Energy Simulation and Parametric Analysis of Water Cooled Thermal Photovoltaic Systems: Energy and Exergy Analysis of Photovoltaic Systems

Round 1

Reviewer 1 Report

Pls see attachment

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 1 Comments

 

 

General comments: Authors have carried out study on Parametric Analysis of Cold-Water Thermal Photovoltaic System pertaining to Energy and Exergy Analysis. The paper need to modifying in depth for further course of action. In this regards, my comments are given below which would help to authors to improve it.

Point 1: The abstract is too general; I did not find any novelty.

Response 1: Thank you so much for your consideration. Abstract was rewritten in the revised version according your comment as following:

“It is generally agreed that solar energy, which can be converted into usable electricity by means of solar panels, is one of the most important renewable energy sources. An energy and exergy study of these panels is the first step in developing this technology. This will provide a fair standard by which solar panel efficiency can be evaluated. In this study, MATLAB tool was used to find the answers to the math problems that describe this system. The system's efficiency has been calculated using the modeled data created in MATLAB. When solving equations, the initial value of the independent system parameters is fed into the computer in accordance with the al-gorithm of the program. A simulation and parametric analysis of a thermal PV system with a sheet and spiral tube configuration have been completed. Simulations based on a numerical model have been run to determine where precisely the sheet and helical tubes should be placed in a PV/T system configured for cold water. Since then, MATLAB code for the proposed model has been developed, and it agrees well with the experimental data. There is an RMSE of 0.94 for this model. The results indicate that the modeled sample achieves a thermal efficiency of be-tween 43% and 52% and an electrical efficiency of between 11% and 11.5%.”

 

Point 2: The language should not have such word; we, I etc.

Response 2: With thanks. We rewiev the manuscript and modified the language of the manuscript.

 

Point 3: Introduction section must be written on more quality way, i.e. more up-to-date references addressed. Research gap should be delivered on more clear way with directed necessity for the conducted research work,

Response 3: With thanks. This section was extensively modified in the revised version and following references was added to the manuscript body for clarification the research gap.

 

“Ruzzenenti et al [10], have studied the technical and environmental aspects of the organic Rankine cycle with the simultaneous production of power and heat and geother-mal and solar energy sources at temperatures of 90 to 95. One of their goals is to provide a plan for exploiting geothermal wells that have been abandoned or fully developed Not found or unsuitable for use in high enthalpy technologies. Calise et al [11], have studied the technical analysis of the organic Rankine cycle with a solar energy source with the aim of producing power and heat at a temperature of 180 to 230. They have concluded that the application of this system is economically feasible for most Mediterranean regions with a return period of about 10 years. Hanifi et al [12], modeled the exergy and economic exergy of a simultaneous hydrogen and refrigeration system based on solar energy and opti-mized it economically. They concluded that the cost of production power, depending on the location of the power plant, is 145 to 280 dollars per megawatt hour, as a competitive option with large and independent concentrated solar power plants. Based on the men-tioned background, it can be seen that in the Rankine cycle with organic fluid, low tem-perature energy sources can be used and in addition to power, low temperature energy sources can be used.”

 

1. Hanifi, K.; Javaherdeh, K.; Yari, M. Exergy and Exergoeconomic Analysis and Optimization of the Cogeneration Cycle under Solar Radiation Dynamic Model Using Genetic Algorithm. In Green Energy and Technology; 2018; pp. 1139–1160.
2. Ruzzenenti, F.; Bravi, M.; Tempesti, D.; Salvatici, E.; Manfrida, G.; Basosi, R. Evaluation of the Environmental Sustainability of a Micro CHP System Fueled by Low-Temperature Geothermal and Solar Energy. Energy Conversion and Management 2014, 78, 611–616, doi:10.1016/j.enconman.2013.11.025.
3. Calise, F.; D’Accadia, M.D.; Vicidomini, M.; Scarpellino, M. Design and Simulation of a Prototype of a Small-Scale Solar CHP System Based on Evacuated Flat-Plate Solar Collectors and Organic Rankine Cycle. Energy Conversion and Management 2015, 90, 347–363, doi:10.1016/j.enconman.2014.11.014.

