The effect of CIS BIPV as a shading device on building life cycle energy performance

Figures & data

Figure 1. The flow diagram of the study.

Table 1. The building scenarios.

	Reference building and Building with ∼100% WWR
İstanbul and Antalya	Neutral position (building without BIPV) Position with a shading device (building with only a shading device applied) Position with BIPV (BIPV applied to build)

Table 2. The studies on the accuracy of the PV software used.

Accuracy	Location	Measurement period	PV type	References
Energy-average annual error 3.84% (min 3.77%, max 3.91%).	Spain	3 years	Monocrystalline, Polycrystalline	Nicolás-Martín, Eleftheriadis, and Santos-Martín (2020)
The average deviation was maintained at 1.6%. Deviation from the simulation between 5.0% −0.6% for 6 months.	Sri Lanka	6 months	Unmentioned	Viduruwan and Induranga (2021)
−0.95% deviation (Energy generated in a year) 12-month average deviation is 0.5% (Monthly average energy production)	Palencia, Spain	2008 to 2020	Model FOTONA 180D	González-Peña et al. (2021)
The average difference is at 1%	Switzerland	2002 until 2014	Mono-crystalline	Wittmer, Mermoud, and Schott (2015)
The accuracy is 1.2%.	Switzerland	6 years	CIS module (Shell ST40)	Mermoud and Lejeune (2010)
Differ 9%	Southern Brazil	August 27 and October 31, 2020	Multi-crystalline silicon	Chepp, Gasparin, and Krenzinger (2021)
Yearly average energy was under-estimated by 3.3%	Southern Italy	43 months	Monocrystalline silicon-Sunpower E19/320	Malvoni et al. (2017)
An uncertainty of 0.47% and 0.32%	Southern India	1 year	CIS p-Si	Ramanan, Kalidasa Murugavel, and Karthick (2019)

Table 3. The city’s global radiation values (KWh/m²-day) by months (Republic of Turkey Ministry of Energy and Natural Resources 2023).

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
İstanbul	2.00	2.57	4.20	5.28	6.30	6.79	6.79	6.07	5.09	3.74	2.37	1.8
Antalya	2.12	2.57	4.37	5.47	6.36	6.93	6.65	6.14	5.16	3.93	2.51	1.92

Figure 2. Normal floor plans and elevations.

Table 4. The U values of building envelope constructions in İstanbul and Ankara.

	Roof	External wall	Ground floor	Window glazing	Window frame
İstanbul	0.4 W/m^2K	0.6 W/m^2K	0.6 W/m^2K	2.4 W/m^2K	1.75 W/m^2K
Antalya	0.45W/m^2K	0.7 W/m^2K	0.7 W/m^2K	2.4 W/m^2K	1.75 W/m^2K

Table 5. The Activity and HVAC system variable selections in the building simulation.

Activity		HVAC
Occupancy (density) Working hours (schedule)	0.12 people/m^2 8:30–18:00 (only on weekdays)	Building HVAC systems	Fan Coil Unit (4 pipes), Air-cooled chiller
Activity Metabolic factor Clothing	light office work, standing, walking 0.90 met in winter 1.00 clo, in summer 0.50 clo	Mechanical ventilation Economiser Heat recovery, type	on off on, enthalpy
Heating setpoint temperatures Cooling setpoint temperatures Minimum fresh air Natural ventilation setpoint temperatures (indoor min temperature control)	heating 20°C, heating set back 12°C cooling 26°C, cooling set back 28°C 10 l/s-person 24°C (min)	Heating Fuel Heating system seasonal CoP	on natural gas 0.83
Lighting-target illuminance Lighting control	400 lux On	Cooling Fuel Cooling system seasonal CoP	on electricity 1.67
Internal gains	10 W/m^2 (5W/m^2 computers and 5W/m^2 office equipments)	Natural ventilation Outside air (ac/h) Outdoor temperature limits	on 1.50 on

Figure 3. The horizontal BIPV system design in the reference building in İstanbul.

