25. JPEM-D-12-00241 Author Copy

INTERNATIONAL JOURNAL OF PRECISION ENGINEERING AND MANUFACTURING Vol. 14, No. 6, pp. 1029-1035 JUNE 2013 / 1029

© KSPE and Springer 2013

Exhaust Air Energy Recovery System for Electrical

Power Generation in Future Green Cities

Wen Tong Chong1,#, Sin Chew Poh1, Ahmad Fazlizan1, Sook Yee Yip2, Mei Hyie Koay3, and Wooi Ping Hew2

1 Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia2 UMPEDAC, Level 4, Wisma R & D, University Malaya, Jalan Pantai Baharu, 59990 Kuala Lumpur, Malaysia

3 Faculty of Mechanical Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia# Corresponding Author / E-mail: [email protected]; [email protected], TEL: +60-127235038, FAX: +60-379675317

KEYWORDS: Cooling tower, Energy recovery, Green technology, Renewable energy, Urban wind energy, Wind turbine

This paper investigates a technology-driven solution to supply a portion of energy demand in future green cities. An idea on

harnessing unnatural wind resources for electricity is presented. Two vertical axis wind turbines with an enclosure are mounted above

a cooling tower to recover part of the energy from the exhaust air. Guide-vanes are designed to create a venturi effect and guide the

wind before it interacts with the turbine blades. Diffuser-plates help to draw more wind and accelerate the exhaust airflow. Safety

concerns that may result from blade failure are minimized by the design of the enclosure. From the laboratory test and field test

results, there is no significant difference in the current consumption of the fan motor with the installation of the wind turbines. The

integration of the enclosure has shown an improvement on the turbine’s rotational speed which is 30.4% higher. The electricity

generated from this system can be fed into the electricity grid. For 3000 units of cooling tower (2 m outlet diameter powered by a

7.5 kW fan motor and operated for 16 hours/day), 13% of the energy to power the fan motor is expected to be recovered from this

system which equals 17.5 GWh/year.

Manuscript received: June 21, 2012 / Accepted: October 10, 2012

1. Introduction

Nowadays, global energy consumption in both developed and

developing countries has increased rapidly due to population growth

and it is expected to double or more by the year 2040.1 In Malaysia

alone, total energy demand is growing at 5.4% per annum with 1.8%

average annual population growth rate. Eventually, the energy demand

in the year 2020 will be approximately 971 TWh with 33.4 million

populations. As a consequence, Malaysia is predicted to become a net

energy importer by 2020.2 This energy consumption growth is

contributed by both industrial and residential sectors. The existing

energy resources for electricity generation in Malaysia mainly depend

on fossil fuels (oil, coal and natural gas) which contribute 94.5% of the

electricity generation while only a small portion of energy supplies

comes from hydroelectricity or others (solar, biomass, etc.). However,

the usage of fossil fuels brings negative impacts to the environment

such as greenhouse gases (GHG) emission. According to Ahmad et al.,

more than 90% of the energy related GHG emission is a result of the

CO2 emissions from fuel combustion globally.3 Currently, the increase

in the concentration of GHG emission has caused a notable rise of

temperature in the earth’s atmosphere (global warming) and thus

widespread melting of snow and ice at the polar ice caps. The melting

of ice causes the rise of sea level and lesser land can be used for an

increasing world population, along with the changes in climate.4

In terms of the economic aspect, the deployment of fossil fuels for

electricity generation will become more and more costly as these

resources are limited in supply and will be exhausted one day. Based

on the commercial tariff of electricity in Malaysia provided by Tenaga

Nasional Berhad (TNB), energy cost is USD 0.113/kWh and it is

predicted to increase by 10% annually.5 In parallel with a country

NOMENCLATURE

GHG = Greenhouse Gas

TNB = Tenaga Nasional Berhad

VAWT = Vertical Axis Wind Turbine

RE = Renewable energy

DAWT = Diffuser Augmented Wind Turbine

DOI: 10.1007/s12541-013-0138-3

1030 / JUNE 2013 INTERNATIONAL JOURNAL OF PRECISION ENGINEERING AND MANUFACTURING Vol. 14, No. 6

experiencing rapid growing energy demand and economic development,

the challenges of supplying sufficient and acceptable cost of electricity

can be addressed with the increase in the usage of renewable energy

resources for electricity generation. According to Shan et al., energy

saving and emission reducing technologies consist of three types, i.e.

