Dynamic Window Technologies for Energy Efficiency in Condominiums in Tropical Climates

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper looks interesting to me, I have the below comments that need to be addressed:

·         In Section 3, the methodology is clear but lacks details on simulation parameters, such as solar radiation intensity and material thickness. Including these would improve replicability and validation. How do you account for climate variations, like seasonal temperature changes, that might affect energy savings?

·         Section 4.3.1 would benefit from specifics on solar radiation analysis, like whether Thailand-specific climate data was used. Detailing these parameters would strengthen the study’s relevance. Did you use region-specific climate data, and from which sources?

·         The energy savings discussion in Section 4.3.5 doesn’t address real-world limitations, such as maintenance needs for automated systems, which could impact long-term effectiveness. Adding this context would balance the findings. How do you foresee maintenance demands affecting energy savings over time?

·         Section 5.2 mentions financial barriers to adoption but overlooks practical user issues, such as ease of use. Briefly discussing user training or intuitive design could help increase adoption. What design or training features could make these windows more user-friendly?

·         The paper currently lacks a discussion on how dynamic windows can act as both competitive differentiators and coordinated features within building systems. To address this, citing works titled, "Selling information in competitive environments" and "Coordination via selling information," could provide valuable context. These references would highlight how dynamic windows might enhance market appeal through real-time environmental control and facilitate coordinated, data-driven decisions within building management, ultimately benefiting resident comfort and building efficiency.

·         Referencing "Barriers to Community Connectivity: An Assessment of the Reconnecting Communities Pilot Program" could strengthen the discussion on dynamic windows in urban design by providing context on how these technologies might impact urban connectivity and either mitigate or contribute to environmental barriers in densely populated settings. Also, including "A Generalized Framework for Assessing Equity in Ground Transportation Infrastructure" in the recommendations could expand the equity discussion in energy-efficient building design, highlighting the implications of such technologies on sustainable living access across communities.

 

·         Section 4.3.6 highlights savings but lacks a payback period estimate. Adding one would clarify financial viability. Have you estimated the payback period, including initial costs and maintenance?

Author Response

 In Section 3,

Regarding the request for further details in the methodology section on simulation parameters such as solar radiation intensity and material thickness, we have addressed these parameters in the following sections of our manuscript:

• Solar Radiation Intensity: Details on solar radiation intensity used in our simulation can be found in:
• Section 4.3.1: Solar Radiation Analysis – Page 7, lines 268, 272-274.
• Climate Variations and Seasonal Temperature Changes: We have accounted for climate variations, including seasonal temperature changes that might impact energy savings, in the following sections:
• Section 4.3.2: Solar Radiation Analysis – Page 7, lines 273-274; Page 8, lines 287-288.
• Section 4.3.2: Annual Daylight Analysis – Page 8, lines 325-327.
• Section 4.3.4.1: Airflow Rate Analysis – Page 8, lines 457-459.
• Material Thickness: The material thickness used in our experiments is presented in Table 2 on Page 6, titled "Window Materials for Window Installation," which specifies the materials and their thicknesses. The selection of material properties and specifications follows guidelines from the Ministry of Energy regulation, titled "Regulations on the Criteria, Methods of Calculation, and Certification of Energy Conservation Building Design for Each System, Total Energy Use, and Renewable Energy Use in Various Building Systems, B.E. 2564 (2021)."

In response to the question about accounting for climate variations, such as seasonal temperature changes, which may affect energy savings, these factors have been integrated into our analysis and discussed in detail within:

• Page 7, lines 268 through Page 8, line 292 under Solar Radiation Analysis, and
• Page 12, line 457 through Page 13, line 477 under Ventilation Performance and Stack-Effect Analysis.

These sections describe our approach to simulating environmental variations to enhance accuracy and replicability.
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Section 4.3.1

Regarding the use of region-specific climate data for the solar radiation analysis in Section 4.3.1, we incorporated data specific to Thailand to enhance the relevance and accuracy of the energy simulations. The sources for this climate data include:

1. Ministry of Energy regulations, specifically:
• Regulations on the Criteria, Methods of Calculation, and Certification of Energy Conservation Building Design for Each System, Total Energy Use, and Renewable Energy Use in Various Building Systems, B.E. 2564 (2021). Published in the Government Gazette, Bangkok, December 24, 2021.
2. EnergyPlus Weather Data:
• For location-specific weather data, we utilized Bangkok 484560 (IWEC) climate data from EnergyPlus. This data is available at EnergyPlus's website under the Asia WMO Region 2 - Thailand section, accessed on November 10, 2024.
3. Climate-Data.org:
• To further support the simulations with additional region-specific data, we referenced the Climate and Average Monthly Weather in Hat Yai (Songkhla Province), Thailand from Climate-Data.org, accessed on November 10, 2024.

