as compared to clear or partially cloudy days in Varanasi, India. The total energy saving has been calculated as 3675.61 kW h per year by using the daylighting concept. The annual energy saving by the thermal heat gain and daylighting for 4 °C and 6 °C is tabulated in Table 2 [34]. Table 4
displays the net CO2 mitigation and corresponding carbon credit earned over the different life spans of building (100 years, 200 years, and 300 years). This shows the net CO2 mitigation and carbon credit earned, both are maximum for 300 years. The energy payback time (EPT) is given in Table 5. This indicates that the total energy saving (thermal heat gain and daylight) increases reducing the EPT of the building. Similarly, trend flow energy production factor (EPF) is tabulated in Table 6. Table 7 lists estimation for life cycle conversion efficiency (LCCE) for different life spans (L = 100, 200, 300 years). It shows that life cycle conversion efficiency (LCCE) higher for 6 °C and lower for 4 °C. The reason behind that is higher the temperature difference temperature difference (DT) between room air and ambient air temperature higher the heat gain. 7. Conclusions The daylight systems were made in the building which provides sufficient daylight in the whole building, and there was no need of artificial light in the day time, except R301 and basement. Annual energy saving has been found 3675.61 kW h by using the daylighting concept in the building.
Please cite this article in press as: M. Sudan, G.N. Tiwari, Daylighting and energy performance of a building for composite climate: An experimental study, Alexandria Eng. J. (2016), http://dx.doi.org/10.1016/j.aej.2016.08.014
10 The energy payback time (EPBT) for 4 °C and 6 °C has been found to be 49.25 years and 34.73 years, respectively. Thermal heat gain increases inside the building life cycle conversion efficiency (LCCE) increases.
Acknowledgment The work described in this paper was fully supported by Bag Energy Research Society (BERS). We are thankful to IIT Delhi for partial financial supports. References [1] A. Freewan, L. Shao, S. Riffat, Interactions between louvers and ceiling geometry for maximum daylighting performance, Renewable Energy 34 (2009) 223–232. [2] J.S. Carlosa, H. Corvachob, Evaluation of the performance indices of a ventilated double window through experimental and analytical procedures: SHGC-values, Energy Build. 86 (2015) 886–897. [3] E. Ghisia, J.A. Tinkerb, An Ideal Window Area concept for energy efficient integration of daylight and artificial light in buildings, Build. Environ. 40 (2005) 51–56. [4] H.H. Alzoubi, S.M. Al-Rqaibat, The effect of hospital design on indoor daylight quality in children section in King Abdullah University Hospital Jordan, Sustain. Cities Soc. 14 (2014) 449– 455. [5] C.G. Granqvist, Electrochromics for smart windows: oxidebased thin films and devices, Thin Solid Films 564 (2014) 1–38. [6] EIA, Energy end-use intensities in commercial buildings. Energy Information Administration, US Department of Energy, Washington, 1994. [7] S. Singh, S. Agrawal, R. Gadh, Optimization of SCGPVT array using evolutionary algorithm (EA) and carbon credit earned by the optimized array, Energy Convers. Manage. 10 (2015) 303– 312. [8] G.F. Min, E. Mills, Q. Zhang, Energy-efficient lighting in China: problems and prospects, in: Right Light Three, Third European Conference on Energy-efficient Lighting. Proceedings. vol. I, Presented papers England, 1995, p. 261–8. [9] S. Agrawal, G.N. Tiwari, Exergoeconomic analysis of glazed hybrid photovoltaic thermal module air collector, Sol. Energy 86 (2012) 2828–2838. [10] M. Sudan, G.N. Tiwari, I.M. Al-Helal, A daylight factor model under clear sky conditions for building: an experimental validation, Sol. Energy 115 (2015) 379–389. [11] W. Sliepenbeek, L.V. Broekhoven, Evaluation of stimev, the allDutch utility-sponsored lighting rebate programs, in: Right Light Three, Third European Conference on Energy-efficient Lighting. Proceedings. vol I, Presented papers England, 1985, p. 247–54. [12] BS, Lighting for Buildings—Part 2: Code of Practice for Daylighting, British, 1992. [13] PROCEL, Manual de conservacao de energia eletrica em predios peeublicos e comerciais [Handbook of energy savings in public and commercial buildings], 1997. [14] E. Ghisi, Desenvolvimento de uma metodologia para retro’t emsistemas de iluminacao: estudo de caso na Universidade Federal de Santa Catarina [Development of a methodology for retro’tting lighting systems: a case study in the Federal University of Santa Catarina], 1997. [15] N.K. Bansal, G. Minke, Climatic Zones and Rural Housing in India, K. Julich Gmbh, Germany, 1998, pp. 25–28.
