Experimental Studies on PV Module Cooling With Radiation Source PCM Matrix

Rise in PV module temperature (<inline-formula> <tex-math notation="LaTeX">$\text{T}_{\mathrm {PV}}$ </tex-math></inline-formula>) majorly drops the electrical output of the PV system. This research presents a novel cylindrical tube PCM matrix that is not in physical contact with the PV module back surface unlike the existing PCM based PV module cooling techniques. This contactless PCM matrix prevents the PV module from thermal and physical stress, also it blocks thermal energy re-conduction from PCM to PV module. While stored thermal energy from PCM retransferred to the PV module during off-sunshine hours and also when the PCM turns to liquid <inline-formula> <tex-math notation="LaTeX">$\text{T}_{\mathrm {PV}}$ </tex-math></inline-formula> starts to rise abruptly, this contactless PCM matrix minimizes these issues as PCM matrix receives thermal energy by the mode of radiation and convection; Besides, PCM matrix surface area is not enclosed with the PV module back surface area that reduces the thermal stress and re-conduction. Developed PCM matrix is integrated beneath the PV module at particular distances of 6 mm, 9 mm and 12 mm to optimize the spacing between PV module and PCM matrix. It is found that 6 mm spacing PCM matrix reduced the <inline-formula> <tex-math notation="LaTeX">$\text{T}_{\mathrm {PV}}$ </tex-math></inline-formula> maximum of 2.5 °C compared to 9 mm and 12 mm spacing. This <inline-formula> <tex-math notation="LaTeX">$\text{T}_{\mathrm {PV}}$ </tex-math></inline-formula> reduction enhanced the PV module electrical output by 0.2 % than PV without PCM and it is observed that 6 mm is an optimal spacing for the radiation source PCM matrix.