resource conservation, energy economizing and environment-friendly.6

In this paper, the authors would like to present a novel application

of wind turbine to recover wasted energy in order to promote the vision

of energy saving and emission reducing. Thus, an innovative idea on

harnessing unnatural wind resources for electrical power generation is

introduced by installing an exhaust air energy recovery system above

an exhaust air system (cooling tower). The feasibility of implementing

the proposed system is investigated by conducting a laboratory test on

a scaled model of a cooling tower. An on-site testing was carried out

as well to further examine the reliability of the system. The main

objective of the design is to produce on-site clean energy generation

without causing negative effects on the performance of the original

exhaust air system.

2. Potential of wind energy in Malaysia

Renewable energy (RE) resources play an important role as

alternative energy sources to limit the dependency on fossil fuels for

electricity generation. Recently, numerous researchers have put RE in

the limelight and intensive researches were done to improve the

efficiency of RE resources for energy generation. All the works

emphasized the sustainability at the early design stages so that they can

perform with minimum usage of energy without producing hazardous

wastes.7 Among the RE resources, wind energy is recognized as the

fastest developing RE resource globally which is reported at a rate of

30% annually.8 Wind energy is clean and inexhaustible allowing a cost-

effective and sustainable energy system. However, the development

and current utilization of wind energy in Malaysia are immature due to

the fact that the country has low wind speed.

Malaysia’s climate is categorized as equatorial and its wind

condition varies throughout the year as it is governed by both the

Northeast (November-March) and Southwest (May-September)

monsoons.9 The wind speed in Malaysia is limited throughout the

year (free-stream wind speed, V∞

< 4 m/s for more than 90% of total

wind hours)10 making it an unreliable source for energy generation.

Based on the weather data collected and analyzed in Penang Island by

Tiang and Ishak, the mean annual wind power density is estimated to

be 24.54 W/m2 while the mean annual wind energy density is

estimated to be about 17.98 kWh/m2 per month.11 Sopian et al.

presented a wind energy potential analysis with Weibull distribution

function for a 10 year period (1982-1991) by collecting wind data

from 10 weather stations throughout Malaysia. He concluded that the

station in Mersing has the greatest potential with a mean annual wind

power density at 86.61 W/m2.12 In addition, there is a great potential

to apply wind energy generation system in Sabah (East Malaysia) as

there was a project with a 150 kW wind turbine set-up in Terumbu

Layang-Layang for power generation and water pumping in 2005 by

Universiti Kebangsaan Malaysia. This project was demonstrated with a

good degree of success.13 Although the above stated areas show

promising results for the application of wind turbine, most of the city

areas in Malaysia e.g. Labuan or Kudat are not suitable for wind energy

generation.14

In order to extract maximum possible wind energy in a low wind

speed region, the design of a suitable wind turbine is crucial. The

existing problems of the wind turbine shall be taken into account

during the design stage, i.e. low efficiency and poor starting behavior.

The wind power can be expressed as below:

(1)

where Cp is power coefficient, ρ is air density, A is blade swept area and

V is wind speed.15 Based on equation (1), a slight increase in the wind

speed approaching a wind turbine will result in increase of power

output significantly since the wind power generation is directly

proportional to the cube of the wind speed. This theory is successfully

utilized by the diffuser augmented wind turbine (DAWT). DAWTs are

the hot topic to improve the output power of a wind turbine. It helps

to accelerate the wind speed by creating a separation region behind the

wind turbine where low-pressure regions act as a sucking effect to draw

more wind compared to a conventional wind turbine.16

One of the most recent experimental investigations on the diffuser

design of a horizontal axis wind turbine showed that the performance

of a diffuser-shrouded wind turbine is better in terms of power

coefficient. It was observed to be about four times higher compared to

a bare wind turbine.17 Besides, a further experiment was carried out by

Ohya et al.18 to examine the optimal form of the flanged diffuser.

Different lengths of diffuser were studied to design a more compact

diffuser. Chen et al. also conducted experiments to study the effects of

flanged diffuser on rotor performance. The results showed that the

flanged diffuser will significantly increase the power output, torque

output, and rotor rotational speed of the wind turbine with 30% solidity

rotor at 10-20 m/s wind speed.19

Despite the low and unsteady wind speed problems in Malaysia, an

innovative approach of extracting unnatural wind resource, i.e. exhaust

air system has been introduced in this paper for electricity generation.

The design is known as exhaust air energy recovery system and it takes

the advantages of the discharged airflow characteristic from exhaust air

systems which have consistent and predictable wind speed. There are

many forced ventilated situations available globally including ventilated

exhaust from air conditioning system.20 These situations allow large

deployment of the exhaust air energy recovery system. The designed

system is surrounded by an enclosure which comprises of diffuser-

plates and guide vanes for better wind turbine performance.

3. General arrangement and working principle of the

designed exhaust air energy recovery turbine system

Fig. 1 shows the general arrangement of the exhaust air energy

recovery system. This patented system comprises of two vertical axis

wind turbines (VAWTs) installed above an exhaust outlet in cross wind

orientation to harness the discharged wind energy. The discharged wind

energy from the exhaust air system is reliable for electricity generation

because it is strong and consistent, allowing VAWTs to operate with

P1

2---C

PρAV

3=

INTERNATIONAL JOURNAL OF PRECISION ENGINEERING AND MANUFACTURING Vol. 14, No. 6 JUNE 2013 / 1031

minimum fluctuation. The design of the system also takes into

consideration the performance of the exhaust air system, where no

negative impact could be expected.

This system is supported by a supporting structure and it can be

installed above the exhaust air system either horizontally or vertically

depending on the orientation of discharged air relative to the turbines.

For instance, when the wind blows up in a vertical direction from

beneath, the whole system is installed in a horizontal orientation and

the supporting structure holds the transmission shaft on both ends of

the VAWT (generator at one side while bearing at the other side). In

contrary, the system is mounted in a vertical direction with the

generator placed on the floor when the discharged air is coming

sideways. An optimum position above the exhaust outlet is essential to

be determined for the installation of two VAWTs to avoid creating any

negative impact on the exhaust air system.

In order to capture the maximum wind energy from the exhaust air

system, both the VAWTs are integrated with an enclosure (equipped with

several guide vanes and two diffuser-plates). Guide vanes are arranged in

between the exhaust outlet and VAWTs to form multiple air flow channels

to guide the exhaust wind direction to an optimum on the turbine blade.

Furthermore, a significant increment on the discharged wind speed can be

obtained as a venturi effect is created. The suction effect that occurs due

to the low pressure region will draw more air for interaction with the

VAWTs and result in better self-starting behavior. Thus, the VAWTs can

rotate closer to its rated rotational speed and a greater amount of

electricity is generated from the system. In addition, there are two

diffuser-plates inclined outwardly at an optimum angle relative to their

vertical axis to further improve the discharged air flow characteristic. The

design of this system also takes the safety issues into consideration. The

enclosure acts as a safety cover to protect the entire system from public

or maintenance worker hazard in the event of blade failure.

This exhaust air energy recovery system has great marketing value

since there are many cooling towers as well as other exhaust air

systems around the world. Besides, it is an on-site green energy

invention as it does not contribute to any kind of pollution but instead,

it re-uses wasted air from the exhaust air system to conserve a part of

the energy consumption. The integration of this green technology with

a building should be able to obtain the green building index rating. Fig. 2

illustrates an artist’s impression of the exhaust air energy recovery

system on top of a high-rise building.

4. Methodology

4.1 Laboratory test of the exhaust air energy recovery turbines on

a scaled model of cooling tower

The laboratory test was performed as an initial experimental

approach to investigate the feasibility of the energy recovery system.

