Muhammad Amir Aziat Ishak | Taylor's University (original) (raw)

Papers by Muhammad Amir Aziat Ishak

Journal of Energy Storage, 2025

Photovoltaic thermal (PVT) systems have emerged as dual-purpose technologies, simultaneously gene... more Photovoltaic thermal (PVT) systems have emerged as dual-purpose technologies, simultaneously generating electricity and utilizing waste heat for enhanced energy efficiency. Despite their potential, elevated photovoltaic (PV) surface temperatures remain a critical challenge, significantly reducing electrical performance. This study presents an innovative PVT system that incorporates dual-directional twisted tape absorbers (clockwise and counterclockwise) combined with nano-enhanced phase change materials (Nano-PCM) for thermal storage. Additionally, silicon carbide (SiC) nanoparticles were dispersed in water-based nanofluids at concentrations of 0.1 %, 0.3 %, and 0.5 % by volume to enhance thermal conductivity and heat transfer. Experiments were conducted using an indoor solar simulator at a constant irradiance of 800 W/m2. The findings demonstrate that the counterclockwise twisted tape configuration, coupled with Nano-PCM and 0.5 % SiC nanofluids, achieved the highest combined efficiency of 96.97 %, including an electrical efficiency of 11.26 % and a thermal efficiency of 85.71 %. This marks a 38 % improvement in electricity generation compared to conventional PV systems, which typically achieve an electrical efficiency of 8.16 %. The integration of advanced absorber geometries with nanomaterials offers superior thermal regulation and heat transfer, establishing a pathway for significantly improving PVT system performance. This research provides a scalable and sustainable solution to enhance the efficiency of renewable energy systems, paving the way for broader adoption in diverse applications.

Case Studies in Thermal Engineering, 2025

A numerical investigation is undertaken, employing a 3D conjugated heat transfer model to examine... more A numerical investigation is undertaken, employing a 3D conjugated heat transfer model to examine the impact of geometric configurations and hydrodynamical parameters on the overall thermal resistance and pumping power in mini-channels heat sinks. The aim lies in its holistic approach, integrating the non-uniform section of the mini-channel, the impact of the inlet velocity, the energy and exergy analysis, multi-objective optimization and performance evaluation criteria (PEC) evaluations, and the consideration of metal Galinstan and Cu-water nanofluid working fluids. The parametric analysis highlighted metal Galinstan as the best coolant for the five configurations involved in the present study. Furthermore, The PEC results indicate that the best performance is achieved by the Converged-Diverged Mini-channel (CDMC)heat sink. CDMC configuration with metal Galinstan performs well in terms of exergy evaluations and shows a better average temperature distribution with a maximum temperature of about 328K. The optimal inlet velocity (
= 0.21 m/s) is determined on the basis of the pumping power and thermal resistance profiles. The optimization process is based on the impact of the mini-channel's maximum width on the PEC. It is shown that the PEC increases with the maximum width of the CDMC and the highest (PEC = 1.31) is obtained at a maximum width of 0.95 mm.

Case Studies in Thermal Engineering, 2024

This study aims to develop 3D numerical models utilizing COMSOL software to analyze the heat tran... more This study aims to develop 3D numerical models utilizing COMSOL software to analyze the heat
transfer (HT) behaviour of water-based photovoltaic/thermal (WPV/T) collectors with circular,
and elliptical tubular cross-sections with different dimensions to find an optimized and efficient
PV/T design. Indoor experimental tests were conducted to validate the numerical results. The
performance of PV/T was evaluated in terms of governing parameters, including the mass flow
rate (m˙ ), solar irradiance (I), heat gain, maximum power (Pmax), Reynolds number (Re), thermal
(ηth) and electrical (ηel) efficiency, the temperature difference between the outlet and inlet water
(To-Ti), the average cell temperature, and total efficiency (ηtotal). It was determined that m˙ = 0.04
kg/s was the optimal water flow rate for the best performance. The results indicate that the PV/T
collector with the elliptical cross-section tube with the least hydraulic diameter achieved the
maximum total efficiency, both numerically and experimentally, at 76.9 % and 72.94 %,
respectively, under turbulent flow conditions with Re = 5502.92 and I = 1000 W/m2. ηtotal of the
elliptical PV/T collectors is approximately 10 % and 6 % higher than that of circular design,
respectively at the optimum flow rate, and I = 1000 W/m2. It is also found that tubes with lower
hydraulic diameter values, while maintaining the same tube cross-section perimeter, exhibit
higher HT characteristics compared to those with greater hydraulic diameters. The findings from
this innovative and comprehensive study indicate an opportunity to enhance the HT properties of
the PV/T system by optimizing the cross-sectional design and hydraulic diameter of the absorber
tube, ultimately increasing total efficiency. Additionally, the optimized design opens avenues for
future research and can be further developed for both industrial and domestic applications.