INDEX TERMS PV module cooling, optimal spacing, PCM matrix, radiation heat transfer, temperature corrected power. The associate editor coordinating the review of this manuscript and approving it for publication was Manoj Datta . C pv PV module specific heat capacity, J kg −1 K −1 C air specific heat capacity of air, J kg −1 K −1 C pcm,s solid specific heat capacity of PCM, J kg −1 K −1 C pcm,l liquid specific heat capacity of PCM, J kg −1 K −1 D diameter of the Al cylindrical tube (PCM matrix tube), mm F pv−air view factor between PV module and PCM matrix h 1 heat transfer coefficient between the PV module and the different spacing by radiation and natural convection, W m −2 K −1 h 2 heat transfer coefficient between PV module glass and the sky by radiation, W m −2 K −1 h 3 heat transfer coefficient between PV module glass and the ambient by convection, W m −2 K −1 h 4 heat transfer coefficient between the PV module and the PCM matrix by radiation and natural convection, m −2 K −1 h 5 heat transfer between the PCM matrix upper wall and inner wall by conduction, W m −2 K −1 h 6 heat transfer in PCM by conduction, W m −2 K −1 h 7 heat transfer coefficient between lower surface of the PCM matrix and the ambient by radiation and convection, W m −2 K −1 I solar irradiance, W m −2 K air thermal conductivity of air, W m −1 K −1 K PCM thermal conductivity of PCM, W m −1 K −1 K Al thermal conductivity of PCM matrix (Al cylindrical tube), W m −1 K −1 L PCM PCM latent heat of fusion, J kg −1 L PV length of PV module, m m air mass of the air, kg m PV mass of the PV module, kg m PCM mass of the PCM, kg Nu air Nusselt number between the PV module and the PCM matrix Ra air Rayleigh number between the PV module and the PCM matrix Pr PV→air Prandtl number between the PV module and the PCM matrix R 1 thermal resistance between the PV module glass and the sky R 2 thermal resistance between the PV module glass and the ambient R 3, R 4 thermal resistance between the PV module and the PCM matrix spacing R 5 thermal resistance between the PV module and the PCM matrix upper surface (selectively coated absorber) R 6 thermal resistance between the PCM matrix upper wall and the inner wall R 7 thermal resistance in the PCM R 8 thermal resistance between the PCM and down wall of the PCM matrix R 9 , R 10 thermal resistance between the down wall of the PCM matrix and ambient t time, min T Al PCM matrix upper wall temperature, • C T Al1 PCM matrix lower wall temperature, • C T air air temperature, • C T amb ambient temperature, • C The adoption of urbanized and modernized culture forces us to consume excessive power in our daily life and it is predicted that global energy consumption will increase by 50% by 2050 [1]. Global total energy production is about 25721 TWh in 2019, among which coal, gas and nuclear energy sources combined to produce 71.4% [2], [3]. This rapid consumption of fossil and nuclear fuels directly increases global warming. To reduce fossil fuel consumption and eradicate the adverse effects of global warming, renewable energy-based power productions should be widely employed. Among various available renewable sources and systems, the solar PV systems gained popularity owing to their low-cost maintenance and fascinating power conversion efficiencies i.e about 19 % for conventional Silicon based PV system [4], [5]. However, the system undergones considerable efficiency loss during hot summer as solar irradiance and ambient temperature soar thereby increasing the T PV abruptly [6]- [10]. Studies reveal that an increase in every 1 • C of T PV higher than the standard test condition (STC) causes reduction in the electrical output power by 0.3-0.4 % [11], [12]. Earlier T PV reductions were widely performed using water and air as they are well known thermal remover [13]- [19]. Following that, phase change materials (PCMs) are examined and they yielded an effective T PV reduction in comparison to water and air [20]- [25]. PCM is a latent heat storage material that stores thermal energy from PV module by changing its physical appearance mostly from solid to liquid. During a phase change, PCM enables latent heat of fusion (H m ) to store the high amount of thermal energy (J/g) without increasing the PCM temperature. But other materials store thermal energy in the form of specific heat capacity (J/g.K) and that are temperature dependent, as it starts to increase VOLUME 8, 2020 the temperature of the storage material [26], [27]. Moreover, PCM is a stationary unit that extracts the thermal energy effectively from PV module without fluid motion and it does not require an external source.
Conventionally, PCMs are stuffed in a box type container that are made up of high thermal conducting metal to avoid the conduction barrier between PV module back surface and PCM as containers are in physical contact with the module [28]. Initially, researchers focused on selecting the appropriate melting temperature of PCM as it is the physical property that dictates the temperature at which heat storage should be carried out in the material [29]- [31]. To optimize the PCM T melt , Waqas and Jie [30] performed the simulation for hot climatic condition using different T melt of PCM (30 • C, 35 • C, 40 • C and 44 • C). Among these 44 • C T melt of RT44 PCM reduced the T PV maximum of 28 • C. Secondly, several researchers worked on establishing the effect of thickness of PCM employed, general thumb rule that increase in PCM thickness enhances the mass heat transfer between PV module back surface and PCM and it favors reducing the T PV in higher-order and for longer time [32]. Further, it is observed that beyond 2 cm thickness of PCM the T PV reduction is poor [30].
Mahamudul et al. [33], [34] figured out that filling PCM in the metal container creates the conduction barrier as it is difficult to attain the perfect physical contact with the PV module back surface. Also, PCM has a low thermal conductivity (K PCM ) that induces the thermal conduction barrier at the time of charging and discharging. Further, to minimize this contact loss PCM is stuffed directly on the PV module back surface and plexiglass is used to seal the backside of the PCM. In such a case, PCM receive thermal energy directly from the back surface of the PV module without any transitional layer [35], [36]. This technique resulted in better T PV reduction. however, still conduction barrier occurred in PCM due to its low K PCM is not addressed [37]. Several studies are performed to minimize this PCM conduction barrier by incorporating thermal distribution heat sink projecting inside the PCM that helps to increase heat transfer. Following that, expandable graphite (EG) [38], [39], metal scrap, copper powder and metal foams [40] are also composited with PCM to enhance the PCM thermal conductivity (K PCM ).
It is noted in above literature and Table 1 most of the research groups focused on finding the suitable PCM and the ways to enhance the K PCM , none of them were considering the PCM re-conduction during the afternoon other than our previous study [39] and also very few of them discussed the disadvantage of the PCM especially the period when phase changes to liquid during this high sunshine hours. Elavarasan et al. [41] examined OM29 organic PCM to cool the PV module under hot climatic conditions, resulting in PCM integrated T PV starts to rise compared to PV without PCM. With a drastic rise in T PV due the extreme outdoor condition such as high ambient temperature (T amb ) and solar irradiance, the entire PCM melted within an hour of experimentation period. As mentioned earlier PCM liquid state is ineffective in extracting the heat from PV module back surface, even though the same PCM achieved effective T PV reduction in winter. PCM performance differs based on the outdoor condition, which is unpredictable and unstable for every day and every month. Under this circumstance, integrating PCM containers with the PV module using physical contact could be effective for some days and exacerbate for somedays also it creates the thermal and physical stress on the PV module.
Major problems finding in conduction-based PV module cooling techniques are summarized below.
145938 VOLUME 8, 2020 • PCM reconduction rise the T PV than conventional PV module during afternoon period of the experimentation [42].
• Integrating PCM container on the back surface of the PV module using physical contact could lead to the physical damage of the fragile PV module.
• Conduction source PCM increases the T PV when the PCM turns to be ineffective due to phase change [41].
• Increase in thickness of PCM container enhances the T PV reduction but also it increases the total weight of the system and requires additional mounting structure, that could increase the investment cost [43].
• It is necessary to optimize the thickness of PCM when it is in conduction mode because low thickness of PCM could turns to ineffective in the early period of experimentation. Further it creates the thermal resistant that directly increase the T PV higher than PV without PCM [41].
• PCM volume expansion can cause damage in the structure of PCM container and the PV module back surface.
To overcome these issues, PCM matrix are decided to be integrated beneath the PV module with non-physical contact.
• This contactless PCM matrix restricts the metal-based potential induced degradation (PID) [44] and indirectly reduces the T PV based PID loss [45].
• Integrating PCM matrix behind the PV module without physical contact allows the environment air to circulate around the PV module and PCM matrix that enhance the heat transfer.
• Cylindrical tube PCM matrix consumes less amount of PCM compared to box type PCM.
• Developed PCM matrix are clamped to the frame of PV module without using separate mounting structure.
The main objective of this research is to minimize or neutralize the T PV using the PCM matrix without increasing the thermal resistance like conduction source PCM. Existing PCM based cooling techniques are discussed and compared with the present radiation source PCM matrix. Developed radiation source PCM matrix installed at 6 mm, 9 mm and 12 mm spacing behind the PV module to find the effect of the radiation to optimize the spacing. it was found that considerable T PV reduction was achieved for 6 mm spacing.