 

Point 4: The novelty of the work must be clearly addressed and discussed, compare your research with existing research findings and highlight novelty, (compare your work with existing research findings and highlight novelty)

Response 4: Thank you for your valuable comment. Following text and references was added to the manuscript for the sake of improvment. 

Additionally, it can be utilized just for the purpose of heating and heating applications, such as solar water heaters. In addition to these two, significant progress has been made in recent years in the development of photovoltaic-thermal systems, which are capable of performing both functions concurrently. There are many different approaches of testing the performance of photovoltaic cells. The investigation of the electrical and thermal performance of these cells is typically required using these approaches (for cells with thermal applications) [6,7].

The rated power, cell internal resistances, operating voltage and current, short-circuit current and open circuit voltage, and a number of other elements all contribute to the electrical performance of these systems [8,9]. The final output power of the system is affected by a variety of elements, including the Radiation intensity, wind speed, the ambient temperature, the cell surface temperature, and the heat transfer coefficient. In order to evaluate and analyze the performance of a solar system, a model needs to be established that takes into consideration the impact of each of these components and, in the end, gives a correct evaluation of system performance by making use of the relevant methods [10]. Because of the importance of solar panel energy analysis and exergy, much research has been conducted on the subject.

Ruzzenenti et al [11], have studied the technical and environmental aspects of the organic Rankine cycle with the simultaneous production of power and heat and geothermal and solar energy sources at temperatures of 90 to 95. One of their goals is to provide a plan for exploiting geothermal wells that have been abandoned or fully developed Not found or unsuitable for use in high enthalpy technologies. Calise et al [12], have studied the technical analysis of the organic Rankine cycle with a solar energy source with the aim of producing power and heat at a temperature of 180 to 230. They have concluded that the application of this system is economically feasible for most Mediterranean regions with a return period of about 10 years. Haifi et al [13], modeled the exergy and economic exergy of a simultaneous hydrogen and refrigeration system based on solar energy and optimized it economically. They concluded that the cost of production power, depending on the location of the power plant, is 145 to 280 dollars per megawatt hour, as a competitive option with large and independent concentrated solar power plants. Based on the mentioned background, it can be seen that in the Rankine cycle with organic fluid, low temperature energy sources can be used and in addition to power, low temperature energy sources can be used.

It was conducted an energy and exergy analysis of a hybrid solar water heater with a constant collector temperature and compared two different modes of module arrangement at the collector level [14]. In the first case, the collector surface was partially covered by solar modules, whereas in the second case, the collector surface was completely covered by solar modules. It was discovered that the first case is superior in terms of energy efficiency, whereas the second case is superior in terms of electricity generation. A solar tracker system was compared to a static photovoltaic tracker system [15,16]. These studies experimentally compared two systems for energy production under varying climatic conditions and found that the system with a solar tracker performs significantly better [17]. In 2019, energy and exergy were modeled and assessed for a 36-watt module in Bhopal, India. Throughout the course of the day, the proportion fluctuates. In addition, the panel's exergy efficiency increases dramatically when its temperature decreases [18]. The effect of partial shadows on the energy efficiency and exergy of a 75-watt solar panel was explored. This study found that horizontal shading reduced exergy efficiencies by 99.98 percent, compared to 69.93 percent for vertical shading, 66.92 percent for cell shading, and 99.98 percent for horizontal shading [19].

