Optimization of Wall Insulation Configurations for Residential Compounds in a Hot Semi-Arid Climate (BSh)

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In the work, the authors investigate, the effects of insulation material type and placement on the thermal performance of external walls, in both newly constructed and refurbished houses under semiarid conditions, by using  the (IES-VE) simulations, and assessing the 4 types of thermal insulating materials in the wall systems of concrete, brick, and lightweight block. When the manuscript is well organized and presented, the results is valuable for other researchers. I suggest that the manuscript can be published.

Author Response

We sincerely thank the reviewer for the positive evaluation of the manuscript and for recognizing the study's relevance and value. We appreciate the acknowledgment of the methodological approach and the potential contribution of the results to other researchers. The manuscript has been carefully revised and organized accordingly, and we are grateful for the recommendation for publication.

Reviewer 2 Report

Comments and Suggestions for Authors

The overall study has provided the guidance in the climate-controlled design strategies for the best materials for envelope system for residential building at Erbil city.

How houses been classified as low- & middle-income residential buildings in Erbil City, Iraq?

In abstract: the classification Erbil is mentioned as “semiarid climate zone”, it should be “hot semiarid”, as per Koppen-Geiger system. Correct it.

Correct the units: (m2K/W) & (Cm, J/m2K) in page 8

In section 4.3: Provide the virtual environment (IES-VE) software version used

Correct the Figure 6 alignment for better visibility

Misalignment of figure 7

In section: “…By incorporating real-world weather data through EnergyPlus Weather (EPW) files”, please provide the EPW file details, weather archived file or with the available weather data EPW file been created for the simulation. The simulation accuracy (the time period of the EPW file) depends on the EPW file for the study adopted.

In a section 4.3.2: “Internal gains: four occupants per unit, 5-W/m2 equipment, and 7-W/m2 529 lighting.” How the distribution of the occupants been modelled, with in the building different zones.

In a figure 9: Mention the outside and inside in the diagrams for better visualization

In the simulation model, adiabatic conditions been provided for the external wall (Check Figure 10), justify the reason for the same.

In section 4.4.2: what is the wall surface heat transfer coefficient is considered.?

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This research discussed the role of insulation type and the overall performance of different wall-compositions (especially referring to the position of the insulation layer) in the climate of Erbil, Iraq. The authors sampled some representative buildings in the city, performed a survey to collect information on the most common construction types and then characterized their performance with conventional metrics from technical standards ISO 6946 and ISO 13786, as well as with IES-VE parametric simulations for a simplified room. Findings were discussed by means of correlation analyses and statistical tests.

Strong points: detailed analysis of the literature, interesting survey to describe the construction technologies used in Erbil and their performance.
Weaknesses: simulations look too simplified. The overall focus appear very narrow and the main findings regarding the preferable wall configuration are somehow expected. 

Some details:

INTRODUCTION AND LITERATURE REVIEW:
- Although the scope of this research is quite narrow and well-investigated (but often for other climates), I believe that the authors explored adequately the existing literature and clarified sufficiently the gap they wanted to investigate (lack of specific studies for the optimization of building envelope insulation in the Erbil climate). However, it is my advise to better underline the goal of the analysis since the beginning of the introduction and the literature review.
- line 93: "Despite the advances in insulation science, the placement of insulation layers within wall assemblies—whether internal or external—remains relatively underexplored.". This is not true. Please, rephrase.

METHODS:
- Section 3.2 should better distinguish those dynamic indicators which are directly referred to the wall/building opaque envelope element (such as those defined in the ISO 13786) and those which depend on the whole building simulation. Heating and cooling loads are affected by many factors besides the properties of the opaque envelope.
- Sections 4.3 and 4.4 about IES-VE could be probably made more compact, reporting just essential information.
- As a whole, some methodological sections are quite long and focus on well-known notions, such as thermal resistance or U-value. I recommend to make those more compact, removing common knowledge and unnecessary paragraphs.
- As regards IES-VE simulations, please, discuss the representativeness of the single room modelled to assess the dynamic behaviour of the opaque wall configuration. Which orientation for the exposed wall did you consider? If the focus was put only on the wall, why did you include a window with fixed properties in your parametric analysis?
- What is described in section 4.6 is not a calibration. You could name it "qualitative comparison" but, still, it has no real scientific robustness. I recommend to remove it entirely (and its results as well).

RESULTS:
- The goal of part of the correlation analyses is not very clear. Some correlations could be mentioned but not be discussed in detail since they are well-known and expected. For example, in line 847, "Heating Saving (%) and Cooling Saving (%) are not independent outcomes but are closely linked to the building’s baseline thermal loads and seasonal energy  demands.". This is already well-known.
- Some comments require clarification. For instance, in line 821, what do you mean with "those configurations achieving substantial heating energy savings also help control internal gains in the warmer periods"? Did you mean transmission gains or solar gains through opaque elements?

TABLES:
- Table 1. Typical or preferred values are strictly dependent on climate, building and code/law. Please, provide more details.
- Table 1. "M2 K/W" should be "m2 K/".
- Table 2. Typical range needs to be better contextualized.
- Table 6. "W/MK" should be "W/m-K".

FIGURES:
Some figures contain really small texts. Please, make the figures larger or increase the font size.

OTHER:
You should leave a blank space between the value of a measurement and its unit of measurement. E.g., 42°C should be 42 °C.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

This article addresses a very interesting topic: external wall insulation in buildings in the local climate of Erbil, Iraq. The authors analyzed several options for insulating external walls based on the location of the thermal insulation (internal and external), its type (XPS, wool, etc.), and the construction material (concrete, brick, etc.)

On the basis of computer simulations, it was demonstrated that the best solution is to use XPS thermal insulation on the external side.

The article provides very valuable information regarding the location (desert climate) and makes a significant contribution to energy-efficient construction in tropical/desert climates.

The following are some minor comments that require further clarification:

What thicknesses of insulation material were used? Table 6 provides only ranges; What specific thickness was used in the simulation conditions? Were the materials compared at the same thickness?

Are there any local/national requirements regarding insulation material thickness?

The analysis was based on a simplified model of a single room, which does not reflect the complexity of real-world residential buildings. What about other partition orientations? What effect does the compass direction have?

Author Response

Please see the attachment

Author Response File: Author Response.pdf