Leow Wai Zhe
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Preferred name
Leow Wai Zhe
Official Name
Wai Zhe, Leow
Alternative Name
Leow, Wai Zhe
Leow, W. Z.
Zhe, Leow Wai
Zhe, L. W.
Main Affiliation
Scopus Author ID
56178375200
Researcher ID
DXJ-9302-2022

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  • Publication
    Technologies of solar tracking systems: A review
    ( 2020-03-20)
    Amelia A.R.
    ;
    Mohd Irwan Yusoff
    ;
    Safwati Ibrahim
    ;
    Leow Wai Zhe
    ;
    Mohd Hafizuddin Mat
    ;
    Mohamad Shukor Abdul Rahim
    Solar energy is abundantly in nature and sustainable energy resources around the world. The main challenge with the solar field is less amount of sun energy captured by using photovoltaic (PV) systems. The great performance of the PV systems can be achieved if the panel is kept perpendicular to the direction of the radiations of sun. Hence, solar tracker system is the method to keep the optimum position of the PV panel for always perpendicular to the solar radiation. This paper aims to review on various technologies of solar tracking to determine the best PV panel orientation. The various types of technologies of solar tracking system have been discussed which includes passive solar tracker, active solar tracker and chronological tracker system. The movement degrees of solar tracking system also have been addressed which consisting single-axis solar tracking system and dual-axis solar tracking system. This paper is also overviews the tracking techniques performance, construction, performance, advantages, and disadvantages of existing solar tracking system. The limitations of solar tracking systems are also highlighted for future action improvement. Through this research studies, the most favorable solar tracking system was identified as active solar tracker with the dual axis rotation.
  • Publication
    Performance power evaluation of DC fan cooling system for PV panel by using ANSYS CFX
    ( 2017-09-26)
    Nur Syafiqah Zhubir
    ;
    Nasrul Amri Mohd Amin
    ;
    Mohd Irwan Yusoff
    ;
    Muhammad Irwanto Misrun
    ;
    Leow Wai Zhe
    ;
    Amelia A.R.
    A research has been conducted to find the optimum combination for DC fan air cooling system of photovoltaic (PV) panel. During normal operation of PV panel, it is estimated that only 15 % of solar radiation is converted into electrical energy. Meanwhile, the rest of the solar radiation is converted into heat energy which affects the performance of the PV panel. Therefore, the aim of this research is to investigate the performance power evaluation of DC fan cooling system for PV panel by using ANSYS CFX. The effect of airflow configuration of DC fan has been investigated. This is to analyze whether the airflow circulation of DC fan cause a change towards the maximum temperature of PV panel. Besides, the impact of varying number of DC fans attached at the back of PV panel is evaluated. The result of airflow circulation of DC fan has been discussed. Meanwhile, with the increment number of DC fans, the PV panel temperature drops significantly. As a conclusion, the optimum number of DC fans is two with the combination of inlet airflow.
  • Publication
    A review of detecting outlier in a circular regression model
    ( 2020-03-20)
    Ramlee, Intan Mastura
    ;
    Safwati Ibrahim
    ;
    Leow Wai Zhe
    ;
    Mohd Irwan Yusoff
    Circular data is very relevant and important application technique in many fields such as physical science, medical science and others. During the last few years, writers have shown a deep interest of outlier detection in the circular regression model. In this case, authors have a tendency to study and explore in detail about the outlier detection in circular regression model. This paper aims to review the outlier detection methods in circular regression model. Here, we concentrate the attention on the methods of identifying outlier in this model. These survey of circular regression models in which many interesting properties and is good enough to detect the occurrence of outlier. Through the survey may highlight the significant of methods to detect outliers in circular regressions model and provide guideline for future work to look into the research gap.
  • Publication
    Assessment of wind power potential in the North region of Malaysia, Chuping Perlis
    ( 2023-01-01)
    Thiraphorn B.L.
    ;
    Leow Wai Zhe
    ;
    Safwati Ibrahim
    ;
    Irwan Y.M.
    ;
    Muhammad Irwanto Misrun
    ;
    Tan X.J.
    ;
    Ananda-Rao K.