 

1. Rashidi, M.M.; Mahariq, I.; Murshid, N.; Mahian, O.; Alhuyi Nazari, M. Applying Wind Energy as a Clean Source for Reverse Osmosis Desalination: A Comprehensive Review. Alexandria Engineering Journal 2022, 61, 12977–12989.
2. Salek, F.; Rahnama, M.; Eshghi, H.; Babaie, M.; Naserian, M.M. Investigation of Solar-Driven Hydroxy Gas Production System Performance Integrated with Photovoltaic Panels with Single-Axis Tracking System. Renewable Energy Research and Applications 2022, 3, 31–40.
3. Eshghi, H.; Kahani, M.; Zamen, M. Cooling of Photovoltaic Panel Equipped with Single Circular Heat Pipe: An Experimental Study. Renewable Energy Research and Applications 2020.
4. Hanifi, K.; Javaherdeh, K.; Yari, M. Exergy and Exergoeconomic Analysis and Optimization of the Cogeneration Cycle under Solar Radiation Dynamic Model Using Genetic Algorithm. In Green Energy and Technology; 2018; pp. 1139–1160.
5. Maleki, A.; Haghighi, A.; El Haj Assad, M.; Mahariq, I.; Alhuyi Nazari, M. A Review on the Approaches Employed for Cooling PV Cells. Solar Energy 2020, 209, 170–185.
6. Ruzzenenti, F.; Bravi, M.; Tempesti, D.; Salvatici, E.; Manfrida, G.; Basosi, R. Evaluation of the Environmental Sustainability of a Micro CHP System Fueled by Low-Temperature Geothermal and Solar Energy. Energy Conversion and Management 2014, 78, 611–616, doi:10.1016/j.enconman.2013.11.025.

 

Point 5: The main objective of the work must be written on the more clear and more concise way at the end of introduction section,

Response 5: According your valuable comment, the final parageraph of the introduction section was modified and redrafted as following for clarify the objective of the work:  

“In recent years a significant amount of focus has been spent on the examination of photovoltaic and photovoltaic-thermal cells through the use of experimental methods. In the this study, to achieve the best design concept of solar panel system, the efficiency of a solar panel and its energy and exergy are analyzed by taking into account aspects of the surrounding environment such as the radiation intensity, the velocity of the wind, and the temperature. In addition, the helical model is investigated analytically through the utili-zation of the energy analysis methodology. In order to create a model of this system, mathematical equations were extracted from the energy balance equations that were pre-sented in a variety of sources for PV/T systems and solar collectors.”

 

Point 6: Data of legend in Fig. 7 is not visible.

Response 6: This Figures data and legend was edited in the new version of manuscript.

Figure 7. (a) Change in overall efficiency by changing the flow rate and distance between pipes, (b) Changing the pressure drop by changing the flow rate and distance between the pipes

 

Point 7: Conclusion section is missing some perspective related to the future research work, quantify main research findings

Response 7: Thank you for this consideration. The conclusion section was redrafted as following for addresed your concern.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript needs following revisions to become acceptable for publication:

1. The title can be improved. The current tile is not suitable and clear. "cold-water thermal PV" is not meaningful. It can be replaced with water cooled or something else.

2. Writing needs modification. There are some typos and errors.

3. "solar" is not a proper keyword. It is better to replace it with "Solar Energy".

4. Importance of the study must be clearly indicated. Following reference could be useful:

"A review on the approaches employed for cooling PV cells" https://doi.org/10.1016/j.solener.2020.08.083

5. All of the variables used in the equations must be defined.

6. Following references are suggested to improve literature review on the applications of renewable energy systems and PV cooling:

"Cooling of Photovoltaic Panel Equipped with Single Circular Heat Pipe: an Experimental Study" 10.22044/rera.2022.11523.1097

"Investigation of Solar-Driven Hydroxy Gas Production System Performance Integrated with Photovoltaic Panels with Single-Axis Tracking System" 10.22044/rera.2021.10768.1056

"Applying wind energy as a clean source for reverse osmosis desalination: A comprehensive review" https://doi.org/10.1016/j.aej.2022.06.056

 

 

 

Author Response

General comments: The manuscript needs following revisions to become acceptable for publication:

 

Point 1: The title can be improved. The current tile is not suitable and clear. "cold-water thermal PV" is not meaningful. It can be replaced with water cooled or something else.

Response 1: Thank you for your suggestion, the title was modified in the revised version.

