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International Journal of Engineering & Technology, 7 (4.13) (2018) 74-80
International Journal of Engineering & Technology
Website: www.sciencepubco.com/index.php/IJET
Research paper
Comparison of horizontal axis wind turbine (HAWT) and
vertical axis wind turbine (VAWT)
Muhd Khudri Johari*, Muhammad Azim A Jalil, Mohammad Faizal Mohd Shariff
Universiti Kuala Lumpur – Malaysian Institute of Aviation Technology, Dengkil, Selangor, Malaysia
*Corresponding author E-mail: mdkhudri@unikl.edu.my
Abstract
As the demand for green technology is rising rapidly worldwide, it is important that Malaysian researchers take advantage of Malaysia’s
windy climates and areas to initiate more power generation projects using wind. The main objectives of this study are to build a function-
al wind turbine and to compare the performance of two types of design for wind turbine under different speeds and behaviours of the
wind. A three-blade horizontal axis wind turbine (HAWT) and a Darrieus-type vertical axis wind turbine (VAWT) have been designed
with CATIA software and constructed using a 3D-printing method. Both wind turbines have undergone series of tests before the voltage
and current output from the wind turbines are collected. The result of the test is used to compare the performance of both wind turbines
that will imply which design has the best efficiency and performance for Malaysia’s tropical climate. While HAWT can generate higher
voltage (up to 8.99 V at one point), it decreases back to 0 V when the wind angle changes. VAWT, however, can generate lower voltage
(1.4 V) but changes in the wind angle does not affect its voltage output at all. The analysis has proven that VAWT is significantly more
efficient to be built and utilized for Malaysia’s tropical and windy climates. This is also an initiative project to gauge the possibility of
building wind turbines, which could be built on the extensive and windy areas surrounding Malaysian airports.
Keywords: HAWT; VAWT; wind energy; wind turbine.
1. Wind energy
Malaysia, just like most countries in the world, is producing most
of its electricity by using coal and fossil fuel. Only around 10.74%
of the country’s electricity is generated from renewable source of
energy that is hydropower due to geological situation of Malaysia
[1]. According to a research, Malaysia has an average between 1.3
m/s and 2.7 m/s of wind speed inland, and variation from 3.5 m/s
to 4.5 m/s of wind speed on coast line that is considered being low
potential wind [2]. In the early 1990s, another wind energy poten-
tial study has been conducted at various cities in Malaysia. From a
set of wind speed data collected by the Malaysian Meteorological
Service Station for the research, it has been shown that Mersing
and Kuala Terengganu have had the most potential for wind power
with annual mean power of 85.61 and 32.50 W/m2, respectively. A
wind power potential that is less than 100 W/m2 is considered low
potential and is not suitable for wind power generation. The per-
centage for green energy is very low and Malaysia has to do some-
thing to reduce our dependency on coal and fossil fuel as our main
source for power generation. For this reason, wind energy is again
becoming an alternative as the modernization and development of
technology take place. IMPSA, a private company specializing in
power generation from renewable sources, has estimated that Ma-
laysia has a capacity to produce power from the wind energy be-
tween 500 to 2000 MW [3]. With 4675 km long coastline, Malay-
sia is ranked at 29th among other countries in the world and this
seems like a very good potential to develop the wind power capac-
ity in Malaysia.
Though it is already known that wind power generation is unpopu-
lar in Malaysia due to its location in equatorial zone that results in
irregular and relatively low wind speed, it does not impede various
research and development for the wind turbine power generation
in Malaysia with the help of development of wind turbine designs
that are specific for low potential wind area. Up until now, Malay-
sia has only few significant progresses in commercial wind energy
production. Small experimental projects such as those at Swallow
Reef and Perhentian Island are proofs that installing wind power
capacity is not an easy task due to low wind speeds and seasonal
variability. A study has suggested that Malaysian researchers shift
from the mesoscales winds to focusing on the macroscale wind as
it is proven to be more effective [4]. This research intends to be a
pioneer and future reference for that as the experiments involved
will imitate the potential surroundings of large, flat lands such as
vast areas surrounding airports rather than risking more failures to
install wind turbines in the sea or near beach areas.
2. HAWT and VAWT
2.1. Applications
Just like windmills, wind turbines take the advantage of the wind
energy and transform it into different form of energy. In this case
study, wind turbine converts the kinetic energy of the wind into
electrical energy. Wind turbines are used for various applications,
from harnessing energy for an entire city to a small power genera-
tion for personal use.
Small wind turbines are usually selected for local usage. With the
capability to produce electricity less than 100 kW, they are usually
installed in the isolated, remote and off-grid areas where there is
no connection to the national grid [5]. Nowadays, the wind turbine
technology has been used for everyday use and not only to power
International Journal of Engineering & Technology
75
up a rural village, through various innovation and development. In
December 2015, built by French Company, New Wind, the “wind
tree” has been introduced to the world. It is a vertical wind turbine
with several vertical blades, made in the shape of a tree. With just
under 30 ft tall and 23 ft wide, the “wind tree” has 54 leaf-turbine
that soundlessly rotating, harnessing energy up to 5.4 kW energy
at a time from wind with speed less than 5 mph [6]. Annually, the
wind tree is capable of producing 2400 kWh of electricity, enough
to power up a house. In addition, they are pleasing to the eyes too.
2.2. HAWT
The HAWT concept as depicted in Figure 1 has already been used
as early as 5000 B.C. where people extracting the energy from the
wind to move boats along the Nile River [7]. Since then, the wind
turbines have gone through significant innovation and improvisa-
tion in their design for optimum performance. HAWT consists of
blades that extract wind energy on horizontal axis and are parallel
to the ground. By facing the wind flow perpendicularly, the blades
work and turn due to aerodynamic lift. HAWT is the most popular
choice of wind turbine and has received more funding for research
and development since it offers significant advantage over VAWT
[8]. HAWT have a greater efficiency then VAWT when extracting
energy from the wind force due to its design that allows it to ex-
tract the energy through the full rotation of the blades when placed
under consistent wind flow [9]. It is also immune to backtracking
effect [10].
Fig. 1: Horizontal axis wind turbine
(Source: Windpower Engineering & Development)
However, HAWT has a major disadvantage, which is the fact that
it must always be pointed in the wind direction to work efficiently.
With unpredictable wind direction, extra mechanism is required to
make sure the blades will always be facing the wind direction to
extract maximum power output. Small wind turbine usually uses a
simple wind vane to position itself into the direction of the wind
stream. For larger wind turbine, it consists of a yaw meter to de-
termine the correct position of the wind flow and a yaw motor to
position the turbine into accurate direction of the wind [11]. Be-
cause of this disadvantage, HAWT works excellently in environ-
ment with consistent and low turbulence wind as it does not need
to change its orientation too frequent.
2.3. VAWT
In contrast to HAWT, Figure 2 shows the blades for VAWT rotate
perpendicularly to the ground and around the vertical axis. This
type of turbine utilizes drag or lift or a combination of the two to
operate. VAWT has also been used for ages and in fact, the first
windmills that people have ever known are VAWT before HAWT
appears and becomes popular at some points in the history of wind
turbine. There are generally two main designs of VAWT and both
designs work on different principles. The first design is Savonius
that uses drag forces to work just like a water wheel and the other
design is Darrieus that uses aerodynamic blade to generate lift and
turn the turbine.
Fig. 2: Vertical axis wind turbine
(Source: Windpower Engineering & Development)
Although VAWT has not been given as much attention as HAWT
in its research and development, it has several significant ad-
vantages compared to HAWT. Unlike HAWT that is required to
face the wind stream all the time in order to give the optimum
output, VAWT is omnidirectional and can receive wind from any
direction [12]. VAWT is the best choice to be installed in the slow
and more turbulent wind environment such as urban areas because
it can generally start to produce power at such low wind speed.
The system for VAWT such as gearbox and other equipment can
be packed together and installed closer to the ground, hence elimi-
nating the need for extra cost for maintenance and making it easier
to be controlled [13]. Finally, the VAWT are quieter than HAWT
too. However, the disadvantage of VAWT also cannot be ignored
easily. VAWT is inefficient in high speed wind environment be-
cause it has very low starting torques and issues on its dynamic
stability. VAWT is also vulnerable to backtracking because its
blade moves in the same direction to the wind and thus the blades
need to travel back into the wind flow before being pushed back
around [14].
It is important to note that previous studies comparing VAWT and
HAWT have shown mixed results. There can either be that there is
no significant difference between them [15] or one is simply better
than the other [16].
2.4. 3D Printing
Thermoplastic is typically used for prototype development as it is
easy to handle. Thermoplastic becomes malleable when heated at
certain temperature, hence allowing it to be moulded and sculpted
into the intended shape prior to cooling. There are several types of
thermoplastic that can be used for 3D printing such as Polylactic
Acid (PLA), Acrylonitrile Butadiene Styrene (ABS), Polyamide
(PA), Thermoplastic Elastomer (TPE) and High Impact Polysty-
rene (HIPS). However, PLA and ABS are the most accessible ones
around and they have their own properties that need to be looked
at before considering using any of these two materials.
PLA thermoplastic is made up of the building blocks of lactic acid
that are derived from sugars and can be found in the common crop
such as corn, which belongs to the aliphatic polyesters family [17].
This makes PLA not only bio-based polymer but also compostable.
Although PLA is very strong and have very high stiffness, it has a
few weaknesses that limit it from being used for wider application.
PLA is brittle and has poor thermal stability at relatively low tem-
perature [18]. Compared to PLA, ABS polymer is synthesized
from three monomeric chemicals: acronym, butadiene and styrene
[19]. ABS thermoplastic is petroleum-based polymer and broadly
used in several industries. ABS is known for its balance properties
including strength, stiffness, toughness and thermal stability. Ta-
ble 1 presents the detailed comparison of both PLA and ABS that
has been derived from a previous study.
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International Journal of Engineering & Technology
Table 1: Properties of ABS and PLA
Properties
ABS
PLA
Tensile strength
27MPa
37MPa
Elongation
3.5 - 50%
6%
Density
1.0 – 1.4 g/cm³
1.3 g/cm³
Melting point
N/A (amorphous)
173°C
Biodegradable
No
Yes
Glass transition temperature
105°C
60°C
3. Methodology
Both types of wind turbine for this research have been constructed
by using 3D printer. The material used is PLA thermoplastic. For
VAWT, Darrieus design has been chosen and a simple HAWT has
been used for this study. Both blades, as illustrated in Figure 3, are
designed using CATIA software before the file is being translated
into STL format to be read and printed by the 3D printer.
(a)
(b)
Fig. 3: Proposed designs of wind blade section, (a) VAWT, (b) HAWT
The power generator selected for this study is a permanent magnet
generator. Before the generator is selected, two tests have been
arranged for the generator to verify the relationship between vari-
able RPM of the commutator and the output voltage and current
generated. This is essential to ensure that the generator chosen will
generate the voltage accordingly and obey the Faraday’s Law. In
these tests, the speed of magnetic flux cutting is manipulated and
the generated voltage and current is the responding variable.
For the first test, the generator is not connected to any load. The
generator shaft is driven by 60 RPM DC motor as the testing mo-
tor, with model number ZGB37RG58i, rated 12 V through same
size of gearing. The input voltage to the DC motor is varied from
0 V to 9 V by using variable resistor to manipulate the RPM of the
motor, hence vary the RPM of the generator. Two multimeters are
used to determine the output voltage to the DC motor and the gen-
erated voltage from the generator. The arrangement and wiring
diagram for the test can be seen in Figure 4. Output voltage read-
ing is done three times and the average reading is taken.
Fig. 4: Generator without load test wiring diagram
Just like in the first test, the arrangement for the second test is the
same but with additional load. A bulb, rated 12 V 3 W, is attached
to the generator. An ammeter is connected in series with the bulb
to measure its current. The arrangement and also wiring diagram
for the test can be seen in Figure 5.
