Solutions for Exposed Structural Concrete Bridged Elements for a More Sustainable Concrete Construction in Hot Climates
Abstract
:1. Introduction
Research Objectives
- To assess the concrete construction of residential housing typical in many Gulf countries,
- To evaluate the impact of solar radiation on thermal bridging through concrete structure,
- To provide more sustainable concrete construction fabric configurations that comply with the new modification of the Saudi code 2018.
- a)
- Monitoring the heat flux entering the building for a period of two weeks,
- b)
- Simulating and analyzing its impact using FEM.
- 1)
- To identify a more sustainable concrete construction, seven new wall section alternatives were investigated and compared to the current situation by establishing effective U-values for the different cases.
- 2)
- The minimum external insulation required for the Gulf countries was investigated.
- 3)
- The most suitable insulation thickness to suit the climate in Saudi Arabia and the other Gulf countries was identified.
2. Methodology
2.1. Experimental Method
2.1.1. Buildings Description
2.1.2. Measurement Setup
2.1.3. Thermal Camera
2.2. Finite Element Modelling
2.3. Boundary Conditions
2.3.1. Shortwave Radiation
2.3.2. Longwave Radiation
2.4. Validation of Finite Element Model
2.5. Evaluating the Impact of Solar Radiation on Energy Performance
2.6. Construction Solutions and Suggestions for Gulf Countries
3. Results
3.1. Experimental Results
3.2. Boundary Condition Evaluation
3.2.1. Convective Boundary Condition
3.2.2. Shortwave Radiation
3.2.3. Longwave Radiation Model
3.3. Evaluating the Impact of Solar Radiation on Thermal Bridging
3.4. Construction Improvement Suggestions
3.4.1. External Insulation System
3.4.2. The Effective External Insulation Thickness for the Gulf Area
4. Limitations
5. Discussion and Conclusions
Author Contributions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Common Materials | Density ρ kg/m3 | Design Thermal Conductivity k W/(m·K) | Specific Heat Capacity c J/(kg·K) | Source |
---|---|---|---|---|
Concrete Block, Hollow, 200 mm | 1105 | 1.04 | 840 | [25,34] |
Concrete Block, Hollow, 150 mm | 1362 | 0.96 | 840 | |
Concrete Block, Hollow, 100 mm | 1618 | 0.81 | 840 | |
Volcanic Block | 800 | 0.34 | 840 | [40,41] |
Cement mortar and plaster | 1800 | 0.72 | 1000 | [42,43] |
Reinforced concrete | 2243 | 1.73 | 840 | [36] |
Molded polystyrene insulation | 23 | 0.034 | 1280 | [44] |
Air Space (20 mm) | 1.1 | 0.17 (keff) | 1007 | [45] |
Surface emissivity coefficient (ε) | 0.9 | [42,46] | ||
Absorptance coefficient (α) | 0.6 | [47] | ||
Internal surface resistance | 0.13 m2K/W | |||
External surface resistance | 0.044 m2K/W |
Model | Site | Author/Reference | Note | ||
---|---|---|---|---|---|
1 | Direct Temperature Models | Australia | Garg (1982), [49] | Clear Sky | |
2 | Australia | Swinbank (1963), [50] | |||
3 | USA | Whillier (1967), [51] | Cloudy Sky | ||
4 | USA AZ, TX, MD, MO, FL, NV | Berdahl and Martin (1982), [52] | Clear Sky Atmospheric Emissivity Models | ||
5 | Israel Negev Highlands | Tang et al. (2004), [53] | |||
6 | USA AZ/MD, and MO | Berdahl and Fromberg (1982), [54] |
Building Name | Element | Energy (KWh) | % Difference |
---|---|---|---|
Building-1 | Exposed-Column | 1.13 | 23% |
Wall | 0.92 | ||
Building-2 | Exposed-Column | 1.89 | 100% |
Wall | 0.63 | ||
Building-3 | Exposed-Column | 2.73 | 111% |
Wall | 0.78 | ||
91% | |||
Covered-Column | 2.06 | ||
