The Optimum Window-to-Wall Ratio in Office Buildings for Hot‒Humid, Hot‒Dry, and Cold Climates in Iran
Round 1
Reviewer 1 Report
Dear Authors,
I read with great interest your manuscript devoted to the optimum value of the transparent/opaque walls ratio for specific climatic areas in Iran. I found the topic well adapted to the issues of Environments and interesting enough.
The paper, unfortunately, is characterized by several lacks which reduce its efficacy.
I am confident that you will consider my observations merely as suggestions addressed to the best result.
Here below my comments.
The energy saving, and, more generally, the sustainability of the building envelope cannot be assured by a mere energy approach. In few words an optimization only aimed to reduce loads in summer and losses in winter risks to be not sustainable from the perspective of the indoor environmental quality (above all indoor thermal comfort). This is not a personal opinion being claimed at international level by European Union since 15 years (see 2018/844, 2002/91) and received by International Standards as EN 15251: 2007 and ISO 17772-1: 2017 (this is also for ASHRAE). With this in mind, it is almost astonishing that in the manuscript no words are spent about indoor operative temperature values in most representative environments (and in the whole building) and related comfort indices values. In addition what a kind of HVAC system has been used for simulation? Finally, used set point values (22 °C in winter and 24 °C in summer) are very far from those suggested by EN 15251 end ISO 17772-1 for office buildings (19-21 °C in winter and 25.5-27 °C in summer). Can this choice affect final results (and indoor thermal comfort conditions)?
Best regards
Author Response
Referee 1
Comment 1:
The energy saving, and, more generally, the sustainability of the building envelope cannot be assured by a mere energy approach. In few words an optimization only aimed to reduce loads in summer and losses in winter risks to be not sustainable from the perspective of the indoor environmental quality (above all indoor thermal comfort). This is not a personal opinion being claimed at international level by European Union since 15 years (see 2018/844, 2002/91) and received by International Standards as EN 15251: 2007 and ISO 17772-1: 2017 (this is also for ASHRAE).
Response 1:
Regarding the response of the above mentioned comment from the respectful referee it shall be mentioned that different aspects should be considered for building stability and the referee`s comment in this regard is completely acceptable.
Although the building energy consumption is one of the most important issues of sustainability, the investigation of all aspects of sustainability was actually outside of the scope of this paper and it includes various and wide articles examinations.
Therefore, in this paper it was attempted to examine one of the important issues which is the percentages of building windows and their impact on building energy consumption. It is important to pay attention to each element of the building in order to reduce energy consumption, all of which are referred in EN 15251: 2007, ISO 17772-1: 2017 and ASHRAE, and additionally it has been mentioned in the LEED law.
It should be noted that a large part of the energy of the building is wasted through the windows. Thus based on the standards paying attention to this issue is very crucial.
Comment 2:
With this in mind, it is almost astonishing that in the manuscript no words are spent about indoor operative temperature values in most representative environments (and in the whole building) and related comfort indices values.
Response 2:
With respect to the response of the respectful referee it shall be noted that the purpose of this article is to examine the impact of the window percentages of the outdoor facade of the building on energy consumption. It should be noted that the purpose of energy consumption is to achieve thermal comfort for residents of the building. Hence, energy consumption settings have been met in order to achieve thermal comfort in all simulation conditions.
Accordingly, the determination of the percentage of the optimal window regarding energy consumption has indicated that the energy consumption is minimum and the thermal comfort has been also provided for individuals.
Comment 3:
In addition what a kind of HVAC system has been used for simulation?
Response 3:
In this simulation, a chiller was utilized for cooling and a radiator was used for heating.
Comment 4:
Finally, used set point values (22 °C in winter and 24 °C in summer) are very far from those suggested by EN 15251 end ISO 17772-1 for office buildings (19-21 °C in winter and 25.5-27 °C in summer). Can this choice affect final results (and indoor thermal comfort conditions)?
Response 4:
In this study, the temperature of 22 °C in winter and 24 °C in summer were used. The numbers are according to the ASHRAE standard for office buildings; these numbers are also based on the standard of the Iranian building which are used for cooling and heating.
Reviewer 2 Report
The paper deals with the determination of the ptomal WWR for office buildings in Iran. Classical subject , widely studied in literature but the novelty is climatic conditions.
I have the following questions/comments:
page 1; lines 42 43 which study does authors refer to? in which country or region?
in literature review section, some sections are too long and need to be reduced...
lines 177 to 186 can be presented in a table...it is better; wind spped 2/2???
is it normal that some references are cited in the text by name (year) and other by number only ???
section 3 and table 1, which standard are authors speaking about? can you specify what are indoor loads (equipments, lighting...?) which kind of lighting are authors using? fluorescent? how is regulated? (is it off when natural lighting is enough???)
Author Response
Referee 2:
Comment 1:
Page 1; lines 42 43 which study does authors refer to? In which country or region?
Response 1:
Thank you for your comment, it was located at Gothenburg, Sweden. Here we cited as:
M. Persson, A. Roos, M. Wall, Influence of window size on the energy balance of low energy houses, Energy Build. 38 (2006) 181–188. doi:10.1016/j.enbuild.2005.05.006.
Comment 2:
Lines 177 to 186 can be presented in a table...it is better; wind speed 2/2???
Response 2:
Thank you for your comment, we just did it as table 1; wind speed 2.2 has been corrected.
Comment 3:
In literature review section, some sections are too long and need to be reduced...
Response 3:
It is true, we just edited the literature review.
Comment 4:
Is it normal that some references are cited in the text by name (year) and other by number only???
Response 4:
Thank you, All citation were checked.
Comment 5:
Section 3 and table 1, which standard are authors speaking about? Can you specify what are indoor loads (equipments, lighting...?) which kind of lighting are authors using? Fluorescent? How is regulated? (Is it off when natural lighting is enough???)
Response 5:
Regarding the comment of the respectful referee it shall be mentioned that all of the considered items are based on previous researches and studies, which are cited in the context of the article. Additionally, other numbers and other settings are based on the ASHRAE standard for office buildings. In the simulation, the lights were considered as LED lights. In software, smart lighting is considered in a way that with the daylight brightness it increases and decreases.
Round 2
Reviewer 1 Report
Dear Authors,
thank you for having accepted a part of my observations and related efforts spent to address them. Unfortunately, my earlier observation (the second) has not been addressed being your reply unrealistic. Particularly you stated: “It should be noted that the purpose of energy consumption is to achieve thermal comfort for residents of the building. Hence, energy consumption settings have been met in order to achieve thermal comfort in all simulation conditions.”
Concerning this statement, I have to observe that fixing a set point consistent with comfort conditions (this is necessary to size HVAC systems) does not assure, in principle, that the dynamic simulation of the building envelope results in microclimatic values consistent with desired set point values. Maybe did you record operative temperature equal to set point in all simulations? Maybe near windows and in the presence of sun mean radiant temperature is uniform?
So, I kindly I ask you to declare explicitly that, for the purposes of this paper you have preferred only deal with energy saving issues.
Best regards.
Author Response
This point is really wonderful to be applied for next research topic. Our present manuscript just focus on WWR and it is not about values regarding indoor thermal comfort, so we just simulate the way that we could find the optimize range of WWR in different climate of Iran (Shiraz, Bushehr and Tabriz).
Reviewer 2 Report
Authors replied to all comments.
Author Response
Thank you or your point, it was done!