M. Sudan, G.N. Tiwari [16] C.S. Jardim, R. Ruther, I.T. Salamoni, T.S. Viana, S.H. Rebechi, P.J. Knob, The strategic siting and the roofing area requirements of building-integrated photovoltaic solar energy generators in urban areas in Brazil, Energy Build. 40 (2008) 365– 370. [17] B. Calcagni, M. Paroncini, Daylight factor prediction in atria building designs, Sol. Energy 76 (2004) 669–682. [18] M. Sudan, G.N. Tiwari, Energy matrices of the building by incorporating daylight concept for composite climate—An experimental study, J. Renew. Sustain. Energy 6 (2014) 053122. [19] G. Courret, J.L. Scartezzini, D. Francioli, J.J. Meyer, Design and assessment of an anidolic light-duc, Energy Build. 28 (1998) 79–99. [20] V. Baker, A. Franchiotti, K. Steemers, Daylighting in Architecture, a European Reference Book, James & James, London, 1993. [21] A. Nabil, J. Mardaljevic, Useful daylight illuminances: a replacement for daylight factors, Energy Build. 38 (2006) 905– 913. [22] R. Canziani, F. Peron, G. Rossi, Daylight and energy performance of a new type of light pipe, Energy Build. 36 (2004) 1163–1176. [23] C.S. Rajoria, S. Agrawal, S. Chandra, G.N. Tiwari, D.S. Chauhan, A novel investigation of building integrated photovoltaic thermal (BiPVT) system: a comparative study, Sol. Energy 131 (2016) 107–118. [24] S. Agrawal, Comparative Analysis of Hybrid Photovoltaic Thermal Air Collectors: Design, Modeling and Experiment to Improve the Overall Efficiency of PV system, LAP LAMBERT Academic Publishing: GmbH & co.KG, Heinrich-Bocking-str 6–8, 66121, Saarbrucken, Germany, 2012 (June 14, 2012), ISBN13: 978-3659154478. [25] S. Agrawal, G.N. Tiwari, Performance analysis in terms of carbon credit earned on annualized uniform cost of glazed hybrid photovoltaic thermal air collector‘‘, Sol. Energy 115 (2015) 329–340. [26] S. Fairuz, S. Fadzil, A. Abdullah, N.A. Al-Tamimi, W.M.W. Haru, The impact of varied orientation and Wall Window Ratio (WWR) to daylight distribution in residental rooms, Appl. Mech. Mater. 409 (2013) 606–611. [27] CIBSE, Code for Interior Lighting, Chartered Institution of Building Services Engineers, London, 1994. [28] M. Krarti, Energy Audit of Building Systems: An Engineering Approach, second ed., CRC Press, Boca Raton, FL, 2010. [29] M. Sudan, G.N. Tiwari, I.M. Al-Helal, Dynamic analysis of daylight metrics and energy saving for rooftop window integrated flat roof structure of building, Sol. Energy 122 (2015) 834–846. [30] M Sudan, G.N. Tiwari, Effect of Orientation of the Wall Window on Energy Saving under Clear Sky Conditions, ICEESD, 2016 (2016/01/paris/ICEESD). [31] A. Chel, G.N. Tiwari, A. Chandra, A model for estimation of daylight factor for skylight: an experimental validation using pyramid shape skylight over vault roof mud-house in New Delhi (India), Appl. Energy 86 (2009) 2507–2519. [32] R.K. Mishra, G.N. Tiwari, Energy matrices analyses of hybrid photovoltaic thermal (HPVT) water collector with different PV technology, Sol. Energy 91 (2013) 161–173. [33] A. Tiwari, P. Barnwal, G.S. Sandhu, M.S. Sodha, Energy metrics analysis of hybridphotovoltaic (PV) modules, Appl. Energy 86 (2009) 2615–2625. [34] V. Singh, Design and Life Cycle Energy Analysis of a Passive Building for Composite Climate of India Phd. thesis, IIT Delhi, India, 2014.
