NOVEL DESIGN WORK IN ENERGY EXTRACTION FROM IN-STREAM WATER BY VARIOUS TYPES OF MICRO HYDRO TURBINES

Abstract

Purpose- Micro-hydroelectricity power projects are becoming popular because it is a proven low cost electricity-generating source. This research designed to evaluate energy extraction efficiency of single stage and multistage blade of micro Hydro turbine. Experiments have been conducted with two-laboratory scale turbine at instream water velocity ranges from 0.5m/s to 1 m/s. The finding shows that energy extraction and transfer efficiency of multistage MHT is about 5.5 percent higher compare to single stage MHT. This study concludes that multistage MHT is cost effective as energy extraction efficiency is higher and it could be an energy solution for rural societies. Indeed, the multistage MHT could be a useful electricity generating equipment for supporting rural economy.

Full text

Sci.Int.(Lahore),29(1),161-166,2017 ISSN: 1013-5316; CODEN: SINTE 8 161
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A NOVEL DESIGN WORK IN ENERGY EXTRACTION FROM IN-STREAM
WATER BY VARIOUS TYPES OF MICRO HYDRO TURBINES
Shahidul. M.I1, S.T. Syed Shazali2, Abdullah Yassin3, A.S.H. Sarip.4.
Department of Mechanical and Manufacturing Engineering, Faculty of Engineering, University Malaysia Sarawak, 94300
Kota Samarahan, Sarawak, Malaysia,
Corresponding author: Shahidul. M.I (mislam@unimas.my)
ABSTRACT: Purpose- Micro-hydroelectricity power projects are becoming popular because it is a proven low cost
electricity-generating source. This research designed to evaluate energy extraction efficiency of single stage and multistage
blade of micro Hydro turbine. Experiments have been conducted with two-laboratory scale turbine at instream water velocity
ranges from 0.5m/s to 1 m/s. The finding shows that energy extraction and transfer efficiency of multistage MHT is about 5.5
percent higher compare to single stage MHT. This study concludes that multistage MHT is cost effective as energy extraction
efficiency is higher and it could be an energy solution for rural societies. Indeed, the multistage MHT could be a useful
electricity generating equipment for supporting rural economy.
Keywords: Micro Hydro Turbin,; Multi-Stage MHT, energy Efficiency, Energy Performance
1. RESEARCH BACKGROUND
This research aims to assess the most efficient way to
generate green energy from instream water by using micro-
hydro turbine. This study carried out to support clean and
renewable energy application to ensure the environment
sustainability. Besides, this study performed to support
communities living in the coastal areas by providing
information to harvest energy from Instream water by using
Micro Hydro Turbine (MHT). Thus, the research on MHT is
an approach to contribute to achieve economic and
environmental sustainability.
In coastal areas, have the difficulties of getting constant
electricity supply due to its remote surrounding where normal
power grid is not available. Currently, fossil fuel based
generator use to carry out this function for supplying
electricity. The problems of using commercial generator are
not environmental friendly due greenhouse gas emission and
the maintenance cost of engine operations. In this context,
renewable energy is the best option. Micro hydropower plant
is one of the favoured options among other alternatives such
as wind power and solar system.
Hydropower is the most favourable because this source is
available constantly. Application of MHT shall be
environmental friendly compared to the conventional hydro
power plant and mini hydro power plant. The method of
energy harvesting of MHT is the same as the conventional
hydropower do. The operating procedure of MHT is the
water velocity turns the turbine blades and produce
mechanical energy; and this energy is transfereg to generator
for producing electrical energy.
The known fact is that energy harvesting optimization from
instream water would contribute to reduce electricity
production cost; and in order to achieve this goal, it is
essential to know MHT configuration and installation criteria.
Abundance of information on MHT operations and energy
extraction procedure are available in the published literature;
even the authors of this paper have published a few research
papers on MHT operations and energy harvesting. However,
in the aspect of energy extraction efficiency difference
between multistage MHT and single stage MHT is not
available in published literature. In order to fil-up this gap,
authors have undertaken this research project.
1.2 Problem Statement
In coastal area, the society living there having difficulty in
getting constantly supply of electricity. In absence of
supplying electricity from national grid, communities living
in these areas, fossil fuel base generators use to produce
electricity. In this aspect, micro hydropower plant has the
potential to solve the energy issue faced by the coastal area.
Thus, micro hydropower plant appears electrical energy
supply source for coastal areas. In this aspect, needs to pay
attention on for fully utilizing production capacity of MH for
increase energy harvesting efficiency.
Therefore, operating properties of MHT is essential to
evaluate optimum electric energy production condition. To
ensure expected energy harvesting from MHT, this research
designed to get answer of the questions about, “which
turbine is energy efficient between single and multistage
blade?
1.3 Objective Of The Study
The objective of this research is to investigate energy
extraction performance of MHT by using multi stage blades
and single stage blade turbine at lower water velocity (V≤ 1.0
m/s). In order to achieve the goal, the broad objectives divide
into three specific objectives:
a) Measuring energy extraction performance by using
multistage blade micro hydro turbine in In-stream water.
b) Measuring energy extraction performance by using single
stage blade micro hydro turbine in In-stream water.
c) To evaluate impact of multistage and single stage blade on
turbine performance at low water velocity (V≤ 1.0 m/s).
1.4 Scope Of Work
For achieving the research goals, theoretical framework
relevant to this research gathered from the published research
papers. Laboratory scale of one-multi stage blades and one
single stage blade MHT used separately for conducting
experiment. The last stage of this research is data analysing
for achieving targeted research goals.
1.5 Novelty Of Research Study
This paper focused on the evaluation of energy extraction
performance of multistage and single MHT at water velocity
ranging of 0.5 m/s to 1 m/see. This type of work is not
available in the published literature. In this aspect, the current
work is original and novel.

