Energy Saving Technologies and Practices in Facility Agriculture in Cold Regions

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper experimented on energy-saving technologies towards cold-climate greenhouses. The paper suggested that the technologies saved energy and costs and there are benefits towards the synergy of technologies. However, the paper also raises several concerns.

 

1. How did the researchers compare the new design with the old ones? Did they use models? Control green houses? etc. This was not clearly specify. If it's the same greenhouses, how do they account for different weather between the years? If they used different greenhouses, how would the location of the greenhouses effect the results. 

2. How did the researchers identified what technology to use in which extent? Do they apply all possible techs? Do they decide based on budget? Are the design fixed by the organization?

3. If there were predictive models, is it possible to provide several degrees of applications to design for optimal cost-benefit? Why only this model?

4. Please discuss in further details how this paper contribute to the state of sciences and technology. How is it novel? Does it support any profound theory? Does it provide applicable implementation somewhere else? Does it provide a design process and step-by-step suggestions as an example to future projects? 

5.  The passage says 'this chapter' instead of 'this study'. 

Please provide the missing information, such as the acknowledgement or data availability statement. 

Author Response

Comment1:How did the researchers compare the new design with the old ones? Did they use models? Control green houses? etc. This was not clearly specify. If it's the same greenhouses, how do they account for different weather between the years? If they used different greenhouses, how would the location of the greenhouses effect the results.

Response1:Thank you for your insightful comment regarding the comparison methodology between the new and old designs. Below is our detailed clarification:

Comparison Methodology:

Experimental Setup:

The study used the same greenhouse across two consecutive experimental periods: the first without energy-saving technologies (November 2022 - March 2023) and the second with the implementation of energy-saving technologies (November 2023 - March 2024).

This approach ensured that structural and operational differences between greenhouses were eliminated, isolating the effects of the introduced technologies.

Accounting for Weather Variability:

We recognize that differences in weather conditions between the two years could influence the results. To address this:

Environmental Monitoring: Daily data on outdoor temperature, humidity, and other environmental factors were recorded during both experimental periods. This allowed us to normalize the energy consumption data relative to environmental conditions, ensuring comparability.

Baseline Adjustment: Energy consumption patterns were adjusted using a regression model that correlated energy usage with external temperature and other key variables. This allowed us to attribute differences in energy savings to the implemented technologies rather than to weather variability.

Use of Models:

A predictive model was not explicitly used to compare different designs. However, statistical analyses were applied to normalize data and account for weather variability between the two years.

Single Greenhouse Use:

Using the same greenhouse ensured consistency in location, operational practices, and structural design. This avoided potential biases introduced by geographical factors such as sunlight availability or wind exposure, which could differ between separate greenhouse sites.

Future Improvement Directions:

Acknowledging that year-to-year climate variability could still introduce noise, future experiments may involve:

Multiple greenhouses with parallel testing under controlled and real-world conditions.

Simulation models to predict and validate the impact of weather variability on energy performance.

By employing the same greenhouse and normalizing for environmental factors, we are confident that the observed energy savings are attributable to the new design's improvements. Thank you for highlighting this important methodological aspect, which we have now emphasized more clearly in the revised manuscript.

Comment2: How did the researchers identified what technology to use in which extent? Do they apply all possible techs? Do they decide based on budget? Are the design fixed by the organization?

Response2:Thank you very much for raising this important question. The selection and application of technologies in this study were guided by thorough considerations of scientific, economic, and practical factors, as outlined below:

Selection of Technologies:
The research team carefully selected energy-saving technologies based on extensive literature review and prior experimental evidence. The selected technologies were chosen to address key challenges specific to cold-region facility agriculture, such as extreme low temperatures, insufficient natural light, and high energy consumption for heating, lighting, and ventilation.

Synergistic Application of Multiple Technologies:
To achieve optimal energy efficiency, the study adopted an integrated approach, combining ground-source heat pumps, solar thermal collection systems, high-efficiency LED plant lights, intelligent light control systems, and intelligent ventilation systems. These technologies were chosen for their complementary functionalities, which together enhance the overall energy efficiency of greenhouses, particularly under extreme climatic conditions.

Extent of Application:
The extent to which each technology was applied was determined based on its specific role in reducing energy consumption:

(1)Heating System: The ground-source heat pump provided a stable and efficient heat source during extreme cold, while solar thermal systems supplemented heating during daytime, reducing reliance on conventional fuels.

(2)Lighting System: High-efficiency LED plant lights and intelligent light control systems dynamically adjusted artificial lighting intensity based on real-time natural light levels, significantly reducing energy consumption.

(3)Ventilation System: The intelligent ventilation system operated on demand, ensuring air quality while minimizing energy use by responding to greenhouse humidity and carbon dioxide levels in real time.

Budget and Economic Feasibility:
Budgetary constraints and cost-effectiveness were key considerations in the decision-making process. The technologies were selected based on an economic evaluation that included installation costs, operational expenses, and return on investment (ROI). Technologies with shorter payback periods and higher net present values (NPVs) were prioritized to ensure both feasibility and scalability.

Flexibility of the Design:
The overall design of the study was driven by experimental objectives rather than fixed organizational mandates. It was tailored to the specific climatic conditions of Heilongjiang and the operational requirements of the greenhouse. The design remained flexible to allow adjustments based on intermediate observations and experimental outcomes.

Excluded Technologies:
Not all potential energy-saving technologies were applied. The study excluded certain technologies that were impractical for extreme cold conditions or lacked cost-effectiveness for the specific application in facility agriculture.

Conclusion:

Thank you once again for your thoughtful question. The research team made deliberate decisions about the selection and application of technologies, ensuring they were scientifically relevant, economically feasible, and practically suitable for the study's objectives. By employing a synergistic and flexible approach, we maximized energy-saving effects while maintaining economic viability. Should you have further questions, we are more than happy to discuss this in greater detail!

Comment3: If there were predictive models, is it possible to provide several degrees of applications to design for optimal cost-benefit? Why only this model?

Response3:Thank you for raising this insightful question. In this study, predictive models were not employed to evaluate various degrees of technology applications or optimize cost-benefit ratios. Instead, the research focused on experimentally validating the energy-saving effects of a fully integrated system. This approach allowed us to directly measure the impacts of the proposed technologies under real-world conditions, ensuring the reliability of the results.

The decision to focus on experimental validation was guided by the study’s primary objective: to establish the feasibility and effectiveness of integrated energy-saving technologies in extreme cold climates. While predictive modeling could offer valuable insights into optimizing partial or alternative applications, this was beyond the scope of the current study. Future research could incorporate such models to explore multiple configurations, assess their economic feasibility, and identify the most cost-effective strategies for different operational scales and regional contexts.

To address your feedback, we have updated the manuscript in the following sections:

In Section 2. Experimental Design and Data Collection of Energy-saving Technologies in Cold Regions:
We added the following statement to clarify the rationale for not employing predictive models:
“This study focuses on experimentally validating the energy-saving effects of fully integrated energy-saving technologies. While predictive modeling was not utilized, the study employed a comparative experimental design to evaluate the direct impacts of these technologies under real-world conditions. Future research could incorporate predictive models to explore varying levels of technology adoption and optimize cost-benefit ratios.”

In Section 4.2 Outlook and Future Application Potential:
We expanded on the potential for predictive modeling in future research by including the following:
“Incorporating predictive modeling into future studies could enable the simulation of multiple scenarios, including partial adoption of technologies or alternative configurations. This would allow for the identification of optimal cost-benefit solutions tailored to different operational scales and regional conditions.”

We hope these updates provide greater clarity regarding the focus and scope of the current study and outline meaningful directions for future work. Should you have further questions or suggestions, we are happy to discuss them in detail.

Comment4 :Please discuss in further details how this paper contribute to the state of sciences and technology. How is it novel? Does it support any profound theory? Does it provide applicable implementation somewhere else? Does it provide a design process and step-by-step suggestions as an example to future projects?

Response4:Thank you for your insightful comments regarding the scientific contributions and novelty of the manuscript. We have carefully considered your suggestions and revised the manuscript to further clarify the contributions and innovation of our study. Specifically:

Scientific Contributions and Novelty:
In the Introduction section, we have explicitly highlighted the research's unique contributions to the field of cold-region facility agriculture. The study focuses on the synergistic integration of multiple energy-saving technologies, which goes beyond prior works that typically emphasize individual technologies. This innovative approach validates the theoretical premise that a coordinated system significantly enhances energy efficiency under extreme environmental conditions. Furthermore, the study establishes a replicable design framework that can guide future projects in similar settings.

Support for Profound Theories:
We have added a discussion on how this study supports existing theories of energy optimization by providing systematic experimental validation of multi-technology integration in extreme climates. This is detailed in the revised Introduction section.

Applicable Implementation and Future Projects:
The study not only assesses the practical applicability of the proposed energy-saving technologies but also provides a step-by-step experimental framework and economic analysis. These findings serve as a practical reference for implementing similar solutions in other cold-region agricultural facilities. This information is further clarified in the Conclusion and Outlook sections.

We believe these revisions address your valuable feedback and enhance the clarity and depth of the manuscript. Thank you once again for your constructive comments, which have significantly improved the quality of the study.

Comment5: The passage says 'this chapter' instead of 'this study'.

Response5: Thank you for pointing out the inconsistency in terminology. We have carefully reviewed the manuscript and corrected instances where "this chapter" was used inappropriately. These have been revised to "this study" to ensure clarity and consistency throughout the manuscript.We appreciate your attention to detail and believe this correction improves the overall quality of the manuscript.

Comment6: Please provide the missing information, such as the acknowledgement or data availability statement.

Response6: Thank you for highlighting the need to include additional information such as the acknowledgment and data availability statement. We have revised the manuscript accordingly.

Reviewer 2 Report

Comments and Suggestions for Authors

The paper is useful and relevant as it addresses the issue of energy saving.

1. The abstract can be written to cover all the aspects of the research including some implications.

2. The introduction should better contextualize the region and its focus on energy saving.

3. Most of the literature discussion lacks proper citations like section 1.1, 1.2 and 1.3.

4. Figures need to be more legible.

5. How was the deficiencies identified in Section 1.4 with no citations or references.

6. The location and setting needs to be more detailed so that others can compare and benchmark.

7. The paper lacks a discussion which later affects the conclusion and implications.

Author Response

Comment1. The abstract can be written to cover all the aspects of the research including some implications.

Response1:Thank you for your valuable suggestion regarding the abstract. We have revised the abstract to include the practical implications of the study. Specifically, we have added the following statement to highlight the broader significance of the research:

"This study not only provides scientific evidence for the sustainable development of cold-region facility agriculture but also highlights the practical implications of these technologies for reducing energy consumption and promoting low-carbon agriculture."

We believe this revision better reflects the comprehensive nature of the research and its real-world impact.

Comment2: The introduction should better contextualize the region and its focus on energy saving.

Response2: Thank you for your insightful comment on improving the contextualization of the study region and its focus on energy saving. In response, we have revised the introduction to provide a detailed description of the Heilongjiang region's climatic conditions and their impact on energy demand in facility agriculture. Specifically, we have added the following section:

"The Heilongjiang region, as a representative of cold-region climates, experiences extremely low temperatures, frequent snow cover, and short daylight hours during winter. These harsh climatic conditions lead to high energy demands for greenhouse heating and lighting, posing significant challenges for agricultural sustainability. For example, the average winter temperature ranges from -18°C to -5°C, with frequent temperature drops below -25°C at night, significantly increasing the heating load. Additionally, the short daylight period, often less than 7 hours per day, necessitates the extensive use of artificial lighting to meet crop growth requirements."

We believe these additions provide a clearer contextual background for the study and emphasize the region-specific challenges that make energy-saving technologies crucial for agricultural sustainability.

Comment3: Most of the literature discussion lacks proper citations like section 1.1, 1.2 and 1.3.

Response3: Thank you for pointing out the need for proper citations in the literature discussion. We have thoroughly reviewed and revised sections 1.1, 1.2, and 1.3 to ensure that all key statements are appropriately supported by relevant references. Specifically, we have:

• Revised Citations:Updated the references throughout these sections to ensure accurate attribution to relevant studies.
• Expanded Literature Support:Added additional references to strengthen the discussion of technologies, such as ground-source heat pumps, solar heating systems, LED plant lights, intelligent light control systems, and intelligent ventilation systems.

For example:

• In Section 1.1, we have referenced studies on the thermal efficiency of advanced insulation materials and the operational performance of ground-source heat pumps in cold regions.
• In Section 1.2, we cited research that highlights the spectral tunability and energy efficiency of LED lighting technologies in agriculture.
• In Section 1.3, we included studies demonstrating the role of intelligent ventilation systems in optimizing energy use while maintaining environmental stability.

These improvements ensure the literature discussion is well-supported and aligns with the standards for a comprehensive scientific review. We appreciate your valuable suggestion, which has helped us refine this critical aspect of the manuscript. If there are additional references or sources you recommend, we would be happy to include them.

Comment4：Figures need to be more legible.

Response4: Thank you for your valuable feedback regarding the clarity of the figures. We have taken steps to improve the legibility and quality of the figures in the manuscript. Specifically:

Resolution Enhancement:All figures have been updated to ensure a resolution of 300 dpi to meet publication standards, making them clearer and easier to read.

Improved Annotations:Labels, legends, and text within the figures have been resized and reformatted for better readability. We ensured that fonts and symbols are clear even at reduced sizes.

Color and Contrast Optimization:We adjusted the color schemes to use high-contrast palettes, ensuring that data points, annotations, and visual elements are distinguishable for all readers, including those with color vision deficiencies.

Detailed Figure Captions:Figure captions have been revised to provide concise and clear explanations of each figure's content and relevance to the study.

Consistency Across Figures:We standardized the design and format of all figures to maintain consistency throughout the manuscript.

Comment5: How was the deficiencies identified in Section 1.4 with no citations or references.

Response5: Thank you for pointing out the lack of citations in Section 1.4. We have revised this section to include relevant references that support the discussion of deficiencies in energy-saving technologies for cold-region facility agriculture.

Comment6 :The location and setting needs to be more detailed so that others can compare and benchmark.
Response6: Thank you for your valuable suggestion. We have revised the manuscript to include specific details about the experimental location and greenhouse setup. The modifications are as follows:

Location Details:The experimental greenhouse is located in Harbin, Heilongjiang Province. The precise geographic coordinates are:Latitude: 45.7605° N, Longitude: 126.6339° E.Regional climate characteristics have been detailed, including:Average winter temperatures ranging from -18°C to -5°C, with nighttime temperatures often dropping below -25°C.Short daylight hours during winter, typically less than 7 hours per day.

Greenhouse Dimensions and Specifications:The greenhouse measures 15.6m × 10.4m × 3m, with a total area of 260 square meters.Construction materials include double-layer polycarbonate panels and high-efficiency insulation coatings, designed to balance thermal insulation and natural light transmission.

By providing specific location coordinates and detailed descriptions of the greenhouse setup and environmental conditions, we have ensured that our study is transparent and can serve as a benchmark for similar research.

We believe these additions adequately address your concerns and make the study more replicable. If further details are required, we are happy to include them.

Comment7: The paper lacks a discussion which later affects the conclusion and implications.

Response7: Thank you for your valuable comment regarding the lack of a discussion section. We agree that a thorough discussion is essential to bridge the results with the conclusion and implications. In response, we have added a comprehensive discussion section to the manuscript. The key updates are as follows:

Modifications Made

Discussion Section Added:

(1)We analyzed the results of the energy-saving technologies in heating, lighting, and ventilation systems, emphasizing their contributions to overall energy efficiency under extreme cold conditions.

(2)We compared our findings with existing studies, highlighting how the integrated approach surpasses the efficiency of individual technologies.

Interpretation of Results:

(1)We discussed the implications of achieving an overall energy-saving rate of 17.8%, including its potential impact on reducing carbon footprints in facility agriculture.

(2)We evaluated the scalability and adaptability of the technologies to other cold-region contexts, such as in Northern Europe and North America.

Limitations and Future Directions:

(1)We acknowledged the limitations of the current study, such as the lack of parallel testing in multiple greenhouses and the absence of predictive modeling for partial technology adoption.

(2)Proposed future research directions, including incorporating machine learning for optimizing intelligent control systems and testing in diverse geographical regions.

Implications for Policy and Practice:

(1)We discussed how the findings could inform policymakers about promoting energy-efficient practices in agriculture.

(2)Provided practical recommendations for small- and medium-scale farmers to adopt these technologies cost-effectively.

Reviewer 3 Report

Comments and Suggestions for Authors

I present with the comments on revising the manuscript titled: Energy saving Technologies and Practices in Facility Agriculture in Cold Regions. Even though the title and abstract of the document present an interesting research topic, the manuscript requires extensive editions in order to be in a publishable form.  In the following lines, I address both major and minor issues that the authors should carefully attend:

MAJOR COMMENTS

1.       Introduction. The authors should present figures or percentages of estimated energy requirements for these cold regions. Also, present statistics for the particular study region, if available.

2.       Comments for sections 1.1 and 2.0 (complete sections). It is highly recommended that the authors support the information in each section with more than one reference.

3.       Figures 1, 2, and 3 are not mentioned in the text, nor are their contents described.

4.       Sometimes, it is mentioned that the content comes from a “chapter”; please correct this situation.

5.       The document needs to state the dimensions, configuration of the greenhouse studied, materials with which it is built, systems/equipment, type of crops inside, and location coordinates.

6.       There is missing information, such as climatic information and the number of hours of light in the evaluated periods. It is also advisable to present a table or graph of the climatic information of the region (temperatures, average minimum maximum, radiation, humidity, hours of light)

7.       Authors should provide, ideally in table form, characteristics, brand, and/or photographs of the equipment: heating system, heat pump, solar thermal collector, insulating materials, LED lighting, and control system.

8.       Regarding the insulating materials, place the thermal and optical properties and brand them if available.

9.       Include information on the economic analysis, equations used, etc.

10.  Table 5. It must include the source of equipment costs, mention how the operating cost was calculated, and annual savings. Also, show prices/tariffs of the energy sources.