    The wind turbines is a main device that convert the kinetic energy from blades to electrical energy. Before installing wind turbines, the Weibull probability distribution must be calculated to determine the certain wind speed probability. Many problems will come if there no analysis the characteristics of wind in selected location, such as wind speed that not suitable for building wind farm to supply the population in that area. Shape and scale factors, which be controlled in a variety of ways, influence the Weibull distribution. Many studies have looked into which of the various Weibull parameter estimation methods is the most dependable. However, because the results of these investigations were inconsistent, research into more trustworthy Weibull parameter estimation methods is still ongoing. An analysis of data collected Chuping, Perlis for two years was conducted in this study (from 2018 to 2019). By using statistical analysis to evaluate the Weibull distribution method, this study used three methods to compared the Weibull parameters and identified the most reliable and effective method to obtain the Weibull probability distribution by using a three approach that compares the variances of RMSE, MSE and R2, which provides comprehensive insight into level error and volatility. Modified maximum likelihood method, graphical method, and power density method are the three methods used in this study. Therefore, the graphical method has the best accuracy in the wind speed distribution prediction, several methods such as the modified maximum likelihood method, and the power density method have the worst prediction of the wind speed distribution based on all the statistical method variances for this region.
  • Publication
    Comparative Study of Three Methods for Determining Weibull Parameters in Pauh Putra, Perlis
    ( 2021-06-11)
    Thiraphorn B.L.
    ;
    Leow Wai Zhe
    ;
    Mohd Irwan Yusoff
    ;
    Safwati Ibrahim
    ;
    Muhammad Irwanto Misrun
    ;
    Kumuthawathe Ananda-Rao
    ;
    Amelia A.R.
    This paper studied about analysis characteristics of wind speed at Pauh Putra, Perlis, where nearest to Chuping station, Perlis, Malaysia. The wind speed characteristics consist of monthly and annual wind speed in Perlis, Malaysia. By using Weibull distribution, three different methods to calculate the potential of wind power generation and analysis the characteristics of wind speed at Pauh Putra, Perlis. The results present the means wind speed is 1.0790 m/s and 1.1321 m/s for 2018 and 2019, respectively. The highest monthly mean wind speed occurred in February for both years, 2018 and 2019. Besides, the lowest monthly wind speed for 2018 in May and for 2019 in October. The Weibull distribution summarized the highest probability density is 120% in the wind speed, 1.1 m/s using the Maximum Likelihood Method (MLM) method for these two years. Furthermore, this research found that the Energy Pattern Factor (EPF) Method is stretched to the right, and its height decreased from other methods for both years based on the graph of the wind speed of probability density function. The Maximum Likelihood Method (MLM) for these two years is higher because its shape parameters are relatively higher based on the graph of the wind speed of probability density function.
  • Publication
    Development A Portable Solar Energy Measurement System
    ( 2021-07-26)
    Atika Z.
    ;
    Leow Wai Zhe
    ;
    Iszaidy I.
    ;
    Mohd Irwan Yusoff
    ;
    Safwati Ibrahim
    ;
    Muhammad Irwanto Misrun
    ;
    Wafi N.M.
    ;
    Saw S.X.
    This project presents the design and development a portable measurement device for measure and monitor solar panel parameters by using Internet of Things (IoT) concept. Solar energy measurement plays a very important role in the measurement of parameter reading for the determination of output generated, but the challenge is only performed manually at the work site using a clamp meter or a multimeter. Furthermore, it was very difficult to get the value at that time, and the data recovery error occurred. There are three specific objectives have been used for the project. Firstly, the relevant circuits for this project are design and built the circuit by using software. The output of the measurement solar irradiance, ambient temperature, solar panel temperature, current and voltage value were displayed on LCD. Next, IoT concept is used for solar panel measurement and monitoring. The value of the measurement and monitoring is used ThingSpeak cloud and ThingView application on the smartphone. It can be collected the portable solar for the energy measurement system can monitor on site, anywhere and anytime using IoT platform.
  • Publication
    Understanding Domain Knowledge in Initialization Method for K-Mean Clustering Algorithm in Medical Images
    ( 2022-01-01)
    Tan X.J.
    ;
    Nazahah Mustafa
    ;
    Mohd Yusoff Mashor
    ;
    Ab Rahman K.S.
    ;
    Wan Zuki Azman Wan Muhamad
    ;
    Leow Wai Zhe
    ;
    Cheor Wai Loon
    ;
    Oung Qi Wei
    This work serves as a preliminary study to investigate and identify the applicability of domain knowledge as an initialization method for K-Mean (KM), typically in medical images. For this purpose, 20 breast histopathology images were used as data set and the evaluations are focused on the clustering of the hyperchromatic nucleus. The iteration numbers and clustering results (i.e., accuracy, over-segmentation, and under-segmentation) are benchmarked with KM++ and the conventional random initialization method. The domain knowledge initialization method is found promising by achieving lower iteration numbers (<9), higher percentage in accuracy (85.5% (±2.27)), and lower percentages in over-segmentation (8.25% (±2.23)), and under-segmentation (7.00% (±2.14)). From this study, we hypothesize that the domain knowledge initialization method has the potential to be implemented as an initialization method and is posited to overperform some established initialization methods, typically for clustering tasks in medical images.