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2. LITERATURE REVIEW
Micro-hydro projects are becoming popular due to society’s
need for generating electricity from green energy sources like
in-stream water. To operate a MHT, dam is not required; the
capital cost equipment of this type of turbine lower than
compare to the large-scale hydro systems [1]. The latest
studies on micro hydro turbine system suggest that this
technology is reliable and friendly to environment compare to
fossil fuel energy. It also provides a solution to energy supply
for remote and hilly areas where the extension of national
grid system is not economically and technically feasible [2,3].
Hydro power plant is a technology that utilizes the energy
contains in in-stream water. Conventionally, a turbine use for
harvesting instream water energy by installing MHT in the
direction of a water stream. The velocity of the water stream
turns turbine blades and transmits mechanical energy to
generator for producing electricity. Micro hydro is a type of
hydroelectric power that typically produces from 5 kW to
100 kW of electricity by using the natural flow of water. The
efficiency of most MHT found to be ranging from 30 percent
to 40 percent [4].
In regards to Cross flow MHT, Verdant Power had made a
test report on operations and which indicates that energy
extraction of MHT depends on water velocity and effective
area of turbine blades [5,6]. New energy corporation
manufactured a turbine, their test report had indicated that it
produced 13.0 kW at water velocity 2.5 m/s. Thropton
Energy Service had made a similar report; they found that
their manufactured turbine had produced 2.0 kW at water
velocity 1.5 m/s. These results proved that the power
extraction efficiency depends on water velocity. Alternative
Hydro Solutions LTD and GCK Technology Inc. had
produced a few turbines with blade area 3.0 m2 and 1.0 m2
respectively. The output power of these turbines was 2.6 kW
and 0.70 kW respectively, though the water velocity for both
cases was 1.4 m/s and 1.3 m/s respectively. These findings
have proved that turbine blade area can play a significant role
in extracting energy from water [7].
2.1 Theoretical Framework For Energy Extraction
Performance By Using Multistage Blade System
Optimizing energy extraction is the key objective of this
research project. To achieve this goal, a mechanical device is
essential to maximize velocity drop across the turbine blades
for maximizing energy harvesting from in-stream water [8].
In order to increase energy extraction efficiency, the outlet
water velocity (Vo) at the turbine exit must be minimized; and
to achieve this condition, the water velocity drop across the
blades must be maximized. Therefore, the challenge of this
research project is to increase velocity drop by reducing
outlet water velocity (Vo) across the blade surface.
2.1.1 Energy Flow Modelling Of Instream Water
The conceptual model of energy extraction and conversion to
mechanical energy of MHT presents in Fig.1.
Fig.1: conceptual model of energy extraction by turbine
blades
Fig.1 demonstrates that the inlet water velocity (Vi) is passed
over the blades surfaces. At the exit of blade surface, water
velocity Vi is reduced to Vo. The difference between Vi and
Vo is known as velocity drop(▲V) across turbine blades. The
velocity drop considered as indicator of energy extraction by
turbine blades. Therefore, the interaction maximization
between water flow and blade surfaces is the determinant of
energy extraction of MHT [9].
2.1.2 Model Development Of Energy Extraction By
Using Multistage Blade System
The energy available in instream water presents by Eq.1:
Eq. (1)
Here, E is kinetic energy carrying by in-stream water. ‘A’ is
the blade area contact with flowing water. ‘C’ is power
coefficient; ‘V’ is water velocity in m/s at inlet point. And ‘ρ’
water density (kg/m3) at normal atmosphere conditions [10].
This equation indicates that blade area is a dominant factor
for energy extraction. Another important factor of energy
extraction is water velocity drop across blades of a turbine
[11].
2.1.3 Model Development For Water Velocity Drop
In a study on MHT, Arena (2011) had found that the velocity
drop in a single stage turbine is about 33 percent with respect
to inlet water velocity [11, 12]. It indicates that in the single
stage turbine, water velocity at MHT exit point is quite high
(about 67 percent). This concept mathematically represents
by Eq.2:
Eq.(2)
Where, Vi is inlet velocity of water at Turbine blade. Vo is
outlet velocity of water at turbine exit point. ‘n’ is the stage
of turbine blades, i =1,2,3------n and ▲V [▲V = Vi-Vo] is
the velocity drop across the turbine blades.
2.1.4. Mode Development For Blade Area For Energy
Extraction Performance
2.1.4 (a) Model Development For Multi-Stage Blade
Area
The basic model of energy extraction that stated by Eq.1
which shows that energy extraction performance depends on
blade surface and water flux. The total blade area of a
multistage turbine presents in Fig. 2 and by Eq.3 [11].

