Rebuttal to “Discussion of ‘Second law analysis of reverse osmosis desalination plants: An alternative design using pressure retarded osmosis’ [Energy 2011] 36: 6617–6626]”
We have had several conversations with Knutson during recent months, and we certainly agree that the one-dimensional mass exchanger model is more appropriate than the zero-dimensional model which has appeared in much of the past literature and which we also applied. We have been working on revisions...
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| Format: | Article |
| Language: | en_US |
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Elsevier B.V.
2017
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| Online Access: | http://hdl.handle.net/1721.1/109472 https://orcid.org/0000-0002-2901-0638 |
| _version_ | 1826189252668424192 |
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| author | Sharqawy, Mostafa H. Zubair, Syed M. Lienhard, John H. |
| author2 | Massachusetts Institute of Technology. Department of Mechanical Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Mechanical Engineering Sharqawy, Mostafa H. Zubair, Syed M. Lienhard, John H. |
| author_sort | Sharqawy, Mostafa H. |
| collection | MIT |
| description | We have had several conversations with Knutson during recent months, and we certainly agree that the one-dimensional mass exchanger model is more appropriate than the zero-dimensional model which has appeared in much of the past literature and which we also applied. We have been working on revisions of these calculations that incorporate the one-dimensional model, and we report some of our findings in Refs. [2] ; [5]. However, we believe that PRO has clear potential for energy recovery, as we explain in detail below. Further, Knutson's analysis of the power generation is flawed and his conclusions regarding energy recovery are not accurate.
Knutson's method of analysis makes the assumption of infinite membrane water permeability (equivalent to infinite surface area), taking the value of A in Eq. (1) to be infinity. Because the value of A for the membrane is assumed to be infinite, the local water flux is equal to zero at the inlet, outlet, or both ends of the PRO module. In another words, the driving force for the water flux will vanish at the inlet, outlet, or both ends. This is similar to the assumption of zero pinch at the end of a heat exchanger, such as might be obtained with infinite surface area. This is an interesting method, and it should give similar trends as given in Ref. [4] if it is applied correctly. |
| first_indexed | 2024-09-23T08:11:53Z |
| format | Article |
| id | mit-1721.1/109472 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T08:11:53Z |
| publishDate | 2017 |
| publisher | Elsevier B.V. |
| record_format | dspace |
| spelling | mit-1721.1/1094722022-09-23T11:34:41Z Rebuttal to “Discussion of ‘Second law analysis of reverse osmosis desalination plants: An alternative design using pressure retarded osmosis’ [Energy 2011] 36: 6617–6626]” Sharqawy, Mostafa H. Zubair, Syed M. Lienhard, John H. Massachusetts Institute of Technology. Department of Mechanical Engineering Lienhard, John H Lienhard, John H. We have had several conversations with Knutson during recent months, and we certainly agree that the one-dimensional mass exchanger model is more appropriate than the zero-dimensional model which has appeared in much of the past literature and which we also applied. We have been working on revisions of these calculations that incorporate the one-dimensional model, and we report some of our findings in Refs. [2] ; [5]. However, we believe that PRO has clear potential for energy recovery, as we explain in detail below. Further, Knutson's analysis of the power generation is flawed and his conclusions regarding energy recovery are not accurate. Knutson's method of analysis makes the assumption of infinite membrane water permeability (equivalent to infinite surface area), taking the value of A in Eq. (1) to be infinity. Because the value of A for the membrane is assumed to be infinite, the local water flux is equal to zero at the inlet, outlet, or both ends of the PRO module. In another words, the driving force for the water flux will vanish at the inlet, outlet, or both ends. This is similar to the assumption of zero pinch at the end of a heat exchanger, such as might be obtained with infinite surface area. This is an interesting method, and it should give similar trends as given in Ref. [4] if it is applied correctly. 2017-05-31T18:42:18Z 2017-05-31T18:42:18Z 2012-09 2012-08 Article http://purl.org/eprint/type/JournalArticle 03605442 http://hdl.handle.net/1721.1/109472 Sharqawy, Mostafa H., Syed M. Zubair, and John H. Lienhard. “Rebuttal to ‘Discussion of “Second Law Analysis of Reverse Osmosis Desalination Plants: An Alternative Design Using Pressure Retarded Osmosis” [Energy 2011] 36: 6617–6626].’” Energy 46, no. 1 (October 2012): 691–693. https://orcid.org/0000-0002-2901-0638 en_US http://dx.doi.org/10.1016/j.energy.2012.08.035 Energy Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf Elsevier B.V. Prof. Lienhard via Angie Locknar |
| spellingShingle | Sharqawy, Mostafa H. Zubair, Syed M. Lienhard, John H. Rebuttal to “Discussion of ‘Second law analysis of reverse osmosis desalination plants: An alternative design using pressure retarded osmosis’ [Energy 2011] 36: 6617–6626]” |
| title | Rebuttal to “Discussion of ‘Second law analysis of reverse osmosis desalination plants: An alternative design using pressure retarded osmosis’ [Energy 2011] 36: 6617–6626]” |
| title_full | Rebuttal to “Discussion of ‘Second law analysis of reverse osmosis desalination plants: An alternative design using pressure retarded osmosis’ [Energy 2011] 36: 6617–6626]” |
| title_fullStr | Rebuttal to “Discussion of ‘Second law analysis of reverse osmosis desalination plants: An alternative design using pressure retarded osmosis’ [Energy 2011] 36: 6617–6626]” |
| title_full_unstemmed | Rebuttal to “Discussion of ‘Second law analysis of reverse osmosis desalination plants: An alternative design using pressure retarded osmosis’ [Energy 2011] 36: 6617–6626]” |
| title_short | Rebuttal to “Discussion of ‘Second law analysis of reverse osmosis desalination plants: An alternative design using pressure retarded osmosis’ [Energy 2011] 36: 6617–6626]” |
| title_sort | rebuttal to discussion of second law analysis of reverse osmosis desalination plants an alternative design using pressure retarded osmosis energy 2011 36 6617 6626 |
| url | http://hdl.handle.net/1721.1/109472 https://orcid.org/0000-0002-2901-0638 |
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