A. PCM SELECTION AND DSC CHARACTERIZATION
PCM is the most efficient materials to reduce the T PV . As mentioned earlier, during phase transformation, heat from PV module is removed effectively with the help of H m without increasing the PCM temperature compared to sensible heat storage material. In the recent decade, PCM employed PV module cooling technique gains attention in turns of its fascinating T PV reduction compared to conventional methods of water, air and other techniques. Organic PCMs are widely experimented to cool the PV module as it contains high H m , non-corrosive to metal, congruent, and thermally stable for after several thousand thermal cycling [57]- [63]. But inorganic PCMs are less likely experimented due to their corrosiveness to metal and incongruent after several hundred thermal cycling [64], [65]. The eutectic mixture is thermally stable like organic PCM [65], [66]. Yet, eutectic PCMs are less explored as they are rare in local market. It requires special skill to prepare the eutectic mixture using probe sonication that makes this material unpopular for PV module cooling. In precise, paraffin wax and commercial PCMs are widely used rather than fatty acids [20], [21], [67]- [70]. Currently relaying on the existing technique, paraffin wax selected as PCM to reduce the T PV in this study Paraffin wax is purchased from the SQI Group, Bangkok, without further processing the PCM is analyzed to find the T melt and H m using Digital Scanning Calorimeter (DSC). A 5.4 mg of the material is placed in the aluminum sample holder and heated up by 5 K/min under nitrogen as a working fluid. The obtained DSC curve and PCM thermal properties are shown in Fig. 1 and Table 2, respectively.