Table 6. The horizontal BIPV system design information designed for building scenarios.

Building scenarios	Protection period and design date	BIPV module length	PV modules in a BIPV module
İstanbul Reference building	21°C and over a period: 1 June–1 October	2.22m	8 units
İstanbul Building with ∼100% WWR	21°C and over a period: 1 June–1 October	2.50 m	140 units
Antalya Reference building	21°C and over a period: 1 May–1 November	2.80 m	10 units
Antalya Building with ∼100% WWR	21°C and over a period: 1 May–1 November	3.14 m	188 units

Figure 4. The vertical BIPV system design in the reference building in İstanbul.

Figure 5. Perspectives of three scenarios from the İstanbul reference building model (neutral position, position with shading device and position with BIPV).

Table 7. The vertical BIPV system design information designed for building scenarios.

Building scenarios	BIPV-facade angle	Dimensions	PV modules in a BIPV module
Reference building	east facade: + 45° west facade: −45°	d = 0.75m w = 0.75m h = 1.85m	3 units
Building with ∼100% WWR	east facade: + 45° west facade: −45°	d = 0.75m w = 0.75m h = 14.40m	24 units

Figure 6. PVsyst models of the scenarios with BIPV in Istanbul (the reference building on the left and the building with ∼100% WWR on the right).

Table 8. PV system specifications and simulation parameters.

Specifications	Rating/details	Specifications	Rating/details
System type	Grid-Connected Building system	Simulation parameters
Characteristics of a PV module		Models used	Transposition: Perez Diffuse: Perez, Meteonorm Circumsolar: separate
Rough module area	0.42 m^2
STC power	Pnom 40 Wp
Open circuit voltage	Voc 23.3 V
Short circuit current	Isc 2.68 A	Horizon	Free horizon
Characteristics of a grid inverter		Albedo	0.2
	monophased	Nominal PV power-Total number of PV modules/ Total number of inverters
Operating mode	MPTT
Maximum efficiency	Max Eff. 97.0%	Antalya Ref. Build. Antalya ∼100% WWR Build. İstanbul Ref. Build. İstanbul ∼100% WWR Build.	30.4 kWp – 760/9 68.5 kWp – 1712/19 27.2 kWp – 680/8 60.8 kWp – 1520/17
European average efficiency	Euro Eff. 96.3%
Nominal AC Power	Pnom AC 3.0 kWac
Technology	25 kHz, IGBT
Frequency	50–60 Hz	PV modules’ connection type	in series modules and in parallel strings (on each facade)
Oper. Voltage	125–440 V
Power threshold	15W

Figure 7. The energy analysis results of the building scenarios in İstanbul.

Figure 8. The energy analysis results of the building scenarios in Antalya.

Table 9. The calculation results of the energy indicators and C_PV of PV systems.

Building scenarios	Ein (kWh) (primary energy)	Eout (kWh/y) (primary energy)	EPBT (year)	ERF	Performance ratio	CPV
İstanbul Reference building	283220	67493.548	4.2	6.5	West 55% East 56% South 66%	18.087%
Antalya Reference building	316540	106032.258	3	9.1	West 55% East 56% South 63%	22.324%
İstanbul Building with ∼100% WWR	633080	128870.967	4.9	7.4	West 50% East 51% South 61%	25.726%
Antalya Building with ∼100% WWR	713048	203774.193	3.5	7.8	West 50% East 51% South 56%	34.557%

Table 10. PV energy production and BIPV_shading energy gain based on building scenario.

Scenarios	İstanbul		Antalya
	Reference building	Building with ∼100% WWR	Reference building	Building with ∼100% WWR
1 m^2 PV energy production	73.260 kWh	62.578 kWh	102.976 kWh	87.853 kWh
1 m^2 BIPVshading energy gain	150.459 kWh	161.527 kWh	205.423 kWh	222.582 kWh

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