Jurnal Kejuruteraan, 2024

When subjected to solar irradiance, the upsurge in photovoltaic (PV) module temperature has const... more When subjected to solar irradiance, the upsurge in photovoltaic (PV) module temperature has constrained the photovoltaic thermal (PVT) technology's ability to generate electrical power, thereby affecting its overall PVT efficiency. Jet impingement has proven to be a viable method in improving a PVT collector's efficiency. This research functions as an extension to the existing established reversed circular flow jet impingement (RCFJI) PVT collector. The present study performed an in-house study to investigate the energy and exergy characteristics of the RCFJI PVT collector outlet configuration. The RCFJI outlet hole was configured into five distinct design settings: one hole (1h), two holes (2h), three holes (3h), four holes (4h), and five holes (5h). The experiment was executed with a uniform irradiance level of 900 W/m 2 and flow rate varying from 0.01-0.14 kg/s. As a result, the peak photovoltaic and thermal efficiency achieved using the 1h configuration was 11.09% and 63.2% at 0.14 kg/s. Particularly, the 1h configuration yielded an overall PVT efficiency of 72.35%. The study noted that the optimal flow rate was 0.06 kg/s, leading to the highest exergy of 12.32%. In a nutshell, increasing the RCFJI outlet numbers does not favourably impact the energy efficiency of the RCFJI PVT collector. The significance of this study contributes to the understanding of outlet configuration effects on the RCFJI performance.

Heat Transfer, 2024

Solar energy could be used to generate both electricity and heat with the aid of photovoltaic the... more Solar energy could be used to generate both electricity and heat with the aid of photovoltaic thermal (PV/T) systems. Although the systems have a variety of advantages, they nevertheless hold a significant constraint. The system suffers a susceptible constraint wherein the photovoltaic (PV) module experiences an increase in temperature due to exposure to solar irradiation. The integration of a cooling system is necessary to enhance its operational efficiency. A novel approach, known as the reversed circular flow jet impingement (RCFJI), was proposed as a means to improve the performance of a PV/T collector. The current work seeks to assess the thermohydraulic and electrohydraulic performance of the RCFJI PV/T collector. The experiment was conducted under an irradiance level of 500–900 W/m2. From the result obtained, the thermohydraulic efficiency reached its maximum value of 59.20% under 900 W/m2 at 0.14 kg/s. Conversely, the electrohydraulic efficiency attained the highest reading of 10.91% under 500 W/m2 at 0.13 kg/s. It was concluded that a higher flow rate reduces the friction coefficient while increasing the pressure drop. The thermohydraulic and electrohydraulic analyses emphasize the importance of assessing the friction coefficient and pressure drop to attain optimal performance. This study addresses the lack of research by presenting a new cooling approach that utilizes jet impingement. In addition, this study provides an understanding of the thermohydraulic and electrohydraulic performance of a RCFJI PV/T collector.

Jurnal Kejuruteraan, 2024

Although photovoltaic thermal (PVT) offers ascertain of benefits, it also has its own limitations... more Although photovoltaic thermal (PVT) offers ascertain of benefits, it also has its own limitations. The efficiency of PVT is diminished due to heat gain experienced by its photovoltaic module when subjected to solar radiation. Jet impingement has been recognised as a highly successful technique for the purpose of cooling solar modules, particularly in the context of bifacial module applications. An energy analysis of a reversed circular flow jet impingement on a bifacial PVT collector was perform through an indoor experiment utilizing a solar simulator. The jet plate outlet was varied into four different configurations: one hole (1h), three holes (3h), four holes (4h) and five holes (5h) to identify the jet plate outlet configuration that contributes to the best energy efficiency. The experiment was carried out using a constant solar irradiance of 900 W/m 2 and mass flow rate between 0.01 kg/s to 0.14 kg/s. The study's findings indicate that configuration 1h exhibited the best photovoltaic efficiency of 11.09%. Additionally, the highest thermal efficiency recorded was 63.2%. In summary, it can be concluded that configuration 1h exhibits an overall photovoltaic thermal efficiency of 74.28% when subjected to a mass flow rate of 0.14 kg/s. This configuration outperforms other jet plate outlet configuration in terms of energy performance.

Case Studies in Thermal Engineering, 2024

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

International Journal of Renewable Energy Research, 2023

The purpose of this study is to evaluate the thermal and electrical efficiency of PVT-PCM and PVT... more The purpose of this study is to evaluate the thermal and electrical efficiency of PVT-PCM and PVT for photovoltaic thermal collectors. A square absorber tube with PCM was utilized in the study, introducing a new approach to photovoltaic thermal collectors. COMSOL computational fluid dynamics (CFD) software was employed to carry out the simulations, and the tests were conducted as indoor experiments in a lab. Water was used as the transmission fluid in this study. Different volume flow rates ranging from 1-3 LPM were assessed for both experiment and simulation by considering the radiation range of 400, 600, and 800W/m 2. At a volume flow rate of 2 LPM, experimental results showed that PVT-PCM achieved higher electrical and thermal efficiencies of 9.95% and 88.3%, respectively, compared to the simulation results of 10.0% and 86.5%. Comparable outcomes were seen with both the simulation and experiment.

Case Studies in Thermal Engineering, 2023

Photovoltaic thermal (PVT) technologies have a significant downside in addition to their numerous... more Photovoltaic thermal (PVT) technologies have a significant downside in addition to their numerous advantages. PVT technologies are constrained by the fact that its photovoltaic module gains heat due to exposure to solar irradiance, which reduces the photovoltaic efficiency. Jet impingement is one of the most effective methods to cool a photovoltaic module. An indoor experiment using a solar simulator was conducted on a bifacial PVT solar collector cooled by a reversed circular flow jet impingement (RCFJI) to evaluate the energy performance of the PVT collector. The study was conducted under a constant solar irradiance of 900W/m 2 and flowrate (mass) ranging from 0.01 to 0.14 kg/s. Three bifacial modules with 0.22, 0.33, and 0.66 packing factors were mounted 25 mm above the RCFJI for cooling. The 0.66 packing factor module recorded the highest photovoltaic efficiency of 10.91 % at 0.14 kg/s flowrate (mass). Meanwhile, the 0.22 and 0.33 packing factors recorded a photovoltaic efficiency of 4.50 % and 6.45 %, respectively. The highest thermal efficiency recorded under the same operating condition was 61.43 %, using a 0.66 packing factor. Overall, the highest combined photovoltaic thermal (PVT) efficiency for 0.22, 0.33, and 0.66 was 56.62 %, 61.88 %, and 72.35 %, respectively.

Photovoltaic Thermal Double Pass Solar Air Heater (PVT-DPSAH) with Phase Change Material (PCM) ca... more Photovoltaic Thermal Double Pass Solar Air Heater (PVT-DPSAH) with Phase Change Material (PCM) capsules in the bottom channel is a promising design for enhancing the system performance. The PVT-DPSAH comprises a glass cover, absorber plate photovoltaic (PV), PCM capsules, and back plate. The current study uses COMSOL Multiphysics software to perform a Computational Fluid Dynamics (CFD) analysis of a novel PVT-DPSAH with vertical cylindrical PCM capsules in the second channel. To solve the differential equations in the 3D computational domain, the Finite Element Method (FEM) is employed. This study uses the high Reynolds (Re) number and κ-ε turbulent flow model with enhanced wall functions. The impact of varying solar irradiance levels (500-800 W/m 2) on the performance of PVT-DPSAH, with mass flow rate (ṁ) ranging from 0.011 kg/s to 0.065 kg/s, is investigated. The optimum mass flow rate was found to be 0.037 kg/s at solar irradiances ranging from 500 W/m 2 to 800 W/m 2 , with average thermal efficiencies, electrical efficiencies, and fluid output temperatures of 60.7% to 63.4%, 11.25% to 11.02% and 42.96 ºC to 49.54 ºC, respectively. PVT collector's maximum combined efficiency was 84.12% at solar irradiance of 800 W/m 2 with the mass flow rate, ṁ of 0.065 kg/s. This study identified RT-47 paraffin-wax-PCM as the best option for the PVT-DPSAH based on the PCM's thermal distribution and melting temperature.

International Journal of Renewable Energy Development, 2023

A relatively new technology, a hybrid photovoltaic thermal (PVT) solar collector, allows for prod... more A relatively new technology, a hybrid photovoltaic thermal (PVT) solar collector, allows for producing electrical and thermal energy. However, the module heats up more when exposed to sunlight thanks to the PVT collector's incorporation, reducing its efficiency. Consequently, lowering the operating temperature is crucial for maximizing the system's effectiveness. This research aims to create a photovoltaic thermal phase change material (PVT-PCM) solar collector and evaluate its energy performance through a controlled laboratory environment. Two different PVT collector designs, one using water and the other using a phase change material (PCM), were evaluated using a spiral flow configuration. Under a sun simulator, the PVT solar collector was subjected to 400 W/m 2 , 600 W/m 2 , and 800 W/m 2 of solar irradiation at three different mass flow rates. The results showed that under 800 W/m 2 of solar irradiation and 0.033 kg/s mass flow rate, the collector using water could only reach an overall maximum efficiency of 64.34 %, whereas the PVT-PCM configuration with spiral flow had the maximum performance, with an overall efficiency of 67.63%.

Case Studies in Thermal Engineering, 2023

The primary limitation of photovoltaic thermal (PVT) technologies is the adverse effect of solar ... more The primary limitation of photovoltaic thermal (PVT) technologies is the adverse effect of solar
irradiance-induced heat absorption. In order to enhance the efficiency of the system, it is essential
to incorporate a cooling mechanism. The utilization of a reversed circular flow jet impingement
(RCFJI) was implemented as a cooling mechanism for a bifacial PVT solar collector. This study
aims to analyze the exergy efficiency of a RCFJI bifacial PVT solar collector. An indoor experiment
was conducted using a solar simulator with a solar irradiance of 500–900W/m2 and a mass
flow rate of 0.01–0.14 kg/s. The findings revealed that the highest photovoltaic exergy attained
was 47.2W under solar irradiance of 900W/m2 and a mass flow rate of 0.14 kg/s. Meanwhile, the
highest thermal exergy attained was 9.67W under 900W/m2 solar irradiance and 0.14 kg/s mass
flow rate. Overall, the exergy efficiency attained a maximum value of 12.64% under 900W/m2,
while the lowest exergy efficiency observed was 12.25% under 500W/m2. In addition, the
optimal operational mass flow determined was 0.06 kg/s. The findings indicate that the optimal
performance of the RCFJI bifacial PVT solar collector is achieved through higher exergy efficiency,
which signifies a reduced requirement for input energy. Consequently, more energy can
be harnessed.