B. EXPERIMENTAL SETUP
PCM matrix is made up of an aluminum cylindrical tubes that are filled by 95 % of liquid PCM and rest are left for PCM volume expansion. In total 36 tubes are placed in parallel with uniform spacing between each tube (S = 2.5D), as shown in Fig. 2 (a). From our previous study, it was clear that selective absorber enhances the heat absorption rate, following that in this research also selective absorber is coated on the front surface of the 36 PCM matrix cylindrical tubes [71].
Further, the developed PCM matrix is installed at 6 mm, 9 mm and 12 mm spacing behind the 310 Wp of the VOLUME 8, 2020 polycrystalline PV module (properties are listed in Table 3) to optimize the critical spacing as this experiment performs with contactless PCM integration unit. In this study, 6 mm spacing is selected as the least spacing distance because, decrease in spacing below 6 mm induces PCM matrix re-radiation effect and low convection which reduces the performance of the system compared to 6 mm spacing. Fig. 2 shows the overview of contactless PCM matrix and the experimentation process. The temperature profile of the PCM matrix and the PV module with and without PCM are measured across nine equidistance points using T-type thermocouples to get an even temperature following that solar analyzer is used to measure the electrical output of the PV modules as shown in schematic diagram of Figure 2 (b) and Figure 2 (c). Solar irradiance data collected from SGtech Meteorological office, Naresuan University, Thailand. This experiment is conducted in School of Renewable Energy and Smart Grid Technology, Naresuan University during the March 2018 which is usually the hottest month of the year. The experiment is deliberately chosen to be conducted in this month to access the consistence of the PCM and the random set of unbiased data are analyzed. All the experimental equipment's are calibrated before starting the experiment and they are in high accuracy up to 99.5%.

III. THERMAL HEAT TRANSFER NETWORK
The development of heat transfer network for PV module cooling using radiation source (contactless) PCM matrix comprises of different form of heat transfer mode, as shown in Fig. 3. First stage depicts the thermal interaction of the PV module front and backside. Thermal energy from PV module glass surface transferred to sky (R1) and the ambient (R2) by radiation and convection, respectively. Following that, PV module tedlar surface transfers thermal energy by radiation (R3) and convection (R4) to the surrounding or ambient without using any auxilary source. In this experiment PCM matrix is integrated at a particular distance to remove the energy from surrounding exactly beneath the PV module.
The second stage represents the thermal absorption of PCM matrix, PV module dissipates some of the thermal energy absorbed by PCM matrix front surface (R 5 ) and rest is left to the surroundings. As PCM matrix surface area is not enclosed with the PV module tedlar surface, that makes thermal energy from PV module transfers to the surrounding without restricting them to store in the PCM unlike existing PCM based PV module cooling technique. PCM matrix absorbed thermal energy is further transferred to the inner wall (R 6 ) where the PCM is present by conduction. Following that, PCM stores thermal energy by changing its phase from solid-liquid (R 7 ) that helps to reduce the T PV . 145940 VOLUME 8, 2020 Stage three represents the thermal dissipation from PCM matrix to surrounding or ambient. During sunshine and off sunshine thermal energy from PCM is transfered to the PCM matrix's lower surface by conduction (R 8 ), further it is transfer to the surrounding or ambient by radiation (R 9 ) and convection (R 10 ) to perform the next day operation. Above mentioned three stages are expressed by energy balancing equations by modifing our previous work from rectangular tube PCM matrix to cylindrical tube PCM matrix in the following subsections [39].