The main concerns are the effect of the energy recovery system on the

exhaust air performance and the performance of the wind turbine. A

scaled model of cooling tower was built with an outlet diameter of

0.8 m (circular duct). The cooling fan was represented by a 0.7 m

diameter cooling fan. At the bottom of the cooling tower, there was a

gap with a distance of 0.195 m from the floor (with the air inlet area

of 0.5329 m2). As for the model of the exhaust air energy recovery

system, two 0.3 m diameter H-rotors were used and they were enclosed

within an enclosure. The VAWTs were positioned at a distance of

0.18 m above the fan outlet (measured from the VAWT transmission

shaft). Diffuser-plates were mounted on the outlet of the circular duct.

According to the experimental investigation carried out by Abe et al.,21

diffusers are best when inclined at 7o relative to the vertical axis. The

laboratory test set-up is shown in Fig. 3.

This laboratory test was performed in three configurations, i.e.:

1) Cooling tower model without wind turbines

2) Cooling tower model with wind turbines

3) Cooling tower model with wind turbines integrated with enclosure

Fig. 1 General arrangement of the exhaust air energy recovery system

at the cooling tower outlet

Fig. 2 Artist’s impression of the designed exhaust air energy recovery

system on top of a high-rise building

Fig. 3 Set-up for laboratory test on a scaled model of cooling tower


Several measurements had been recorded to identify the difference

among all the test configurations. The fan motor current consumption

was measured by using a mini clamp meter at the power cable. A hot

wire anemometer was used to measure the air intake speed of the

scaled model of cooling tower at four intake points after the rotational

speed of the wind turbine had stabilized. Then, the rotational speed of

the wind turbine was measured by a hand held laser tachometer.

4.2 Field test of the exhaust air energy recovery turbine system on

an actual cooling tower

Field test was conducted to investigate the performance and reliability

of the system on an actual cooling tower. Malaysia’s biggest cooling

tower manufacturer, Truwater Cooling Towers Sdn. Bhd., provided a

demonstration unit for this experiment. The outlet diameter of the

cooling tower is 2 m and the cooling fan is powered by a 7.5 kW motor.22

The exhaust air energy recovery system used a combination of a

3-bladed Darrieus type VAWT (rotor diameter of 1.24 m) and a 2-

stage Savonius rotor. It was supported at both ends of its center shaft

and mounted above the cooling tower with an outlet diameter of 2 m.

The system was held by the supporting structure and mounted to the

main structure of the cooling tower (Fig. 4). The center shaft of the

rotor was shifted from the center of the cooling tower outlet at a

predefined distance in order to get an optimum performance of the

wind turbine based on the measured velocity profile of the exhaust

air. The rotor height (distance between the nearest circumference of

the VAWT to the outlet of the cooling tower was set at half of the

rotor diameter. The horizontal distance between the rotor shafts to the

outlet center of the cooling tower was also at half of the rotor

diameter. The system was mounted onto the supporting structure at

both ends of the power-transmission shaft with the generator at one

side and a bearing at the other.

The field test was performed in two configurations, i.e:

1) Cooling tower model without wind turbines

2) Cooling tower model with wind turbines

In order to measure the air flow performance of the cooling tower,

a measurement standard developed by the Cooling Technology Institute

has been used. The wind speed was measured by using a hot-wire

anemometer. Since the outlet duct is circular in shape, the duct was

divided into 5 concentric circular bands of equal areas for measure-

ment. Then, the outlet wind speed was obtained by averaging the

velocities taken at 90o intervals on every circle.23 The discharged air

flow rate was calculated by multiplying the outlet wind speed with the

outlet area. A laser tachometer was used to measure the cooling fan and

wind turbine rotational speed, and a 3-phase power meter was used to

measure the power consumption by the fan motor.

5. Result and discussion

5.1 Laboratory test of the exhaust air energy recovery turbine

system on the scaled model of cooling tower

Table 1 shows the measured results for all the three test

configurations obtained from the laboratory test. For the first

configuration (cooling tower model only), the average discharged air

speed at the outlet of the scaled model of cooling tower was recorded at

4.15 m/s while the fan motor current consumption was 0.85 Ampere and

the average intake air speed at 1.97 m/s. The measured results for the

configuration were taken as baseline throughout the entire experiment.