International Journal of Renewable Energy Development, 2023

As the world shifts towards a more sustainable future, solar energy has emerged as a preeminent a... more As the world shifts towards a more sustainable future, solar energy has emerged as a preeminent and economically feasible alternative to traditional energy sources, gaining widespread adoption. This study presents a reversed circular flow jet impingement (RCFJI) which aims to improve the performance of a bifacial PVT collector. An indoor experiment using a solar simulator to assess the energy, exergy, and economic efficiency of a RCFJI bifacial PVT collector. The study was carried out using a solar irradiance ranging from 500-900W/m 2 and a mass flow rate between 0.01-0.14 kg/s. Energy performance-wise, the highest photovoltaic efficiency achieved was 11.38% at solar irradiance of 500 W/m 2 , while the highest thermal efficiency achieved was 61.4% under 900 W/m 2 , both obtained at 0.14 kg/s mass flow rate. Regarding exergy performance, the highest photovoltaic exergy obtained was 47.27 W under 900 W/m 2 at 0.14 kg/s, while the highest thermal exergy was 9.67 W at 900 W/m 2 at 0.01 kg/s. Overall, higher solar irradiance is more desirable for energy and exergy performance. Meanwhile, economic point of view, lower solar irradiance is preferable. Based on the findings, the optimal mass flow rate was 0.06 kg/s.

MDPI, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

International Journal of Renewable Energy Research, 2023

Jet impingement mechanism has been extensively studied in previous research due to its ability to... more Jet impingement mechanism has been extensively studied in previous research due to its ability to enhance the efficiency of a solar collector. The photovoltaic module temperature can be effectively lowered while preserving the temperature uniformity and enhancing the solar collector performance. Since jet impingement offers such a broad application, numerous studies have focused on its heat transfer characteristic. This article provides a comprehensive review of recent jet impingement solar collectors. Additionally, the design and performance of the jet impingement cooling methods on solar air collectors, photovoltaic and photovoltaic thermal systems are discussed. The comprehensive review is classified into four main components involving jet impingement in solar collector applications: single pass, double pass, concentrated and jet configuration. A critical review is discussed at the end of each classification. The nozzle streamwise and spanwise pitch, nozzle to target spacing, nozzle diameter, nozzle shape, and Reynold number significantly impact the heat transfer properties of jet impingement. Research on applying single pass-single ducts using jet impingement is still lacking and needs further research. Thermally, a double passsolar collector outperforms a single pass-solar collector due to the absorber plate's high heat extraction rate and more significant interaction caused by the doubled heat transfer surface.

International Journal of Renewable Energy Research, 2023

Jet impingement is commonly used to enhance the performance of solar collectors by improving the ... more Jet impingement is commonly used to enhance the performance of solar collectors by improving the heat transfer rate. This paper presents a Novel Circular Flow Jet Impingement applied to a bifacial photovoltaic thermal (PVT) solar collector. The energy performance of the PVT solar collector was analyzed using CFD COMSOL simulation. The circular flow cup was attached to the jet plate with 36 jet plate holes and streamwise pitch, X = 113.4mm, and spanwise pitch, Y= 126mm. The inlet circular cup diameter of 6mm and outlet jet plate hole of 3mm are used to promote impinging jet effects on the photovoltaic module. The mass flow rate ranges between 0.01-0.14kg/s, and Reynolds number ranges between 2,738-14,170 to promote turbulent flow. The swirling and diffusive properties of turbulence enhance the heat transfer rate. The study was conducted to analyze two distinct scenarios: the first sought to identify the optimal diameter size, and the second sought to determine the optimal depth for the circular cup. Each model was tested with a solar irradiance ranging from 600W/m 2 to 900W/m 2. The optimum design for the Circular Flow Jet Impingement was achieved using a 40mm diameter and 20mm depth with a maximum photovoltaic, thermal, and overall efficiency of 63%, 11.09% and 74.09% at an irradiance of 900W/m 2 and flow rate of 0.14kg/s.

Books by Muhammad Amir Aziat Ishak

Penerbit UTeM Press, 2024

Photovoltaic thermal technologies, commonly called solar PVT, offer a broad range of advantages i... more Photovoltaic thermal technologies, commonly called solar PVT, offer a broad range of advantages in its application. The unique capability of solar PVT allows the production of electrical and thermal energy simultaneously presents a significant advantage. Generally, the PVT solar collector relies on the photovoltaic (PV) module, an integral part of the system. However, the photovoltaic module has a negative downside due to the heat absorbed from being exposed to solar irradiance, which results in a decline in the module’s efficiency. Thus, a cooling system plays a pivotal role in enhancing the efficiency of a PVT collector. Compared to mono-facial modules, a bifacial module can potentially absorb energy from the sunlight from both the front and rear surfaces of the bifacial module. However, cooling methods to cool off a bifacial PV module are restricted and lacking as both sides of the PV module are essential and must be exposed to sunlight. A reversed circular flow jet impingement (RCFJI) technique was introduced in this study to cool down the temperature of a bifacial PVT solar collector while enhancing its performance. An indoor experiment was conducted using a solar simulator to analyse the energy and exergy performance of the RCFJI bifacial PVT solar collector. The indoor experiment was carried out under varying solar irradiance of 500-900W/m2 with a mass flow rate of 0.01-0.14kg/s. The findings show that the maximum photovoltaic efficiency achieved was 11.38% under 500W/m2 and 0.14kg/s using a 0.66 packing factor, while the maximum thermal efficiency was 61.4% under 900W/m2 and 0.14kg/s. Meanwhile, in terms of exergy performance, the highest exergy efficiency achieved was 12.64% at 900W/m2 at 0.06kg/s.

