Structural Design and Optimization of Knitted Heaters for Optimized Heat Distribution

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Review of the paper “Structural Design and Optimization of Knitted Heaters for Uniform Heat Distribution”

The paper addresses a highly relevant and practically valuable topic—development of heating textiles. The manuscript is well structured, and the research demonstrates a clear methodology, including application of a theoretical model to the analyzed system, its experimental verification, and demonstration of a developed prototype (a heating glove). However, several points require clarification, improvement, or correction:

1. The authors should clarify why two technologies were used for the fabrication of heating samples—knitting for the heating lines and embroidery for the lead wires (power lines)—instead of employing knitting for both. Since the applied equipment is capable of producing both structures, such an approach would likely minimize problems related to weak contact between heating and power lines.
2. The choice of double jersey stitch for the heating textile also requires justification. According to the literature cited in the introduction, interlock and rib structures generally provide superior heating performance compared to jersey structures.
3. The authors emphasize geometrical parameters of the heating and power lines; however, to increase the generality of the results, it would be valuable to correlate these parameters with stitch density and/or loop length. At minimum, the stitch density used in the experiments should be reported explicitly for all samples.
4. The differences between predicted and measured temperatures should be presented not only in absolute terms but also in relative values. This would allow easier estimation of error levels and, consequently, the applicability of the proposed theoretical model.
5. In Table 1, the column title “Course/Wale Number” corresponds to the format used only for double jersey samples. For other samples, the data are presented in reverse order (W/C). This inconsistency requires correction.
6. Some reported data require clarification:
   • In line 399, the resistance of the lead wire is given as approximately 0.65 Ω·cm⁻¹. However, Figure S3 suggests that in the presented case (0.2 cm lead wire), the resistance is approximately 3 Ω·cm⁻¹ [12Ω/(20×0.2cm)][12 Ω / (20 × 0.2 cm)][12Ω/(20×0.2cm)].
   • In lines 360–370, the values of ε\varepsilonε used in the calculations are reported as ranging from 0.027 to 0.006. Please provide the values of the heating and power line resistances that were used to obtain these results.
   • Some of the data in Table 1 appear inconsistent and require verification or further explanation. For example, in the single jersey samples, the difference in CR values between W=3 and W=6 is much smaller than between W=6 and W=9, which seems illogical. Likewise, the CR values for silver-tech yarn samples differ by more than a factor of five between W=6 and W=8, which also raises questions.
7. A more detailed analysis of the data presented in Table 1 is necessary. Without such discussion, the rationale for including this table in the paper remains unclear.
8. In the conclusions, the authors state: “By establishing safety limits for both current and voltage, we show that typical heater units should have a resistance of approximately 24 Ω, resulting in a power output of about 6 W.” This statement requires clarification, as the experimental results presented in the paper involve power outputs up to only 2 W. Moreover, no experimental evidence or theoretical calculations are provided to substantiate the 6 W claim.
9. The authors use the same notation W for both width and watt. In addition, two different terms—heater and heating lines—are applied to describe the heating elements knitted from electroconductive yarn. Such inconsistencies create ambiguity and should be corrected to ensure clarity and adherence to good scientific writing practice.

Recommendation:
The paper addresses an important and practically valuable topic and presents promising results. However, significant revisions are required to resolve methodological ambiguities, clarify and verify data, and improve consistency of terminology and notation. The paper can be recommended for publication after a thorough revision taking into account the above comments.

Author Response

Please see the attached document for our point-by-point responses to the reviewer’s comments.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This research focuses on the structural design of the knitted heater and the optimization of its thermal distribution uniformity. A physical-based analytical model was proposed, and the validity of the model was verified through experiments. The research content has a clear engineering application background, and has high practical value especially in the field of wearable heating textiles. Overall, this manuscript is relatively well organized and can be accepted upon addressing the following questions and suggestion.

1. It is recommended to add more diagrams. Further comparison charts or three-dimensional heat maps can be included to present the performance differences under different wire counts and configurations more intuitively, thereby enhancing the persuasiveness of the results.

2. It is suggested to provide more detailed data processing and analysis procedures. The formulas for equivalent resistance and temperature distribution are given in the text, but the derivation process is too brief.

3. It is recommended to expand the discussion section by integrating specific data. Currently, the explanation of model and experimental deviations in the discussion section is still too general. It is suggested to conduct quantitative analysis of the causes of the deviations by combining chart data.

4. It is recommended to add a verification section for practical applications. Although the study demonstrated the heated prototype, no actual wearing tests or comfort evaluations were conducted. It is suggested to supplement human wearing experiments to assess the thermal comfort, durability, and safety of the prototype in real usage environments, thereby enhancing the practical value of the research.

5. Importantly, the title of journal is wrong. Please correct that.

Author Response

Please see the attached document for our point-by-point responses to the reviewer’s comments.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The revised version of the manuscript Structural Design and Optimization of Knitted Heaters for Optimized Heat Distribution demonstrates clear progress and represents an overall improvement compared with previous iterations. The topic is relevant, the methodology is generally sound, and the results have potential significance for the design and optimization of textile-based heating systems. Nevertheless, several minor but important issues remain and should be addressed prior to publication.

1. Figure 14 appears to have been generated using image engineering (IE) techniques; however, the resulting visualization is unclear. Specifically, the term heater index k is not adequately defined, and the overall presentation does not allow readers to easily interpret the data. It seems that the use of generative IE may have come at the expense of data transparency and readability.

It is recommended that the authors revise this figure using conventional data visualization methods, such as standard graphs or plots, to ensure that the distribution of error or performance indices is presented in a clear and comprehensible manner.

2. The conclusions section requires revision for consistency and clarity. The following passage should be reconsidered:

“Heated clothing can include several heating units, each powered separately. To estimate the needed resistance and power, we can start with safe values of 12 V and 500 mA for one heating unit. This yields a maximum power output of 6 Watt per heating unit and a corresponding resistance of 24 Ω.”

This statement does not appear to align with the main body of the text, and the derivation or justification of these numerical values is not clearly supported by the presented data or analysis. Unless the authors can provide a clear rationale or reference for these values, this passage should be revised or omitted from the conclusions entirely.

Overall Recommendation

The manuscript is close to publishable form and offers valuable contributions to the field of textile heating systems. Addressing the minor issues outlined above — particularly the clarification of Figure 14 and the revision of the conclusions—would significantly improve the quality and clarity of the paper.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Accept.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf