Assessing the Effectiveness of Phase Change Materials in Residential Buildings for Reducing Urban Heat Island Effects

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Line 36, "Green roofs absorb heat..." Clarify a little more, they absorb but their merit is that not all passes to increase temperature (sensible heat), besides that, there are latent heat effects (greenery means live plants that have water), and plant metabolism effects

Line 74-75, phase shift -> phase transition

line 102, are the symbols from Koppens climate  clasification? (please, clarify/cite)

line 107, if the low of 19.2 a low of daily averages? what was the minimum temperature (optional: could you provide also maximum and minimum temperatures?)

line 113, give humidity (daily average if possible) or dry bulb besides wet bulb temperatures, if possible, or refer to the fig. 1. A high wet bulb temperature alone does not indicate high humidity (think of dry, hot climates)

line 121 (Fig. 1), could you label axis of Fig. 1 (a) with months?

If possible, clarify a little more the meaning of Direct Normal Irradiance (is it daily averaged over a moving surface oriented normal to the Sun direction?)

(around line 137) building design - it would be necessary to discuss the "representativity" facing actual buildings there. Is this a block often used in recent building construction?

line 155, Table 2, please clarify if you refer to window to wall ratio (window surface divided by total wall surface. (the same on table 3 and all the text)

Maybe could be better to joint tables 2 and 3, to compare more easily the changes between Base and Case models.

Line 156 and following: Please, give some indication to ascertain the origin of the quantity of PCM indicated. 

line 177, please, give indication as for what reason you divide the model into two sections (why have you chosen this division: Sun exposure? exposed surface for flat?)

Also, you try to evaluate consumption (or demand), clarify this further (the comfort would be nearly the same if using artificial energy methods to condition the flats)

line 193, Figure 6, (a and b) "Fuel (kWh)" -> "Energy (kWh)" (or "Conditioning Energy", or "Cooling Energy"...

Line 198 and following:  It would be interesting to compare the contribution to the changes (from Base to Model) due to only triple glazing and due to only PCM in the walls.

line 201, indicate reason why Domestic Hot Water usage is lower (is not so straightforward the reduction from changing glazing and adding PCM to the walls). Also, the reduction of Lighting is not so clear.

Line 207, Table 5, please clarify if in this case you consider no climatization

Please try to explain the strong change in Lighting energy use

Line 216 and following: It is absolutely necessary to justify why the triple glazing INCREASES the lowest interior daylighting. Also, the mention to the PCM at this point seems difficult to justify (were the dwellings designed with different interior painting??)

Line 244, please give currency equivalent in some other (more current) units (US$, Euro...)

 

Anyway, besides the regular notes above: The subject could be interesting, but seems more appropriate for some other journals: Buildings, Energy and Buildings,...

The scope of the study, by centering on only one design, and almost not giving indications on generalization, or how could influence other designs, might be too "a kind of a case study". The selected items to modify the original design -adding PCM and substituting simple, clear glass by tripe glass- might need more discussion and justification (for instance, even a double glazing would perform worse than triple, cost is also lower. Some considerations could be added, as in the conclusions it is mentioned the large increase in cost for the dwellings due to the changes proposed)

 

Author Response

1. Comment: Line 36: "Green roofs absorb heat..."

Response: Green roofs diminish heat flow into buildings by transforming sensible heat into latent heat through evapotranspiration. The process is facilitated by vegetation, which retains water and cools the surrounding air through evaporation and plant metabolism. Urban forestry offers shade, evapotranspiration, and enhanced thermal comfort. Increasing vegetation in urban areas, such as parks and green spaces, can help to reduce the UHI effect by cooling the air and enhancing urban microclimate.

2. Comment: Line 74-75: "phase shift" ->

Response: Corrected the terminology from "phase shift" to "phase transition"

3. Comment: Line 102: "Are the symbols from Köppen's climate classification?"

Response: Yes, the symbols follow Köppen's climate classification system. The climate classification ('Aw') corresponds to a Tropical Savanna climate with dry winters.

