Energy Procedia 47 ( 2014 ) 29 – 36

1876-6102 © 2014 The Authors. Published by Elsevier Ltd. Selection and peer-review under responsibility of the Scientifi c Committee of Indonesia EBTKE Conex 2013doi: 10.1016/j.egypro.2014.01.193

ScienceDirect

Conference and Exhibition Indonesia Renewable Energy & Energy Conservation [Indonesia EBTKE CONEX 2013]

A Technical Review of Building Integrated Wind Turbine System and a Sample Simulation Model in Central Java, Indonesia

Dany Perwita Saria,*, Wida Banar Kusumaningruma

aRND Unit for Biomaterials, Indonesian Institute of Sciences (LIPI), Jln. Raya Jakarta-Bogor Km 46, Cibinong, Bogor 16911, Indonesia

Abstract

Indonesia is an archipelago country and has significant wind energy potential. This paper investigated the potential of wind energy on the building based on location in Central Java Province, Indonesia. The results show that overall, Yogyakarta and Semarang, offers a much higher wind potential than other location. Four different sample models for buildings and houses are explained with CFD models. This study reports the investigation results of wind energy potential in building especially in Yogyakarta and Semarang. Hence, Yogyakarta has potential for high rise building that integrated with wind turbine and Semarang has potential for roof mounted-micro wind turbine. © 2014 The Authors. Published by Elsevier Ltd. Selection and peer-review under responsibility of the Scientific Committee of Indonesia EBTKE Conex 2013.

Keywords: building integrated wind turbines; micro-wind turbine; CFD; wind energy; Yogyakarta; Semarang; Indonesia

1. Introduction

Indonesia is the world’s largest archipelago, which consist of more than 17,000 islands. This country has coastal line as long as more than 81,000 km. Considering the natural geography, Indonesia is blessed with great potential of renewable energy that is shown in Table 1. Wind energy, one of alternative energy that can replace traditional fossil fuels in daily life, while harmless to the environment. The number of installed wind power plants is yearly increasing [1]. Large wind energy resources are located at the oceans and near coasts. Wind power plan can be constructed along coastal areas where energy demands are high. The Government of Indonesia commit to reduce

* Corresponding author. Tel.: +62-813-2569-3808.

E-mail address: dany.perwitasari@gmail.com

Available online at www.sciencedirect.com

© 2014 The Authors. Published by Elsevier Ltd. Selection and peer-review under responsibility of the Scientific Committee of Indonesia EBTKE Conex 2013

30 Dany Perwita Sari and Wida Banar Kusumaningrum / Energy Procedia 47 ( 2014 ) 29 – 36

fossil fuel consumptionff up to 26% by the year 2020 [2] with vision energy mixes based on four main sources: oil(30%), coal (22%), gas (23%) and new renewable energy (25%) (Figure 1) [3]. Produced wind energy from windturbine which installed on or around building can be defined as building integrated wind turbine. Building integratedwind turbines become new icon of green building. This technology brings the power generation close to the user toreduce the fossil fuel consumption.

Table 1. Renewable energy development [3].

No. Non Fossil Energy Resources Installed Capacity Ratio (%)

1 2 3 4 5=4/3

1 Hydro 75.670 MW 5.771 MW 7.62

2 Geothermal 28.543 MW 1.228 MW 4.30

3 Mini/Microhydro 769.69 MW 217.89 MW 28.31

4 Biomass 49.810 MW 1.618.40 MW 3.25

5 Solar Energy4.80

kWh/m2/day 20 MW -

6 Wind Energy 3-6 m/s 1.87 MW -

This paper reports the investigation result of wind energy on buildings in four sections. At section one, generalwind power density of Java Island is calculated using wind power application [4] and section two, the visualrepresentation of building integrated wind turbine design for Indonesia’s climate is shown. Section three, analysewind power potential in Yogyakarta and Semarang using data from The Meteorological Department wind power application. High rise building integrated wind turbine in Yogyakarta and roof-ff mounted micro wind turbine inSemarang is examined briefly using computational fluidff dynamic at section four. (NRE : New Renewable Energy)

2. Building integrated wind turbine concept design

The principle of building integrated wind turbine aims to reduce negative impacts on the environment and humanhealth and is therefore more sustainable than conventional construction methods [5]. There are three significantdrives are shifting land owners forward green buildings [6]:

Unstable energy prices that always rising because of limited availability of oil and gas.Healthy quality of live. American spend 90 percent of their time indoors, where asthma and allergy attacks can be triggered by air pollutions. With detail ventilation design could reduce the negative effect.Global warming and climate change.