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H O S T E D BY
Alexandria University
Alexandria Engineering Journal www.elsevier.com/locate/aej www.sciencedirect.com
ORIGINAL ARTICLE
Daylighting and energy performance of a building for composite climate: An experimental study Madhu Sudan *, G.N. Tiwari Centre for Energy Studies, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India Received 20 May 2016; revised 28 July 2016; accepted 18 August 2016
KEYWORDS Daylighting; Energy saving; CO2 mitigation; Carbon credit; Energy matrices
Abstract The present study includes overall energy saving through thermal as well as daylighting for composite climate for the building known as SODHA BERS COMPLEX (SBC) situated at Varanasi, India. The building has been designed including all the passive concepts for thermal comfort as well daylighting to maximize the use of natural lighting for the occupants in day to day activities. This approach can be useful for multi-story building for rural and urban areas for both residential and commercial buildings. The energy saving potential and corresponding CO2 mitigation have been determined for different lifetimes of the building. The energy matrices namely energy payback time (EPBT), energy production factor (EPF) and life cycle conversion efficiency (LCCE) of the building have also been estimated by considering overall energy saving. An annual energy saving has been obtained as 3675.61 kW h due to daylight concept by considering different Zones in each floors of the building. Further, the EPBT has been determined as 49.25 years and 34.73 years for average 4 °C and 6 °C temperature difference between ambient and room, respectively. It has been found that when thermal heat gain increases in the building LCCE and EPF increase. Ó 2016 Faculty of Engineering, Alexandria University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
1. Introduction The energy is the integral part of the human life for almost all activities e.g. industrial, domestic, medical, transport. The world is facing a grim situation such as depletion of fossil fuel reserves, global warming and other environmental concerns, geopolitical and military conflicts and continuing fuel price rise if continuing the use of conventional energy sources [1–3]. Building of future has to take into account the tasks and the opportunities brought about by, environmental, societal and * Corresponding author. E-mail address: [email protected] (M. Sudan). Peer review under responsibility of Faculty of Engineering, Alexandria University.
technological changes [4]. Energy saving can be done not by bringing down the standard of living, but by utilizing more efficient technologies to produce the similar, or higher, levels of comfort and convenience, we have come to enjoy and appreciate [5]. Due to the environment and sustainable development issues, governments have increased their focus on energy saving technologies in the building and other sectors. For the commercial and residential building evaluation of energy efficiency is difficult to describe with precision as there is often a lot of vague information and various types of inaccurate assessment of data. The evaluation of energy saving in the building design selection has uncertainty and complexity. To select a suitable design, one needs to consider the use of function, technology, economics, and many other factors. The energy saving through the daylighting opening in the building
http://dx.doi.org/10.1016/j.aej.2016.08.014 1110-0168 Ó 2016 Faculty of Engineering, Alexandria University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article in press as: M. Sudan, G.N. Tiwari, Daylighting and energy performance of a building for composite climate: An experimental study, Alexandria Eng. J. (2016), http://dx.doi.org/10.1016/j.aej.2016.08.014
2
M. Sudan, G.N. Tiwari
Nomenclature Af CW Ein Esol Eaout Ig
floor area (m2) of the room clerestory window embodied energy (kW h) annual solar radiation (kW h/m2) total annual energy saving (kW h) global solar radiation (W/m2)
is not only easy for quantitative calculation of the indicators, but also for qualitative description [6,7]. The energy efficient building design selection at the present time depends on the selector’s awareness about energy crisis and experience. In buildings, lighting systems are responsible for consuming large amount of energy all around the world [8,9]. Nowadays significant energy can be saved by creating cost-effective efficiency developments in the buildings and their equipment – which will reduce any nation’s energy consumption and GHG emissions which lead to significant economic savings to consumers [4]. It is reported that in the commercial sector around 25% of the total electricity is consumed by lighting systems [10,11]. The range of energy consumption varies greatly from country to country and is not only due to design and climatic conditions, but also to cultural habits. In USA, the lighting enduse in commercial building is 39% [11]; in the China, 15% [8]; in the Netherlands, 55% [11]; and in India more than 20% [12]; and in the UK it ranges from 30% to 60% [13]. Bansal and Minke (1988) has concluded that conventional energy resources are being exhausted through its limited resource and uncontrolled harnessing. To meet the energy requirements the world heavily relies on fossil fuels [14]. Almost 80% of the global energy demand is met by fossil fuels such as oil, gas and coal [15]. Presently renewable energy and nuclear power are contributing 13.5% and 6.5%, respectively of the total energy needs in the world. The enormous amount of energy being consumed across the world has led to adverse effects on the ecosystem of the planet [16]. According to recent studies, natural light not only improves students test score but also provides better physical health. Human beings also prefer to work in daylighting. It is an important component of the passive building. The interior of the buildings can be illuminated in several ways such as window, light well, clerestory [17], the laser cut penal [18], light shelf, light pipes [19,20], anidolic light-duct [21]. The use of the all these daylighting systems can save the artificial lighting in the buildings. These provisions are equipped to maintain coincidence to human visual response, attractive indoor environment, and allow people to maintain visual contact with the outside world [22–28]. Daylighting concept in building is an effective option of saving fossil fuels which ultimately leads to saving substantial amount of money and reducing emission of greenhouse gases [17]. In the present study, the complete energy and economics analysis has been determined by considering both thermal and daylighting concepts for the whole building, which is divided into different Zones in each floors. This paper presents monthly daylight performance of the building based on hourly
EPBT EPF SBC TLB LCCE LW
energy payback time (years) energy production factor SODHA BERS COMPLEX lifetime of the building (years) life cycle conversion efficiency light well
measured illuminance data under clear sky conditions. The paper evaluates the lighting energy saving and CO2 mitigation of the building. Further, the three energy matrices namely life cycle conversion efficiency (LCCE), energy payback time (EPBT), and energy production factor (EPF) of the building have also been determined by considering energy saving due to both thermal heat gain and daylighting. The embodied energy of the whole material has been taken to determine the energy matrices of the building. 2. Background information The building featured is located at Varanasi, Uttar Pradesh, India (latitude 25.28°N, longitude 82.95°E and altitude 76.8 m). It is four-storey building. 2.1. Building geometry The building was designed with wall windows, clerestory windows and light well, with the provision of natural ventilation through environmental conservation measures and sufficient daylight. Fig. 1a shows the photograph of the building. The SODHA BERS COMPLEX (SBC) has been built on land area of 236.91 m2. The covered area of the each floor is 152.42 m2 of the SBC. Each floor of the building is divided into three Zones. The brief discussion of basement, ground floor, first and second floor has been given in coming sections. 2.1.1. Basement Fig. 1b shows the top view of the basement which is made by using earth shelter concept for cooling and daylighting. For evaluation of energy saving, it is divided into three Zones. The daylighting and natural ventilation is provided by clerestory window and rooftop window through light well (LW304) which is located on the top of east (Zone 3) and south (Zone 1) for the basement, respectively. In the Zone 2 of the basement there is no special provision to provide daylight; this Zone illuminates through clerestory window and rooftop window. It is commonly used for community services. 2.1.2. Ground floor Fig. 1c shows the top view of the ground floor plan. It has facility of two light well in addition to sufficient crossventilation from north to south direction due to unique naturally made wind channel from east being a dead end of the road to cool the rest of whole building. The Zones 1–3 of the ground floor illuminate through east wall opening, light
Please cite this article in press as: M. Sudan, G.N. Tiwari, Daylighting and energy performance of a building for composite climate: An experimental study, Alexandria Eng. J. (2016), http://dx.doi.org/10.1016/j.aej.2016.08.014
Daylighting and energy performance of a building for composite climate
Figure 1a
Figure 1b
3
View of SODHA BERS COMPLEX (SBC).
Isometric typical view of the basement.
well (LW304) and light well (LW305). Further, in order to provide more daylight in Zone 1 south wall has also been opened. It is used for religious functions. It has no partition wall due to nature of its application which provides natural passage for first and second floor ventilations.
furnished daylight in Zone 3 (kitchen, toilet, bathroom, rooms and corridor). The south wall in Zone 3 has minimum exposed area (daylight opening) in comparison with east and west wall which minimizes the role of heat fraction from exposed south interior wall. The percentage of embodied energy of the material used in SBC has been shown in Fig. 2.