4. Comment: Line 107: "If the low of 19.2 is a low of daily averages? What was the minimum temperature?"

Response: The average daily low temperature was 19.2°C, with the absolute minimum being 16.8°C and the maximum at 41.8°C. The dry bulb temperature showed significant monthly variations, with a maximum of 41.8°C in April and a low of 19.2°C in January.

5. Comment: Line 113: "Give humidity (daily average if possible) or dry bulb besides wet bulb temperatures."

Response: The mean daily relative humidity is 67%, fluctuating between 42% in March and 85% in November. The dry bulb temperature data is illustrated in Figure 1.

6. Comment: Line 121 (Fig. 1): "Label the axis of Fig. 1 (a) with months?"

Response: The x-axis of Fig. 1(a) has been labeled with months to improve clarity.

7. Comment: Clarify the meaning of Direct Normal Irradiance (DNI).

Response: DNI is the quantity of solar radiation that a surface perpendicular to the Sun's rays receives per unit area.

8. Comment: Line 137: "Building design - discussing the representativity of the block. Is this a common construction practice?"

Response: The selected residential block is a representative model of common multi-family dwellings in Trichy. The design adheres to the region's prevailing construction trends and urban planning guidelines.

9. Comment: Line 155, Table 2: "Clarify if you refer to window-to-wall ratio (WWR)."

Response: Yes, the values represent the window-to-wall ratio (WWR), calculated as the window surface divided by the total exterior wall surface.

10. Comment: "Merge Tables 2 and 3 to compare Base and Case models more easily

Response: Tables 2 and 3 have been combined into a single comparative table to highlight differences more clearly.

11. Comment: Line 156: "Provide the rationale for the amount of PCM used

Response: The amount of PCM utilised was calculated according to empirical studies and manufacturer specifications (Rubitherm 21). It was chosen to provide optimal heat management while being feasible for wall use.

12. Comment: Line 177: "Why is the model divided into two sections?"

Response: The division of the model into two sections (Parts A and B) is based on solar exposure and building orientation. Part A receives greater direct sunlight, while Part B includes interior and shaded sections.

13. Comment: Clarify whether you evaluate consumption or demand.

Response: The study evaluates energy demand rather than just consumption. Energy demand is the total power required to maintain thermal comfort, influenced by passive strategies like PCM integration.

14. Comment: Line 193, Figure 6: "Fuel (kWh)" -> "Energy (kWh)"

Response: The term "Fuel (kWh)" has been changed to "Cooling Energy (kWh)" for accuracy.

15. Comment: Line 198: "Compare the individual contributions of triple glazing and PCM

Response: A separate comparison has been included to isolate the energy savings due to PCM and triple glazing.

16. Comment: Line 201: "Explain the reason for lower Domestic Hot Water usage."

Response: The reduction in DHW energy consumption is primarily due to better insulation, which minimizes heat loss from storage tanks and pipelines.

17. Comment: Line 207, Table 5: "Does this table assume no air conditioning?"

Response: The table represents energy consumption with and without air conditioning.

18. Comment: Explain the strong change in Lighting energy use.

Response: The lighting energy reduction is attributed to improved daylight penetration due to the increased reflectivity of PCM-enhanced walls and optimized window design.

19. Comment: Line 216: "Justify why triple glazing increases interior daylighting."

Response: The triple-glazed windows let in more natural light because they eliminate glare and improve light diffusion. This effect is facilitated by incorporating PCM, which modifies surface reflectance.

20. Comment: Line 244: "Provide cost equivalent in other currencies."

Response: The additional Rs. 4.35 lakhs per owner is approximately $5,220 (USD) or €4,800 (EUR). Currency conversions have been added.

 

Reviewer 2 Report

Comments and Suggestions for Authors

The paper should be rejected, in my opinion, due to the following reasons:

1- The contribution is not well written in the abstract. It does not highlight the novelty of the study, and they did not add any numerical results to support the claims. A strong abstract should include the main findings and related quantitative outcomes.
2- In the introduction, they did not review similar studies sufficiently, which makes it difficult to understand how this work builds upon or differentiates itself from other existing research.
3- The research gap is not clearly identified, which makes the reader uncertain about the problem this study is going to solve.

Author Response

1. Comment: The contribution is not well written in the abstract. It does not highlight the novelty of the study, and they did not add any numerical results to support the claims. A strong abstract should include the main findings and related quantitative outcomes.

Response: We appreciate the reviewer’s feedback and have revised the abstract to highlight the study's novelty and include quantitative results that support our claims.

2. Comment: In the introduction, they did not review similar studies sufficiently, which makes it difficult to understand how this work builds upon or differentiates itself from other existing research.

Response: We have expanded the introduction by incorporating a more comprehensive literature review that discusses recent studies on UHI mitigation using PCMs and advanced glazing systems. The revised section clearly differentiates our study from previous research by emphasizing our methodological innovations and site-specific findings.

3. Comment: The research gap is not clearly identified, which makes the reader uncertain about the problem this study will solve.

Response: We acknowledge the need to explicitly define the research gap and have revised the introduction to articulate the problem statement and how our study addresses it.

 

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

1. There are three application methods for phase change materials: direct application, micro-encapsulation, and macro-encapsulation. The article's discussion on the optimal integration method for PCMs is inadequate, as it fails to explore the impact of these integration methods on the effectiveness of PCMs within walls.

2. Although the article mentioned the application of phase change materials (PCMs) in building walls, it did not provide a detailed discussion on their applicability and limitations under various climatic and environmental conditions. It is recommended that an analysis of the scope of application, performance optimization, and limitations of PCMs be included, particularly regarding their performance over extended periods of use.

3. Some of the analyses of the charts in the text are somewhat brief, particularly the discussions regarding the results of thermal analysis and changes in energy efficiency.

4. The simulation analyses presented in the text lack empirical data and verification from related simulations. To enhance the accuracy and reliability of the results, it is recommended to include more actual experimental data or to conduct comparative analyses with results obtained from other tools.

5. This study concentrated on the integration of phase change materials (PCMs) with triple-pane windows; however, it did not perform a comprehensive comparison with other prevalent strategies for alleviating the Urban Heat Island (UHI) effect, such as green roofs, cool pavements, and reflective coatings.

6. The Urban Heat Island effect is a phenomenon that impacts the large-scale environment of a city. However, the research has primarily focused on enhancing the energy efficiency and thermal comfort of individual buildings, neglecting a comprehensive examination of the contributions and roles of buildings in the overall Urban Heat Island effect. In addition to improving individual structures, can we clarify how these technologies influence the surrounding urban environment, particularly concerning the Urban Heat Island effect?

Author Response

1. Comment: Three application methods for phase change materials are direct application, micro-encapsulation, and macro-encapsulation. The article's discussion on the optimal integration method for PCMs is inadequate, as it fails to explore the impact of these integration methods on the effectiveness of PCMs within walls.

Response: Various factors, including the integration method influence the effectiveness of polymer concrete (PCM) in building walls. Integration is mainly employed in direct, micro-encapsulation, and macro-encapsulation. For the direct application, PCMs are mixed directly into building materials like concrete. This is a cost-effective method, but it can lead to problems like leaks and weaker structures. By enclosing PCMs in thin capsules, micro-encapsulation improves thermal stability and prevents leakage, enabling improved control over the phase change process. While macro-encapsulation makes installation and replacement easier by enclosing PCMs in bigger containers or panels, it can be expensive and occupies additional space in the wall structure.