 

Point 2: Writing needs modification. There are some typos and errors.

Response 2: We are grateful to you for taking this into consideration. The language usage throughout the entire manuscript was checked, and the abstract portion was rewritten.

 

Point 3: "solar" is not a proper keyword. It is better to replace it with "Solar Energy".

Response 3: Your concern was addressed in the revised version.

 

Point 4: Importance of the study must be clearly indicated. Following reference could be useful:

"A review on the approaches employed for cooling PV cells" https://doi.org/10.1016/j.solener.2020.08.083

Response 4: This interesting paper was used for enhancement the manuscript.

“Fossil fuel-based power facilities will be replaced with renewable energy plants. Solar energy is intriguing to policymakers due to its dependability, availability, and small-scale power production [1].”

 

Maleki, A.; Haghighi, A.; El Haj Assad, M.; Mahariq, I.; Alhuyi Nazari, M. A Review on the Approaches Employed for Cooling PV Cells. Solar Energy 2020, 209, 170–185.

 

Point 5: All of the variables used in the equations must be defined.

Response 5: With thanks. Your concern was addressed in the revised version.

 

Point 6: Following references are suggested to improve literature review on the applications of renewable energy systems and PV cooling:

"Cooling of Photovoltaic Panel Equipped with Single Circular Heat Pipe: an Experimental Study" 10.22044/rera.2022.11523.1097

"Investigation of Solar-Driven Hydroxy Gas Production System Performance Integrated with Photovoltaic Panels with Single-Axis Tracking System" 10.22044/rera.2021.10768.1056

"Applying wind energy as a clean source for reverse osmosis desalination: A comprehensive review" https://doi.org/10.1016/j.aej.2022.06.056

 

Response 6: Thank you for your suggestion. These valuable researches was used to improve the manuscript.

Author Response File: Author Response.pdf

Reviewer 3 Report

 - The Photovoltaic System Modeling section should be referenced.

Author Response

Point 1: The Photovoltaic System Modeling section should be referenced.

Response 1: Thank you for your consideration. following references was added to this section according to your comment.

 

1. Eshghi, H.; Kahani, M.; Zamen, M. Cooling of Photovoltaic Panel Equipped with Single Circular Heat Pipe : An Experimental Study. Renewable Energy Research and Applications 2022.
2. Seyedmahmoudian, M.; Mekhilef, S.; Rahmani, R.; Yusof, R.; Renani, E.T. Analytical Modeling of Partially Shaded Photovoltaic Systems. Energies 2013, 6, 128–144, doi:10.3390/en6010128.
3. Rosa-Clot, M.; Tina, G.M. Submerged and Floating Photovoltaic Systems: Modelling, Design and Case Studies; 2017; ISBN 9780128123232.
4. Nurwidiana, N.; Sopha, B.M.; Widyaparaga, A. Modelling Photovoltaic System Adoption for Households: A Systematic Literature Review. Evergreen 2021, 8, 69–81, doi:10.5109/4372262.

Author Response File: Author Response.pdf

Reviewer 4 Report

Dear Authors,


General comment:
The paper has many disadvantages.

„According to the findings, the modeled sample has a thermal efficiency that ranges somewhere between 43 and 52 percent and an electrical efficiency that ranges somewhere around 11.5 percent.”
And
 „However, as the flow rate increases from 0.016 to 0.02 kg/s, the overall efficiency rises from 53% to 55%, representing a significant increase in overall efficiency.”

My comment
The efficiency slightly improved.


„The configuration of sheet and helical tubes for the PV/T system of cold water was simulated using a numerical model. As a result of the construction of a MATLAB code, the proposed model with an RMSE=0.94 has a good agreement with experimental data.”

My comment
These are only the simulation results. I see two serious limitations
1.
Cooling only makes sense over a large surface area. Pipe contact with the flat surface is minimal. The efficiency of such a solution is minimal.
2.
The cost of this solution is high. Pumping water under pressure requires external electricity or some other fuel. So is it profitable? What is the end economic balance?