Journal of Energy Storage, 2025

Photovoltaic thermal (PVT) systems have emerged as dual-purpose technologies, simultaneously gene... more Photovoltaic thermal (PVT) systems have emerged as dual-purpose technologies, simultaneously generating electricity and utilizing waste heat for enhanced energy efficiency. Despite their potential, elevated photovoltaic (PV) surface temperatures remain a critical challenge, significantly reducing electrical performance. This study presents an innovative PVT system that incorporates dual-directional twisted tape absorbers (clockwise and counterclockwise) combined with nano-enhanced phase change materials (Nano-PCM) for thermal storage. Additionally, silicon carbide (SiC) nanoparticles were dispersed in water-based nanofluids at concentrations of 0.1 %, 0.3 %, and 0.5 % by volume to enhance thermal conductivity and heat transfer. Experiments were conducted using an indoor solar simulator at a constant irradiance of 800 W/m2. The findings demonstrate that the counterclockwise twisted tape configuration, coupled with Nano-PCM and 0.5 % SiC nanofluids, achieved the highest combined efficiency of 96.97 %, including an electrical efficiency of 11.26 % and a thermal efficiency of 85.71 %. This marks a 38 % improvement in electricity generation compared to conventional PV systems, which typically achieve an electrical efficiency of 8.16 %. The integration of advanced absorber geometries with nanomaterials offers superior thermal regulation and heat transfer, establishing a pathway for significantly improving PVT system performance. This research provides a scalable and sustainable solution to enhance the efficiency of renewable energy systems, paving the way for broader adoption in diverse applications.

Case Studies in Thermal Engineering, 2025

A numerical investigation is undertaken, employing a 3D conjugated heat transfer model to examine... more A numerical investigation is undertaken, employing a 3D conjugated heat transfer model to examine the impact of geometric configurations and hydrodynamical parameters on the overall thermal resistance and pumping power in mini-channels heat sinks. The aim lies in its holistic approach, integrating the non-uniform section of the mini-channel, the impact of the inlet velocity, the energy and exergy analysis, multi-objective optimization and performance evaluation criteria (PEC) evaluations, and the consideration of metal Galinstan and Cu-water nanofluid working fluids. The parametric analysis highlighted metal Galinstan as the best coolant for the five configurations involved in the present study. Furthermore, The PEC results indicate that the best performance is achieved by the Converged-Diverged Mini-channel (CDMC)heat sink. CDMC configuration with metal Galinstan performs well in terms of exergy evaluations and shows a better average temperature distribution with a maximum temperature of about 328K. The optimal inlet velocity (
= 0.21 m/s) is determined on the basis of the pumping power and thermal resistance profiles. The optimization process is based on the impact of the mini-channel's maximum width on the PEC. It is shown that the PEC increases with the maximum width of the CDMC and the highest (PEC = 1.31) is obtained at a maximum width of 0.95 mm.

Case Studies in Thermal Engineering, 2024

This study aims to develop 3D numerical models utilizing COMSOL software to analyze the heat tran... more This study aims to develop 3D numerical models utilizing COMSOL software to analyze the heat
transfer (HT) behaviour of water-based photovoltaic/thermal (WPV/T) collectors with circular,
and elliptical tubular cross-sections with different dimensions to find an optimized and efficient
PV/T design. Indoor experimental tests were conducted to validate the numerical results. The
performance of PV/T was evaluated in terms of governing parameters, including the mass flow
rate (m˙ ), solar irradiance (I), heat gain, maximum power (Pmax), Reynolds number (Re), thermal
(ηth) and electrical (ηel) efficiency, the temperature difference between the outlet and inlet water
(To-Ti), the average cell temperature, and total efficiency (ηtotal). It was determined that m˙ = 0.04
kg/s was the optimal water flow rate for the best performance. The results indicate that the PV/T
collector with the elliptical cross-section tube with the least hydraulic diameter achieved the
maximum total efficiency, both numerically and experimentally, at 76.9 % and 72.94 %,
respectively, under turbulent flow conditions with Re = 5502.92 and I = 1000 W/m2. ηtotal of the
elliptical PV/T collectors is approximately 10 % and 6 % higher than that of circular design,
respectively at the optimum flow rate, and I = 1000 W/m2. It is also found that tubes with lower
hydraulic diameter values, while maintaining the same tube cross-section perimeter, exhibit
higher HT characteristics compared to those with greater hydraulic diameters. The findings from
this innovative and comprehensive study indicate an opportunity to enhance the HT properties of
the PV/T system by optimizing the cross-sectional design and hydraulic diameter of the absorber
tube, ultimately increasing total efficiency. Additionally, the optimized design opens avenues for
future research and can be further developed for both industrial and domestic applications.