Fig. 5: Generator with load test wiring diagram
To measure the power generated by the generator, wires from the
generator are passed through the voltmeter and ammeter. The cur-
rent and voltage output are taken, and the power generated is cal-
culated. The anemometer is used to measure wind stream speed.
The arrangement and wiring diagram for the wind turbine can be
seen in Figure 6.
Fig. 6: Wind turbine wiring diagram
Both wind turbines are tested in two different environment: indoor
testing with steady air stream source and outdoor testing for ambi-
ent air stream. For indoor testing, which is reported in this paper,
there are two variables that are manipulated. First is the speed of
air stream source and second is angle of the air source with respect
to the direction of wind turbine. Both variables are varied in order
to observe their effects on the performance of both types of wind
turbine against certain behaviour of the wind.
International Journal of Engineering & Technology
77
The first variable that is varied during the indoor testing is speed
of the airstream. The speed of air coming from air stream source is
varied and output voltage and current readings are taken. Just like
the generator testing, the wind turbines are tested with load (12 V,
3 W bulb) and without load. For the second variable, which is the
wind angle, the direction of air source with respect to the direction
of the wind turbine and anemometer is varied while maintaining
the speed of air stream source. The test arrangement can be seen in
Figure 7.
Fig. 7: Indoor testing plan
4. Analysis
4.1. Functional wind turbines
The functional wind turbine prototype has been constructed using
two types of material, which are PLA thermoplastic for the blade
section and steel for the stand. This prototype, as shown in Figure
8 and Figure 9, is equipped with block bearing, generator section
and metal stand. Both wind turbines have undergone a functional
test and successfully generating power.
Fig. 8: VAWT prototype
Fig. 9: HAWT prototype
The main section of the wind turbine is the blade where both de-
signs are using PLA thermoplastic as the main material. Both pro-
totypes have been constructed using 3D printing technique. Proto-
type of HAWT blade section consists of four main parts which are
blades, center, pin and adaptor. Just like HAWT, the prototype of
VAWT blade section also consists of 4 main parts, which are wind
catcher, center, pin and adaptor. Table 2 and Table 3 below list the
details of the parts.
Table 2: HAWT parts details
Part Number
Part
Qty.
Weight (G)
AJ1
Centre Part
1
77
AJ2
Wind Blade
3
60
AJ3
Lock Pin
3
6
AJ4
Generator Adapter
1
1
Total Weight
276
Table 3: VAWT parts detail
Part number
Part
Qty.
Weight (g)
AJ1
Centre part
1
77
AJ5
Wind catcher
3
118
AJ3
Lock pin
3
6
AJ4
Generator adapter
1
1
Total Weight
450
Both the weight and material of the prototype have been analyzed
carefully. It can seen that the weight of VAWT is almost double of
that for HAWT. This has significantly affected the performance of
the prototype as more weight produces higher torque. Much faster
wind speed is needed to turn VAWT than HAWT to produce the
same amount of electrical power. The weight, as well as torque, is
important to be considered in designing wind turbines. Torque is
not only affected by weight of the blade section but also the gen-
erator and friction in bearing.
A major drawback in using PLA thermoplastic compared to ABS
is its low glass transition temperature at 60°C. Though PLA ther-
moplastic is easier and safer to use, and have a better level of print
detail, it is prone to warping and melting when it is stored in high-
temperature locations. These prototypes have melted and warped
after being stored inside a car at 3.00 pm. From this finding, it can
be concluded that PLA thermoplastic is not suitable to be used for
prototype that is built for high temperature environment applica-
tion. The high ambient temperature, especially in the hot countries
such as Malaysia, can get as high as 40.0°C [20]. The temperature
issue can be worsen with additional heat coming from friction and
generator that affect the material of the prototype during its opera-
tion.