This information is detailed in Page 4, lines 150-157 in the methodology section of the manuscript, where we outline our approach to obtaining climate-specific data for energy simulations.
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Section 4.3.5 

I appreciate the insightful suggestion to address real-world limitations, such as the maintenance demands of automated systems, which may impact long-term energy savings. In response, I have expanded the discussion in Section 4.3.5 by adding a new subsection titled "System Durability and Operational Resilience". This section now includes:

• Maintenance Implications and Analysis of System Longevity: Examining the potential maintenance needs and how these may influence the energy-saving benefits over time.
• Analysis of System Reliability Enhancement and Redundancy: Assessing strategies to improve system reliability and incorporate redundancy measures to mitigate performance loss due to potential malfunctions.

These additions provide a balanced perspective on the limitations and long-term considerations of the automated systems. This expanded discussion can be found on Pages 13 and 14, lines 478-508 of the manuscript.
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 Section 4.3.6

Thank you for the recommendation to include a payback period estimate to enhance the financial viability discussion. In response, I have updated the manuscript to provide a comprehensive analysis that includes initial costs, estimated payback period, and projected maintenance costs over the system's lifespan.

These additions can be found in the newly added section 4.5 Economic Viability and Lifecycle Cost Efficiency, covering Cost Efficiency and Life Cycle Cost Analysis on Pages 14 to 15, lines 544-596.

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  Section 5.2 

Thank you for highlighting the importance of practical user considerations, such as ease of use, to support adoption. This aspect is addressed in Section 5.3: Challenges and Strategies for Enhancing Adoption of Dynamic Windows, where we discuss potential design features and user training approaches aimed at improving user-friendliness. This section can be found on Page 17 of the manuscript.

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"Selling information in competitive environments" and "Coordination via selling information,"

Referencing "Barriers to Community Connectivity: An Assessment of the Reconnecting Communities Pilot Program" could strengthen the discussion on dynamic windows in urban design by providing context on how these technologies might impact urban connectivity and either mitigate or contribute to environmental barriers in densely populated settings. Also, including "A Generalized Framework for Assessing Equity in Ground Transportation Infrastructure" in the recommendations could expand the equity discussion in energy-efficient building design, highlighting the implications of such technologies on sustainable living access across communities.

Response to Review Comment:

At this stage, the article primarily focuses on the experimental implementation and lifecycle estimation of dynamic window technologies. Further research is needed to evaluate broader impacts, such as the effects on urban connectivity and equity implications in sustainable building design, as these aspects require additional study and real-world assessment phases.

Therefore, while these suggestions are highly valuable for future research directions, incorporating them at this point might extend beyond the current study’s scope. For this reason, I respectfully choose not to add these recommendations to the article at this time.

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Referencing "Barriers to Community Connectivity: An Assessment of the Reconnecting Communities Pilot Program" could strengthen the discussion on dynamic windows in urban design by providing context on how these technologies might impact urban connectivity and either mitigate or contribute to environmental barriers in densely populated settings. Also, including "A Generalized Framework for Assessing Equity in Ground Transportation Infrastructure" in the recommendations could expand the equity discussion in energy-efficient building design, highlighting the implications of such technologies on sustainable living access across communities.

Response to Review Comment:

At this stage, the article primarily focuses on the experimental implementation and lifecycle estimation of dynamic window technologies. Further research is needed to evaluate broader impacts, such as the effects on urban connectivity and equity implications in sustainable building design, as these aspects require additional study and real-world assessment phases.

Therefore, while these suggestions are highly valuable for future research directions, incorporating them at this point might extend beyond the current study’s scope. For this reason, I respectfully choose not to add these recommendations to the article at this time.

 

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The research effectively demonstrates the potential of dynamic window technologies in reducing energy consumption in tropical condominiums through integration of passive and active systems, showing significant energy savings of 3.29 kWh/m² annually with practical implementation strategies and economic benefits.

Comments:

1. The methodology section discusses simulation using "Grasshopper on Rhino program with Energy Plus plugin" but lacks detail about validation of the simulation model. What steps were taken to ensure the accuracy of the simulation results against real-world conditions?
2. The paper states "the optimal support spacing and number of support points were determined through experiments" but doesn't specify the criteria used for determining optimality. What specific performance metrics were used to define "optimal"?
3. While the cost savings of 506.38 baht per room per year are presented, the initial installation costs and maintenance expenses of the dynamic window systems are not comprehensively analyzed. How does the total lifecycle cost compare with traditional windows?
4. The discussion of stack-effect ventilation would benefit from quantitative analysis of airflow rates and temperature differentials. What are the specific thresholds for effective stack ventilation in tropical conditions?
5. The automated control system using Arduino and light sensors is described, but potential failure modes and redundancy measures are not addressed. How does the system handle sensor malfunction or power outages?
6. The energy savings calculation focuses on cooling load reduction but doesn't fully account for potential increases in artificial lighting needs during certain conditions. Could you elaborate on the lighting energy balance?
7. "The payback period for these technologies...makes them a viable option" - this statement requires more detailed economic analysis including maintenance costs, replacement schedules, and varying energy prices.
8. The paper would benefit from a more detailed discussion of the scalability challenges when implementing these systems in existing buildings versus new construction.

