Assessment of Building Integrated Photovoltaic Panels on Facades of

Commercial Buildings with Respect to Energy

Conservation Building Code

Achinta N Shetty

, Pradeep G. Kini

2,*

, Pranav Kishore

and Vipin

Tandon

Manipal School of Architecture & Planning, Manipal Academy of Higher Education, Manipal, India

Center of Sustainable Built Environment, Manipal School of Architecture and Planning,

Manipal Academy of Higher Education, Manipal, India

Keywords: BIPV Panels, Performance Analysis, Energy Production, Optimal Tilt Angle, Design Builder, Payback

Period, BIPV Integration Style.

Abstract: The formulation of the paper considered the need for adapting to renewable resources in fast-growing world.

The integration of Building Integrated Photovoltaic (BIPV) panels will minimize the environment damage,

climate change, and resource shortages. The BIPV system implemented on the facade is one of the suitable

solutions to increase the building performance using the on-site renewable resource with a reduced impact on

the surroundings. The methodology introduced in this paper is carried out by using Design Builder software

initially, which provides an understanding of the PV energy produced to achieve 3% renewable energy in a

modelled commercial building of 20,000 m

according to the Energy Conservation Building Code (ECBC)

while placed in a moderate climatic zone. This paper aims at studying various approaches to further enhance

the energy production of the modelled building after attaining the ECBC minimum requirement. PVGIS

system is used to assess parameters such as PV technology used, integration of the panels, system loss, year

to year variability, tilt angles of the panels. Further, shadow analysis of the optimal angle to maximize energy

production is analysed. A comparative study between the modelled building and the PVGIS system on the

panel cost and payback period is conducted. Based on the optimum tilt and azimuth angles, shadow analysis

and daylighting analysis is carried out. The paper provides an understanding of the optimal integration style

of the BIPV panels on the building facade.

1 INTRODUCTION

The escalating growth of the world and energy use

has raised concerns globally on the prolonged

exhaustion of energy resources and their destructive

environmental impacts. Commercial, residential, and

public buildings are presently contributing to 31% of

the world’s energy demand. Alternatively, fossil fuels

are presently in use as the world’s most primary

energy source. However, the use of fossil fuels has its

own disadvantages, such as, environmental

destruction, lack of energy, and change in the climate.

Hence, the use of alternative energy resources which

non-polluting and renewable, is the need of the hour.

(lHassanGholami, 2019)

Pradeep.kini@manipal.edu

Figure 1: Sector-wise energy consumption (Energy

Statistics).

Fig.1. represents the total energy consumption in

India in 2015, i.e., 948,328 GWh, in which the highest

energy-consuming sector is the industries followed

by domestic power consumption. India’s combined

key energy demand is expected to grow by 2.3 times

in the following two decades due to continued

economic progress in the building, industrial sectors,

and transportation (Joshi, 2018).

44%

18%

23%

2% 5%

Industry

Agriculture

Domestic

Commercial

148

Shetty, A., Kini, P., Kishore, P. and Tandon, V.

Assessment of Building Integrated Photovoltaic Panels on Facades of Commercial Buildings with Respect to Energy Conservation Building Code.

DOI: 10.5220/0010438501480155

In Proceedings of the 10th International Conference on Smart Cities and Green ICT Systems (SMARTGREENS 2021), pages 148-155

ISBN: 978-989-758-512-8

A building to become a zero energy or zero-

emission building, the use of non-renewable energy,

i.e., solar energy plays a very important role. In this

regard, the use of building-integrated photovoltaics

(BIPV) can play an important part towards the zero

energy or zero-emission building. The BIPV is

photovoltaic cells which can be used in building

envelopes such as facade or roof. The lifetime of the

BIPV system is expected to be 30 years

(B.Winnettabc, 2012), however, additional studies

indicate the lifetime to be around 50 years. The BIPV

system capacity can differ from a limited

kilowatt(kW) for a residential building to several

megawatts (MW) for a commercial purpose.

The present study focusses on the use and

implementation of the BIPV system on improving

energy efficiency and consequently enhance the

overall building performance according to ECBC

(ENERGY CONSERVATION BUILDING CODE,

2017).

1.1 Background and Literature Review

The BIPV products were found in 1990; initially, the

rooftop mounted PV panel was installed on metal

frames. In the later period, technological

developments led to the creation of easier

architectural designs that carefully integrates the

collection of solar energy into its building design

(Hall, 2014).

The BIPV panels are suitable for significant

buildings and cities. However, it is quite expensive as

compared to the conventional solar system. Yet, the

researchers consider the supplementary costs reduced

significantly if a revamp or new building envelope is

needed anyway. The clients can be benefitted of

around ten years of payback time for these additional

costs incurred (Bhambhani, 2019).

The vertical integration provides a chance to

substitute with solar panels, resulting in reduced

energy footprint and delivering a positive ROI (return

on investment) on the supplementary investment.

The factors affecting the function of the panel

(MarcoCasini, 2016) are:

(i) Shape and size of the glazing factor

(iii) the distance amongst the PV cells (gradation

of transparency)

(ii) technology (monocrystalline and

polycrystalline silicon)

Various studies were conducted considering several

parameters such as the energy generation, types of

material, tilt angles, etc. Biyik et al. (BaverAtlıf,

2017) aimed at increasing the system efficiency

considering various factors affecting the BIPV panels

such as ambient temperature, the direction of the

building and the slope of the PV to get higher power

output using simulation tools Energy plus and

TRNSYS. YilinLi et al. (Yilin Li a Zhi, 2017)

examined the influence of the PV facade's on

different tilt angles (30, 45, and 60°) on the surface

temperature and PV cell efficiency of the naturally

ventilated PV façade. The optimum tilt angle of 30

degrees has the lowest mean surface temp, which

provides the optimal performance of elimination of

heat from the PV panel. Daniel Tudor Cotfas at el.

(Daniel Tudor Cotfas, 2014) provides simple

methods to enhance the amount of the electrical

energy delivered by the PV panels. Photovoltaic

Geographical Information System was used to get

calculations based on various materials and angles.

The results showed an increase in energy produced

without additional costs and materials. AliceBellazzi

at el. (Alice Bellazzi, 2018) investigates the energy

and thermal performance of a BIPV integrated façade

based on different configurations, the global

efficiency and the electric production were assessed

through a supervising operation of the environmental

and energy variables in physical working

environments and a mathematical model designed to

compare the performance of the system. It was found

out that all the parameters were interdependent and

depended mainly on climatic variations. A. K.

Sharma at el. (Sharma, 2017) provided an

understanding of design tool for BIPV systems

considering factors such as orientation, location, and

panel efficiency and reported that the facade's

orientation and the building's location which provided

an ideal solution. Grasshopper, Ladybug, and

Honeybee are all Rhinoceros 3d plug-ins, were all

used to interface Energy Plus and Radiance for the

illuminance and calculation for the annual energy

computations.

2 DESCRIPTION OF THE

METHODS

The fig.2 shows the flow chart of methods followed

to assess the BIPV panels-

- The design-builder is initially used to identify the

PV energy production (according to ECBC) and the

modelled building's active façade area placed in

Bangalore (temperate zone-ECBC).

- PVGIS system is used to assess the PV

technologies based on the energy production and

active area resulted in the Design-Builder (optimum

angle, orientation, PV technology, and the cost is

identified).

Assessment of Building Integrated Photovoltaic Panels on Facades of Commercial Buildings with Respect to Energy Conservation Building

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149

- A comparative study between the Design-Builder

and PVGIS system is carried out based on the energy

production and payback period.

- Based on the PVGIS result (optimum

combination), Google sketch-up is used to illustrate

the panels' integration styles on the facade, and

shadow analysis is conducted (Location-Bangalore).

Figure 2: Outline of the methods followed.

2.1 Design Builder

To understand the minimum PV energy produced by

a commercial building (according to ECBC) out of

the total energy consumption and to identify the

active area on the façade.

The design-builder is used to provide minimum

PV energy production to reach the ECBC requirement

for a 20,000m

commercial building considering

parameters such as the U value of different elements,

WWR ratio, climatic condition, etc. to calculate the

EPI of the building.

A commercial building of 20,000 m

should have

a minimum of 3% of the total power consumption that

should be generated using Renewable Energy

Generating Zone (REGZ) as per the ECBC. A 10-

story building was modelled on Design Builder with

a total area of the building to be 20,000 m

. PV cells

were integrated into the south façade of the building.

The location of the building was Bangalore (26℃

annual temperature temperate zone). The building

was modelled, according to (Mayank Bhatnagar,

2019). Parameters considered are shown in table 1

(ECBC 2017).

Table 1: Parameters followed in the modelled building

according to ECBC.