2.1.3. First and second floor The layout planes of the first and second floors have been shown in Fig. 1d. The Zone 1 accommodates typical room, LW304, LW305, kitchen, conference and computer with open corridor for east and north side. The room is illuminating east or north window and clearstory window. Daylighting provided through the east window (or clearstory window) and west clearstory window, illuminates the conference room and computer room. The Zone 2 has been illuminated through light well (LW305). The light well (LW304) and south wall opening
3. Energy saving The energy saving potential from daylight has been determined by using the following equations. 3.1. Luminous flux The hourly luminous flux, /ðlumenÞ of the daylighting inside the room can be calculated [29,30] as follows:
Please cite this article in press as: M. Sudan, G.N. Tiwari, Daylighting and energy performance of a building for composite climate: An experimental study, Alexandria Eng. J. (2016), http://dx.doi.org/10.1016/j.aej.2016.08.014
4
M. Sudan, G.N. Tiwari
Figure 1c
Figure 1d
/ ¼ ðEia Af Þ
Isometric typical view of the ground floor plane.
Isomeric typical view of first and second floor.
ð1Þ
3.3. Daily artificial energy saving, E (kW h)
where Eia ðlxÞ is the hourly average daylight illuminance inside the working surface and Af (m2) is the horizontal working surface area.
The daily lighting energy saving potential, E (kW h) can be expressed [31,32] as
3.2. Lighting power, Pi (W)
E¼
N X Pi
ð3Þ
i¼1
The hourly lighting power, Pi (W) can be determined [31,32] as / Pi ¼ ð2Þ BF ee
where N (h/day) is sunshine hour for a typical day.
where ee (lm/W) is the luminous efficacy of the artificial light source and BF is the efficiency of ballast (or ballast factor).
The annual mitigation of CO2 can be determined by using the relation as follows [31,32]:
3.4. Mitigation of CO2
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Daylighting and energy performance of a building for composite climate Bricks/tiles
Reinforcement
Cement
Other
21%
Activities/process
4.2. Energy production factor (EPF) The overall performance of the building can be predicted with help of the energy production factor. The ratio of these two quantities is referred as the energy production factor (va ). It is based on the lifetime of the building and can be expressed as Eaout ð7Þ va ¼ TLB Ein
21%
18%
5
19%
where TLB is the lifetime of the building. 21%
Figure 2 SBC.
4.3. Life cycle conversion efficiency (LCCE)
Percentage embodied energy of the material used in
1 CO2 mitigation ¼ ðE TLB Ein Þ 1 La 1 0:98 kg 1 Ltd
/ðtÞ ¼
ð4Þ
3.5. Carbon credit earned The carbon credit earned from the mitigation of CO2 (in tons/ year) can be calculated as follows [31,32]: Carbon credit earned ¼ CO2 mitigation ðtonsÞ ð5Þ
4. Energy matrices The performance of the building is evaluated by using three fundamental energy matrices: namely the energy payback time (EPBT), energy production factor (EPF) and life cycle conversion efficiency (LCCE) [33,34]. 4.1. Energy payback time (EPBT) Energy payback time (EPBT) is the total time period required to recover the total energy consumed to prepare the materials (embodied energy) used for construction of the building. It is one of the main parameters for analysing the energy sustainability of the building which can be expressed as EPBT ¼
embodied energy ðEin Þ Years annual energy saving ðEaout Þ
ðEaout TLB Þ Ein ðEsol TLB Þ
ð8Þ
where Esol is the annual solar radiation.
where EðkW h=yearÞ is an annual lighting energy saving by daylighting, La ð%Þ is the loss due to poor electrical lighting and Ltd ð%Þ is transmission and distribution loss. TLB ðyearÞ is lifetime of the building, Ein is the embodied energy of materials used in the building.
12ð€=ton of CO2 Þ
It is the net energy productivity with respect to the solar input exposed different faces over the lifetime of the building and can be expressed as
ð6Þ
where Ein ðkW hÞ is the embodied energy of the total materials used in the building and Eaout ðkW hÞ is the annual energy saving by the daylighting and thermal heat gain.