      1
  • Publication
    Analysis on the Effect of DC Current Changes on the Magnetic Field of Wireless Power Transfer
    ( 2023-01-01)
    Muhammad Irwanto Misrun
    ;
    Ali M.B.
    ;
    Nugraha Y.T.
    ;
    Baharuddin Ismail
    ;
    Nisja I.
    ;
    Leow Wai Zhe
    The generation of electromagnetic radiation in a solenoid, driven by alternating current (AC) voltage, is directly influenced by the voltage and current flowing through the solenoid. Exploiting this concept, wireless power transfer (WPT) systems can be developed. These systems consist of a sending coil and a receiving coil, both equipped with solenoids. The sending coil is connected to a half bridge circuit to generate AC voltage, which is then transmitted to the receiver coil. In this study, the effects of various factors on the performance of the wireless power transfer system were investigated, with a particular focus on the impact of DC voltage and input DC current. To examine these effects, an experimental setup was employed where the transmitter and receiver coils were powered by a DC voltage source. By varying the voltage and current parameters, the study aimed to analyze their influence on the wireless power transfer process. The simulation results show that 100 V and 150 V of DC current will produce 36.54 A and 54.8 A of input DC current respectively with constant resistor 7.54×10-2 Ω. The result shows that the input DC current is directly proportional with the magnetic field, AC current at sending and receiving coil, voltage at sending and receiving coil and AC power at receiving coil. Increasing the input DC current will increase the magnetic field, AC current at sending coil and receiver coil, voltage at transmitter coil and receiving coil and AC power at receiving coil and vice versa.
  • Publication
    Improvement of the photovoltaic output performance using hybrid active and passive cooling system
    ( 2017)
    Leow Wai Zhe
    This thesis presents the improvement of the photovoltaic (PV) output performance using hybrid active and passive cooling system. The PV technology has been used for several years and has proven successful for power generation, but the challenge is to adapt to local environment conditions, mainly caused by changes in weather conditions. Furthermore, the output power of the PV panel decreases as the operating temperature of the PV panel increases. Therefore, the main purpose of this current research is to design various types of cooling system in order to improve output power of the PV panel. This study has four specific objectives. Firstly, the effects of weather conditions on the thermal behaviour of PV panels were studied using simulation and experimental methods. In the simulation study, the effect of weather conditions in the thermal behaviour of the PV panel was simulated using CATIA and ANSYS simulation software. This study was conducted based on the weather of Centre of Excellence for Renewable Energy (CERE), UniMAP, Malaysia. It was shown that as solar irradiance and ambient temperature increased, the operating temperature of the PV panel increased. As the wind speed increased, the operating temperature of the PV panel decreased. In the experimental study, the dust appearing on the surface of the PV panel resulted in a decrease in the performance of the PV panel. However, the presence of wind on the surface of the PV panel resulted in an increase in the performance of the PV panel. Secondly, the PV panels with various types of cooling system were designed and simulated using ANSYS simulation software in order to analyse their thermal behaviour under weather conditions of CERE, Perlis. This included direct current (DC) fan cooling system, DC water pump cooling system, paraffin wax cooling system, hybrid DC water pump and paraffin wax cooling system as well as hybrid DC water pump and DC fan cooling system. The results showed that the PV panel with hybrid DC water pump and DC fan cooling system has the lowest operating temperature of 35.43 °C compared to other PV panels.
  • Publication
    A Potential Controller for Smart Electrical Energy Management System
    ( 2021-06-11)
    Kumuthawathe Ananda-Rao
    ;
    Mohd Alif Ismail
    ;
    Afifah Shuhada Rosmi
    ;
    Leow Wai Zhe
    ;
    Surina Mat Suboh
    ;
    Muhammad Izuan Fahmi Romli
    ;
    Abdullah A.M.
    Integrated energy utilization has been recognized as a productive way towards better energy management, besides increasing Renewable Energy (RE) penetration. Thus, the combination of RE integrated with the Battery Energy Storage System (BESS) has been recognized as the primary solution where it is necessary to have a controller to interface the system efficiently. Hence, a smart electrical energy management system controller is designed and developed based on load leveling and peak shaving applications for real-time AC power management in this work. The main function of the controller is to continuously monitor and maintain the load demand and to produce a leveled or shaved load profile that will be seen at the grid network by controlling the battery operation. The testing results concluded that the controller able to perform both the energy applications. Overall, a dual function controller based on energy applications to maintain consumer load demand usage more securely and reliably, so that the utility bill is reduced and the battery lifetime is prolonged simultaneously is achieved in this work.
      1