In Indonesia, Government already released some guidelines for green building. Visual representation of buildingintegrated wind turbine design for Indonesian climate is presented in Figure 2.

Fig. 1. Estimation energy policy derection 2010-2025 [3].

Dany Perwita Sari and Wida Banar Kusumaningrum / Energy Procedia 47 ( 2014 ) 29 – 36 31

SITE ANALYSIS CLIMATE

SITE ORIENTATION

DESIGN FORM AND ORIENTATION

EXPLORE OF THE BUILDING SHAPE

PHILOSOPHY AND AESTHETIC OF THE BUILDING

2D AND 3D BUILDING DESIGN OUTPUT

ENVELOPE DESIGN; SNI 03 6389 2000

ENERGY ANALYSIS - SNI 6390 2011 - SNI 03 6197 2000 - Energy consumption analysis - Fossil fuel analysis - Renewable energy analysis

GREEN BUILDING

COST ESTIMATION

STRUCTURE ANALYSIS; SNI 1726 2002

ENERGY PERFORMANCE ANALYSIS - CFD analysis - Wind tunnel test

FINAL DESIGN

Fig. 2. Building integrated wind turbine design concept.

Optimize site potential and analyze high priority wind energy resource is important. The most important factor in building integrated wind turbine is how much it can produce the power for energy consumption. Different effect of wind velocity was observed through the different roof shape, placed within urban configuration [7]. Looking for best location, estimating monthly energy from building consumption and from turbine [8], best building aerodynamic shape and wind turbine position are essential for harvesting maximum potential wind energy.

3. Wind energy potential in Yogyakarta and Semarang city

Most of world’s wind energy is over the oceans. Oceans provide plenty of energy to atmospheric motions, and its roughness is generally smaller than over land. Wind power density directly determines cost efficiency in using wind energy. There are four categories for wind power density [4]:

Poor : < 150 Watt/m2 Fair : 150-250 Watt/m2 Good : 250-350 Watt/m2 Excellent : > 350 Watt/m2

In another hand, Soeripno [9] categorizes wind power density in Indonesia into three resources potential: marginal, fair and good (Table 2). Table 2 expressed that Yogyakarta and Central Java have wind potential for wind.

32 Dany Perwita Sari and Wida Banar Kusumaningrum / Energy Procedia 47 ( 2014 ) 29 – 36

Table 2. Summary wind data Indonesia (50m above the surface) from Institute of Aeronautics and Space Agency (LAPAN) [9] Resources potential Wind speed (m/s) Wind power density

(Watt/m2) Number of sites Provinces

Marginal

3 - 4

< 75

84

Maluku, Papua, Sumba, Mentawai, Bengkulu, Jambi, East and West Nusa Tenggara, South and North Sulawesi, North Sumatra, Central Java, Maluku, Yogyakarta, Lampung, Kalimantan

Fair

4 – 5

75 – 150

34

Central and East Java, Yogyakarta, Bali, Benkulu, East and West Nusa Tenggara, South and North Sulawesi

Good

> 5

> 150

35

Banten, DKI, Central and West Java, Yogyakarta, East and West Nusa Tenggara, South and North Sulaawesi, Maluku

To ensure that Yogyakarta and Central Java are truly potential for wind energy, Quanhua Liu [4] calculation are used. General wind power density results of Java Island using wind power application [7] is depicted in Figure 3. Java Island has a high potential of wind energy. The detail result presented that West Java has the best performance and potential for wind turbine because of its wind power density. Central Java and East Java in Southern Hemisphere does not have high wind energy but fair enough to install wind turbine. Central Java province has been chosen presently for the case study, Yogyakarta and Semarang city are both of the locations with most populated and wind potential in Central Java.

Fig. 3. Wind power density around Java Island.