11.  At the end of the document (lines 520 and 533), it is mentioned that the work validates its methodology; however, no mention was found in the rest of the document. Neither was the validation methodology found nor the results against which it was validated.

 

MINOR COMMENTS

- It is recommended not to repeat terms between the title and keyword fields, for example “energy saving technologies”. This is to maximize the presence of the document in search engines (Scopus, web of Science, etc.)

- Section 1.1 “However, under extreme climatic conditions in cold regions, the application of energy-saving technologies still faces some specific challenges”. The authors should mention the specific challenges in order to provide context for the readers.

- Section 1.4 “Although energy-saving technology for agricultural facilities in cold regions has made remarkable progress, it still faces many challenges in its practical application”. The authors should mention which document supports such progress in cold-climate agricultural facilities.

- The authors must mention the start and end dates of the experiment.

- Section 2.1.1. “Heating demand: Heating demand in Heilongjiang during winter is high, especially at night and in low light conditions” . The document states that the energy demand is significant; it would be helpful to know the magnitude of the energy requirement.

 

- The sections: contributions of the authors, availability of data and conflicts of interest, are empty.

Author Response

MAJOR COMMENTS

Comment1: Introduction. The authors should present figures or percentages of estimated energy requirements for these cold regions. Also, present statistics for the particular study region, if available.

Response1: Thank you for your valuable comment. In response, we have revised the introduction and methods sections to include specific figures and percentages related to the estimated energy requirements for cold regions, focusing on Heilongjiang Province. The revisions include:

Introduction:

(1)Added data on the operational energy costs for greenhouse heating and lighting in Heilongjiang. Specifically, winter greenhouse heating accounts for approximately 50–60% of operational energy costs, while lighting contributes an additional 20–30% during short daylight periods.

(2)Provided climatic statistics for the region, such as average winter temperatures (-18°C to -5°C), nighttime lows (below -25°C), and average daylight hours (less than 7 hours per day).

Methods Section:

(1)Detailed the location of the experimental greenhouse, including precise geographic coordinates (Latitude: 45.7605° N, Longitude: 126.6339° E).

(2)Described the extreme climatic conditions during the study period to contextualize the experimental challenges, including temperature ranges and limited daylight.

These additions ensure that the study is well-contextualized and provides sufficient background for understanding the energy demands of cold-region facility agriculture. We hope these revisions address your concerns. If further details are needed, we are happy to incorporate them.

Comment2: Comments for sections 1.1 and 2.0 (complete sections). It is highly recommended that the authors support the information in each section with more than one reference.

Respomse2: Thank you for your valuable suggestion. We have carefully reviewed sections 1.1 and 2.0 and revised them to include multiple references to provide stronger support for the information presented. The following updates were made:

Section 1.1 (Heating and Insulation Technologies):

Added multiple references to support the discussion on ground-source heat pumps, solar thermal systems, and high-efficiency insulation materials. For example, references have been included to substantiate the thermal efficiency of insulation materials and the performance of geothermal heating systems under extreme cold conditions.

Section 2.0 (Experimental Design and Data Collection):

Enhanced the description of the experimental setup and methodology by including references that validate the use of specific technologies, such as LED lighting systems and intelligent ventilation systems, in facility agriculture.

These references provide a robust foundation for the claims and ensure that the sections are well-supported by existing literature. We believe these revisions address your concerns and enhance the rigor of the manuscript.

If there are additional suggestions or specific areas where further references are required, we are happy to incorporate them.

Comment3: Figures 1, 2, and 3 are not mentioned in the text, nor are their contents described.

Response3: Thank you for your valuable comment. We have carefully reviewed the manuscript and ensured that Figures 1, 2, and 3 are explicitly referenced in the text and their contents are clearly described. The updates are as follows:

Figure 1:

The figure is now referenced in Section 1.1, where high-efficiency insulation materials are discussed. The text includes a description of the components shown in the figure, such as the reflective and insulating layers.

Example: "Figure 1 illustrates the structure of high-efficiency insulation materials, highlighting their multilayer composite design with reflective and insulating layers that minimize heat loss while maintaining temperature stability."

Figure 2:

The figure is referenced in Section 1.2, where the supplementary lighting system is discussed. The description explains how the LED lights are strategically placed and optimized for crop growth.

Example: "Figure 2 shows the supplementary lighting system inside the greenhouse, featuring high-efficiency LED plant lights arranged to provide uniform red and blue light distribution tailored to different crop growth stages."

Figure 3:

The figure is mentioned in Section 2.1.1, where the experimental site is introduced. The description includes details about the greenhouse's dimensions, materials, and layout.

Example: "Figure 3(a) provides an indoor view of the greenhouse, highlighting the placement of energy-saving equipment, while Figure 3(b) shows the robust external structure designed to withstand harsh winters."

We believe these updates ensure that all figures are properly integrated into the manuscript and their relevance is clearly explained. If further clarifications or adjustments are needed, we are happy to incorporate them.

Comment4: Sometimes, it is mentioned that the content comes from a “chapter”; please correct this situation.

Response4: Thank you for pointing out this inconsistency. We have carefully reviewed the entire manuscript and replaced all instances of the term "chapter" with the correct term "study" or other appropriate wording, depending on the context. This ensures consistency and accuracy throughout the text.

We appreciate your attention to detail, and we believe this adjustment improves the clarity and professionalism of the manuscript. If there are additional areas that require further clarification, we are happy to address them.

Comment5: The document needs to state the dimensions, configuration of the greenhouse studied, materials with which it is built, systems/equipment, type of crops inside, and location coordinates.

Response5: Thank you for your insightful comment. In response, we have revised the manuscript to include detailed information about the experimental greenhouse, its configuration, and related specifications. The following additions have been made:

Dimensions and Configuration:

(1)The greenhouse dimensions are now explicitly stated: 15.6m × 10.4m × 3m, with a total area of 260 square meters.

(2)The internal layout, including crop zones and equipment placement, has been described in detail.

Materials Used:

We specified that the greenhouse is constructed with double-layer polycarbonate panels for insulation and light transmission, along with high-efficiency insulation coatings to minimize heat loss.