A. PV MODULE FRONT AND BACK SIDE
Physical appearance of the PV module front and back side heat transfers are expressed in the form of mathematical representation as expressed in equation (1). Thermal energy from PV module glass surface is transferred to the sky (h PV→sky ) and ambient (h PV→amb ) with the help of PV module glass emissivity and wind. Further, PV module tedlar surface transfers the thermal energy to the PCM matrix by radiation and natural convection (h PV→Al ) as PCM matrix is not in physical contact that helps to enhance electrical efficiency (η PV ).
From equation (1), h pv→air represents the convection and radiation mode of heat transfer from PV module tedlar surface to PCM matrix, that are expressed in equation (2).
Nusselt number for various spacing of 6 mm, 9 mm and 12 mm is expressed in equation in (3).
View factor for various spacing of 6 mm, 9 mm and 12 mm is expressed in equation in (4).
From equation (1), h PV→sky represents the PV module glass surface radiation to the sky as expressed in equation (5), this radiation is truly based on the T amb as expressed in equation (6) [20].
T sky = 0.0522T 1.5 amb (6) From equation (1), h PV→amb represents the PV module glass surface convection to ambient with the help of wind as expressed in equation (7) where, Equation (9) represents the amount of thermal energy that has been transferred to the critical spacing. (9) C. RADIATION SOURCE PCM MATRIX Equation (10) represents the amount of thermal energy that has absorbed at particular distance and it is stored in the form of solid-phase, melting phase and liquid phase concerning the T PCM as expressed in equation (11). As mentioned earlier, thermal energy from PCM matrix transferred to surrounding or ambient by radiation and natural convection, to enhance the heat transfer from PV module tedlar surface during sunshine hours and also to perform the consecutive day operation as expressed in equation (12).  Further, equation (1), (8), (9) and (10) are solved analytical to find the unknown variables of T PV , T Al , T air and T PCM , (13)- (16), as shown at the bottom of the page, where, (14), (15) and (16) can not solve directly as unknown variables are present in each, to mitigate this issue Newton Raphson method is applied. At the end of these process, electrical efficiency of the PV module is greatly enhanced as expressed in equation (17).

A. RADIATION SOURCE PCM MATRIX AT 6 mm SPACING
In general, PCM containers are integrated on the PV module tedlar surface using physical contact to achieve the effective heat transfer. In this experiment, developed PCM matrix installed at 6 mm spacing, considering the least possible spacing between the PV module tedlar surface and PCM matrix served the purpose. This contactless PCM matrix does not restrict the airflow to the PV module back surface that makes this system unique and free from thermal resistance, as an increase in resistivity could create a negative impact on the PV module cooling process. Fig. 4 shows an experimental result of PCM matrix at 6mm spacing, during experimentation, T amb reached a maximum of 33 • C due to low wind speed and high humidity (not shown). Also, solar irradiance started to rise from 11:00 to 13:00, following this T PV raised to a maximum of 60 • C that causes to drop the system performance by 15 %. For PV system with PCM matrix integrated, T PV is reduced until 15:00 with a maximum of 2.5 • C. After 15:00, PCM turns to liquid, but this novel PCM matrix did not increase the T PV as PV module back surface transmits thermal energy to surrounding and ambient without any disturbance with the influence of Tedlar emissivity factor and wind speed. In general, conduction based PCM had its disadvantage in PV module cooling [32], [73]- [75].
As mentioned earlier, this radiation source PCM matrix did not increase the T PV at the time of solar irradiance drop that makes this system has novel performance than conduction source PCM [42].

B. RADIATION SOURCE PCM MATRIX AT 9 mm SPACING
In order to optimize the critical spacing, a PCM matrix is integrated at 9 mm spacing to observe the thermal distribution of the PV module. An increase in spacing shows that thermal absorption of PCM matrix is ineffective, where the 6 mm spacing plays a vital role in T PV reduction. However, it did not increase the T PV until 11:00 as shown in Fig. 5, but after 11:00 slightly, T PV started to increase than PV without PCM. As PCM matrix at an inappropriate distance causes to increase the thermal resistance and it affects the rise in T PV . Even though this thermal resistance could not bear and sustain the rise in T PV for a longer time like conduction source PCM, at the time of 16:30 both T PV remains the same.