For the second configuration (cooling tower model with wind

turbines), it was observed that the VAWTs were able to self-start and

their average stabilized rotational speed was recorded at 464 rpm. The

discharged airflow rate of the cooling tower model showed 8.6%

improvement (from 1.05 m3/s to1.22 m3/s). This increment shows that

the integration of the VAWTs with the cooling tower is able to help the

fan to discharge more air to the atmosphere and thus the power

Fig. 4 The design and installation of a wind turbine on top of a cooling tower supported by the supporting structure

Table 1 Laboratory test results of the energy recovery system

ParameterCooling tower

model only

Cooling tower

model with wind

turbines

Cooling tower

model with wind

turbines and

diffuser

Fan motor current

consumption0.85 Ampere

Average intake air

speed1.97 m/s 2.28 m/s 2.14 m/s

Discharged air

flow rate1.05 m3/s 1.22 m3/s 1.14 m3/s

Turbine rotational

speed- 464 rpm 501 rpm


consumption of the fan would be reduced.

After the installation of the enclosure, the average rotational speed

of the VAWTs was further enhanced as it was recorded at 501 rpm.

There was no measurable difference observed on the fan motor current

consumption as it remained at 0.85 Ampere and minimum changes on

the airflow rate for all three cases. This scenario proves that the

installation of the exhaust air energy recovery system does not bring

any significant negative effect on the cooling tower performance.

5.2 Field test

5.2.1 Discharged air velocity profile of the cooling tower

Discharged air velocity profile measurement was conducted to

determine the position for the VAWTs for optimum performance. Fig. 5

shows the average discharged air speeds at the cooling tower outlet,

measured at five bands on every quarter. The graph shows that the

discharged air speed in the region between band 3 and band 4 is the

highest.

However, the lowest wind speed is observed at band 1 where the

region is close to the center as there is a belting cover blocking the air

flow. Wind speed at band 5 (close to the outlet outer radius) is low due

to blade tip loss, and the clearance between the blade tip and the inner

wall duct. Based on the measurement results, it is best to locate the

VAWTs at the region between band 3 and band 4 where the wind

speeds are strong.

5.2.2 Exhaust air energy recovery turbine system tested on an

actual cooling tower

This test was conducted to examine if there is any negative effect

on the cooling tower due to the blockage effect after the installation of

the exhaust air energy recovery system. Table 2 summarizes the results

from the field test.

During the test, the VAWT was spinning at 875 rpm in free-running

condition (no load application) with the average discharged air speed

from the cooling tower at 10.363 m/s. It was observed that the average

discharged air speed was slightly reduced from 10.545 m/s to

10.363 m/s with the presence of the VAWTs (1.73% lower). This result

shows that there is a minimum blockage effect when the system is

positioned above the cooling tower outlet. However, there was no

significant difference observed on the power consumption of the fan

motor where the increment was only 0.39% (from 7.048 kW to

7.075 kW).

6. Estimation of energy conserved

An estimation of energy that is able to be recovered through the

installation of the exhaust air energy recovery system is discussed in

this section. An optimized energy recovery system with 2 units of

VAWTs is capable of generating 1 kW of power when installed above

a cooling tower outlet with 2 m outlet diameter and powered by a

7.5 kW fan motor. If there are 3000 units of cooling towers (same

specifications and conditions) operating for 16 hours per day, the fan

power consumption is 131.4 GWh/year and a total of 17.5 GWh of

energy is expected to be recovered by the installation of the energy

recovery system in a year. This amount of energy recovered is 13% of

the energy consumed by the fan motor of the cooling towers.

7. Future Work

Further investigations are needed to obtain an optimum

configuration and to improve the efficiency of the designed exhaust air

energy recovery system. The blockage effect which is caused by the

integration of the VAWTs at the outlet of the exhaust air system that

may affect the performance of the exhaust air system will first be

investigated. It will cover topics such as the exhaust air flow

characteristics, fan performance, heat rejection effectiveness, system

efficiency, etc. to ensure the normal operation condition of the exhaust

air system. Over-heating problem that may cause fire or safety issue

from the fan motor current increment due to air flow reduction will be

focused upon as well as to ensure safety of the occupants in the

building. In addition, the impact of flow mixing between the exhaust

air and the natural turbulence in urban areas which may influence the

performance of the system (exhaust air system and energy recovery

system) will also be included in future studies.