5. Methodology The data of solar radiation, outside and inside illuminance have been taken at SBC, Varanasi, India, in the duration of January-December 2014. The following methodology has been adopted to calculate energy saving and energy matrices of the building. Step 1: The hourly experimental observation has been taken at working surface in the SODHA BERS COMPLEX (SBC), Varanasi, India. Step 2: The hourly luminous flux, /ðlumenÞ on the working surface inside the building was calculated using Eq. (1). The value of horizontal working surface area (Af) is given in Figs. 1b–1d. Step 3: The hourly lighting power, Pi (W) and daily energy saving potential, E (kW h) were determined by using Eqs. (2) and (3), respectively. The value of ee ðlm=WÞ and BF is taken 70 lm/W and 0.90 respectively. Step 4: Daily energy saving potential has been determined by summing the hourly energy saving. Step 5: Monthly energy saving has been calculated by summing daily energy saving for each month. Step 6: The energy saving in each month is summed to get annual energy saving potential by the daylight. Step 7: The mitigation of CO2 and carbon credit earn has been determined by using Eqs. (4) and (5), respectively. The value of the loss due to poor electrical lighting, La ð%Þ and the transmission and distribution loss, Ltd ð%Þ has been taken is 20% and 40%, respectively. Step 8: The embodied energy (Table 1) of used materials in building and annual thermal heat gain (Table 2) has been taken [34]. Step 9: Total energy saving has been determined by summing the energy saving by the daylight and thermal heat gain. Step 10: The analysis of three fundamental matrices namely, The energy payback time (EPBT), energy production factor (EPF) and life cycle conversion efficiency
Please cite this article in press as: M. Sudan, G.N. Tiwari, Daylighting and energy performance of a building for composite climate: An experimental study, Alexandria Eng. J. (2016), http://dx.doi.org/10.1016/j.aej.2016.08.014
6
M. Sudan, G.N. Tiwari Breakup of embodied energy of materials used in SODHA BERS COMPLEX (SBC) [32,34].
Table 1 Serial
Material/name of work
Total embodied energy (kW h)
1 Cement 186770.83 2 Bricks/tiles 234677.08 3 Stone ballast 14919.67 4 Sand 12171.08 5 Lime/Pop/Putty 3268.33 6 Reinforcement 221977.67 7 Aluminium 1463.89 8 Glass 5200.00 9 Plywood 45625.00 10 Wood 19361.11 Total embodied energy 1120753.83 kW h
Table 2
Serial
Material/name of work
Total embodied energy (kW h)
11 12 13 14 15 16 17 18 19 20
PVC/plastic Paint (oil bound) Paint (water bound) Marvel/Makrana stone Ceramic tiles/sanitary ware Iron Copper Brass Activities/process Transportation
3593.33 3966.67 16562.50 291.67 24761.11 30958.33 2100.00 1833.33 241017.78 50234.44
Total annual energy saving by thermal heat gain and daylighting in SBC [34].
Total embodied energy (kW h)
Average temperature difference (DT) between room air and ambient air temperature (°C)
Total annual thermal heat gain for complete building (kW h)
Annual Energy by daylighting for complete building (kW h)
The total annual energy saving for SBC (Eaout) (kW h)
1120753.83
4 6
19079.28 28592.64
3675.61 3675.61
22754.89 32268.25
Annual solar radiation incident (KW h/m2)
Area (m2)
Horizontal East South West North Total
750 428 465 435 405 2463
152.42 327.60 126.72 329.40 80.40 1016.54
Total annual solar energy (Esol) 114315.00 140212.80 58924.80 143289.00 32562.00 2503738.02
Solar radiation
illuminance
90000
800
80000
700
70000
600
60000
500
50000
400
40000
300
30000
200
20000
100
10000
0
Illuminance (Lux)
Exposer part of the Building
900
Solar radiation (W/m2)
Table 3 Calculation for annual solar radiation incident different exposes of the building.
0 8.00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18.00
Time (h)
(LCCE) has been computed using Eqs. (6)–(8), respectively. The value of the annual solar radiation (Esol ) has been given in Table 3.
Figure 3 Hourly variation of solar radiation and outside illuminance for Varanasi climate conditions in the month of May.
6. Results and discussion The illuminance level of daylighting was measured at daytime when all the lights were off and occupants do our commercial activity in the building. The illuminance levels along the corridor, rooms, T1, T2, B1, B2, were measured for each Zone. The illuminance was measured at one hour intervals, weekly, from 8 am to 6 pm between January and December 2014. Fig. 3 shows the variation of solar radiation and outside illuminance corresponding to the clear sky conditions at the horizontal surface in the month of May 2014. Fig. 4 shows the hourly variation of illuminance level in the basement for Zone 1–3. It displays the respective hourly averages illuminance beings to increases in the early in the morning, reaches maximum value at around noon and gradually decreases towards the evening for Zones 1 and 2. The key reason behind this, the Zones 1 and 2 illuminate through light well and south daylight
Illuminance (Lux)
450
Zone1
Zone2
Zone3
400 350 300 250 200 150 100 50 0 8.00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18.00
Time (h)
Figure 4 Hourly variation of inside illuminance in the basement in the month of May.