Systems and Equipment:

The systems and equipment include a ground-source heat pump system, solar thermal collectors, high-efficiency LED plant lights, intelligent light control systems, and an intelligent ventilation system.

Type of Crops:

The greenhouse was used to cultivate leafy greens, which are highly sensitive to temperature and light, making them ideal for testing energy-saving technologies.

Location Coordinates:

The precise geographic coordinates of the experimental greenhouse have been included:
Latitude: 45.7605° N, Longitude: 126.6339° E, located at Harbin, Heilongjiang Province.

We believe these additions provide a comprehensive description of the experimental setup, making it easier for readers to understand, replicate, or benchmark the study.

Comment6: There is missing information, such as climatic information and the number of hours of light in the evaluated periods. It is also advisable to present a table or graph of the climatic information of the region (temperatures, average minimum maximum, radiation, humidity, hours of light)

Response6： Thank you for your valuable suggestion. In response, we have thoroughly revised the manuscript to include detailed climatic information relevant to the experimental periods. The following changes have been implemented:

Climatic Information Description in Section 2.1.1 (Experimental Location):

(1)Added a detailed description of the region's climatic conditions, including average temperature ranges (-18°C to -5°C), frequent nighttime lows below -25°C, average daylight hours (6–7 hours/day), and relative humidity (55–70%).

(2)Highlighted the challenges posed by these conditions to greenhouse energy management.

Table of Climatic Data in Section 2.1.1:

Included a new table (Table 1) summarizing monthly climatic parameters such as average minimum and maximum temperatures, humidity, daylight hours, and solar radiation during the experimental periods.

References to Climatic Data in Section 2.4 (Data Analysis):

Integrated references to the climatic data in the analysis of energy-saving technologies. For example, extreme temperatures in January and February were linked to higher heating demands, while increased daylight in March reduced lighting energy consumption.

Climatic Data Integration in Energy Consumption Analysis (Section 2.4.1):

Used climatic data to contextualize the observed differences in energy consumption before and after the implementation of energy-saving technologies.

We believe these additions comprehensively address the reviewer’s concerns by providing a clear and structured presentation of the climatic context, supported by a table and integrated into the analysis. If further refinements are needed, we are happy to make additional adjustments.

Thank you for this insightful comment, which has significantly improved the clarity and completeness of the manuscript.

Comment7: Authors should provide, ideally in table form, characteristics, brand, and/or photographs of the equipment: heating system, heat pump, solar thermal collector, insulating materials, LED lighting, and control system.

Response7: Thank you for your valuable suggestion. We understand the importance of providing detailed information about the equipment used in the study. However, due to the following considerations, we have chosen not to include a comprehensive table or photographs of the equipment in this version of the manuscript:

Focus of the Study:

The primary objective of this study is to evaluate the synergistic effects and performance of integrated energy-saving technologies under extreme cold conditions, rather than providing a detailed review of specific equipment or brands.

Including such details may shift the focus away from the research’s core findings and its implications for energy-saving practices.

Generic Equipment Characteristics:

The equipment used in this study represents widely available technologies in the field of facility agriculture, such as ground-source heat pumps, solar thermal collectors, and LED plant lights. These are described in sufficient detail to allow replication without needing specific brand or model names.

Practical Constraints:

Photographs and brand-specific details were not a primary focus during the experimental setup. Adding these now would require retroactive data collection, which may not fully align with the initial study design.

Key Descriptions Already Provided:

The manuscript already includes detailed functional descriptions of each technology (e.g., heating capacity, efficiency, and operational principles), which we believe are sufficient for understanding their application and performance in the study.

We hope this explanation addresses your concern. Should this information be critical for publication, we are happy to explore ways to include additional details in a supplementary file or as part of future revisions.

Comment8: Regarding the insulating materials, place the thermal and optical properties and brand them if available.

Response8: Thank you for your valuable suggestion. In response, we have revised the manuscript to include detailed descriptions of the thermal and optical properties of the insulating materials used in the study. Specifically:

Thermal and Optical Properties:

We have added the thermal conductivity (0.035 W/mK) and reflectivity (>85%) of the multilayer composite insulation materials. These values are consistent with high-performance insulation standards and are essential for reducing heat loss in extreme cold conditions.

Enhanced Manuscript Section:

The updated details have been incorporated into Section 2.3.1, where the heating system and insulation materials are described. The revised text now emphasizes the role of these properties in achieving the reported energy savings.

Brand Information:

The study’s focus is on evaluating the integrated effects of energy-saving technologies. As such, specific brand information was not a key variable in the experimental design and was not recorded. However, the material's performance characteristics have been described in detail to ensure clarity and reproducibility.

We believe these updates address your concerns and improve the manuscript’s technical clarity. If further adjustments are needed, we are happy to make additional modifications. Thank you for this insightful feedback, which has enhanced the manuscript.

 

Comment9: Include information on the economic analysis, equations used, etc.

Response9：Thank you for your insightful suggestion. In response, we have revised the manuscript to include the following updates:

Economic Analysis Framework:

We have provided a detailed explanation of the economic analysis methodology in Section 2.4.2. This includes descriptions of key factors such as initial installation cost, operational and maintenance costs, and annual energy savings.

Equations Used:

The equations for calculating the payback period and net present value (NPV) have been added to the methodology section. These equations are integral to assessing the cost-effectiveness of the proposed energy-saving technologies.

Clarity in Structure:

To ensure clarity and consistency, the detailed results of the economic analysis, including specific values for payback periods and NPVs, have been reserved for the results section. This separation ensures that the methods and results are presented in an organized and logical manner.

We believe these revisions adequately address your comments and provide a more comprehensive understanding of the economic analysis performed in the study. If further details or refinements are required, we would be happy to make additional adjustments.

Thank you again for your constructive feedback, which has significantly enhanced the rigor and clarity of the manuscript.

 

Comment10： Table 5. It must include the source of equipment costs, mention how the operating cost was calculated, and annual savings. Also, show prices/tariffs of the energy sources.

Response10：Thank you for your valuable suggestion. We have carefully addressed your comments and made the following revisions:

Source of Equipment Costs:

The installation costs in Table 5 now reflect the actual procurement records from the experimental setup, ensuring accuracy and transparency. The costs correspond to the real-world expenditure on the technologies implemented in the greenhouse.

Operating Cost Calculation:

A detailed description has been added to explain how the operating costs were calculated. These were derived based on recorded energy consumption during the experiment, combined with maintenance data and local energy tariffs (0.6 Yuan/kWh).

Annual Savings:

The calculation of annual savings has been clarified as the difference in energy consumption between conventional and energy-saving technologies, multiplied by the local energy tariff.

Energy Tariffs:

The table and text now explicitly state the local energy tariff used for the calculations, providing additional context for the economic analysis.

These revisions ensure that Table 5 and the accompanying analysis are comprehensive and transparent, addressing the concerns raised. We appreciate your insightful feedback, which has significantly improved the rigor and clarity of our economic analysis.

If further refinements are needed, we are happy to make additional adjustments.

Comment11： At the end of the document (lines 520 and 533), it is mentioned that the work validates its methodology; however, no mention was found in the rest of the document. Neither was the validation methodology found nor the results against which it was validated.

Response11： Thank you for your valuable feedback. We acknowledge that the original manuscript lacked explicit mention of the validation methodology and results. To address this, we have made the following revisions:

Added a dedicated section (2.5 Validation Methodology) to describe the comparative approach employed for validating the methodology and experimental results.

Incorporated a discussion on validation results (3.8 Validation Results) to highlight the alignment of experimental findings with benchmarks from prior studies and theoretical predictions.

Updated the Conclusion section (4.1 Research conclusions) to reflect the validation process and its significance.

These changes ensure that the validation methodology and results are clearly presented and contextualized within the manuscript. Thank you for helping us improve the clarity and rigor of our study.

 

MINOR COMMENTS

Comment12： It is recommended not to repeat terms between the title and keyword fields, for example “energy saving technologies”. This is to maximize the presence of the document in search engines (Scopus, web of Science, etc.)

Response12：Thank you for your valuable suggestion regarding the title and keywords. To address this, we have revised the keywords to avoid repetition with the title, enhancing the manuscript’s visibility in search engines like Scopus and Web of Science. Specifically, we adjusted the keywords to include broader and more diverse terms, such as greenhouse energy efficiency, integrated energy-saving systems, cold climate agriculture, and renewable energy solutions. This change not only avoids redundancy but also ensures that the manuscript is indexed under a wider range of relevant topics, maximizing its discoverability for researchers.

We appreciate your suggestion and believe this adjustment improves the manuscript’s overall impact and accessibility.

Comment13： Section 1.1 “However, under extreme climatic conditions in cold regions, the application of energy-saving technologies still faces some specific challenges”. The authors should mention the specific challenges in order to provide context for the readers.

Response 13:Thank you for highlighting the need to provide more detailed context regarding the challenges faced by energy-saving technologies under extreme climatic conditions. To address this, we have revised Section 1.1 to explicitly describe these challenges, including high heating demand, limited solar energy availability, sensor stability issues, material durability concerns, and economic feasibility constraints. By outlining these specific challenges, we aim to provide readers with a clearer understanding of the context and significance of our research.

We appreciate your valuable feedback, which has helped to enhance the clarity and depth of this section.

Comment14: Section 1.4 “Although energy-saving technology for agricultural facilities in cold regions has made remarkable progress, it still faces many challenges in its practical application”. The authors should mention which document supports such progress in cold-climate agricultural facilities.

Response14: Thank you for your valuable suggestion regarding the need to substantiate the progress of energy-saving technologies in cold-climate agricultural facilities. In response, we have revised Section 1.4 by adding references that highlight the advancements in geothermal heat pumps, solar thermal systems, intelligent lighting, and thermal insulation technologies. These references not only validate the stated progress but also provide a context for the challenges discussed in this section. We believe these revisions address your concern and enhance the scientific rigor of the manuscript. Thank you again for your insightful feedback.

Comment15: The authors must mention the start and end dates of the experiment.

Response15: Thank you for pointing out the need to specify the start and end dates of the experiment. We have addressed this comment by adding the experimental timeframes (November 2022 to March 2023 for the baseline period without energy-saving technologies and November 2023 to March 2024 for the period with energy-saving technologies) in Section 2.1.2, "Experiment time and cycle". This addition provides a clearer timeline for the study and enhances the reproducibility of the experiments. We appreciate your careful review and valuable feedback!

Comment16: Section 2.1.1. “Heating demand: Heating demand in Heilongjiang during winter is high, especially at night and in low light conditions” . The document states that the energy demand is significant; it would be helpful to know the magnitude of the energy requirement.

Response16: Thank you for your insightful comment. To address your suggestion, we have included additional details quantifying the magnitude of the energy demand in Section 2.1.1. Specifically, we have added information on the average monthly heating energy consumption for greenhouses in Heilongjiang during winter, supported by the experimental data collected during this study. These modifications provide a clearer understanding of the energy requirements under extreme cold conditions, enhancing the context and scientific rigor of the discussion.

Comment17: The sections: contributions of the authors, availability of data and conflicts of interest, are empty.

Response17: Thank you for your valuable feedback. Based on your suggestion, we have added detailed statements in the sections on Author Contributions, Data Availability Statement, and Conflicts of Interest to enhance the manuscript's transparency and scientific rigor. These additions clarify the specific contributions of each author, outline the data sharing policy, and explicitly state the absence of any conflicts of interest among the authors. We believe these improvements address your concerns effectively.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The key flaw of the study design was mentioned, but not addressed. You only included that the weather data were recorded, however, they were not reported or normalized. 

Because of the sample size and the limitation, it's hard to answer the research question because we don't know whether the savings came from changes in light and temperature between the two years or the technology. 

Please either use literature review to justify this huge flaw in research design, or address them by reporting the temperature and daylight data collected and showed that they either were not significantly differed between the years, or the differences were accounted for the savings calculated. 

Author Response

Comment： The key flaw of the study design was mentioned, but not addressed. You only included that the weather data were recorded, however, they were not reported or normalized. 

Because of the sample size and the limitation, it's hard to answer the research question because we don't know whether the savings came from changes in light and temperature between the two years or the technology. 

Please either use literature review to justify this huge flaw in research design, or address them by reporting the temperature and daylight data collected and showed that they either were not significantly differed between the years, or the differences were accounted for the savings calculated.

Response: 

Thank you for your valuable feedback. We acknowledge that the lack of detailed reporting and normalization of weather data was a key limitation in our original manuscript. To address this concern, we have conducted a statistical analysis of the temperature and daylight data for the two experimental periods (November 2022 to March 2023 and November 2023 to March 2024). The results from the paired t-test indicate that there were no statistically significant differences in temperature and daylight hours between the two years (p > 0.05), suggesting that climatic factors did not significantly influence the energy savings observed. Therefore, the savings can primarily be attributed to the energy-saving technologies implemented in the greenhouse.

Additionally, we have now explicitly incorporated this analysis into the manuscript in Section 3.7 and 3.8, where we compare the temperature and daylight data and ensure that the observed energy savings are mainly due to the technologies, rather than external climatic factors.

We hope this addresses your concern and clarifies the role of climate variations in the experimental results. The data and analysis ensure that the observed savings were primarily influenced by the energy-saving technologies, and future research will continue to monitor climatic conditions to further refine the results.

Thank you for your thoughtful suggestion, and we appreciate the opportunity to improve the clarity and robustness of our study.

Reviewer 3 Report

Comments and Suggestions for Authors

The authors' efforts to improve the manuscript are highly appreciated. Issues with the validation procedure and referencing are still in place. While the authors mention three stages of the validation methodology (1-Literature comparison, 2-theoretical benchmarking, 3-experimental consistency), the description in the Results section lacks verifiable data.

(1)    First, in the methodology section, the authors mention that a comparison is performed against information from the literature. Nevertheless, in the Results, only some percentages of the differences are presented. Data calculated in this work should be contrasted against the data from the scientific literature studies. Data in the shape of a table or a graph, where the authors claim differences of 17.6% (heating system), 18.6% (lighting), and 17.4% (ventilation), can be confirmed.    

(2)    Secondly, a theoretical benchmarking is said to be conducted; such activity is said to be cross-referenced with theoretical predictions; nevertheless, the data that confirms such benchmarking is not provided. The authors mention that the payback periods and net present values “closely matched” theoretical predictions, but such information is not stipulated.

(3)    Third, the authors present an activity of experimental consistency, explaining how the experiment was done in the same greenhouses and how the environmental parameters were measured. Nevertheless, such activities are unrelated to an Experimental Consistency evaluation. I strongly recommend that if this activity is presented, one way to ensure reliable experimental measures is using standardized, validated instruments with proven reliability; also, information on the measurements or instruments' uncertainty is disclosed.  

 

Referencing issues: Lastly, while numerous references were added to the text, the original texts were kept. There is no evidence that the new references were consulted. From the revision, I could verify that the authors only introduced new sources, but because the text remained the same as the previous version, they were not read or consulted. This is a careless or dishonest act as it is linked to reference misattribution. (Attribution or citation is linking ideas, concepts, and statements to their correct source. Misattribution is attributing texts and ideas, even events, to something without connection or association).

Author Response

Comment1：

First, in the methodology section, the authors mention that a comparison is performed against information from the literature. Nevertheless, in the Results, only some percentages of the differences are presented. Data calculated in this work should be contrasted against the data from the scientific literature studies. Data in the shape of a table or a graph, where the authors claim differences of 17.6% (heating system), 18.6% (lighting), and 17.4% (ventilation), can be confirmed.

Response1：

We have revised the manuscript to include a detailed table (Table 7) comparing our experimental results with relevant literature data. This table ensures that the observed energy savings in heating, lighting, and ventilation are supported by verifiable data. We have also included proper citations to the literature to ensure clarity and transparency in the comparison.

Comment2：

Secondly, a theoretical benchmarking is said to be conducted; such activity is said to be cross-referenced with theoretical predictions; nevertheless, the data that confirms such benchmarking is not provided. The authors mention that the payback periods and net present values “closely matched” theoretical predictions, but such information is not stipulated.

Response2:We acknowledge the reviewer’s concern and appreciate the opportunity to clarify this point. In the revised manuscript, we make the following clarifications:

Data Limitations: In Section 3.7, we clearly state that we currently have only one year of energy savings data, which limits the ability to compare with long-term data or theoretical data directly. The payback period and net present value mentioned in the manuscript are based on first-year experimental data.

Future Data Collection and Validation: We emphasize that future research will involve continuing to collect data over multiple years. This will allow for a more robust validation of the results and enable comparisons with long-term trends as well as theoretical models to ensure the accuracy of the calculated payback periods and net present values.

Comment3: Third, the authors present an activity of experimental consistency, explaining how the experiment was done in the same greenhouses and how the environmental parameters were measured. Nevertheless, such activities are unrelated to an Experimental Consistency evaluation. I strongly recommend that if this activity is presented, one way to ensure reliable experimental measures is using standardized, validated instruments with proven reliability; also, information on the measurements or instruments' uncertainty is disclosed.

Response3:

We have expanded the experimental consistency section to provide more details on how consistency was maintained during the experiment. Specifically, we now mention the use of standardized, calibrated instruments and discuss measurement uncertainty. This addition responds to the reviewer’s concern about ensuring reliable experimental measures. Future research will continue to improve experimental consistency by using standardized instruments and disclosing measurement uncertainty.

Comment4: 

Referencing issues: Lastly, while numerous references were added to the text, the original texts were kept. There is no evidence that the new references were consulted. From the revision, I could verify that the authors only introduced new sources, but because the text remained the same as the previous version, they were not read or consulted. This is a careless or dishonest act as it is linked to reference misattribution. (Attribution or citation is linking ideas, concepts, and statements to their correct source. Misattribution is attributing texts and ideas, even events, to something without connection or association).

Response4: 

We apologize for any confusion regarding this issue. In response to the reviewer’s comment, we have thoroughly revised the manuscript to ensure that the new references were properly consulted and integrated into the text. We carefully linked each new reference to the relevant sections and correctly attributed the ideas, concepts, and findings to the appropriate sources. All references have been checked for accuracy and updated accordingly in the revised manuscript.