Fig. 5 Discharged air velocity profile at the cooling tower outlet

Table 2 Field test results on an actual cooling tower

ParameterCooling

tower only

Cooling

Tower with

wind turbines

Percentage

Difference

Average

discharged air

speed

10.545 m/s 10.363 m/s 1.73%

Cooling tower

fan rotational

speed

386.0 rpm 385.8 rpm 0.05%

Fan motor power

consumption7.048 kW 7.075 kW 0.39%

Turbine

rotational speed-

875 rpm

(free-running

condition)

-


8. Conclusions

An on-site green energy generation system that converts the wasted

wind resource from exhaust air systems to electricity is presented. The

design of the exhaust air recovery system is expected to recover 13%

of the power consumption by the cooling tower’s fan motor. Besides,

it is built with wind power augmentation features (guide-vanes and

diffuser-plates) that greatly improve the performance of the VAWTs by

accelerating the on-coming discharged airflow.

Based on the test results obtained from the laboratory test, it is

proven that the energy in the discharged air is extractable by installing

the energy recovery system without affecting its original performance

significantly. The motor current consumption remains at 0.85 Ampere

for all the three testing configurations. Meanwhile, the VAWTs’

performance has been improved when they are integrated with an

enclosure as the turbine rotational speed was raised from 463.72 rpm to

500.98 rpm. Minimum blockage effect from the designed system was

observed during field test since the discharged airflow was reduced by

1.73%. The performance of the VAWT is expected to match its rated

power when exposed to this discharged air speed. Also, there was no

significant difference on the motor power consumption as it was

maintained in between 7.0 to 7.1 kW.

An optimized system with two VAWTs installed on a common

cooling tower (2 m outlet diameter and powered by a 7.5 kW fan

motor) is expected to recover 1 kW of power. This system is retrofit-

able to any exhaust air system, which makes it has a high market

potential. The electricity generated can be fed into the electricity grid

or used for commercial purposes. It is a green technology invention

with great potential of reducing CO2 emission that leads us to future

greener cities. The system optimization and blockage effect

investigation will be the next focus of this project. It will take into

account the exhaust air system performance, environmental impacts

and conformance to building regulations to ensure this design is a safe

and reliable energy recovery system.

ACKNOWLEDGEMENT

The authors would like to thank the University of Malaya for the

research grants allocated for the development of this project which are

High Impact Research Grant (D000022-16001) and University of

Malaya Research Grant (RG113-11AET). A sincere gratitude is also

dedicated to the Malaysian Ministry of Higher Education (MOHE) for

Exploratory Research Grant Scheme (ER023-2012A). Special

appreciation is credited to Truwater Cooling Towers Sdn. Bhd. as well

for providing the facilities, fabrication material and manpower to

perform the field test.

REFERENCES

1. ExxonMobil, “2012 The Outlook for Energy: A view to 2040,”

2012.

2. Ali, R., Daut, I., and Taib, S., “A review on existing and future

energy sources for electrical power generation in Malaysia,”

Renewable and Sustainable Energy Reviews, Vol. 16, pp. 4047-

4055, 2012.

3. Ahmad, S., Kadir, M. Z. A. A., and Shafie, S., “Current

perspective of the renewable energy development in Malaysia,”

Renewable and Sustainable Energy Reviews, Vol. 15, pp. 897-904,

2011.

4. Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M.,

Averyt, K. B., Tignor, M., and Miller, H. L., “Climate Change

2007: The Physical Science Basis,” IPCC Fourth Assessment Report

(AR4), International Governmental Panel on Climate Change, New

York, 2007.

5. Chong, W. T., Naghavi, M. S., Poh, S. C., Mahlia, T. M. I., and

Pan, K. C., “Techno-economic analysis of a wind-solar hybrid renewable

energy system with rainwater collection feature for urban high-rise

application,” Applied Energy, Vol. 88, pp. 4067-4077, 2011.

6. Shan, Z., Qin, S., Liu, Q., and Liu, F., “Key manufacturing

technology & equipment for energy saving and emissions reduction

in mechanical equipment industry,” Int. J. Precis. Eng. Manuf., Vol.

13, pp. 1095-1100, 2012.

