Study on Thermal Storage Wall Heating System of Traditional Houses in Cold Climate Zone of China: A Case Study in Southern Shaanxi

Round 1

Reviewer 1 Report

This manuscript investigated a passive thermal storage wall heating system in a traditional house in a Southern Shaanxi area. The performance of this system was verified by a numerical method. By comparing with the original heating system, the new system has the certain practicability and saved a certain energy consumption. This study could be an interesting topic, however, from the viewpoint of research, there are too many problems that should be addressed first, including but not limited to writing, method, discussion/conclusions issues. Detailed info can be found below.

 (1) The title was not clear. In other words, it is too simple. The system’s performance? The application potential of the system? Moreover, Southern Shaanxi was not acceptable. Normally, it is an area located in the cold climate zone. The climate zone with the specific area is better than the locations, e.g., “in cold climate zone of China: A case study in Southern Shaanxi”.

(2) The keywords used the “Southern Shaanxi”, it is not a good decision.

(3) The reference citation format was not correct, Weiwei Xu, Qingyuan Wang… Those authors’ name should be changed according to the format of the manuscript.

(4) For the introduction, authors provided so many reference, it is not bad. However, the way the authors listed them one by one was not acceptable. It is not quite professional.

(5) The research purpose section mentioned that “ANSYS software is used to verify the performance of the system”. In the method, the info was lost regarding the software.

(6) The purposes/goals of this study including Thermal properties of PCM, Thermal efficiency of TSWHS, The applicable time of the TSWHS throughout the year, the new system reduces heat load and energy savings throughout the year were not completely observed. Please double check.

(7) In the method section (simulation section), reviewer cannot find the detailed simulation setting, which is extremely important problem. The boundary condition in/around the model.

(8) The evaluation indices and operating principles were not different. The authors should provide the evaluation indices in the method section.

(9) As the method did not provide the simulation setting, reviewer cannot evaluate the results including the indoor temperature conditions, in different cases.

(10) In the figure 10, what is temperature variation? The location, the height of the simulated values?

(11) In the writing issues, some of the content of this manuscript should be modified, e.g., the using time, the figures number, …..

(12) In the figure 10 (actually, no. 13), what is the unit? The comfort level?

(13) Due to the limitation of this study, reviewer strongly suggests the authors provide a deep discussion section.

(14) In the conclusion, the description of “The annual heat load of TSWHS was simulated by software”, what is the software? There is not relevant info, please clarify it.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

The topic of the paper Research on Thermal Storage Wall Heating System of Traditional Houses in Southern Shaanxi is relevant, timely, and of interest to the audience of this journal. In this paper a fully passive thermal storage wall heating system (TSWHS) is proposed for traditional houses in the southern Shaanxi area. The heating conditions of OHS and TSWHS were simulated and evaluated separately using software, covering the usage time, temperature increase, and energy saving capability. The reliability and practicality of TSWHS are also discussed in depth.

This research area is of great importance not only for the China but also in the many places around the world. The paper is based on academic standards. The abstract is concise and sufficient. The introduction provides the necessary background information. However, the research problem and research gap were not clearly defined.

Result and Discussion section, there should be a relation to other research projects … or other regions … set your results in relation to other works. The article was written carelessly and major revision is necessary.

The following comments are suggested to be addressed in the revised manuscript:

Please format the references according to Atmosphere style (the DOI identifiers are missing).

Incorrect axis description the graph shown in Figure 2c - "Wink speed (m/s)"?

Incorrect drawings numbering on the pages: 7, 8, 9, 12, 13, 14, 17, 18, 19.

No units of measure for the equations (1), (2), (3).

The unit errors on line 294.

In the description of formula (3) there is no definition of a W.

Line 310 - The symbol q does not appear in equation (3).

Line 317 - Does "indoor heat disturbance sources" mean "Internal Heat Gains"?

Lines 504-505 - What does "At 15:00, the indoor temperature reaches a maximum of 9.1 °C and an average of 8.6 °C, or 5" mean?

There is no description of the graphs presented in the Figure 10 a), b) c) (pages: 18-19).

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

The article contains interesting simple idea to apply Tombe-like heat storage wall to existing house in rural area. The results can have practical applitactions and are worth publishing but the presentation should be vastly improved. The detalis are as follows:

Can you desciribe the details od HDPE layer. Such materials have desity about 1000 kg/m3 and specific heat about 2000 J/(kgK).
Therefore heat capacity of such layer is similar to brick wall. It may be better
to heat just the surface of wall directly. The nighttime energy losses from wall will be to the under glass space and to the room so in both ways is could be converted into usable energy.

Figure 1 on page 7 should have number 3. Please check all figure referencing and numbering.

Figure 3. In Boundary Conditions right rectangle: With solar radiation

Figure 4. Step 2 Heat transfer instead od Heating transfer

lines 288-290 Please explain what you mean. In my opinion it will be only trainsient heat transfer here, as the solar radiation varies in time and so do the temperature in air cavity.

line 298 Equation (2) at least the rightmost part is known as the Fourier law. I tried to search internet for Borie law but
found nothing, can you explain?

lines 304-306 I don't understand this phrase, can only think you are trying to say that a temperature difference is a condition for the heat exchange to occur but an explanation is needed. What you mean by "inner wall" and "outer wall" (also used in lines 320-322). Is the outer wall a glass
plate or its just a outer surface of brick wall.

In line 338 you write that HDPE have high heat accumulation capacity so I may just dont know this material, if so please write a one or two sentences about its thermal properties.

Equation (3) Units are usually put in brackets [] with space between units and equation. You don't put units in other euqations I think it will be better looking if you unify this. Also there is no F in equation (3).

Table 2 Please explain what material is "watt". Also column 4 seems to be specific thermal capcity, not conductance.

In paragraph 3.1 there seem to be something wrong with figures referncing. In line 376 maybe it should be Figure 5 instead of Figure 7, the same apply to line 378.
Line 395 and line 398 maybe refers to Figure 6 not Figure 8.

Starting form Figure 7 the subsequend numbers are messed up, there is a figure 7, then 10, then 11, then 8.
The indor (air?) temperature are quite uniform in room crossections, did you take for account convenction in the air?

In paragraph 3.3 can you  define what is TSWHS using time? It is the time when TSWHS heat flux is flowing into the room?

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The revised manuscript can be accepted after the significiant modifications.

Reviewer 2 Report

In accordance with the comments contained in the review, the content of the manuscript was supplemented. The resubmitted paper is clearly written and technically sound. 

After the revision, the article is ready for publication.

Reviewer 3 Report

All remarks were adressed.

Best wishes