C. RADIATION SOURCE PCM MATRIX AT 12 mm SPACING
Further, the PCM matrix is integrated at 12 mm, resulting minor T PV reduction noticed until 10:30 however, this reduction is lower than 6 mm spacing as shown in Fig. 6. An increase in spacing reduces the radiation effect but convection dominates with the help of wind better than 9 mm spacing. As mentioned earlier, increase in spacing beyond 6 mm causes to increase the T PV at the time of peak sunshine, but in this 12 mm spacing also both T PV remains constant after 16:00. Comparatively, 6mm spacing yields higher T PV reduction than other spacing; also, it did not increase the T PV like 9 mm and 12 mm spacing that makes 6 mm is an optimal spacing for developed radiation source PCM matrix. To confirm the stability of the PCM matrix performance, consecutive one day optimized PCM matrix experimental results shown in Fig. 7 and another selective two days experimental results are shown in Table 4.
However, this novel radiation source PCM matrix reduced less T PV than most of the conduction source PCM VOLUME 8, 2020  Following that, several researchers obtained and expected T PV reductions also projected based on the present study to make the effective comparison. All the existing conductionbased method records higher T PV reduction, but linearity fails compared to present study at the same time performance is better than the existing model that makes this system is the replacement for conduction based PCM container. Integrating high amount of PCM enhances the higher electrical efficiency but payback period will be questionable and higher than the loss obtained by T PV [76]. In such way our proposed method will favor in attractive payback period as this method consumes 45.4 % of less PCM compared the existing methods. Also, this radiation type did not increase the thermal resistance, controls PID, avoids physical damage and easy in installation and maintenance.

D. ELECTRICAL PARAMETERS FOR OPTIMIZED PCM MATRIX
A solar cell is a semiconductor that converts incident photon into electrical energy during this process solar cell gains heat from sun. Increase in every 1 • C of T PV higher than STC causes to reduce the open-circuit voltage (V oc ) by 145944 VOLUME 8, 2020  0.30 -0.48%. Fig. 9 shows a reduction in T PV increases the V max until 15:00 further Vmax is neutralized for PCM matrix at 6 mm as T PV for both systems is neutralized after 15:00.
PV module voltage profile is temperature-dependent; at the same time PV module current profile has less effect as an increase in T PV because solar cell is a current generator that is highly correlated with solar irradiance. Experimental data reveals that the temperature coefficient of I sc is 0.049%/ • C from STC that makes minor fluctuation in current profile (not shown here) because less T PV reduction is obtained in the present study. However, clear variation is noticed in power curve with a maximum enhancement of 10 Wp as depicted in Fig. 10. An increase in solar irradiance increases the I max and it contributes to generate high power. However, PCM matrix integrated system is not close to the nominal power as it is difficult to achieve in real time condition also in this experiment less amount of PCM is performed to cool the PV module. In precise, Fig. 11 shows the power loss of both experimented PV modules compared to the nominal power but there is a noticeable difference between PV with and without PCM matrix.

E. ELECTRICAL EFFICIENCY FOR OPTIMIZED PCM MATRIX
Manufacturer rated electrical efficiency (%) is highly impossible to achieve, at the field level PV system undergoes various losses like soil loss, AC and DC cable loss, inverter loss, shading loss and T PV loss. Among other losses, T PV loss takes a bigger number. Since PV module electrical efficiency is sensitive to T PV and it becomes imperative to reduce it or to run the T PV close to ambient temperature, especially in a hot region like Thailand. In this experiment, PV module electrical efficiency enhanced maximum of 0.2 % using PCM matrix. Once the PCM matrix stopped its performance, PV module electrical efficiency closely remains the same as with the PV without PCM as shown in Fig.12.

F. PERFORMANCE RATIO FOR OPTIMIZED PCM MATRIX
In general, the performance ratio (PR) is used to find the loss obtained in the actual power production compared to the predicted power. In this study, PR is calculated for PV with and without PCM matrix to evaluate the performance enhancement of the proposed novel PCM matrix. Fig. 13 depicts until 15:00 PR of PCM matrix integrated PV module greatly enhanced 3 % than PV without PCM, however an increase in solar irradiance drops the PR profile against current and power as T PV majorly affects the PR and efficiency of the PV module.

G. ENVIRONMENTAL IMPACT ON PV MODULE EFFICIENCY
Fig. 14 depicts Pearson's correlation heat map of PV without PCM and PV with optimized PCM matrix to find the thermal correlation. In this study Pearson's correlation is used to find the association and direction of relationship between the environmental data (solar irradiance, T amb , wind) VOLUME 8, 2020  and output of the PV module as it is a well-known and effective method to measure the co-variance relationship. This heat map shows PV without PCM matrix T PV has a strong positive correlation with solar irradiance, moderate positive correlation with T amb , and has no correlation with the wind. As mentioned earlier, increase in solar irradiance raises the T PV with the help of T amb . This rise in T PV has a high negative correlation with the PV module electrical efficiency, such as increase in T PV drops the PV module electrical efficiency. Also, PCM matrix integrated PV module shows a similar strength of direction compared to PV without PCM matrix but it has noticeable variation in the correlation chart that makes the necessity of T PV reduction using PCM matrix.