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155Wind Turbin Location Around Java Island

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

1600

1700

1800

Pow

er

Den

sity (

W/m

2)

LegendTower height for wind turbine 10mTower height for wind turbine 25mTower height for wind turbine 50mTower height for wind turbine 100mTower height for wind turbine 200m

Dany Perwita Sari and Wida Banar Kusumaningrum / Energy Procedia 47 ( 2014 ) 29 – 36 33

Fig.4. Wind power density and annual electricity in Yogyakarta.

Northern Part

Southern Part

3.1. Wind turbine power

However, building integrated with wind turbine are limited installation because of low mean wind speeds, high turbulence levels and relatively high aerodynamic noise levels generated by the turbine in built environment [10]. Researh showed that roof shapes could maximize the energy harvesting from the acceleration of the wind above the building [7]. Wind turbine power of a wind generator [11] can be expressed as:

(1) where: Pturbine = the wind turbine power, Ρ = the air density (kg/m3), Cp = the coefficient of performance, A = the swept area of the blades (m2), V = free wind speed (m/s). From the equation (1) showed that the power of the wind increases with the cube of the wind speed. It is clear that wind speed have an important part to maximize the power generation. Wind turbine should be located at relatively windy site (coastal area) [12] and best roof shape.

3.2. Wind energy potential in Yogyakarta

Yogyakarta is located in Java Island and has high potential wind energy. Wind power density at populated area in Yogyakarta show two different kinds of wind power density (Fig. 4). Higher wind power density is in southern part while lower wind power density is in northern part. Wind power density and annual electricity result are presented in Table 3. Southern part is the best area for built building which integrated with wind turbine.

Table 3. Wind power density and annual electricity in Yogyakarta. Northern Part

Wind turbine tower height (m)

Power density (W/m2)

Annual electricity (kWh)

10 34 18710

25 50 27700

50 68 37270

100 91 50140

200 123 67450

Southern Part

Wind turbine tower height (m)

Power density (W/m2)

Annual electricity (kWh)

10 161 88620

25 238 131200

50 321 176500

100 431 237400

200 580 319400

34 Dany Perwita Sari and Wida Banar Kusumaningrum / Energy Procedia 47 ( 2014 ) 29 – 36

3.3. Wind energy potential in Semarang

Different with Yogyakarta results, Semarang wind power density is stable. Semarang city’s forecasting within period 5 years (2008-2012) [13] shows that has huge potential for power generation. Predicting wind power density is chosen around coastal area (Fig. 5). Table 4. Percentage wind speed and wind direction at Semarang (2008-2012).

Wind Speed Wind Direction Total

(km/hr) N E SE S SW NW (%)

7 - 9 13.33 11.67 6.667 3.333 5 8.333 48.33

10 - 12 10 5 6.667 3.333 1.667 10 36.67

13 - 15 - - - 1.667 - 1.667 3.333

16 - 18 - 1.667 - - 1.667 6.667 10

19 - 20 - - - - - 1.667 1.667 Total (%) 23.33 18.33 13.33 8.333 8.333 28.33 100

4. Concept and application

Yogyakarta has high potential for wind energy. Populated area combined with high wind density is suitable for high rise mounted wind turbine. Some of high rise building integrated wind turbine which already built show in Figure 6.

CFD is one of wind velocity measurement method. It can be used to simulate and calculate the wind flow around

the building to help analyze and locate turbine. Best building integrated wind turbine design for Yogyakarta are expressed in Figure 7. Figure 7 show that wind velocity increase 39.89% from the wind velocity approach. The highest wind velocity are located at 1m after passing the circular rounded shape (red contour in Figure 7).

Fig. 5. House samples in Semarang to be tested by installing a wind-turbine.

Fig. 6. High rise building integrated wind turbine from left to right: Greenway self park (USA), Pearl river tower (China) [14].

Fig. 7. High rise building samples to be tested by installing wind-turbine.

Dany Perwita Sari and Wida Banar Kusumaningrum / Energy Procedia 47 ( 2014 ) 29 – 36 35

In other, Semarang city has lower wind power density and more stable wind velocity than Yogyakarta. Roof

shapes are very dominant to increase the wind velocity. Traditional roof shapes like gable roof and hip roof are better than flat roof because could increase the wind velocity. Building integrated micro-wind turbines are potential low-cost renewable energy devices that could be adopted in these environments [10]. Micro wind turbines are defined as wind turbines with capacity less than 2.5 kW [13] and rotor diameter less than 1.25m [14]. Several micro wind turbines are demonstrated in Figure 8 [8]. Simulation for houses (Figure 9) show that wind velocity on the top gable roof are stable but for house which using hip roof, wind velocity increase on the edge (red colour in Figure 9).