Jurnal Kejuruteraan, 2024

When subjected to solar irradiance, the upsurge in photovoltaic (PV) module temperature has const... more When subjected to solar irradiance, the upsurge in photovoltaic (PV) module temperature has constrained the photovoltaic thermal (PVT) technology's ability to generate electrical power, thereby affecting its overall PVT efficiency. Jet impingement has proven to be a viable method in improving a PVT collector's efficiency. This research functions as an extension to the existing established reversed circular flow jet impingement (RCFJI) PVT collector. The present study performed an in-house study to investigate the energy and exergy characteristics of the RCFJI PVT collector outlet configuration. The RCFJI outlet hole was configured into five distinct design settings: one hole (1h), two holes (2h), three holes (3h), four holes (4h), and five holes (5h). The experiment was executed with a uniform irradiance level of 900 W/m 2 and flow rate varying from 0.01-0.14 kg/s. As a result, the peak photovoltaic and thermal efficiency achieved using the 1h configuration was 11.09% and 63.2% at 0.14 kg/s. Particularly, the 1h configuration yielded an overall PVT efficiency of 72.35%. The study noted that the optimal flow rate was 0.06 kg/s, leading to the highest exergy of 12.32%. In a nutshell, increasing the RCFJI outlet numbers does not favourably impact the energy efficiency of the RCFJI PVT collector. The significance of this study contributes to the understanding of outlet configuration effects on the RCFJI performance.

Heat Transfer, 2024

Solar energy could be used to generate both electricity and heat with the aid of photovoltaic the... more Solar energy could be used to generate both electricity and heat with the aid of photovoltaic thermal (PV/T) systems. Although the systems have a variety of advantages, they nevertheless hold a significant constraint. The system suffers a susceptible constraint wherein the photovoltaic (PV) module experiences an increase in temperature due to exposure to solar irradiation. The integration of a cooling system is necessary to enhance its operational efficiency. A novel approach, known as the reversed circular flow jet impingement (RCFJI), was proposed as a means to improve the performance of a PV/T collector. The current work seeks to assess the thermohydraulic and electrohydraulic performance of the RCFJI PV/T collector. The experiment was conducted under an irradiance level of 500–900 W/m2. From the result obtained, the thermohydraulic efficiency reached its maximum value of 59.20% under 900 W/m2 at 0.14 kg/s. Conversely, the electrohydraulic efficiency attained the highest reading of 10.91% under 500 W/m2 at 0.13 kg/s. It was concluded that a higher flow rate reduces the friction coefficient while increasing the pressure drop. The thermohydraulic and electrohydraulic analyses emphasize the importance of assessing the friction coefficient and pressure drop to attain optimal performance. This study addresses the lack of research by presenting a new cooling approach that utilizes jet impingement. In addition, this study provides an understanding of the thermohydraulic and electrohydraulic performance of a RCFJI PV/T collector.

Jurnal Kejuruteraan, 2024

Although photovoltaic thermal (PVT) offers ascertain of benefits, it also has its own limitations... more Although photovoltaic thermal (PVT) offers ascertain of benefits, it also has its own limitations. The efficiency of PVT is diminished due to heat gain experienced by its photovoltaic module when subjected to solar radiation. Jet impingement has been recognised as a highly successful technique for the purpose of cooling solar modules, particularly in the context of bifacial module applications. An energy analysis of a reversed circular flow jet impingement on a bifacial PVT collector was perform through an indoor experiment utilizing a solar simulator. The jet plate outlet was varied into four different configurations: one hole (1h), three holes (3h), four holes (4h) and five holes (5h) to identify the jet plate outlet configuration that contributes to the best energy efficiency. The experiment was carried out using a constant solar irradiance of 900 W/m 2 and mass flow rate between 0.01 kg/s to 0.14 kg/s. The study's findings indicate that configuration 1h exhibited the best photovoltaic efficiency of 11.09%. Additionally, the highest thermal efficiency recorded was 63.2%. In summary, it can be concluded that configuration 1h exhibits an overall photovoltaic thermal efficiency of 74.28% when subjected to a mass flow rate of 0.14 kg/s. This configuration outperforms other jet plate outlet configuration in terms of energy performance.

Case Studies in Thermal Engineering, 2024

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

International Journal of Renewable Energy Research, 2023

The purpose of this study is to evaluate the thermal and electrical efficiency of PVT-PCM and PVT... more The purpose of this study is to evaluate the thermal and electrical efficiency of PVT-PCM and PVT for photovoltaic thermal collectors. A square absorber tube with PCM was utilized in the study, introducing a new approach to photovoltaic thermal collectors. COMSOL computational fluid dynamics (CFD) software was employed to carry out the simulations, and the tests were conducted as indoor experiments in a lab. Water was used as the transmission fluid in this study. Different volume flow rates ranging from 1-3 LPM were assessed for both experiment and simulation by considering the radiation range of 400, 600, and 800W/m 2. At a volume flow rate of 2 LPM, experimental results showed that PVT-PCM achieved higher electrical and thermal efficiencies of 9.95% and 88.3%, respectively, compared to the simulation results of 10.0% and 86.5%. Comparable outcomes were seen with both the simulation and experiment.