opening. In Zone 3 daylight enters through the east opening due to this illuminance decreases from morning to evening. The minimum illuminance was 30 lux in Zone 2 at 6 pm while
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Daylighting and energy performance of a building for composite climate
700
7
Kitchen
T1
T2
B1
B2
Open
Zone2
zone3
Illuminance (Lux)
600 500 400 300 200 100 0 8.00
9:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18.00
Time (h)
Hourly variation of inside illuminance for ground floor in the month of May.
Figure 5
450
Kitchen
T1
T2
B1
B2
Open
400
Illuminance (Lux)
350 300 250 200 150 100 50 0
8.00
Figure 6a
9:00
10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18.00 Time (h)
Hourly variation of inside illuminance in the Zone 1 (first and second floor).
1600
R301
R302
R304
R305
LW305
Corridor
Illuminance (Lux)
1400 1200 1000 800 600 400 200 0 8.00
9:00
10:00
11 :00
12 :00
13:00
14:00
15 :00
16:00
17:00
18.00
Time (h)
Figure 6b
Hourly variation of inside illuminance in Zone 2 (first and second floor).
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8
M. Sudan, G.N. Tiwari R304
1600
R307
R308
Illuminance (Lux)
1400 1200 1000 800 600 400 200 0 8.00
9:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18.00
Time (h)
Figure 6c
Hourly variation of inside illuminance Zone 3 (First and second floor).
the maximum was 400 lux in Zone 3 at 8 am. Fig. 5 represents the variation of illuminance level inside the Zones 1–3 for ground floor. The ground floor follows same trend of variation illuminance as the basement is maximum in Zone 3 and minimum was Zone 2. The range of illuminance has been found in kitchen as, T1–2 or B1–2 as 30–80 lux in Zone 1. The illuminance level in Zones 2 and 3 is varies in the range of 40–112 and 80–650 lux, respectively that is the sufficient, and no need artificial light in the daytime. Figs. 6a–6c, display
Zone1
Zone2
the distribution of the illuminance level in first or second floor for Zones 1–3. It is clear from Fig. 6a; illuminance level inside the kitchen (first or second floor) is approximately 3–4 times higher than the ground floor kitchen. The main reason behind this result is of daylighting opening and the distance of the working surface from the daylight source. The illuminance level maximum has been found 1500 for LW305 at 12 pm in Zone 2 and minimum was 35 lux for R301 at 6 pm in Zone 2. It is clear from Figs. 6a–6c; maximum illuminance has been
Zone1
Zone3
Energy Saving (kWh)
Energy Saving (kWh)
60 50 40 30 20 10
Jan
0 Jan
Feb Mar Apr May Jun
Jul
Aug Sep
Zone2
Zone3
100 90 80 70 60 50 40 30 20 10 0 Feb Mar Apr May Jun
Jul
Aug Sep Oct Nov Dec
Months
Oct Nov Dec
Months
Figure 7a basement.
Monthly energy saving of the different Zones for
Zone1
Zone2
Figure 7c Monthly energy saving in each Zone for first and second floor.
900
Zone3
Basement
Ground Floor
First Floor
Second Floor
800
Energy Saving (kWh)
Energy Saving (kWh)
60 50 40 30 20 10
700 600 500 400 300 200 100
0 Jan
Feb Mar Apr May Jun
Jul
Aug Sep
Oct Nov Dec
0
Zone1
Zone2
Zone3
Months
Figure 7b
Monthly energy saving in each Zone for ground floor.
Figure 8 the SBC.
Annual energy saving potential for different floors of
Please cite this article in press as: M. Sudan, G.N. Tiwari, Daylighting and energy performance of a building for composite climate: An experimental study, Alexandria Eng. J. (2016), http://dx.doi.org/10.1016/j.aej.2016.08.014
Daylighting and energy performance of a building for composite climate Table 4
9
Net CO2 mitigation and carbon credit earned for the different lifetimes of the buildings.