Fig.7a and 7b - Is missing in the text.


My conclusion
The advantage of connecting a photovoltaic module to a flat plate water cold collector consists in the possibility to reduce operation temperature of the cells.
But
Cost analysis is another important factor. Results of cost analysis of its application are not described in this paper.

Author Response

General comments: The paper has many disadvantages.

 

Point 1: “According to the findings, the modeled sample has a thermal efficiency that ranges somewhere between 43 and 52 percent and an electrical efficiency that ranges somewhere around 11.5 percent.”
And
 “However, as the flow rate increases from 0.016 to 0.02 kg/s, the overall efficiency rises from 53% to 55%, representing a significant increase in overall efficiency.”

My comment
The efficiency slightly improved.

Response 1: Thank you for your consideration. According to your comment these sectences was modified and redrafted in the abstract and result section.

 

Point 2: “The configuration of sheet and helical tubes for the PV/T system of cold water was simulated using a numerical model. As a result of the construction of a MATLAB code, the proposed model with an RMSE=0.94 has a good agreement with experimental data.”

 

My comment

These are only the simulation results. I see two serious limitations:

1. Cooling only makes sense over a large surface area. Pipe contact with the flat surface is minimal. The efficiency of such a solution is minimal.
2. The cost of this solution is high. Pumping water under pressure requires external electricity or some other fuel. So is it profitable? What is the end economic balance?

Response 2: With pluses, such as user-friendly operations and flawless heating capabilities, Helical's central air cooling system empowers you with a number of benefits, and elevates your experience to the next level of ease and comfort.

 

• Assures better air quality
• Consistently maintains temperature
• Decreases noise levels

A novel configuration of compact cross-flow helical tube heat exchanger for cooling applications is proposed, in view of its inherent high surface area density and tortuous flow path. The cooling potential of such a configuration is assessed against that of its straight tube counterpart i.e., cross-flow straight tube heat exchanger for similar volumetric air flow rates under laminar regime.

Analysis reveals (i) flow intensification reflected in ~2.3 times increase in Re and (ii) 3D flow that eliminates dead zones otherwise observed behind the straight tubes. The flow features result in 1.4-2.5 times increase in N_u, 2-4 times increase in the rate of heat extracted and higher heat exchanger efficiency upto 90% [1]. Meanwhile, The fins with the helical tube increases the heat transfer performance of radiator about 55.8% compared to existing radiator [2]

 

1. Jha, V.K.; Bhaumik, S.K. Enhanced Cooling in Compact Helical Tube Cross-Flow Heat Exchanger through Higher Area Density and Flow Tortuosity. International Journal of Heat and Mass Transfer 2020, 150, doi:10.1016/j.ijheatmasstransfer.2019.119270.
2. Sudhakar Babu, S.; Yasin, S. Heat Transfer Analysis of Automobile Radiator with Helical Tubes Using CFD. International Journal of Innovative Technology and Exploring Engineering 2019, 8, 999–1003.

Meanwhile, following text was added to the manuscript for cost balance clarification:

"2.4. Economic analysis

The sum of private and external costs for each power plant unit represents its social cost. Private electricity generation costs include investment, maintenance, and fuel expenses, among others. External cost is an external effect, thus the effects of environmental contaminants on a power plant might be called external costs. Given the private costs of the power plant and the assessment of the cost price of the produced energy as one of the most important economic concerns in power plants, thermoeconomic analysis of the cycle is crucial. According to the norms of thermoeconomic analysis, the cost balance, input exergy flow, and output exergy flow of the cycle are expressed by the Equation 4.

 

(4)

 

i refers to input currents, j refers to output currents, and Z is equipment cost. It is with the equipment investment cost that can be estimated using existing models. The values of C (flow cost) can be calculated from Equation 5.

 

,

(5)

 

where, c is unit cost. By applying the above relationships to the cycle studied in this study:

 

(5)

 

In order to examine the economics of solar systems, the assumptions outlined in Table 2 have been taken into account. Regarding spiral tubes, a cost average comprising all of their necessary expenses has been assumed. Considering the solar panels, inverter, and battery as the primary components of the photovoltaic system, the total cost has been computed based on the conditions of the research.

