Nested Optimization of Oil-Circulating Hydro-Pneumatic Energy Storage System for Hybrid Mining Trucks

Round 1

Reviewer 1 Report

Suggestions for minor changes in the manuscript - 

- Readers might benefit from a brief description of the DP algorithm

- Highlight why there is need for nested optimization. What prohibits the author from including all design variables in a single optimization routine.

-Check grammar on line 116. Rephrase. Elaborate better results relative to what ?
-"Truck need" instead of "truck needed" on line 136
- Label axes on fig 13

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

none

Author Response

Thanks very much for your scrupulous review and overall evaluation of our manuscript, which are very valuable and will definitely help us in our future publications.

Reviewer 3 Report

Congratulations on your paper!

Author Response

Thanks very much for your scrupulous review and overall evaluation of our manuscript, which are very valuable and will definitely help us in our future publications. Thank you for your support on our work.

Reviewer 4 Report

 - In the introduction, page 1, line 31, you are talking about the losses dissipated as heat on the braking resistors and the following loss of energy. Quantify the truck parameters. What kind of power are you talking about (? Tens of kW)

- fig. 3, fig. 4 – what is “lifing pump”? should be lifting pump?

- is there some coupling that allows you to mechanically uncouple the combustion engine from the generator?

- why in fig. 4 you don´t keep at least some breaking resistance? What if for some reason you need to dissipate more energy that you can store in the system? Do you count in that case purely on the mechanical brakes?

- in fig. 5 number the cylinders and explain the functionality using cylinder numbers instead of the “top”, “middle”, “bottom” cylinder. Also add arrows in the figure to show the flow in the steps.

- why is it optimal to have 3 cylinders? It is unclear from your explanation.

- fig. 6 is unexplained in the text, what should the reader see, why is it important? This figure needs a more detailed explanation.

- fig. 10 – I believe you have an error in the units in this figure. Y axis is labeled in kW, scale goes up to 7x 10^5, so for example the peak at 500 seconds is about 6.5x10^5 = 6.5 GW? I don’t believe it

- fig. 9 – in what units is slope?

- fig. 13 – you are missing units both Y axes and in the fuel consumption (L / hour, L / km? ) as well

- add the parameters of your generator/motor in a table (voltage, current, power, …)

- in the conclusion you state to save “ 23.57 kg/ day of fuel … 72.12 kg/day of CO2”. I don’t doubt that there is some saving, but does it make any sense? To save 23.57 kg/day of fuel? Really? Why should we care at all? What is the daily fuel consumption of the truck? Thousands of kg? Hundreds of kg?  How much does the system you are proposing cost? What is the economy? Fine, I save as you say 23.57 kg/ day of fuel, so in how many years will it pay itself? In few hundred years?

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf