Evolutionary Design Optimization of an Alkaline Water Electrolysis Cell for Hydrogen Production

Round 1

Reviewer 1 Report

The manuscript presents a computational model and algorithms for an optimization of electrolyze parameters to maximize void fraction of hydrogen and to minimize its costs.

The model is a flexible one. It can be particularized for different parameters as a pressure, ohmic resistance and the geometrical parameters.  The reported computational method can be used for cost optimization of hydrogen production for energy long-term storage.

It is important to mention that the authors of the manuscript clearly highlight the necessity of further experimental studies with an aim to improve the accuracy of the proposed model.

Some formal comments:

In Fig.1, the current density as a function of area have to shown in the volume of  electrochemical cell. In a wire or circuit element the charge flow should be represented by an electrical current I.

Page 4, line 11: Should be equation (4) instead of equation (6).

Faraday constant F is not described in equation   (7).

The designation of a cost function in equation (45) and table 6 is the same as Faraday constant designation and should be changed.

Author Response

Reviewer 1

 

Comments and Suggestions for Authors

The manuscript presents a computational model and algorithms for an optimization of electrolyze parameters to maximize void fraction of hydrogen and to minimize its costs.

The model is a flexible one. It can be particularized for different parameters as a pressure, ohmic resistance and the geometrical parameters.  The reported computational method can be used for cost optimization of hydrogen production for energy long-term storage.

It is important to mention that the authors of the manuscript clearly highlight the necessity of further experimental studies with an aim to improve the accuracy of the proposed model.

Some formal comments:

In Fig.1, the current density as a function of area have to shown in the volume of  electrochemical cell. In a wire or circuit element the charge flow should be represented by an electrical current I.

We appreciate the reviewer’s comment. In agreement with the reviewer the current density is added. In addition, subscripts such as “cath” and “an” are added to the variables a and b.

Page 4, line 11: Should be equation (4) instead of equation (6).

In agreement with the reviewer, we corrected the equation number. 

Faraday constant F is not described in equation   (7).

For clarification, the Faraday constant  has been described at line 127 “ =the Faraday constant 96500 C mol^-1”

The designation of a cost function in equation (45) and table 6 is the same as Faraday constant designation and should be changed.

The  has been replaced by  

 

Reviewer 2

Comments and Suggestions for Authors

The manuscript conducted modeling study on the parameter of void fraction and cost optimization for alkaline water electrolyzer by using ANN and GA, respectively. The employment of the evolutionary algorithms for the optimal design is very interesting. The manuscript was well written, and I recommend for publication of the manuscript after correcting the following minor issues:

1. Adjustment of the section numbers. line 275, 505, 527, 571, 605.

In agreement with the reviewer, the adjustment has been made.

 

2. Line 62. Change the position of the subscript “act an/cath” in equation (1).

The position of the  subscript has been changed and  has been divided into two terms and  for more clarity.

3. Line 111. “Equation (6)” should be Equation (4).

We corrected the equation number.

4. Line 131. “30 bars” should be “30bar”.

The “30 bars” has been changed to “30 bar” in the whole article

 

5. Line 228, 229 and Table 3. Correct the form of numbers, e.g., 1.5 10-3 to 1.5×10-3

In agreement with the reviewer, we amended the format of the exponential terms from “X 10^y”  to “X ×10^y” throughout the manuscript.

6. Line 233. Explain why for each parameter (e.g., T) in Figure 4-7, only one case for the maximum value (e.g., T_max) was selected in the sensitive analysis.

In agreement with the reviewer, the following text has been added starting from a line 228“Therefore, we performed a fractional factorial design of experiment (DOE). The DOE used is a "one factor at a time" (OFAT), referred to the minimal parameter-values curve (red). In all other curves, a single parameter among (T, Y, j, H and h) changes from min to max value to assess the effect of each one on the void fraction and electrolyte ohmic resistance.”

Further corrections

-In the Fig. 1, the notation has been changed to be consistent with the rest of the text (from normal notation to mathematical notation).

-Some minor modifications have been made in the paragraph (the mathematical symbols have been added).

-In Table 12, the unnecessary =14 000 € m^-2 has been deleted.

 

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript conducted modeling study on the parameter of void fraction and cost optimization for alkaline water electrolyzer by using ANN and GA, respectively. The employment of the evolutionary algorithms for the optimal design is very interesting. The manuscript was well written, and I recommend for publication of the manuscript after correcting the following minor issues:

1. Adjustment of the section numbers. line 275, 505, 527, 571, 605.

2. Line 62. Change the position of the subscript “act an/cath” in equation (1).

3. Line 111. “Equation (6)” should be Equation (4).

4. Line 131. “30 bars” should be “30bar”.

5. Line 228, 229 and Table 3. Correct the form of numbers, e.g., 1.5 10-3 to 1.5×10-3

6. Line 233. Explain why for each parameter (e.g., T) in Figure 4-7, only one case for the maximum value (e.g., T_max) was selected in the sensitive analysis.

Author Response

Reviewer 1

 

Comments and Suggestions for Authors

The manuscript presents a computational model and algorithms for an optimization of electrolyze parameters to maximize void fraction of hydrogen and to minimize its costs.

The model is a flexible one. It can be particularized for different parameters as a pressure, ohmic resistance and the geometrical parameters.  The reported computational method can be used for cost optimization of hydrogen production for energy long-term storage.

It is important to mention that the authors of the manuscript clearly highlight the necessity of further experimental studies with an aim to improve the accuracy of the proposed model.

Some formal comments:

In Fig.1, the current density as a function of area have to shown in the volume of  electrochemical cell. In a wire or circuit element the charge flow should be represented by an electrical current I.

We appreciate the reviewer’s comment. In agreement with the reviewer the current density is added. In addition, subscripts such as “cath” and “an” are added to the variables a and b.

Page 4, line 11: Should be equation (4) instead of equation (6).

In agreement with the reviewer, we corrected the equation number. 

Faraday constant F is not described in equation   (7).

For clarification, the Faraday constant  has been described at line 127 “ =the Faraday constant 96500 C mol^-1”

The designation of a cost function in equation (45) and table 6 is the same as Faraday constant designation and should be changed.

The  has been replaced by  

 

Reviewer 2

Comments and Suggestions for Authors

The manuscript conducted modeling study on the parameter of void fraction and cost optimization for alkaline water electrolyzer by using ANN and GA, respectively. The employment of the evolutionary algorithms for the optimal design is very interesting. The manuscript was well written, and I recommend for publication of the manuscript after correcting the following minor issues:

1. Adjustment of the section numbers. line 275, 505, 527, 571, 605.

In agreement with the reviewer, the adjustment has been made.

 

2. Line 62. Change the position of the subscript “act an/cath” in equation (1).

The position of the  subscript has been changed and  has been divided into two terms and  for more clarity.

3. Line 111. “Equation (6)” should be Equation (4).

We corrected the equation number.

4. Line 131. “30 bars” should be “30bar”.

The “30 bars” has been changed to “30 bar” in the whole article

 

5. Line 228, 229 and Table 3. Correct the form of numbers, e.g., 1.5 10-3 to 1.5×10-3

In agreement with the reviewer, we amended the format of the exponential terms from “X 10^y”  to “X ×10^y” throughout the manuscript.

6. Line 233. Explain why for each parameter (e.g., T) in Figure 4-7, only one case for the maximum value (e.g., T_max) was selected in the sensitive analysis.

In agreement with the reviewer, the following text has been added starting from a line 228“Therefore, we performed a fractional factorial design of experiment (DOE). The DOE used is a "one factor at a time" (OFAT), referred to the minimal parameter-values curve (red). In all other curves, a single parameter among (T, Y, j, H and h) changes from min to max value to assess the effect of each one on the void fraction and electrolyte ohmic resistance.”

Further corrections

-In the Fig. 1, the notation has been changed to be consistent with the rest of the text (from normal notation to mathematical notation).

-Some minor modifications have been made in the paragraph (the mathematical symbols have been added).

-In Table 12, the unnecessary =14 000 € m^-2 has been deleted.

 

Author Response File: Author Response.docx