 

Table 2. Economic data of solar system

Item	Assumption
Helical Tube	250 ($/m2)
Photovoltaic Panel	10000 ($/kW)
Inverter	1200 ($/kW)
Battery	120 ($/kW)

"

" Economic results based on energy source in different modes are presented in Table 3. As expected, it can be seen that in the case of heat source with open flow and simultaneous production of power and heat compared to the case of heat source with closed flow, the required primary energy has increased and this requires energy supply equipment and investment cost. It is more basic; although in this case, we will have the byproduct of useful heat in addition to the power, but the increase in the initial investment cost will lead to an increase in the total price of the production power. Therefore, it can be seen that, in general, the production power in the open current source mode has a higher cost than the batch current source mode. In addition, according to the methods and technologies used, the cost of producing power using natural gas is lower than solar energy, which has more expensive equipment. However, an important issue in this regard is the environmental consequences of using natural; So that no environmental pollutants are produced in the use of solar energy, and this will result in a reduction of external costs. In order to classify solar energy technologies in terms of cost, spiral tubes, photovoltaic panels and conventional tubes can be mentioned respectively.

 

Table 3. Cost of generated power based on energy resources ($/kWh)

Source	Equipment	Power Cost
open flow (T= 30 °C)
Solar	Conventional tube	1.074
Gas	Boiler	0.024
Gas & Solar	Conventional tube & Boiler	0.820
Solar	Helical tube	0.346
Gas & Solar	Helical tube & Boiler	0.185
Close flow (T= 60 °C)
Solar	Helical tube	0.345
Gas	Boiler	0.023
Gas & Solar	Helical tube & Boiler	0.184
Solar Pump
Solar	Photovoltaic System	0.44

"

 

 

Point 3: Fig.7a and 7b - Is missing in the text.

Response 3: With thanks. The text about Figure 7 in the revised version was rewritten as following:

“Figure 7 depicts how flow and distance between pipes affect overall efficiency and pressure drop. The overall efficiency decreases from 53 to 37 percent (Figure 7-a), as the distance between the pipes increases, and the pressure drops from 47.5 to 13.5 kPa (Figure 7-b). The number of pipes in a given area decreases as the distance between them increas-es. The thermal efficiency of the system decreases as the number of pipes is reduced. Fur-thermore, by reducing the number of pipes, the length of the pipes and the pressure drop are reduced.”

Figure 7. (a) Change in overall efficiency by changing the flow rate and distance between pipes, (b) Changing the pressure drop by changing the flow rate and distance between the pipes

Point 4: My conclusion
The advantage of connecting a photovoltaic module to a flat plate water cold collector consists in the possibility to reduce operation temperature of the cells.
But
Cost analysis is another important factor. Results of cost analysis of its application are not described in this paper.

Response 4: Thank you for your comment. Your concern was addressed in the revised version by adding section 2.4 to material and method as well as Table 3 in the results and discussion.   

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Authors have modified manuscript as per my comments. 

Author Response

Thank you for reviewing. The spell check was done and the errors were modified in the revised version.

Reviewer 4 Report

Dear Authors,

Thank you very much for your response.

The Author's paper is correct and balanced. It’s written using proper language in a way that is interesting to the Reader.

I have only one question. Are the prices quoted including tax? If not, this information must be provided (The prices do not include VAT). All necessary information to the Reader must stand out directly.

And
The mistakes
Correct any mistakes, please.
e.g.
initial . line 199
byproduct line 328

Author Response

Point1: I have only one question. Are the prices quoted including tax? If not, this information must be provided (The prices do not include VAT). All necessary information to the Reader must stand out directly.

Answer: Thank you so much for reviewing. because the tax rate is different in the countries these price do not include VAT.  We applied your suggestion to Tables 2 and 3.

All mistakes in the text were checked in the new version.