Evaluation of a Back-up Range Extender and Other Heavy-Duty BEV-Supporting Systems
Round 1
Reviewer 1 Report
i would to thank the authors for the efforts in this paper, the following comments are not decrease the value and the efforts but are intending to enhance the work to be suitable to publish.
1- The title is too long, it should be shorted to be interesting and be to be understandable for the readers.
2- The abstract in this paper seems like an introduction or a part of it, but I would like to read a summary of your paper in the abstract, everything about the paper should appear in it, so rewrite and take into consideration the methodology, the results, also the originality.
3- Fig.1, and Fig.2 need to decrease their sizes also rearrange them, also the introduction should have a part that describes the following sections in the paper, it is required to add.
4- Fig4 to 7, need more comments and explanation, the discussion is very poor, the same for table1.
5- The conclusion should rewrite.
Author Response
Reviewer 1: I like to thank you for good and understandable comments.
The title is shortened and also I feel this is better.
The abstract is also improved and more snappy now.
I have tried to improve figure 1 and 2. Figure 2 was ok but I got opposite opinion from another reviewer on figure 1 stating that reading inside the figure was not so easy. I have tried a compromise.. I have improved the description in the introduction about the different concepts.
For table 1 I agree and have improved the explanation. Also for figure 7 I have added explanation how to use the diagram. I hope this helps.
Figure 4 re simulation model calibration I am both impressed and happy about the notes. For me it takes a lot of space to explain and some can be seen in the references. Anyway, I tried to find a compromise explaining better.
The conclusion is rewritten and more inine with the abstract
Reviewer 2 Report
Lennarth Zander et al. provides an interesting comparison between different ways to solve problems associated with heavy duty electric vehicles. They compared different types of range extender as well as on-board fuel cells. The main problem of the manuscript is the introduction part, which has the basic content but is poorly organized.
- Line 5. Authors’ information missing here.
- Lines 24-86. This is a single paragraph that expands 60+ lines. It is too long. This paragraph contains several ideas, I suggest the authors to decompose it into a few separate ones, to give readers a clearer idea of what each idea is.
- Resolution of Figure 1 and 3 needs to be increased. It is hard to read these figures.
- Figure 4. There is large discrepancy between simulation and experiment, particularly at large engine speed (11,000 to 12,000). What costs the power to decrease even though the engine speed is larger in the simulation? This apparently did not happen in the experiment.
- Lines 191-193. This seems to be irrelevant to the discussion.
- Lines 334-336, and Figure 7. BUREX emits less CO2 than the BEV because BUREX uses less battery and more fossil fuel. The authors’ point is that battery manufacturing emits more CO2 than the burnt fossil fuel. However, the CO2 emission from battery manufacturing is one time event, while the burning of fossil fuel is continuous. In another words, Figure 7 depends on how often the BUREX is used annually. The authors should discuss this aspect.
- Line 341-342. What sources are the CO2-neutral ethanol? They are usually more expansive than fossil fuel-derived ethanol.
Author Response
Author information; improved now.
Re the introduction I have introduced sub pararaphs to improve the organization of introduction.
Figure 1 and 3: Regarding figure 1 I have opposite opinions from different reviewers but decided to go for your comments since reading inside the figure is important. The font is increased. In figure 3 I have a challenge. I really like the complete 1D model to be visible and then the text is small. I am sorry..
Figure 4: I am happy to see interest in the details in the spine of my research regarding engines and very good comments. I have expanded the text to cover some of the comments but to do it completely take much more room. There is more information available n my references.
191-193: What I try to explain is that the required 150 kW ICE with conventional engine technology will be a much to big engine to be installed directly on the existing electric transmission. The installation issue is a very important driver for the power dense concept in the BUREX.
334-336: I have taken your notes to me and rewritten the text and also updated figure 7 (related)
There is a reference added for the ethanol discussion
Reviewer 3 Report
Dear Authors,
This paper compared the back up range extender (BUREX) with other types of range extenders and fuel cells. Following are my comments
The paper is interesting as it provides a temporary solution while charging infrastructure and FC technologies gradually become more mature.
The discussion regarding figures 6a and 6b is not clear. Kindly provide a detailed discussion since these figures are very important to understand the advantages of REX utilization.
A brief discussion regarding the economics of manufacturing BEX, IUREX, and BUREX will add lot of value to the paper. Discussion regarding the charging cost will also be helpful.
Author Response
Re figure 6a and 6b I got similar feedback from other reviewers. A good one. I ave tried in the text to express better how to operate the curves in the figure,
Re cost we have been avoiding this part in too much details. One reason is the rapid cost changes in some of the technologies
Round 2
Reviewer 1 Report
Thank you very much for your response. No more comments.
Author Response
Thanks for your feedback and I am happy my updates were appreciated. Best regards, Lennarth
Reviewer 2 Report
The authors have addresssed most of my questions.
(Just FYI) The authors suggested biomass as the way for generating CO2-neutral ethanol, which is more expansive than fossil-fuel derived ethanol. That was the point in my previous question.
Author Response
I like to thank the reviewer for the clarification below. Best regards, Lennarth
Reviewer 3 Report
Dear All,
Thank you for answering all my questions.
I hope the cost aspect will be addressed in the future.
Author Response
Dear reviewer. In my thesis under the headline "Further work" I will add a recommendation to add the cost aspects. Thanks again for the good feedback! Best regards, Lennarth