5. Conclusion

This paper presents a general simulation evaluation framework for best building integrated wind turbines design in Yogyakarta and Semarang, Indonesia. To maximize the performance of building design, building concept is essential. Building design concept has given the idea for complete method to bring the efficiency in wind turbines on buildings. By investigating the building aerodynamic shape, local meteorological data, local building

Fig. 8. Micro wind turbines left to right: (L-R): D400 StealthGen, Windsave, renewable devices swift turbine, Turby vertical axis [8].

Fig. 9. House design samples to be tested by micro-wind turbine, left to right: Gable Roof, Hip Roof.

Wind direction

Wind direction

36 Dany Perwita Sari and Wida Banar Kusumaningrum / Energy Procedia 47 ( 2014 ) 29 – 36

characteristics and location could enhance wind velocity. It explains the effect of building shape and location in the productivity of power in wind turbine. High rise building integrated wind turbine is suitable for Yogyakarta because of its potential wind density. This building can support annual office building’s electricity 6%. Semarang city which the power density lower than Yogyakarta is suitable for micro wind turbine. House with gable roof installed micro-wind turbine on the top of the roof due to a stable wind velocity. Hip roof is better installed micro-wind turbine in the building or roof side which wind velocity higher than in the top of the roof. In the future work, considering Indonesia’s natural potential renewable energy, researcher will analyse others city and province using CFD analysis especially for micro wind turbine at housing in coastal area.

Acknowledgements

We would like to thank The Indonesian Institute of Sciences (LIPI) for allowing this study to be undertaken.

References

[1] Keyhani A, Ghasemi-Varnamkhasti M, Khanali M, Abbaszadeh R. An assessment of wind energy potential as a power generation source in the capital of Iran, Tehran. Energy 2010; 35:188-201.

[2] National Standarization Agency of Indonesia (BSN). Presidential regulation (peraturan Presiden) No.6/2011: Rencana aksi nasional penurunan emisi gas rumah kaca; 2011.

[3] Directorate General of New Renewable Energy and Energy Conservation, Ministry of Energy and Mineral Resources. Renewable energy development; 2012.

[4] Liu Q, Miao Q, Liu JJ & Yang W. Solar and wind energy resources and prediction. Journal of Renewable and Sustainable Energy American Institute of Physics 2009; 1:43-105.

[5] Johansen O. The spatial diffusion of green building technologies: the case of Leadership in Energy and Environment Design (LEED) in the United States. International Journal of Technology Management and Sustainable 2011; 10(3):251-266.

[6] Denem S, Howard B. Buildings that breathe: Green construction is coming of age. E. Magazine: January/February 2007. [7] Abohela I, Hamza N, Dudek S. Effect of roof shape, wind direction, building height and urban configuration on the energy yield and

positioning of roof mounted wind turbine. Renewable Energy 2013; 50:1106-1118. [8] Bahaj AS, Miyers L, James PAB. Urban energy generation: Influences of micro-wind turbine output on electricity consumption in

buildings. Energy and Buildings 2007; 39:154-165. [9] Soeripno S. Wind energy potential and development in Indonesia. In: Proceeding of The 2nd Clean Energy Power Asia Denpasar-Bali. May

14th-15th, 2012. [10] Ledo L, Kosasih PB & Cooper P. Roof mounting site analysis for micro-wind turbines. Renewable Energy 2011; 36:1379-1391. [11] Sinisa S, Campbell, Harris, Haris J. Urban wind energy. UK & USA: Earthscan; 2009. [12] Li QS, Chen FB, Li YG, Lee YY. Implementing wind turbines in a tall building for power generation: A study of wind loads and wind

speed amplifications. Journal of Wind Engineering and Industrial Aerodynamics 2013; 116:70-82. [13] Pececock AD, Jenkins D, Ahadzi M, Berry A & Turan S. Micro wind turbines in the UK domestic sector. Wind Energy and Buildings

2008; 40:1324-1333. [14] Gipe P. Wind energy basics. Vermont, Totnes, England: Chelsea Green Publishing Company; 1999.