U value of wall 0.4 W/m2K

U value of roof 0.33 W/ m2K

U value of glass 3 W/m2K

WWR ratio 40%

2.2 Using PVGIS System

PVGIS helps to assess the PV capacity for various

patterns and technologies of grid-connected and

stand-alone systems. PVGIS system is used to assess

Slope angle [°], Yearly PV energy production [kWh],

Azimuth angle [°], Yearly in-plane irradiation

[kWh/m2], Year-to-year variability [kWh] in

Bangalore, which design builder does not provide.

Hence after reaching the minimum requirement

according to ECBC using design builder and

identifying the active area on the façade and PV

energy production, further enhancement is carried out

by assessing the PV technology.

The assessment is conducted based on three

different PV technologies: Crystalline (C-Si),

Cadmium Telluride (CdTe) and Copper Indium

Gallium Selenide(CIS). The efficiency and price per

kWh are considered as follows: C-Si: 12-15%, 36.01

INR, CdTe: 6-9% ,22.78 INR and CIS: 7.5-9.5%,

26.46 INR. The lifetime of the BIPV system is

expected to be 25 years.

Alternate 1 -The slope angles, i.e., 30°,45°,60°,

and 90°, is tested with different azimuth angles (for

other PV technology) to understand the optimal

orientation and tilt angle for the panel integration.

Alternate 2- The most efficient PV technology (C-

Si, CdTe, CIS) is also identified by comparing yearly

PV energy production [kWh], Yearly in-plane

irradiation [kWh/m2], Year-to-year variability

[kWh], and the total loss (%).

Alternate 3 - The PV cost (INR) is calculated for

various PV technology.

2.3 Using Google Sketchup

Google SketchUp is a freeware 3D modelling

software, used to illustrate various integration of

Figure 3: Illustration showing various tilt angles on building

façade.

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150

panels on the façade. The same building was used as

designed in the design-builder for further assessment.

Alternate 1 – Fig. 3 shows an illustration for the tilt

angles integrated on the building facades used in the

PVGIS system.

Alternate 2 – Assessing the optimal orientation, tilt

angle and yearly PV energy production.

Figure 4: Various integration styles on the building façade

with sections.

Further enhancement of the suitable combination is

carried out by integrating various design strategies on

the façade (fig. 4), conducting shadow analysis by

modelling a similar building modelled in Design

builder (3.1.). The shadow analysis is carried

throughout the day when the sky is clear. The shadow

cast is measured (%), and an optimal design strategy

is identified.

2.4 Using VELUX (Badri Mohapatra,

2018)

VELUX Daylight Visualizer is a specialized lighting

simulation tool for the assessment of daylight

requirements in buildings. It is intended to boost the

use of daylight and help professionals by assuming

and documenting daylight factor and the appearance

of an area before reaching the building design. The

daylighting analysis is conducted on a building with

40% WWR according to ECBC 2017.

Alternate 1 - The design integration styles (fig. 4)

modelled in Google SketchUp for the optimal

combination identified using PVGIS are further

assessed for daylighting (after results achieved from

2.2.).

The building modelled in Google Sketchup is

simulated in VELUX, in Bangalore

(12.9716°N,77.5946°E) at 15:00 IST with the

integrated design style on the southern side.

3 RESULTS & ANALYSIS

3.1 Using Design Builder to Achieve

ECBC Minimum Requirements:

(2.1)

The amount of energy consumption in the modelled

building of 20,000 sq.m. resulted in 46,80,000 kWh

in the commercial building. Hence the EPI was

calculated to be:

EPI= Annual energy consumption in kWh

Total built-up area

= 46,80,000 = 234 kWh/m

-yr

20,000

The above calculated EPI index produced is for a 24h

operating commercial building modelled in a

temperate zone.

The photovoltaic power generated is 89,076.537

kWh, with a power conversion loss of 4,453.83 kWh

providing efficiency of renewable energy efficiency

of 4.27 %. To achieve 3% renewable energy of the

Assessment of Building Integrated Photovoltaic Panels on Facades of Commercial Buildings with Respect to Energy Conservation Building

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total power consumption of the building (ECBC), a

comparative calculation is carried out based on the

modelled building; 59,453.91 kWh (59.45MW/h) of

photovoltaic power is generated (includes power

conversion loss). The active photovoltaic area

calculated is 450 m

on the southern façade.

3.2 Using PVGIS System (2.2)

Table 2 was formulated based on the outputs

produced by the PVGIS system. Each slope angle is

tested with different azimuth angles to identify the

optimal orientation for the panel integration. The

assessment also finds out the optimal tilt angle of the

panel when integrated in Bangalore. The most

efficient PV technology is further identified by

comparing yearly PV energy production(kWh),

Yearly PV energy production [kWh], Yearly in-plane

irradiation [kWh/m2], Year-to-year variability

[kWh], and the total loss (%).

Table 2. shows the data collected for PV

technologies- C-Si, CdTe, CIS. Each technology is

assessed based on each tilt angle (30°,45°,60°, and

90°); each tilt angle is placed in different azimuth

angles (N/180°, NW/135°, NE/-135°, W/90°, SE/-

45°, S/0°, SW/45°, E/-90°) for the various PV

technology.

Table 2: Comparison of PV technologies based on energy

production, system loss, electricity cost, variability.

Analysis: PV technology- Crystalline Silicon

produces maximum yearly PV energy production

while compared to CdTe and CIS.

Orientation- The South and South-East provide

maximum yearly PV energy production (kWh) due to

high yearly in-plane irradiation (kWh/m

) and low

system loss (%).

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Optimal angle-The optimal angle is identified to

be 30 degrees with the highest annual PV energy

production (kWh).

Cost- The crystalline technology is the costliest

while compared to the CdTe and CIS technology but

has higher PV energy production and reduced system

loss.

- Summary of the above tabulated form (table 2)

is shown in fig. 5 and 6

Figure 5: Graph showing a comparison between PV

technology, yearly energy production (kWh) and the PV tilt

angle.

The crystalline silicon PV technology has the highest

yearly PV energy production with an optimum tilt

angle of 30° followed by 45°,60° and 90°. The second

highest PV energy is produced by the CdTe

technology with an optimum angle of 30° and CIS has

the least energy production comparatively (fig.5).

Figure 6: Graph showing a comparison between PV

technology, price in INR and the PV tilt angle.

The crystalline silicon PV technology is the costliest

technology i.e. 34.74 INR/kWh, followed by CdTe -

22.12 INR/kWh and CIS-27.12 INR/kWh while

integrated at an optimum angle of 30° (fig.6).

3.3 Comparing Modelled Building in

Design Builder with PVGIS System

The modelled building (Design builder) 's total

energy production is 46,80,000 kWh, integrated on

the southern façade. A comparison between the

modelled building and the results achieved in the

PVGIS system is carried out to provide an

understanding with respect to the PV technology,

yearly PV energy production, and the cost incurred.

The comparison is carried on based on the most

suitable factors identified in Table 2, i.e., optimal tilt

angle 30 degrees is considered, and a comparison is

conducted for all the PV technologies (C-Si, CdTe &

CIS) based on the energy production, cost, etc.

The direct solar heat gain is noted to be five hours

per day i.e., 13:00 -18:00 IST, i.e., 5h x 365 =

1825h/year. The PV energy produced is 59,453.9

kWh/year by the modelled building; 38.8 kWp is

produced in Bangalore when installed on the

Southern side.

kWp x PV energy production = total energy

generated by the system,

Using the above formula, yearly PV energy

production is calculated considering the PV energy

production for C-Si:1542.83 kWh, CdTe:1532.82

kWh & CIS:1451.76kWh and the peak performance

to be 38.8kWp.

Table 3: Yearly PV energy production and panel cost.

technolo

Yearly PV energy

production (kWh)

Panel cost (INR)

C-Si 59,861.80 20,79,598.93

CdTe 59,473.41 13,15,551.83

CIS 56,328.28 15,27,622.95

Table 3-Considering the PV price based on the PV

technology (fig.6) i.e. C-Si -34.74 INR/kWh, Cdte-

22.12 INR/kWh and CIS-27.12 INR/kWh while

integrated at an optimum angle of 30°,the panel cost

is calculated for the yearly PV energy production

(kWh).

3.3.1 Payback Period

The amount of energy consumption resulted in

46,80,000 kWh in the commercial building with

59,453.9 kWh of PV energy produced yearly (3.1).

Considering C- Si PV technology from table 3 yearly

PV energy production results in 59,861.80 kWh with

BIPV panel cost of 20,79,598.93 INR (table 3). The

lifetime of the system is expected to be 25 years

according to the PVGIS tool. The cost per kWh

electricity in India is 5.43 INR (Jaganmohan, 2020),

1542

1439,09

1260,46

796,16

1532

1424,54

1235,78

760,26

1451,76

1346,72

1169,05

733,62

0 500 1000 1500 2000

30°

45°

60°

90°

SlopeanglevsPVenergyproduction

CIS Cdte C‐Si

34,74

37,24

42,52

74,81

22,12

23,8

27,44

49,54

27,12

29,24

33,71

59,42

0 20406080

30°

45°

60°

90°

PVpriceinrupees/kWh

SlopeanglevsPVcost

CIS Cdte C‐Si

Slopeangle(°)

Assessment of Building Integrated Photovoltaic Panels on Facades of Commercial Buildings with Respect to Energy Conservation Building

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for 59,861.80 kWh of PV energy produced would

result in savings equivalent to 3,25,049.57 INR

annually. Hence the payback period for the PV panel

cost is 6.4 years, the system is expected to function

with profit for the remaining 18.6 years (The system

losses projected consists of all the losses in the system

due to which the power distributed to the electricity

grid could be lesser than the power generated by the

PV modules. There are numerous reasons for this

loss, as the loss in the cables, dirt (snow at times) on

the modules, power inverters, etc. Over the years the

modules tend to lose their power over time, so the

average yearly output over the system's lifetime will

be a few percent lesser than the output in the initial

years which has been considered 14% in table 2).

Similarly, the payback period for the CdTe

technology with 59,473.41 kWh PV energy and panel

cost 13,15,551.83 INR, the electricity cost per annum

is equivalent to 3,22,940.61 INR yearly the payback

period will be 4.1 years and CIS technology with

56,328.28 kWh PV energy and panel cost

15,27,622.95, the electricity cost per annum is

equivalent to 1,94,332.56 INR yearly the payback

period will be 7.9 years.

3.4 Design Consideration for

Maximum Energy Production

using Google Sketchup(2.3)

The design considerations are analyzed based on the

optimum angle, i.e., 30 degrees installed on the

southern façade (table 2). Various integration styles

on the façade are carried on. A shadow analysis is

carried out for panels integrated on the S façade in

Bangalore using Google Sketchup.

Shadow analysis: It is observed that the integrated

panels receive direct solar heat gain from 13:00 to

18:00 IST. Partial shadow is casted from 13:00 -14:30

IST (14:30 – 18:00 IST no shadow is observed).

Assuming that the shadow casted is solely by the

overlying panels (integration style).

Table 4: Shadow overcast on various integration style.

Integration

style

Overcast at

13:00 (in %)

Overcast at

14:00 (in%)

1 0.67 0.24

2 0.59 0.23

3 0.56 0.21

4 0.34 0.00

Figure 7: Illustration showing various styles 30-degree PV

panels can be integrated on the façade.

The table 4 shows the percentage of shadow casted on

the panels based on the integration style. Design

alternate 4 is identified to be the most suitable

integration style with minimal shadow casted i.e.,

0.34% which will lead to increased energy production

due to increased direct solar heat gain. Followed by

design alternate 3 design alternate 2 and design

alternate 1.

3.5 Daylight Simulation using VELUX

(2.4)

The daylight simulation carried out for the design

integration style modelled in Google Sketchup.

The Daylighting Factor (DF) is the ratio of the

light level inside the structure to the light level outside

the structure. It is defined as: DF = (Ei/Eo) x 100%.

The designate alternate 1,2,3 and 4 have

1%,0.79%,0.76% and 1.35% daylighting factor

ranging from 2.62-3.00.The daylighting factor

ranging from 2.62-3.00 design alternate four is

identified to be the most efficient, followed by design

alternate 1, design alternate two, and design alternate

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3. The daylighting factor assessment is restricted to

the region with BIPV panels.

Figure 8: Daylighting analysis conducted on various design

integration styles.

4 CONCLUSIONS

This study examined the ways to improve PV energy

production when integrated on a building façade. It

identifies the optimal combinations to be integrated

on the building façade to rigorously increase the PV

energy production. The analysis of adopting BIPV

panels in projects based on the optimal tilt angle,

orientation, payback period, integration style, etc.

The study conducted could be helpful to the

practitioners in the industry to understand the

working and advantages of the system and ways to

integrate the panels to generate maximum energy

production in Bangalore. A similar methodology can

be followed to study the performance of BIPV panels

in various parts of the world. The optimal PV

technology identified in this study is crystalline

silicon with annual energy production of 59,861.80

kWh in a 20,000 sq.m. commercial building,

integrated at an optimal angle of 30 degrees on the

southern façade for maximum solar heat gain and has

a payback period of 6.4 years. Further analysis can be

done in various places by following similar

methodology to enhance energy production using

BIPV panels installed on the façade and the large

spectrum of PV technology can be assessed by

conducting on-site or

laboratory experiments, since

using software tools have limited access to assess

various PV technology.

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Assessment of Building Integrated Photovoltaic Panels on Facades of Commercial Buildings with Respect to Energy Conservation Building

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