Case Studies in Thermal Engineering, 2023

Photovoltaic thermal (PVT) technologies have a significant downside in addition to their numerous... more Photovoltaic thermal (PVT) technologies have a significant downside in addition to their numerous advantages. PVT technologies are constrained by the fact that its photovoltaic module gains heat due to exposure to solar irradiance, which reduces the photovoltaic efficiency. Jet impingement is one of the most effective methods to cool a photovoltaic module. An indoor experiment using a solar simulator was conducted on a bifacial PVT solar collector cooled by a reversed circular flow jet impingement (RCFJI) to evaluate the energy performance of the PVT collector. The study was conducted under a constant solar irradiance of 900W/m 2 and flowrate (mass) ranging from 0.01 to 0.14 kg/s. Three bifacial modules with 0.22, 0.33, and 0.66 packing factors were mounted 25 mm above the RCFJI for cooling. The 0.66 packing factor module recorded the highest photovoltaic efficiency of 10.91 % at 0.14 kg/s flowrate (mass). Meanwhile, the 0.22 and 0.33 packing factors recorded a photovoltaic efficiency of 4.50 % and 6.45 %, respectively. The highest thermal efficiency recorded under the same operating condition was 61.43 %, using a 0.66 packing factor. Overall, the highest combined photovoltaic thermal (PVT) efficiency for 0.22, 0.33, and 0.66 was 56.62 %, 61.88 %, and 72.35 %, respectively.

Photovoltaic Thermal Double Pass Solar Air Heater (PVT-DPSAH) with Phase Change Material (PCM) ca... more Photovoltaic Thermal Double Pass Solar Air Heater (PVT-DPSAH) with Phase Change Material (PCM) capsules in the bottom channel is a promising design for enhancing the system performance. The PVT-DPSAH comprises a glass cover, absorber plate photovoltaic (PV), PCM capsules, and back plate. The current study uses COMSOL Multiphysics software to perform a Computational Fluid Dynamics (CFD) analysis of a novel PVT-DPSAH with vertical cylindrical PCM capsules in the second channel. To solve the differential equations in the 3D computational domain, the Finite Element Method (FEM) is employed. This study uses the high Reynolds (Re) number and κ-ε turbulent flow model with enhanced wall functions. The impact of varying solar irradiance levels (500-800 W/m 2) on the performance of PVT-DPSAH, with mass flow rate (ṁ) ranging from 0.011 kg/s to 0.065 kg/s, is investigated. The optimum mass flow rate was found to be 0.037 kg/s at solar irradiances ranging from 500 W/m 2 to 800 W/m 2 , with average thermal efficiencies, electrical efficiencies, and fluid output temperatures of 60.7% to 63.4%, 11.25% to 11.02% and 42.96 ºC to 49.54 ºC, respectively. PVT collector's maximum combined efficiency was 84.12% at solar irradiance of 800 W/m 2 with the mass flow rate, ṁ of 0.065 kg/s. This study identified RT-47 paraffin-wax-PCM as the best option for the PVT-DPSAH based on the PCM's thermal distribution and melting temperature.

International Journal of Renewable Energy Development, 2023

A relatively new technology, a hybrid photovoltaic thermal (PVT) solar collector, allows for prod... more A relatively new technology, a hybrid photovoltaic thermal (PVT) solar collector, allows for producing electrical and thermal energy. However, the module heats up more when exposed to sunlight thanks to the PVT collector's incorporation, reducing its efficiency. Consequently, lowering the operating temperature is crucial for maximizing the system's effectiveness. This research aims to create a photovoltaic thermal phase change material (PVT-PCM) solar collector and evaluate its energy performance through a controlled laboratory environment. Two different PVT collector designs, one using water and the other using a phase change material (PCM), were evaluated using a spiral flow configuration. Under a sun simulator, the PVT solar collector was subjected to 400 W/m 2 , 600 W/m 2 , and 800 W/m 2 of solar irradiation at three different mass flow rates. The results showed that under 800 W/m 2 of solar irradiation and 0.033 kg/s mass flow rate, the collector using water could only reach an overall maximum efficiency of 64.34 %, whereas the PVT-PCM configuration with spiral flow had the maximum performance, with an overall efficiency of 67.63%.

Case Studies in Thermal Engineering, 2023

The primary limitation of photovoltaic thermal (PVT) technologies is the adverse effect of solar ... more The primary limitation of photovoltaic thermal (PVT) technologies is the adverse effect of solar
irradiance-induced heat absorption. In order to enhance the efficiency of the system, it is essential
to incorporate a cooling mechanism. The utilization of a reversed circular flow jet impingement
(RCFJI) was implemented as a cooling mechanism for a bifacial PVT solar collector. This study
aims to analyze the exergy efficiency of a RCFJI bifacial PVT solar collector. An indoor experiment
was conducted using a solar simulator with a solar irradiance of 500–900W/m2 and a mass
flow rate of 0.01–0.14 kg/s. The findings revealed that the highest photovoltaic exergy attained
was 47.2W under solar irradiance of 900W/m2 and a mass flow rate of 0.14 kg/s. Meanwhile, the
highest thermal exergy attained was 9.67W under 900W/m2 solar irradiance and 0.14 kg/s mass
flow rate. Overall, the exergy efficiency attained a maximum value of 12.64% under 900W/m2,
while the lowest exergy efficiency observed was 12.25% under 500W/m2. In addition, the
optimal operational mass flow determined was 0.06 kg/s. The findings indicate that the optimal
performance of the RCFJI bifacial PVT solar collector is achieved through higher exergy efficiency,
which signifies a reduced requirement for input energy. Consequently, more energy can
be harnessed.

