Sustainable Ventilation Strategies for a Medium-Sized Space with Regional Effect
Round 1
Reviewer 1 Report
The paper investigates the regional effects on life cycle analysis of different ventilation strategies. The study seems to be well conducted and provides relevant results.
For a good understanding of your work by the readers, some points may need to be clarified:
- it is stated that air conditioning installations account for 30% of the commercial sector's electricity consumption. How much of the total electricity consumption does the commercial sector represent?
- what is the electricity mix (do the emissions from electricity production vary over the year? is this variation taken into account?)
- better explain how the discount rate is taken into account (by including it directly in equation (1) for example);
- it would be useful to better identify what can explain the differences in energy consumption and CO2 emissions (especially in the operation phase) between the different regions: energy mix, weather conditions,...
Author Response
The paper investigates the regional effects on life cycle analysis of different ventilation strategies. The study seems to be well conducted and provides relevant results. For a good understanding of your work by the readers, some points may need to be clarified:
Point 1: it is stated that air conditioning installations account for 30% of the commercial sector's electricity consumption. How much of the total electricity consumption does the commercial sector represent?
Response 1: According to the “Hong Kong Energy End-use Data 2020”, 67% of the total electricity is consumed by the commercial sector in Hong Kong.
Point 2: what is the electricity mix (do the emissions from electricity production vary over the year? is this variation taken into account?)
Response 2: The CO2 emission factor taken in the paper was considering the electricity mix factor at the time of writing. It is difficult to project the future 20 years’ CO2 emission factor since it mostly depends on the power company policy and local government’s intention.
Point 3: - better explain how the discount rate is taken into account (by including it directly in equation (1) for example); it would be useful to better identify what can explain the differences in energy consumption and CO2 emissions (especially in the operation phase) between the different regions: energy mix, weather conditions,...
Response 3: The annual discount rate has been incorporated into equation (1). The difference in energy consumption between Hong Kong and Guangdong would be explained in term of outdoor temperature differences. Presented in Table 5, the outdoor enthalpy in Hong Kong is slightly higher than in Guangdong. In light of this, it is expected that under the same indoor design condition, the energy consumed by the AHU in Hong Kong would be higher than in Guangdong.
In Guangdong, a greater amount of electricity is produced by coal-burning, in comparison with Hong Kong. So as the CO2 emission factor in Guangdong is higher than in Hong Kong. However, due to the different outdoor condition in Hong Kong and Guangdong, the electricity consumption in Guangdong is less than in Hong Kong. In light of this, the CO2 saving in the operation phase in Guangdong is higher than in Hong Kong.
The above responses (highlighted in BLUE), as well as moderate English changes in term of grammatical enhancement, are incorporated into the revised version (as attached).
Author Response File: 
Author Response.pdf
Reviewer 2 Report
In this paper three ventilation strategies have been applied to a medium size of air-conditioned space with an approach dealing with energy consumption, construction costs, and emissions of carbon dioxide.
Three ventilation systems, for small-to-medium-sized spaces, would alleviate the regional LCC and emission of CO2 in HKSAR and Guangdong.
It's an interesting research. A suggestion: the formatting of the text differs from the proposed journal style
Author Response
In this paper, three ventilation strategies have been applied to a medium size of air-conditioned space with an approach dealing with energy consumption, construction costs, and emissions of carbon dioxide. Three ventilation systems, for small-to-medium-sized spaces, would alleviate the regional LCC and emission of CO2 in HKSAR and Guangdong. It's an interesting research.
Point 1: A suggestion: the formatting of the text differs from the proposed journal style
Response 1: Thanks for your above encouraging response and suggestion! The revised version has been modified to fully match this journal style. General modification is also involved and highlighted in Blue for your easy reference.
Author Response File: Author Response.pdf
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