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Eq.(3)
Here, ‘At ‘ is total blade area of turbine; ‘Ai ‘ is area of
individual blade; ‘n’ is the number of blades of a turbine.
Fig. 2a: Single Stage Blade assembly
Fig. 2a: Single Stage Blade assembly
Fig. 2b: Multistage Turbine Blade Assembly
The energy vector shown in Fig. 2b indicates that ‘R’ is the
reactive force, which generates during water flow over the
blades. The magnitude of ‘R’ depends on the amount of water
velocity drop over the blade surface and this force contributes
to rotating turbine shaft.
2.1.4 (a) Model Development For Single Stage Blade
Area
In the single stage MHT, the blades installed parallel to each
other and in-stream water only hits blades nth time during the
flow over blade. This scenario has depicted in Fig.3. The area
of the blades presents by Eq.4 [11].
Eq(4)
Here, ‘At ‘ is total blade area of turbine; ‘At ‘is area of
individual blade which can be measured by using blade
length(L) and width (W).
Model Development For Energy Extraction And
Transfer Efficiency
The hydro energy flow from water to blades and transfer to
turbine shaft sated in 2.1.1 and by Figure 1. This energy
transfer model indicates that a part of kinetic energy of water
stream absorbs by turbine blades (Pb) when water moves
over the blade surface; and a part of Pb transfer to turbine
shaft (Ps). The difference between Pb and Ps consider as
energy loss due to friction within the turbine system. Finally,
the shaft energy Ps convert to electricity through a generator.
Based on this statement, the Energy Extraction and Transfer
Efficiency’ model develop presents by Eq.5.
(Eq.5)
Here,. ‘ƞ’ is energy extraction and transfer efficiency (ƞ >0).
2.1.5 Mode Development Of Energy Loss In Turbine
System
The energy loss in turbine system is the difference between
the amounts of energy absorbs by the turbine blades (Pb) and
energy transfer by turbine shaft (Ps). The energy loss model
presents by Eq.6
(Eq.6)
The energy loss in percentage form is:
100 (Eq.7)
3. RESEARCH METHODOLOGY AND
EXPERIMENT SETUP
The study on evaluating energy extraction performance by
MHT conducted at operations research laboratory of
Universiti Malaysia Sarawak. At the first state, a significant
number of relevant published papers reviewed for collecting
latest research information on MHT research. At the second
stage of research, a few number of conceptual models and
mathematical models have developed relating to energy
extraction and energy transfer performance. The authors did
experiment with multistage MHT and single stage MHT at
the third stage. At fourth stage, data collection, quality
control of data and model estimate performed. The authors
did reporting writing at the last stage of this research.
3.3 Research Design
Two-laboratory scale MHT have used for conducting this
research. One multistage MHT with five blades (five blades
are installed in series format in a common shaft); and another
single stage blade MHT (blades are installed in a shaft in
parallel format) have used. The water velocity ranges of this
research were from 0.5m/s to 1.0 m/s. To achieve research
objectives, Inlet (Vi) and outlet (Vo) water velocity were
measured, and energy extraction efficiency model estimated
as present by Eq 5 [13,14].
3.2 Experiment Setup And Data Collection Procedure
The layout and machinery setup of this experiment presents
in Fig.3a and In Figure 3b.. The main equipment associated
with the experiment were water channel, variable speed water
pump, water flow piping system, five stage MHT, single
stage MHT and alternator for converting mechanical energy
to electrical energy.

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Fig3a. layout of Experiment Setup (b) machinery
Fig 3b. Experiment Setup
Two centrifugal pumps used to maintain water flow. Water
flow rate and water velocity regulated by using frequency
inverter. Two velocity meters used to measure inlet and outlet
water velocity. One manual-drive tachometer used to measure
turbine speed (RPM). The total operating time of machinery
was 240 hours in different working days. Four sets of data
(0.5m/s, 0.7m/s, 0.9m/s and 1.0 m/s) gathered from
experiments. In order to reduce estimated error and achieving
higher data quality, statistical technique, and SPSS software
used. The data within 3.0 standard deviations (3σ) used for
model estimation.
4. DATA ANALYSIS AND FINDINGS
This study conducted to evaluate the energy extraction
performance of multistage blade and single stage blade micro
hydro turbine at water velocity ranging from 0.5m/s to
1.0m/s. Energy extraction performance measured in terms of
energy extraction efficiency, velocity drop at blade surface
and energy transferred by turbine shaft. The findings of this
research relating to three objectives listed in Table 1. The
analysis of three research objectives presents in sections 4(a),
4(b) and 4(c).
4(a). Measuring Energy Extraction Performance By
Using Multi Stage Blade Micro Hydro Turbine In
In-Stream Water
The energy extraction performance of multistage MHT listed
in column 3 of Table 1, which relates to objective number
one of this research. The estimated results indicate that
energy extraction performance increased with velocity. At
water velocity 1.0 m /s energy, extraction appeared 75.2
percent which highest value recorded during the experiment.
The velocity drop found 24.8 percent with energy transfers
54.3 percent, which appeared the highest value at 1 m/s of
water velocity. On the other hands, energy lost in the turbine
system found 24.5 percent, which appeared highest value
compared to energy lost at water velocity 0.5m/s. Thus, this
study achieved research objective as stated in 1.3(a).
4(b). Measuring Energy Extraction Performance By
Using Single Stage Blade Micro Hydro Turbine In
In-Stream Wate
The energy extraction performance of single stage MHT
listed in column 4 of Table 1. The estimated results indicate
that energy extraction performance increased with velocity.
At water velocity 1.0 m/s, energy extraction found 68.1
percent, which appeared the highest recorded value during
the experiment. The velocity drop found 23.5 percent with
energy transfers 43.2 percent at 1.0 m/s water velocity. On
the other hands, energy lost in the turbine system found 31.7
percent, which appeared highest value compare to energy lost
at water velocity 0.5m/s. Thus, this study estimated energy
extraction performance of single stage MHT that state in
1.3(b).
4(c). To Evaluate Impact Of Multistage And Single Stage
Blade On Turbine Performance At Low Water
Velocity (V≤ 1.0 M/S)
The research findings indicate that te energy extraction
efficiency of multistage MHT is about 10.5 percent higher
compared to single stage MHT. The water velocity drop
across the multistage MHT blades found about 5.5 percent
higher compare to single stage MHT. However, the energy
loss at single stage MHT found about 3.9 percent higher. In
this aspect, multistage turbine appeared energy efficient
compare to single stage MHT. The energy transfer of
multistage MHT found about 18 percent higher compare to
single stage MHT. Based on these experimental findings, the
study concludes that the performance of multistage MHT is
higher than single stage MHT at water velocity ranging of 0.5
m/s to 1.0 m/s. Thus, this study achieved the research
objective that stated in 1.3(c) [15].