2. Comment: Although the article mentioned the application of phase change materials (PCMs) in building walls, it did not provide a detailed discussion on their applicability and limitations under various climatic and environmental conditions. It is recommended that an analysis of the scope of application, performance optimization, and limitations of PCMs be included, particularly regarding their performance over extended periods of use.

Response: Polymer concrete (PCM) is increasingly used in building walls for enhanced thermal insulation and energy efficiency. However, their efficiency differs significantly based on the environmental conditions, such as hot-arid, temperate, and humid. In hot, arid regions, PCMs can stabilise indoor temperatures by reducing heat gain; however, the efficiency of PCMs is affected by factors such as the orientation of the walls and the intensity of solar radiation. In temperate settings, PCMs can help control indoor temperature variations and minimise energy usage, but their failure to solidify during heat waves limits their effectiveness. While PCMs may reduce cooling loads and increase energy efficiency in humid conditions, their effectiveness is affected by their ability to interact with thermal insulation. To maximise their energy-saving potential, PCMs must be able to undergo phase shifts effectively over longer durations if they are to remain efficient over a long time frame. The efficacy of PCMs can be further improved by incorporating dynamic insulation systems.

3. Comment: Some of the analyses of the charts in the text are somewhat brief, particularly the discussions regarding the results of thermal analysis and changes in energy efficiency.

Response: The discussions on thermal analysis and energy efficiency changes have been expanded with more detailed interpretations of trends and variations observed in the charts. The significance of temperature fluctuations and energy savings has been explained thoroughly.

4. Comment: The simulation analyses presented in the text lack empirical data and verification from related simulations. To enhance the accuracy and reliability of the results, it is recommended to include more actual experimental data or to conduct comparative analyses with results obtained from other tools.

Response: The above study is part of a student's mini project work in B.tech Civil Engineering. The study itself is the first of its kind in this geographical location. However, experiments will be conducted in their major project work as suggested.

5. Comment: This study concentrated on the integration of phase change materials (PCMs) with triple-pane windows; however, it did not perform a comprehensive comparison with other prevalent strategies for alleviating the Urban Heat Island (UHI) effect, such as green roofs, cool pavements, and reflective coatings.

Response: As stated earlier, other UHI mitigation strategies, such as green roofs, cool pavements, and reflective coatings, will be used in their major project work.

6. Comment: The Urban Heat Island effect is a phenomenon that impacts the large-scale environment of a city. However, the research has primarily focused on enhancing the energy efficiency and thermal comfort of individual buildings, neglecting a comprehensive examination of the contributions and roles of buildings in the overall Urban Heat Island effect. In addition to improving individual structures, can we clarify how these technologies influence the surrounding urban environment, particularly concerning the Urban Heat Island effect?

Response: A new section is added to discuss the broader implications of PCM integration on the urban environment.

 

 

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The paper has improved, however, some points might merit more clarification:

Lines 15-16 (Abstract): "There was an annual drop in room electricity consumption of 380 kWh from 480 kWh and 15 a 3°C decrease in maximum indoor temperatures" -> Please, Clarify and make sure this is coherent with the previous statement (reduction in energy consumption per m2 and year)

Lines 40-41, Suggerence: "...through evapotranspiration." -> "...through evapotranspiration and metabolism." 

Line 115: Avoid mentioning chemical bonds, because the chemical specimen should be the same, solid or liquid: "...and when exposed to heat, chemical bonds break, leading the PCM to transition..." -> "...and when exposed to heat, it leads the PCM to transition..."

Lines 173-176: Clarify, if May is the most humid, how is November cited as of higher humidity?

Also, indicate in some point the daily temperature oscillation (Daily T Max- T Min) with some emphasis, because this is what makes PCM useful.

Line 179-180, de-humidifying can require energy. Maybe cite as avoiding too high humidity by design? Clarify a little more

Line 193, Figure 1 (caption): change the lettering of the figure, should be (a), (b), (c) (now is only (a) and (b))

Line 230, Table 2, please indicate the meaning of VLT (better, in the table caption, indicate the meanings of SHGC -Solar Heat Gain Coefficient- and VLT

Line 250, Table 3, revise the units of "Heat storage capacity" (is the value the latent heat?)
As a suggerence, some advice should be given as avoid dark colors, to limit temperatures always under the Max-operative temperature.

