Solid Oxide Fuel Cell-Based Polygeneration Systems in Residential Applications: A Review of Technology, Energy Planning and Guidelines for Optimizing the Design
Round 1
Reviewer 1 Report
Dear Authors! Thank you for your manuscript, submitted to "Processes". I have read it with interest, because your review article, devoted to applications of SOFCs in polygeneration energy systems, covers really actual problems.
However after the reading of submitted review, I have two serious comments, concerning: 1) depth opening of presented topic, and 2) recent and relevant references, covered 2018-2022 years.
1) Actually, declared subject of review, aimed by design of polygeneration systems used SOFCs, was revealed in Sections 5-7 shortly, which were about third of the text.
Whereas Sections 1-4 presented overview of polygeneration systems. The problem of this part is in sufficient number of analogues recent reviews (Scopus: 18 reviews on "polygeneration systems", covered 2020-2022 years).
2) Besides, references in the LIst of submitted manuscript is very old. Review contains only 11 references (including mentioned reviews), covered 2019-2022 - and they are located all in Introduction Part. For example, Scopus on request "polygeneration system" and "SOFC" got 32 references, covered 2019-2022.
Summing up, I would to propose, that manuscript would be rewritten before publication with shortening of overview with delete of well-known facts, and adding more recent data about applications of SOFCs with using fresh relevant articles.
Author Response
Please see the attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
the design of solid oxide fuel cell-based polygeneration systems in residential applications. The meaning of several sentences is unclear. The three different terms are probably used for one property.
Comments:
1. Line 129: Sentence “There is 2.344 carbon emission in one liter of 129 gasoline [21].”
The meaning of the sentence is unclear. Something is probably missing. 2.334 kilograms?
2. Table 1 – Units: NOX emissions (kg/MWh), CO2 emissions (kg/MWh)
It is not clear to which MWh the emissions are related – thermal MWh, or electrical MWh?
3. Line 298: “ Because ST is more energy-efficient and less expensive than reciprocating engines, it has been used for bigger applications”
This statement does not correspond to the data presented in Table 1.
From Table 1:
Steam turbine: electrical efficiency = 10-37 %, overall efficiency = 60-80 %, investment cost = 2000-32000 USD/kWe
Reciprocating engines: electrical efficiency = 25-45 %, overall efficiency = 65-80 %, investment cost = 340-1600 USD/kWe
4. Line 329: system efficiency
The term “overall efficiency” is used in the previous and next parts. What is the difference between system efficiency and overall efficiency?
5. Figure 4 – abbreviations used in the figure should be explained in the figure caption.
6. Page 12: table numbering
The table presented on page 12 should be numbered as Table 2 probably.
7. Page 2 – table 2 energy conversion efficiency (heat and power)
What is the difference between energy conversion efficiency (heat and power) and overall efficiency?
8. Page 14, line 44: “Since 2000 years ago, the advantages of creating ultra-pure hydrogen through hydrolysis have been discovered .”
The meaning of the sentence is unclear.
9. Page 14, line 50: “From the research, the produced hydrogen can supply 500 MW of electricity and hot water for a residential sector.”
The meaning of the sentence is unclear. Some information is probably missing.
The information regarding the amount of produced hydrogen for which 500 MW of electricity and hot water can be supplied.
Author Response
Please see the attachment
Author Response File: 
Author Response.docx
Round 2
Reviewer 1 Report
Dear Authors! Thank you for your attention to my comments!