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Table 1: Micro Hydro Turbine Performance Matrix
 Water velocity –meter/see. ** Defined in section 2.1.1 to 2.1.
5. CONCLUSION AND RECOMMENDATIO
This study evaluated energy extraction performance of
multistage and single stage MHT. Based on findings,
authors conclude that the performance of multistage MHT is
higher than single stage MHT at water velocity ranging of
0.5 m/s to 1.0 m/s. This finding is very similar and
comparable with other studies of the authors. Shahidul et al.
(2015) reported that multiage MHT significantly efficient
compared to single stage MHT. Shahidul et al (2011) also
reported that velocity drop across turbine blade and the
energy extraction are significantly higher at water velocity
ranges from 1.0 m/s to 2.5m/s [3]. Based on all research
findings, the authors conclude that multistage MHT at low
water velocity could give energy solution [11, 15].
5.1 Implication Of Research Findings
The outcomes of this research have a few implications in the
rural economy. The established fact is that multistage MHT is
an energy solution for remote area; indeed, the higher
efficiency of MHT will contribute to reduce energy
production cost. In this aspect, multistage MHT is a cost
effective energy solution for rural economies. The multistage
MHT is an energy solution for coastal area in generating
electricity for household activities, agriculture farming and to
operate water desalination process. These findings would
insist policy makers for commercializing this turbine.
5.2 RECOMMENDATION FOR FUTURE RESEARCH
The current study focused on evaluating energy extraction
performance of multistage and single MHT at water velocity
ranging from 0.5m/s to 1m/s. The operating properties of this
turbine at higher water velocity is unknown. The
recommendation from the authors for future study is to test
multistage MHT with velocity ranging of 1.5 m/s to 2.5 m/s.
Another direction for future study is to model energy
extraction with more than five stages of blades.
ACKNOWLEDGEMENTS
Authors would like to acknowledge the financial supports
received from The Ministry of Higher Education Malaysia
under FRGS grant (FRGS/TK01(01)973/2013). Authors are
pleased to offer special thanks to academic and technical staff
of Engineering Faculty, Universiti Malaysia Sarawak.
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Water Velocity (m/s)*
Performance Indicator**
Efficiency of
Multistage blade MHT
Efficiency of
Single Stage Blade MHT
0.5
Ƞ-Turbine Efficiency
in percent (%)
59.5
51.1
0.65
65.3
59.3
0.80
69.5
62.8
1.0
75.2
68.1
▲ Ƞ= (ȠM - ȠS).The multistage MHT on average is 10.5 percent more efficient compared to single stage turbine
0.5
▲V- velocity drop
in percent (%)
16
15
0.65
17.5
16.5
0.80
21.0
20
1.0
24.8
23.5
▲ V= (VM - VS), The velocity drop of multistage MHT is at an of average 5.5 percent more efficient compared to single stage turbine
0.5
▲E- energy loss at turbine in percent
(
39.2
48.8
0.65
34.2
40.6
0.80
20.3
37.1
1.0
24.5
31.7
▲E- EM-ES. The energy loss at multistage MHT is 3.8 percent less than single stage turbine.
Ps-Energy transfer by turbine shaft
0.5
24.1W (40W/m2)
19.2W(32W/m2)
0.65
33.2W(55W/m2)
27.0W(45W/m2)
0.80
45.0W(75W/m2)
37.8W(63W/m2)
1.0
54.3W(90W/m2)
43.2W(72W/m2)
▲Ps- PM-PS. The energy transfer efficiency of multistage MHT is about 18 percent higher compared to single stage MHT

166 ISSN: 1013-5316; CODEN: SINTE Sci.Int.(Lahore),29(1),161-166,2017
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