Line 280, explain more (you have answered partially to this) the reduction of Domestic Hot Water. Better insulation would mostly produce a lower interior temperature (only slight effects are expected for the less hot periods?) If pipes and storage tanks have been further isolated, indicate this.   

Line 282, Due to the fact that solar gains through windows are lowered, a decrease in lighting energy would mean that now light could be allowed to enter while in the base case was not allowed because of too high solar gain? Please explain a little more, as a lower transparency to visible is expected for triple glazing (Optional; you have answered partially to this).

Line 290, Table 4: Please clarify better if the proposed case model forced the same temperatures as the base case (or very similar, not reaching the interior 27ºC whole year). Clarify better how the "gains" in thermal performance were divided in operative interior temperature and reduction in energy use

(Comment to table 4: Lighting energy seems quite high, even related to "Room Electricity" (Maybe is the result of time schedule of uses in the software?). Revise values, and comment a little on this)

(Comment to Tables 4, 5 and 6: Are the values and units fully coherent? Tables 5 and 6, parts A anb B separated give values that (nearly) add as "Overall", but all are values (per m2 year). Please explain more the values and how were obtained. Table 4 give values in kWh, per month? 
 

Author Response

1. Comment: Lines 15-16 (Abstract): "There was an annual drop in room electricity consumption of 380 kWh from 480 kWh and 15 a 3°C decrease in maximum indoor temperatures" -> Please, Clarify and make sure this is coherent with the previous statement (reduction in energy consumption per m2 and year)

Response: Lines 13-16: As suggested, the sentence has been rephrased with better clarity: “Room electricity consumption decreased from 480 kWh to 380 kWh, demonstrating the energy-saving benefits of the modifications. Overall energy consumption was reduced to 271.9 kWh/m²/year from 312.23 kWh/m²/year in the base case, a 13% decrease, equating to 40.33 kWh/m²/year in energy savings”.

 

2. Comment: Lines 40-41, Suggerence: "...through evapotranspiration." -> "...through evapotranspiration and metabolism." 

Response: Lines 42: The phrase has been modified to "...through evapotranspiration and metabolism" to acknowledge the metabolic heat processes in vegetation.

 

3. Comment: Line 115: Avoid mentioning chemical bonds, because the chemical specimen should be the same, solid or liquid: "...and when exposed to heat, chemical bonds break, leading the PCM to transition..." -> "...and when exposed to heat, it leads the PCM to transition..."

Response: Lines 116-117: The phrase has been restructured as "...and when exposed to heat, it leads the PCM to transition from solid to liquid," avoiding the mention of chemical bonds while maintaining scientific accuracy.

 

4. Comment: Lines 173-176: Clarify, if May is the most humid, how is November cited as of higher humidity?

Also, indicate at some point the daily temperature oscillation (Daily T Max- T Min) with some emphasis, because this is what makes PCM useful.

Response: Lines 170-176: As suggested, we have added: In tropical savanna regions like Trichy, Phase Change Materials (PCMs) are useful for lowering cooling loads and regulating indoor temperatures. They function optimally when there are substantial diurnal temperature variations, enabling them to capture heat during the day and emit it at night. The observed temperature range in Trichy's tropical savanna climate is 10-15°C in summer and 8-12°C in winter, with extremes of 41.8°C (April) and 16.8°C (January). These variations improve PCM performance by regulating indoor temperatures and lowering cooling demands.