% between Exposed and Covered Columns | 28% |
Accuracy Measurement Indicator | S1—Exposed Column | S2—Wall | S3—Covered Column | |
---|---|---|---|---|
R-square coefficient | R2 | 0.76 | 0.78 | 0.91 |
% Root Mean Square Error | RMSE | 24.0 | 26.1 | 33.5 |
% Mean Absolute Error | MAPE | 24.1 | 25.7 | 32.3 |
Accuracy Measurement Indicator | S1—Exposed Column | % Difference | S2—Wall | % Difference | S3—Covered Column | % Difference | ||||
---|---|---|---|---|---|---|---|---|---|---|
Convective BC | Convective + Shortwave Rad. | Convective BC | Convective + Shortwave Rad. | Convective BC | Convective + Shortwave Rad. | |||||
R-square coefficient | R2 | 0.76 | 0.80 | 6% | 0.78 | 0.80 | 2% | 0.91 | 0.92 | 1% |
% Root Mean Square Error | RMSE | 24.0 | 18.1 | 28% | 26.1 | 20.0 | 25% | 33.5 | 22.7 | 38% |
% Mean Absolute Error | MAPE | 24.1 | 20.1 | 14% | 25.7 | 22.1 | 15% | 32.3 | 26.5 | 20% |
Accuracy Measurement Method | S1 Convective + Shortwave Rad. | Sky Temperature Model | ||||||
---|---|---|---|---|---|---|---|---|
Ber&Mar [52] | Garg [49] | Swinbank [50] | Whillier [51] | Tang [53] | Ber&Fro [54] | |||
% R-square coefficient | R2 | 0.80 | 0.83 | 0.71 | 0.68 | 0.78 | 0.81 | 0.81 |
% Root Mean Square Error | RMSE | 18.1 | 14.4 | 26.6 | 31.1 | 16.0 | 14.6 | 14.5 |
% Mean Absolute Error | MAPE | 20.1 | 15.3 | 24.7 | 29.2 | 16.2 | 15.6 | 15.5 |
Total Energy Transmittance without Solar Radiation Applied to the Model (KWh/m2) | Total Energy Transmittance with Solar Radiation Applied to the Model (KWh/m2) | |
---|---|---|
Un-bridged model | 0.63 | 0.79 |
Bridged Model | 1.39 | 1.81 |
System Name | Wall Construction System | Column Construction System | Block materials | Ut-Value (W/m2·K) |
---|---|---|---|---|
W0 | Two layers of 15 cm blocks + 5 cm insulation | (No column) | Volcanic | 0.42 |
W1-(a) | Two layers of 15 cm blocks + 5 cm insulation | Exposed column | Volcanic | 1.20 |
W1-(b) | Two layers of 15 cm blocks + 5 cm insulation | Covered by 15 cm block | Volcanic | 0.81 |
W2 | A layer of 20 cm block + A layer of 10 cm block + 5 cm insulation | Covered by 5 cm insulation and 10 cm block | Volcanic | 0.45 |
W3 | A layer of 20 cm insulated block + A layer of 10 cm block + 5 cm insulation | Covered by 5 cm insulation and 10 cm block | Concrete | 0.42 |
W4 | Two layers of 15 cm blocks + 5 cm insulation | Covered by 5 cm insulation and 10 cm block | Volcanic | 0.45 |
W5 | A layer of 15 cm block + A layer of 10 cm block + 10 cm insulation | Covered by 5 cm insulation and 10 cm block | Volcanic | 0.36 |
W6 | A layer of 20 cm block | Covered by 5 cm insulation | Concrete | 0.60 |
W7 | A layer of 20 cm block | Covered by 10 cm insulation | Concrete | 0.32 |
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Alayed, E.; O’Hegarty, R.; Kinnane, O. Solutions for Exposed Structural Concrete Bridged Elements for a More Sustainable Concrete Construction in Hot Climates. Buildings 2022, 12, 176. https://doi.org/10.3390/buildings12020176
Alayed E, O’Hegarty R, Kinnane O. Solutions for Exposed Structural Concrete Bridged Elements for a More Sustainable Concrete Construction in Hot Climates. Buildings. 2022; 12(2):176. https://doi.org/10.3390/buildings12020176
Chicago/Turabian StyleAlayed, Essam, Richard O’Hegarty, and Oliver Kinnane. 2022. "Solutions for Exposed Structural Concrete Bridged Elements for a More Sustainable Concrete Construction in Hot Climates" Buildings 12, no. 2: 176. https://doi.org/10.3390/buildings12020176