V. CONCLUSION
Developed radiation source PCM matrix was integrated beneath the PV module at three different spacings to investigate the thermal distribution between the PV module tedlar surface and the PCM matrix upper surface. In this study, experimental results are compared with the developed numerical model and also with existing PCM based passively cooled PV module. It has been proved that beyond 6 mm spacing heat transfer is not occurring effectively and it leads to increase thermal resistance. This increase in thermal resistance shows the necessity of finding the optimal spacing, the experimental result reveals that beyond 6mm spacing T PV reduction is not effective that makes 6mm is an optimal spacing for radiationsource PCM matrix.
• Optimized PCM matrix reduced the T PV maximum of 2.5 • C compared to other spacing, reportedly this optimized PCM matrix did not increase the T PV like existing conduction based PCM at the time of solar irradiance drop.
• This optimized PCM matrix enhanced the electrical output power and efficiency maximum of 10 Wp and 0.2 %, respectively.
• Following output power and efficiency, PR also enhanced maximum of 3 % compared to PV without PCM.
• Further, it is recommended to prepare the eutectic PCM that can have high latent heat of fusion with the enhanced K PCM . In such case, optimized PCM matrix can reduce the T PV for longer time. Electrical and Automotive Parts Manufacturing Unit, AA Industries, Chennai, India. He has published papers in international journals and international and national conferences. His research interests include renewable energy and smart grid, wind energy research, power system operation and control, and artificial intelligence control techniques. He is a member of the IEEE Power and Energy Society. He received the Gold Medal for his master's degree.
HASSAN HAES ALHELOU (Senior Member, IEEE) received the B.Sc. degree (Hons.) from Tishreen University, Latakia, Syria, in 2011, the M.Sc. degree (Hons.) from the Isfahan University of Technology (IUT), Isfahan, Iran, in 2016, all in electrical power engineering, power systems, where he is currently pursuing the Ph.D. degree. He is also a Faculty Member with Tishreen University. He is included in the 2018 Publons's list of the top 1% best reviewer and researchers in the field of engineering in the world. He has published more than 30 research papers in the high-quality peer-reviewed journals and international conferences. He has also performed more than 160 reviews for high-prestigious journals, including the IEEE TRANSACTIONS ON INDUSTRIAL INFORMATICS, the IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, Energy Conversion and Management, Applied Energy, and the International Journal of Electrical Power and Energy Systems. He has participated in more than 15 industrial projects. His major research interests include power systems, power system dynamics, power system operation and control, dynamic state estimation, frequency control, smart grids, micro-grids, demand response, and load shedding. He was a recipient of the Outstanding Reviewer Award from many journals, such as Energy Conversion and Management (ECM), ISA Transactions, and Applied Energy. He was also a recipient of the Best Young Researcher in the Arab Student Forum Creative among 61 researchers from 16 countries at Alexandria University, Egypt, in 2011.
UMASHANKAR SUBRAMANIAM (Senior Member, IEEE) worked as an Associate Professor, the Head, and a Senior Research and Development Engineer, and a Senior Application Engineer in the fields of power electronics, renewable energy, and electrical drives with the Vellore Institute of Technology (VIT), Vellore. He is currently with the Renewable Energy Laboratory, College of Engineering, Prince Sultan University, Saudi Arabia, and has more than 15 years of teaching, research, and industrial research and development experience. Under his guidance, 24 master's degree students and more than 25 bachelor's degree students completed the senior design project work. Also, six Ph.D. scholars completed the doctoral thesis as a Research Associate. He has published more than 250 research papers in national and international journals and conferences. He is also involved in collaborative research projects with various international and national level organizations and research institutions. He has also authored/coauthored/contributed 12 books/chapters and 12 technical articles on power electronics applications in renewable energy and allied areas.