 

5. Comment: Line 179-180, de-humidifying can require energy. Maybe cite as avoiding too high humidity by design? Clarify a little more

Response: Lines 187-192: Implementing dehumidification strategies, such as natural ventilation and passive moisture absorption techniques like baking soda, can help manage energy consumption more efficiently while preventing excessive moisture accumulation. Additionally, behavioral modifications, such as taking shorter showers with open bathroom doors, further contribute to effective humidity regulation, enhancing indoor comfort and reducing energy use.

 

6. Comment: Line 193, Figure 1 (caption): change the lettering of the figure, should be (a), (b), (c) (now is only (a) and (b))

 

Response: I’m guessing this is under section 3.3 3D Modeling. Looks like this has already been implemented

 

7. Comment: Line 230, Table 2, please indicate the meaning of VLT (better, in the table caption, indicate the meanings of SHGC -Solar Heat Gain Coefficient- and VLT

Response:  The meanings of SHGC (Solar Heat Gain Coefficient) and VLT (Visible Light Transmittance) have been included in the table bottom for clarity.

8. Comment: Line 250, Table 3, revise the units of "Heat storage capacity" (is the value the latent heat?)
   As a suggerence, some advice should be given as avoid dark colors, to limit temperatures always under the Max-operative temperature.

 

Response: The "Heat storage capacity" value has been confirmed as the latent heat of fusion, and appropriate units have been included as joules per kelvin (J/K)

 

9. Comment: Line 280, explain more (you have answered partially to this) the reduction of Domestic Hot Water. Better insulation would mostly produce a lower interior temperature (only slight effects are expected for the less hot periods?) If pipes and storage tanks have been further isolated, indicate this.   

Response: Lines 300-310: For instance, if pipes and storage tanks have been further isolated, the heat transfer rate with the external environment lessens.  By minimizing heat transfer with the external environment, insulation reduces the need for additional heating in winter and prevents excessive heat gain in summer. During the winter, when heat losses are usually higher, the drop in DHW use is higher. Consequently, the utilisation of domestic hot water (DHW) decreases substantially during colder periods, when heat losses are higher, while still giving advantages in milder conditions. Additional improvements to efficiency can be obtained by insulating domestic hot water pipelines and storage tanks using methods such as pipe lagging, tank insulation jackets, or reflecting barriers.  

10. Comment: Line 282, Due to the fact that solar gains through windows are lowered, a decrease in lighting energy would mean that now light could be allowed to enter while in the base case was not allowed because of too high solar gain? Please explain a little more, as a lower transparency to visible is expected for triple glazing (Optional; you have answered partially to this).

Response: Lines 311-317: Integrating PCM and triple-glazed windows minimises illumination energy consumption by balancing solar gain and daylighting. Single-pane windows produced increased solar heat gain and VLT, necessitating more sunshine to ensure indoor comfort. While triple-glazed windows have a lower SHGC (0.47) and VLT (0.65) than single-glazed windows, this enables more effective light diffusion throughout the interior. This enhances the indoor environment by favouring natural light over artificial illumination.

 

11. Comment: Line 290, Table 4: Please clarify better if the proposed case model forced the same temperatures as the base case (or very similar, not reaching the interior 27ºC whole year). Clarify better how the "gains" in thermal performance were divided in operative interior temperature and reduction in energy use

Response: As suggested we have added the below as how thermal performance improvements were distributed between operative interior temperature control and energy savings.

By incorporating triple-glazed windows and Phase Change Materials (PCMs), the proposed case model enhances thermal performance and mitigates interior temperature fluctuations. This prevents extreme temperature fluctuations and promotes a more consistent indoor climate. In the baseline scenario, interior temperatures exhibited considerable variability, reaching 35°C during summer and declining to 27°C in cooler months. Phase Change Materials and triple-glazing mitigated peak temperatures to 34°C during summer, decreasing indoor warming by 1°C. However, the minimum temperature remained at 27°C during cooler periods, suggesting that insulation prevented considerable heat loss. The proposed model guarantees a more agreeable thermal environment by reducing temperature fluctuations.

 

12. Comment: (Comment to table 4: Lighting energy seems quite high, even related to "Room Electricity" (Maybe is the result of time schedule of uses in the software?). Revise values, and comment a little on this)

 

Response: The software likely follows a default or predefined occupancy and lighting usage schedule, which may not fully account for daylight availability.

Energy consumption could be overestimated if the schedule assumes longer lighting hours throughout the day.

 

13. Comment: (Comment to Tables 4, 5 and 6: Are the values and units fully coherent? Tables 5 and 6, parts A anb B separated give values that (nearly) add as "Overall", but all are values (per m2 year). Please explain more the values and how were obtained. Table 4 give values in kWh, per month? 

Response:

• Table 4 presents a monthly breakdown of energy consumption in kWh per month for key loads (Room Electricity, Domestic Hot Water, and Lighting). These values represent the total energy consumed each month for the entire building.
• Table 5 provides the base case's annual energy consumption per square meter in kWh/m²/year.
• Table 6 presents the annual energy consumption per square meter in kWh/m²/year for the proposed case, which includes energy-efficient interventions.
• Since Tables 5 and 6 report per-m² values, they represent normalised energy use that allows for a direct comparison of building performance across different scenarios, while Table 4 provides the actual monthly energy trends.
• Since Table 4 primarily focuses on key loads (Room Electricity, DHW, Lighting), it does not include all building energy end-uses (e.g., HVAC, ventilation, plug loads).
• Tables 5 & 6 represent the total energy consumption for all loads, so they report higher overall values than the sum of Table 4’s individual categories.
• The discrepancy is expected and not an inconsistency—it reflects the inclusion of additional energy-consuming systems in the total energy analysis.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you for sharing your work. Your study is well-structured and methodologically sound, and I appreciate the effort that went into it. However, the research does not bring enough novelty or contribution to justify publication at this stage. The use of PCMs for improving building thermal performance has been widely explored, and this study does not introduce a significantly new approach. Additionally, while it provides valuable insights into indoor temperature reduction, it does not directly address UHI mitigation on an urban scale, lacks experimental validation, and does not compare PCMs with other mitigation strategies. That said, I believe there is potential here, and I encourage you to refine your study by incorporating a novel aspect, expanding the urban-scale analysis, and adding real-world validation. I look forward to seeing how your research evolves.

Author Response

Comment: Thank you for sharing your work. Your study is well-structured and methodologically sound, and I appreciate the effort that went into it. However, the research does not bring enough novelty or contribution to justify publication at this stage. The use of PCMs for improving building thermal performance has been widely explored, and this study does not introduce a significantly new approach. Additionally, while it provides valuable insights into indoor temperature reduction, it does not directly address UHI mitigation on an urban scale, lacks experimental validation, and does not compare PCMs with other mitigation strategies. That said, I believe there is potential here, and I encourage you to refine your study by incorporating a novel aspect, expanding the urban-scale analysis, and adding real-world validation. I look forward to seeing how your research evolves.

Response:

• The study, part of a B.Tech student mini-project, aimed to analyze the impact of Phase Change Materials (PCMs) on indoor temperature reduction in Trichy's tropical savanna climate. The findings highlighted how diurnal temperature variations influence PCM effectiveness, which could inform local building practices. However, the study acknowledges the need for a more novel approach and plans to explore hybrid mitigation strategies that combine PCMs with other passive cooling techniques in future work.

 

• The study primarily focuses on building-level thermal performance rather than urban heat island (UHI) mitigation on an urban scale. As part of the student's major project, urban-scale simulations will be conducted using computational tools like ENVI-met or CFD modelling to evaluate the broader impact. Experimental validation is underway, with small-scale test cells embedded with PCMs monitored for temperature and energy performance under real climatic conditions.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

All the comments have been addressed.

Author Response

Comment: All the comments have been addressed.

Response: We extend our sincere gratitude sir, for your constructive feedback, which has significantly contributed to refining our manuscript.