Thermal Assessment of a Ventilated Double Skin Façade Component with a Set of Air Filtering Photocatalytic Slats in the Cavity

Round 1

Reviewer 1 Report

Summary:

When evaluating habitability, indoor air quality is a crucial factor, especially in developed nations where people spend the majority of their time inside. This study describes a novel double skin façade (DSF) system that combines physical and photocatalytic filtering techniques. The air purification system is made up of fixed slats that are both solar protection and an air purification system. This study's goal is to ascertain the proposed system's thermal behavior so that its suitability for use in various environments may be assessed. Both a physical 1:1 scale model and a Computational Fluid Dynamics (CFD) model were used for this. The scale model cavity's top temperature was 17–20°C higher than ambient air. Additionally, it was discovered that the air flow through the DSF would require forced ventilation. To determine the emissivity values of the photocatalytic coating, additional experimental measurements were made. In Barcelona, Chicago, and Vancouver, the CFD model was tested in both summer and winter circumstances. This article has an excellent research that might be published in a famous journal like Buildings. The following enhancements must be made to this manuscript in order to raise its caliber:

 

Major Issue

·         The purpose, justification and motivation of conducting this research must be stated explicitly in the abstract. In order to clearly communicate the contribution of this research work, the abstract must be fully revised and rewritten.

 

·         Studying earlier scholarly works on the subject is crucial in order to understand the recommendation given in the introduction section of the revised article. As a result, the new version has to include more deep survey. Please attempt to compare your findings to other materials that have been published in the same field of study in order to contribute and recommend improvements. Please have look at such related  references:

 

 

Al-Quraan A, Al-Mahmodi M, Al-Asemi T, Bafleh A, Bdour M, Muhsen H, Malkawi A. A New Configuration of Roof Photovoltaic System for Limited Area Applications—A Case Study in KSA. Buildings. 2022; 12(2):92. https://doi.org/10.3390/buildings12020092

 

·         More details and explanation of the methodology for emissivity tests in 3.1 should be added in the revised manuscript.

·         The English of the entire document should be carefully checked and corrected.

 

Minor Issue:

·         List of acronyms and abbreviations should be included in the revised version as the manuscript includes many of them.

Author Response

Thank you for your comments and suggestions. Please see the attachment,

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper presents an innovative facade system combining both physical and photocatalytic filtering strategies. The main goal of the study lies in determining the thermal character of the proposed facade system. The thermal analysis was performed using both the experimental and computational techniques. First, a full-scale model was built and used for experimental estimations. Second, a CFD digital twin was built and validated against the experimental results. The CFD model was used for to improve aerodynamics of the facade by means of the louver geometry variation. The relevance of the paper is without question.

The paper is clear and well-written, however, there are several questions and remarks.

1) It is suggested to add the nomenclature section.

2) The flow is supposed to be laminar. What was the background for this assumption? What were the Grashof number for the free convection and the Reynolds number for the flow through the flow the inter-louver channel (visible, e.g., in Figure 11)?

3) Time step of 150s was used for the transient simulations. Was this value sufficient to perform unsteady simulations? It is visible in Figures 9 and 10 that CFD simulation does not reproduce some unsteady effects registered in the experiments.

4) The difference in computed and measured temperature achieves 8 degrees C (see Figures 9 and 10). It seems that more detailed discussion of the sources of the experimental and CFD data uncertainties is required (the only discussion presented in lines 315-318 seems to be insufficient).

5) Is it possible to add more details on the optimization procedure? The geometry optimization performed to improve aerodynamics of the facade is only briefly mentioned in page 13.

Author Response

Thank you for your comments and suggestions. Please see the attachment,

Author Response File: Author Response.pdf

Reviewer 3 Report

the authors studied experimentally and numerically the double skin façade system with a set of air filtering photocatalytic slats.

The introduction is to be extended.

Some figures have low resolutions.

For the experimental study, the measurement techniques and the data acquisition system are to be described.

An experimental uncertainty study is to be performed.

The English level is to be improved.

For the CFD study, the governing equations are to be presented.

The boundary conditions are to be expressed mathematically.

Have you considered, laminar or turbulent flow?

What is the range of Rayleigh number corresponding to the considered conditions.

What is the convergence criterion?

What is the time step?

The streamlines are to be presented for a better understanding of the flow structure

Use ‘’.’’ instead of ‘’,’’ for the decimals.

The curves of figs 15 and 16 are very confusing, there are several variations with the same colours and legend.

The English level is very low.

 

 

 

 

 

Author Response

Thank you for your comments and suggestions. Please see the attachment,

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The comments have been addressed. No further comments.

Reviewer 3 Report

afer revision, the paper can be accepted for publication