4.2. Generator details
The power generator selected for this study (refer specifications in
Table 4) is a permanent magnet generator, JGB37-3530 12 V DC
geared motor that is turned into a generator. It is equipped with the
gearbox and holder. The generator is connected to the blade sec-
tion through the adapter. The selection of generator is important as
it will affect the total torque of the wind turbine. An ideal choice is
a generator with low torque and high-power output. This can re-
duce the minimum wind speed required to turn the generator and
produce power. The diameter of the blade section is determined by
the torque of the generator as longer diameter blade design is re-
quired to increase the moment to overcome it. Before the genera-
tor is selected, two tests have been arranged for the generator to
verify the relationship between variable RPM of the commutator
and the output voltage and current generated. Two generators have
been tested, JGB37-3530 and M3N-2 generator motors, where in
this test the speed of the magnetic flux cutting is manipulated. The
generated voltage and current are the responding variables. The
generators are tested with load (12 V, 3 W bulb) and without load.
Table 4: Generator specifications
Motor model
JGB37-3530
Gear ratio
18.8:1
Weight
180g
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International Journal of Engineering & Technology
The result of the tests, which is presented in Figure 10 and Figure
11, shows that both generators can be used for the wind turbine as
both obey the Faraday’s Law. As the input voltage to the testing
motor increases, the output voltage from generator also increases.
This is due to the increase of speed of magnetic flux cutting in the
generator, driven by the increased speed of the testing motor. The
output of the generator is directly proportional to the output of the
generator.
Fig. 10: JGB37-3530 testing with no load
Fig. 11: M3N-2 testing with no load
Similar to first test, Figure 12 and Figure 13 show that as the input
voltage to the testing motor increases, output current from genera-
tor also increases. The current output of the generator is directly
proportional to the output of the generator. However, JGB37-3530
is chosen due to its higher current and voltage output compared to
M3N-2. At 9 V input to testing motor that is rotating the generator,
JGB37-3530 gives out 70.1 mA, which is almost triple than that of
M3N-2, which gives out only 26.9 mA. This result makes JGB37-
3530 a clear choice. The reason behind higher output of JGB37-
3530 generator is the 18.8:1 ratio gearbox attached to it. The gear-
box increases the rotation of the commutator of JGB37-3530 gen-
erator, 18.8 times higher compared to that for M3N-2 generator.
Higher rotation of commutator means higher speed of magnetic
flux cutting in the generator, hence higher current output. JGB37-
3530 generator is used for wind turbine construction in this study.
Fig. 12: JGB37-3530 testing with load
Fig. 13: M3N-2 testing with load
4.3. Indoor testing
The test for both wind turbines has been done in an indoor testing
with steady air stream source. For this test, two variables are ma-
nipulated. The first one is the speed of air stream source and the
second one is the angle of air source with respect to the direction
of wind turbine. This test is done to see how both variables affect
the performance of both type of wind turbine against various be-
haviours of the wind. The generators are tested with the load (12
V, 3 W bulb) and without load. The first variable that is varied
during indoor testing is the speed of air stream. The output voltage
and current from the wind turbines are taken.
The results of the test are presented in Figure 14 and Figure 15,
which show that both wind turbines obey the Faraday’s Law. As
the speed of the air stream that hit the blade of the wind turbine
increases, the output voltage from generator also increases. This is
due to the increase of speed of magnetic flux cutting in the genera-
tor, driven by the increase speed rotation of the blade section. The
voltage output of the generator is directly proportional to speed of
the air stream.
Fig. 14: HAWT indoor testing without load
Fig. 15: VAWT indoor testing without load
Similar to the test with no load, as the speed of the air stream that
hit the blade of the wind turbine increases, the output voltage from
generator also increases. Current output of the generator is directly
proportional to the output of the generator. However, it can be
observed that there is a big difference in current and voltage out-
put between HAWT (as shown Figure 16) and VAWT (as shown
in Figure 17) in the indoor testing. At 23.8 km/h speed of wind
that is turning the blade section, HAWT produces 8.6 V voltage
output without load and 3.85 A current output with load. Mean-
while, the VAWT produces just 1.42 V without load and 1.83 mA
with load. This huge gap in current and voltage output is due to
certain factors. The major factor is the weight difference between
both wind turbines. The weight of the VAWT is almost double the
weight of the HAWT. This factor really affects the performance of
the prototype as more wind speed is needed to turn heavier blade
section. Heavier prototype results in higher torque, hence reduces
the wind turbine performance. Reducing weight in design is im-
portant since torque is not only affected by the weight of the blade
section blade but also from the generator and friction in bearing.
International Journal of Engineering & Technology
79
Fig. 16: HAWT indoor testing with load
Fig. 17: VAWT indoor testing with load
The other factor that results in a huge different in current and volt-
age output is the efficiency between HAWT and VAWT. VAWT
is not as efficient as HAWT in high-speed wind environment. This
is because VAWT has exceptionally low starting torques and is-
sues on its dynamic stability. It is also vulnerable to backtracking
since its blade moves move in the same direction to the wind and
it makes the blade needs to travel back into the wind flow before
being push back around. Compared with HAWT, it has a greater
efficiency then VAWT when extracting energy from wind force.
The second variable that has been varied during the indoor testing
is the wind angle, the direction of air source with respect to direc-
tion of wind turbine and anemometer. The speed of air stream is
maintained at 24 km/h. The angle is varied at 90°, 45°, 0°, -45°
and -90°. The voltage output from the generator is collected. From
the test, two different kinds of patterns can be seen in the graphs.
Figure 18 indicates that HAWT test result starts at 0 V when wind
angle at 90°, increasing to 5.10 V at 45°, reaching maximum 8.99
V at 0°, decreasing to 5.52 V at -45° and then reaching 0 V back at
-90° wind angle. Compared with HAWT, VAWT has more steady
output, which the voltage output maintains between 1.28 V to 1.4
V when the wind angle is changing as in Figure 19.
The difference of the pattern between both results can be ex-
plained. This is because of difference in design of the wind turbine
and the two designs work efficiently in different environment. For
HAWT, it is efficient in steady and also consistent air stream. This
is because the design only allows it to extract energy through the
full rotation of the blades when placed under a consistent wind
flow directly to the direction of the blade. When the angle of the
wind changes away from the direction of the blade, HAWT effi-
ciency decreases abruptly. This is different for VAWT, which is
efficient to work in unpredictable change of the wind angle.
VAWT is omnidirectional and can pick up wind energy from any
direction around its blade. This makes VAWT has a steady output
although there are changes in angle of the wind stream.
Fig. 18: HAWT angle testing
Fig. 19: VAWT angle testing
5. Conclusion
As energy resources in the world continuously depleting, the im-
portance of green energy keeps rising every day. Malaysia, one of
the lucky countries blessed with not just windy beaches around the
country but also airports surrounded by massive, empty land areas,
should optimize this gift and start considering wind energy as one
of the energy sources. This can significantly boost not just Malay-
sian airports’ performance and ranking in general [21], but also
other related institutions such as aircraft maintenance training [22]
and renewable energy institutions in this country. However, cur-
rently there is a lack of research in wind turbine, especially focus-
ing between comparison of HAWT and VAWT performance in
this country. This study is focused on building the functional wind
turbines and comparing the performance of HAWT and VAWT
under certain wind speed and behaviours, which is just one of the
aspects that need to be considered. In term of power generation
under steady wind stream, HAWT is clearly the better one. The
HAWT is able to produce much higher energy in steady and high
wind stream. However, this is not a feasible form of analysis be-
cause the two types of wind turbines are not comparable in this
regard. The huge gap in current and voltage output is due the ma-
jor weight difference between both wind turbines. The weight of
the VAWT is almost double the weight of the HAWT. This factor
really affects the performance of the prototype as more wind speed
is needed to turn heavier blade section. A better comparison can
be made based on the second indoor testing: wind angle change.
VAWT is efficient in this environment where the direction of the
wind is changing. While the performance of HAWT is dropping as
the direction of the wind is away from the direction of the blade,
VAWT is capable to maintain the output throughout the test. In
sporadic environment, HAWT is facing the difficulties to respond
while VAWT flourishes in turbulent and sporadic wind pattern. In
Malaysia where the wind direction is unpredictable, a VAWT with
improvable performance would most likely perform better than the
HAWT due to its ability to handle turbulent and omni-directional
wind.
Acknowledgement
This project is financially supported by Universiti Kuala Lumpur’s
Short-Term Research Grant.
80
International Journal of Engineering & Technology
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