7. Chiu, M.-C. and Chu, C.-H., “Review of sustainable product design

from life cycle perspectives,” Int. J. Precis. Eng. Manuf., Vol. 13, pp.

1259-1272, 2012.

8. Kalantar, M. and Mousavi G, S. M., “Dynamic behavior of a stand-

alone hybrid power generation system of wind turbine,

microturbine, solar array and battery storage,” Applied Energy,

Vol. 87, pp. 3051-3064, 2010.

9. Ahmad, S., Hussin, W. M. A. W., Bawadi, M. A., and Sanusi, S.

A. M., “Analysis of wind speed variations and estimation of weibull

parameters for wind power generation in Malaysia,” University of

Science Malaysia, 2009.

10. Chong, W. T., Fazlizan, A., Poh, S. C., Pan, K. C., and Ping, H.

W., “Early development of an innovative building integrated wind,

solar and rain water harvester for urban high rise application,”

Energy and Buildings, Vol. 47, pp. 201-207, 2012.

11. Tiang, T. L. and Ishak, D., “Technical review of wind energy

potential as small-scale power generation sources in Penang Island

Malaysia,” Renewable and Sustainable Energy Reviews, Vol. 16,

pp. 3034-3042, 2012.

12. Sopian, K., Othman, M. Y. H., and Wirsat, A., “The wind energy

potential of Malaysia,” Renewable Energy, Vol. 6, pp. 1005-1016,

1995.

13. Shafie, S. M., Mahlia, T. M. I., Masjuki, H. H., and Andriyana, A.,

“Current energy usage and sustainable energy in Malaysia: A

review,” Renewable and Sustainable Energy Reviews, Vol. 15, pp.

4370-4377, 2011.

14. Islam, M. R., Saidur, R., and Rahim, N. A., “Assessment of wind

energy potentiality at Kudat and Labuan, Malaysia using Weibull


distribution function,” Energy, Vol. 36, pp. 985-992, 2011.

15. Mathew, S., “Wind Energy: Fundamentals, Resource Analysis and

Economics,” New York: Springer, 2006.

16. Akhgari, A., “Experimental investigation of the performance of a

diffuser augmented vertical axis wind turbine,” Ph. D. Thesis,

Department of Mechanical Engineering, University of Victoria,

2011.

17. Abe, K., Nishida, M., Sakurai, A., Ohya, Y., Kihara, H., Wada, E.,

and Sato, K., “Experimental and numerical investigations of flow

fields behind a small wind turbine with a flanged diffuser,” Journal

of Wind Engineering and Industrial Aerodynamics, Vol. 93, pp. 951-

970, 2005.

18. Ohya, Y., Karasudani, T., Sakurai, A., Abe, K. I., and Inoue, M.,

“Development of a shrouded wind turbine with a flanged diffuser,”

Journal of Wind Engineering and Industrial Aerodynamics, Vol. 96,

pp. 524-539, 2008.

19. Chen, T. Y., Liao, Y. T., and Cheng, C. C., “Development of small

wind turbines for moving vehicles: Effects of flanged diffusers on

rotor performance,” Experimental Thermal and Fluid Science,

Vol. 42, pp. 136-142, 2012.

20. Chilugodu, N., Yoon, Y.-J., Chua, K., Datta, D., Baek, J., Park, T.,

and Park, W.-T., “Simulation of train induced forced wind draft for

generating electrical power from Vertical Axis Wind Turbine

(VAWT),” Int. J. Precis. Eng. Manuf., Vol. 13, pp. 1177-1181, 2012.

21. Abe, K.-I. and Ohya, Y., “An investigation of flow fields around

flanged diffusers using CFD,” Journal of Wind Engineering and

Industrial Aerodynamics, Vol. 92, pp. 315-330, 2004.

22. Truwater, “TX-S Series Cooling Tower - Modular Design Crossflow

Type,” Truwater Cooling Towers Sdn Bhd, 2011.

23. Herrman, D. D., “Field tests of fan performance on induced draft

cooling towers,” Cooling Tower Institute, 1962.

25. JPEM-D-12-00241 Author Copy

Documents

Transcript of 25. JPEM-D-12-00241 Author Copy