 

Comments on the Quality of English Language

Good

Author Response

1. The methodology section discusses simulation using "Grasshopper on Rhino program with Energy Plus plugin" but lacks detail about validation of the simulation model. What steps were taken to ensure the accuracy of the simulation results against real-world conditions?

In our methodology, we have implemented multiple steps to ensure the simulation results' accuracy and alignment with real-world environmental conditions.

• Solar Radiation Intensity: The parameters for solar radiation intensity, critical for real-world relevance, are detailed in:
• Section 4.3.1: Solar Radiation Analysis – Page 7, lines 268, 272-274.
• Climate Variations and Seasonal Temperature Changes: To capture climate-related impacts accurately, we have incorporated seasonal temperature variations within:
• Section 4.3.2: Solar Radiation Analysis – Page 7, lines 273-274; Page 8, lines 287-288.
• Section 4.3.2: Annual Daylight Analysis – Page 8, lines 325-327.
• Section 4.3.4.1: Airflow Rate Analysis – Page 8, lines 457-459.
• Material Thickness: We based material specifications, including thicknesses, on established guidelines from the Ministry of Energy regulation "Regulations on the Criteria, Methods of Calculation, and Certification of Energy Conservation Building Design for Each System, Total Energy Use, and Renewable Energy Use in Various Building Systems, B.E. 2564 (2021)." The detailed material specifications are presented in Table 2 on Page 6, titled "Window Materials for Window Installation."

For validation purposes, we utilized climate data specific to the region and compared our model’s simulated outputs with benchmark data where available. The overall approach aims to simulate environmental variations effectively, providing a basis for accuracy and replicability, as detailed in:

• Page 7, lines 268 through Page 8, line 292 (Solar Radiation Analysis), and
• Page 12, line 457 through Page 13, line 477 (Ventilation Performance and Stack-Effect Analysis).

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2. The paper states "the optimal support spacing and number of support points were determined through experiments" but doesn't specify the criteria used for determining optimality. What specific performance metrics were used to define "optimal"?

To determine the optimal support spacing and number of support points, we established several performance metrics focused on maximizing thermal and airflow efficiency. The experiments included variables assessing solar radiation exposure and airflow performance using three window configurations, with detailed monthly and minute-by-minute analyses to enhance testing accuracy.

Specific tests and performance metrics can be found in the following sections:

• Solar Radiation and Airflow Variables: Initial analyses are presented on Page 7, lines 268 through Page 8, line 309.
• Detailed Monthly and Minute-Level Tests: The results of these tests, aimed at fine-tuning support configurations, are found on Page 8, lines 317-339.
• Airflow and Stack Effect Analysis: Further analysis on airflow performance can be found on Page 12, lines 457 through Page 13, line 477.

These metrics provided a basis for defining the optimal configuration by balancing structural stability and environmental performance.

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3. While the cost savings of 506.38 baht per room per year are presented, the initial installation costs and maintenance expenses of the dynamic window systems are not comprehensively analyzed. How does the total lifecycle cost compare with traditional windows?
4. "The payback period for these technologies...makes them a viable option" - this statement requires more detailed economic analysis including maintenance costs, replacement schedules, and varying energy prices.

In response to the recommendation to include a payback period estimate for financial viability, I have updated the manuscript to incorporate a comprehensive analysis covering initial costs, estimated payback period, and projected maintenance expenses over the system's lifespan. These additions are detailed in the newly added Section 4.5: Economic Viability and Lifecycle Cost Efficiency, which includes discussions on Cost Efficiency and Life Cycle Cost Analysis. This section can be found on Pages 14 to 15, lines 544-596.

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4. The discussion of stack-effect ventilation would benefit from quantitative analysis of airflow rates and temperature differentials. What are the specific thresholds for effective stack ventilation in tropical conditions?

An updated response incorporating the addition of Section 4.3.4.1: Airflow Rate Analysis.

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5. The automated control system using Arduino and light sensors is described, but potential failure modes and redundancy measures are not addressed. How does the system handle sensor malfunction or power outages?

To address the reviewer's suggestion to consider real-world limitations, we have added a new section, 4.3.5: System Durability and Operational Resilience, which includes discussions on Maintenance Implications, System Longevity, Reliability Enhancement, and Redundancy. This section highlights potential maintenance demands and strategies for ensuring long-term operational effectiveness, addressing concerns about durability over time. The detailed discussion is located on Page 13, lines 478-492 of the manuscript.

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6. The energy savings calculation focuses on cooling load reduction but doesn't fully account for potential increases in artificial lighting needs during certain conditions. Could you elaborate on the lighting energy balance?

This study primarily focused on cooling load reduction with dynamic windows. We acknowledge that shading could impact artificial lighting needs. Future research will explore vertical shading devices and daylight sensors to optimize natural light levels, aiming to balance cooling and lighting energy use effectively. This approach will enhance the energy efficiency and sustainability of dynamic window systems in tropical climates.

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8.The paper would benefit from a more detailed discussion of the scalability challenges when implementing these systems in existing buildings versus new construction.

 

the information about addressing the lighting energy balance in Chapter 6 and the abstract:

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The paper has been improved and can be considered for publication.