International Journal of Renewable Energy Development, 2023

As the world shifts towards a more sustainable future, solar energy has emerged as a preeminent a... more As the world shifts towards a more sustainable future, solar energy has emerged as a preeminent and economically feasible alternative to traditional energy sources, gaining widespread adoption. This study presents a reversed circular flow jet impingement (RCFJI) which aims to improve the performance of a bifacial PVT collector. An indoor experiment using a solar simulator to assess the energy, exergy, and economic efficiency of a RCFJI bifacial PVT collector. The study was carried out using a solar irradiance ranging from 500-900W/m 2 and a mass flow rate between 0.01-0.14 kg/s. Energy performance-wise, the highest photovoltaic efficiency achieved was 11.38% at solar irradiance of 500 W/m 2 , while the highest thermal efficiency achieved was 61.4% under 900 W/m 2 , both obtained at 0.14 kg/s mass flow rate. Regarding exergy performance, the highest photovoltaic exergy obtained was 47.27 W under 900 W/m 2 at 0.14 kg/s, while the highest thermal exergy was 9.67 W at 900 W/m 2 at 0.01 kg/s. Overall, higher solar irradiance is more desirable for energy and exergy performance. Meanwhile, economic point of view, lower solar irradiance is preferable. Based on the findings, the optimal mass flow rate was 0.06 kg/s.

MDPI, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

International Journal of Renewable Energy Research, 2023

Jet impingement mechanism has been extensively studied in previous research due to its ability to... more Jet impingement mechanism has been extensively studied in previous research due to its ability to enhance the efficiency of a solar collector. The photovoltaic module temperature can be effectively lowered while preserving the temperature uniformity and enhancing the solar collector performance. Since jet impingement offers such a broad application, numerous studies have focused on its heat transfer characteristic. This article provides a comprehensive review of recent jet impingement solar collectors. Additionally, the design and performance of the jet impingement cooling methods on solar air collectors, photovoltaic and photovoltaic thermal systems are discussed. The comprehensive review is classified into four main components involving jet impingement in solar collector applications: single pass, double pass, concentrated and jet configuration. A critical review is discussed at the end of each classification. The nozzle streamwise and spanwise pitch, nozzle to target spacing, nozzle diameter, nozzle shape, and Reynold number significantly impact the heat transfer properties of jet impingement. Research on applying single pass-single ducts using jet impingement is still lacking and needs further research. Thermally, a double passsolar collector outperforms a single pass-solar collector due to the absorber plate's high heat extraction rate and more significant interaction caused by the doubled heat transfer surface.

International Journal of Renewable Energy Research, 2023

Jet impingement is commonly used to enhance the performance of solar collectors by improving the ... more Jet impingement is commonly used to enhance the performance of solar collectors by improving the heat transfer rate. This paper presents a Novel Circular Flow Jet Impingement applied to a bifacial photovoltaic thermal (PVT) solar collector. The energy performance of the PVT solar collector was analyzed using CFD COMSOL simulation. The circular flow cup was attached to the jet plate with 36 jet plate holes and streamwise pitch, X = 113.4mm, and spanwise pitch, Y= 126mm. The inlet circular cup diameter of 6mm and outlet jet plate hole of 3mm are used to promote impinging jet effects on the photovoltaic module. The mass flow rate ranges between 0.01-0.14kg/s, and Reynolds number ranges between 2,738-14,170 to promote turbulent flow. The swirling and diffusive properties of turbulence enhance the heat transfer rate. The study was conducted to analyze two distinct scenarios: the first sought to identify the optimal diameter size, and the second sought to determine the optimal depth for the circular cup. Each model was tested with a solar irradiance ranging from 600W/m 2 to 900W/m 2. The optimum design for the Circular Flow Jet Impingement was achieved using a 40mm diameter and 20mm depth with a maximum photovoltaic, thermal, and overall efficiency of 63%, 11.09% and 74.09% at an irradiance of 900W/m 2 and flow rate of 0.14kg/s.

Penerbit UTeM Press, 2024

Photovoltaic thermal technologies, commonly called solar PVT, offer a broad range of advantages i... more Photovoltaic thermal technologies, commonly called solar PVT, offer a broad range of advantages in its application. The unique capability of solar PVT allows the production of electrical and thermal energy simultaneously presents a significant advantage. Generally, the PVT solar collector relies on the photovoltaic (PV) module, an integral part of the system. However, the photovoltaic module has a negative downside due to the heat absorbed from being exposed to solar irradiance, which results in a decline in the module’s efficiency. Thus, a cooling system plays a pivotal role in enhancing the efficiency of a PVT collector. Compared to mono-facial modules, a bifacial module can potentially absorb energy from the sunlight from both the front and rear surfaces of the bifacial module. However, cooling methods to cool off a bifacial PV module are restricted and lacking as both sides of the PV module are essential and must be exposed to sunlight. A reversed circular flow jet impingement (RCFJI) technique was introduced in this study to cool down the temperature of a bifacial PVT solar collector while enhancing its performance. An indoor experiment was conducted using a solar simulator to analyse the energy and exergy performance of the RCFJI bifacial PVT solar collector. The indoor experiment was carried out under varying solar irradiance of 500-900W/m2 with a mass flow rate of 0.01-0.14kg/s. The findings show that the maximum photovoltaic efficiency achieved was 11.38% under 500W/m2 and 0.14kg/s using a 0.66 packing factor, while the maximum thermal efficiency was 61.4% under 900W/m2 and 0.14kg/s. Meanwhile, in terms of exergy performance, the highest exergy efficiency achieved was 12.64% at 900W/m2 at 0.06kg/s.