Average temperature difference (DT) (°C)
For L = 100 Year Net CO2 mitigation (Tons)
Carbon credit earned (US$)
Net CO2 mitigation (Tons)
Carbon credit earned (US$)
Net CO2 mitigation (Tons)
Carbon credit earned (US$)
4 6
2355.66 4296.39
28267.92 51556.68
6997.66 10879.11
83971.92 130549.32
11639.65 1761.83
139675.8 21141.96
Table 5
For L = 200 Year
For L = 300 Year
The energy payback time of SODHA BERS CONPLEX (SBC).
Average temperature difference (DT) between room air and ambient air temperature (°C)
The total annual energy saving for SBC (Eaout) (kW h)
The energy payback time (Years)
4 6
22754.89 32268.25
49.25 34.73
Table 6
Calculation for Energy Production Factor (EPF) for different lifetimes of SBC.
Average temperature difference (DT) between room air and ambient air temperature (°C)
The total annual energy saving for SBC (Eaout) (kW h)
EPF for L = 100 Years
EPF for L = 200 Years
EPF for L = 300 Years
4 6
22754.89 32268.25
2.03 2.08
4.06 5.75
6.09 8.64
Table 7
Life Cycle Conversion Efficiency (LCCE) for different lifetimes of SBC.
Temperature difference (DT) between room air and ambient air temperature (°C)
Total annual average energy saving for SBC (Eaout) (kW h)
LCCE for L = 100 Years
LCCE for L = 200 Years
LCCE for L = 300 Years
4 6
22754.89 32268.25
0.0046 0.0048
0.0068 0.0106
0.0076 0.0113
received in Zone 3 and minimum in Zone 2 for all floors. In Zone 2 of the first or second floor, LW305 provides the illuminance inside the room and corridor. In the daytime, no required artificial light excludes R301. In the building maximum illuminance received in Zone 3 for first or second floor and minimum was in the Zone 2 for basement. Figs. 7a–7c represent the monthly variation of energy saving of the Basement, ground, first and second floor (Zone 1–3). Zone 3 scored greater energy saving than Zones 1 and 2 of all floors. It is clear from these figures the monthly energy saving in Zone 1–3 for each floor increases from January to May and decreases from July to December. The key reason behind this Jun to August increased frequency of rain in comparison with April to May. Fig. 8 represents the total annual energy saving by the daylighting for each Zone for each floor of the building. The annual energy saving potential in the basement, ground, first and second floor was estimated as 452.17, 815.70, 1411.11 and 1411.11 kW h, respectively for the clear sky conditions. However, for the full cloudy day daylight does not perform better as compared to clear or partially cloudy days in Varanasi, India. The total energy saving has been calculated as 3675.61 kW h per year by using the daylighting concept. The annual energy saving by the thermal heat gain and daylighting for 4 °C and 6 °C is tabulated in Table 2 [34]. Table 4
displays the net CO2 mitigation and corresponding carbon credit earned over the different life spans of building (100 years, 200 years, and 300 years). This shows the net CO2 mitigation and carbon credit earned, both are maximum for 300 years. The energy payback time (EPT) is given in Table 5. This indicates that the total energy saving (thermal heat gain and daylight) increases reducing the EPT of the building. Similarly, trend flow energy production factor (EPF) is tabulated in Table 6. Table 7 lists estimation for life cycle conversion efficiency (LCCE) for different life spans (L = 100, 200, 300 years). It shows that life cycle conversion efficiency (LCCE) higher for 6 °C and lower for 4 °C. The reason behind that is higher the temperature difference temperature difference (DT) between room air and ambient air temperature higher the heat gain. 7. Conclusions The daylight systems were made in the building which provides sufficient daylight in the whole building, and there was no need of artificial light in the day time, except R301 and basement. Annual energy saving has been found 3675.61 kW h by using the daylighting concept in the building.
Please cite this article in press as: M. Sudan, G.N. Tiwari, Daylighting and energy performance of a building for composite climate: An experimental study, Alexandria Eng. J. (2016), http://dx.doi.org/10.1016/j.aej.2016.08.014
10 The energy payback time (EPBT) for 4 °C and 6 °C has been found to be 49.25 years and 34.73 years, respectively. Thermal heat gain increases inside the building life cycle conversion efficiency (LCCE) increases.
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Please cite this article in press as: M. Sudan, G.N. Tiwari, Daylighting and energy performance of a building for composite climate: An experimental study, Alexandria Eng. J. (2016), http://dx.doi.org/10.1016/j.aej.2016.08.014