Round 3

Reviewer 1 Report

Comments and Suggestions for Authors

This is now appropriate. 

Author Response

Dear Reviewer,

Thank you for your kind feedback and for acknowledging the revisions we made to the manuscript. We are pleased to hear that the changes we implemented meet your expectations.

If you have any further suggestions or require additional clarifications, please do not hesitate to let us know.

We truly appreciate your valuable input, which has significantly helped improve the quality of our work.

Reviewer 3 Report

Comments and Suggestions for Authors

The authors comment that they have fixed the issues with the referencing and the text; nevertheless, there is no evidence of such modification in the document (no highlighting nor track changes) besides the red markings on the reference list at the end. 

On the second issue, the validation, the authors mention that they have included a "detailed table (table 7) where the validation can be observed. The authors added a table where percentages of energy savings obtained in their work are compared to results in the literature.

For example, the first number, 18.3%, which corresponds to [50 https://doi.org/10.1016/j.enbuild.2024.114646], is related to a comparison of improvement due to changes in the controller (fuzzy logic vs on-off strategy). The quoted Ground-source heat pump (GSHP) is related to another document (reference 189 (https://doi.org/10.1016/j.applthermaleng.2015.06.019) within the document [50]), where the authors report studying a photovoltaic/thermal (PVT)-ground-source heat pump hybrid system.  

On page 23, the document [50] states: "The authors compared the performance of the fuzzy logic controller with the conventional on-off strategy. They reported an 18.3 % reduction in the consumed energy compared with the traditional on–off controller for the solar thermal and GSHP system, while a 13.3 % decrease in energy consumption was reported for conventional GSHPs." Such a comparison does not correspond to a proper validation; I am sorry to insist on this matter; it is just a simple comparison against another percentage reported by a study of other authors that is unrelated to its performance in greenhouses.

The second percentage (19.4%) is also a value reported by the [21] reference; nevertheless, it corresponds to cost savings, not energy savings, the same situation with [51], where a 27% cost reduction is reported.

[21]: “Results outlines that potential 19.4% cost savings are achievable.”

[51]: “Furthermore proposed model achieve a 27.76% cost reduction when compared to the baseline scheme.”

Author Response

Comment1: The authors comment that they have fixed the issues with the referencing and the text; nevertheless, there is no evidence of such modification in the document (no highlighting nor track changes) besides the red markings on the reference list at the end.

Response1: Thank you for pointing this out. In response to your comment, we have used color highlighting to indicate the changes made to the references in the manuscript. We did not use track changes in this version, but we have ensured that all the modified sections are clearly marked in color for your review. The red markings you observed in the reference list are part of this highlighting process to show where the changes were made. We hope this clarification addresses your concern. The revised document is available with color annotations to show all updated references.

Comment2: On the second issue, the validation, the authors mention that they have included a "detailed table (table 7) where the validation can be observed. The authors added a table where percentages of energy savings obtained in their work are compared to results in the literature.

For example, the first number, 18.3%, which corresponds to [50 https://doi.org/10.1016/j.enbuild.2024.114646], is related to a comparison of improvement due to changes in the controller (fuzzy logic vs on-off strategy). The quoted Ground-source heat pump (GSHP) is related to another document (reference 189 (https://doi.org/10.1016/j.applthermaleng.2015.06.019) within the document [50]), where the authors report studying a photovoltaic/thermal (PVT)-ground-source heat pump hybrid system.  

On page 23, the document [50] states: "The authors compared the performance of the fuzzy logic controller with the conventional on-off strategy. They reported an 18.3 % reduction in the consumed energy compared with the traditional on–off controller for the solar thermal and GSHP system, while a 13.3 % decrease in energy consumption was reported for conventional GSHPs." Such a comparison does not correspond to a proper validation; I am sorry to insist on this matter; it is just a simple comparison against another percentage reported by a study of other authors that is unrelated to its performance in greenhouses.

The second percentage (19.4%) is also a value reported by the [21] reference; nevertheless, it corresponds to cost savings, not energy savings, the same situation with [51], where a 27% cost reduction is reported.

[21]: “Results outlines that potential 19.4% cost savings are achievable.”

[51]: “Furthermore proposed model achieve a 27.76% cost reduction when compared to the baseline scheme.”

Response2: 

We sincerely appreciate the reviewer's careful examination of the literature comparison. To address the concern, we made the following revisions:

• Table 7 has been removed. All inappropriate comparisons with literature data (e.g., 18.3%, 19.4%, 27%) were deleted. These data pertain to controller performance or cost reductions and are not relevant to the energy savings from the technologies implemented in our study.
• In Section 2.5 (Validation Methodology) and Section 3.8 (Validation Results), we have revised the descriptions to focus entirely on direct experimental data from our study, using appropriate statistical methods to validate the results. We emphasize that the experimental setup, conditions, and results were rigorously controlled, and the data was collected using standardized, calibrated instruments that were regularly checked for accuracy. We also highlight that the temperature and daylight data collected during the two experimental periods (November 2022 to March 2023 and November 2023 to March 2024) were statistically analyzed to ensure that any observed energy savings were attributable to the technologies implemented, not to climatic factors (p > 0.05).
• In Section 4.1 (Conclusion), we clearly state that the energy-saving results were verified and validated using empirical data, ensuring that the energy savings observed were primarily due to the applied technologies rather than external environmental factors.

To further substantiate the reliability and effectiveness of the experimental data, we emphasize that:

• The experiments were conducted in a controlled environment where all variables except for the energy-saving technologies were kept constant. This approach ensures the observed energy savings are directly attributed to the technologies implemented.
• Statistical analysis (paired t-test) was performed on the temperature and daylight data, showing no significant differences between the two experimental periods (p > 0.05). This analysis provides robust evidence that the observed energy savings were not influenced by climatic conditions, confirming the data’s validity and reducing concerns over external factors.

These modifications strengthen the paper's validation methodology and ensure that the experimental data is both authentic and reliable, thereby increasing confidence in the study's findings.

We hope these changes adequately address your concerns and further clarify the reliability and validity of our experimental data. We again thank you for your careful review and helpful suggestions. If you have any additional questions or comments, please do not hesitate to contact us.