New Equation for Optimal Insulation Dependency on the Climate for Office Buildings
The comparison of building energy efficiency in different climates is a growing issue. Unique structural solutions will not ensure the same energy use, but the differences also remain if cost-optimal solutions are applied. This study developed a new equation for the assessment of building envelope o...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-01-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/14/2/321 |
| _version_ | 1827603188117667840 |
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| author | Kaiser Ahmed Jarek Kurnitski |
| author_facet | Kaiser Ahmed Jarek Kurnitski |
| author_sort | Kaiser Ahmed |
| collection | DOAJ |
| description | The comparison of building energy efficiency in different climates is a growing issue. Unique structural solutions will not ensure the same energy use, but the differences also remain if cost-optimal solutions are applied. This study developed a new equation for the assessment of building envelope optimal insulation in different climates for office buildings. The developed method suggests determining actual degree days from simulated heating energy need and the thermal conductance of a building, avoiding in such a way the use of a base temperature. The method was tested in four climates and validated against cost-optimal solutions solved with optimization. The accuracy of the method was assessed with sensitivity analyses of key parameters such as window-to-wall ratios (WWRs), window g-values, costs of heating, and electricity. These results showed that the existing square root equation overestimated the climate difference effect so that the calculation from the cold climate U-value resulted in less insulation than cost-optimal in warmer climates. Parametric analyses revealed that the power value of 0.2 remarkably improved the accuracy as well as performance worked well in all cases and can be recommended as a default value. Sensitivity analyses with a broad range of energy costs and window parameters revealed that the developed equation resulted in maximum 5% underestimation and maximum 7% overestimation of an average area-weighted optimal U-value of building envelope in another climate. The developed method allows objectively to compare optimal insulation of the building envelope in different climates. The method is easy to apply for energy performance comparison of similar buildings in different climates and also for energy performance requirements comparison. |
| first_indexed | 2024-03-09T05:34:35Z |
| format | Article |
| id | doaj.art-8c5a8a96dbfa485e8316d56438570d0d |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-09T05:34:35Z |
| publishDate | 2021-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-8c5a8a96dbfa485e8316d56438570d0d2023-12-03T12:29:56ZengMDPI AGEnergies1996-10732021-01-0114232110.3390/en14020321New Equation for Optimal Insulation Dependency on the Climate for Office BuildingsKaiser Ahmed0Jarek Kurnitski1Department of Civil Engineering, School of Engineering, Aalto University, PO Box 12100 FI-00076 Aalto, 02150 Espoo, FinlandDepartment of Civil Engineering, School of Engineering, Aalto University, PO Box 12100 FI-00076 Aalto, 02150 Espoo, FinlandThe comparison of building energy efficiency in different climates is a growing issue. Unique structural solutions will not ensure the same energy use, but the differences also remain if cost-optimal solutions are applied. This study developed a new equation for the assessment of building envelope optimal insulation in different climates for office buildings. The developed method suggests determining actual degree days from simulated heating energy need and the thermal conductance of a building, avoiding in such a way the use of a base temperature. The method was tested in four climates and validated against cost-optimal solutions solved with optimization. The accuracy of the method was assessed with sensitivity analyses of key parameters such as window-to-wall ratios (WWRs), window g-values, costs of heating, and electricity. These results showed that the existing square root equation overestimated the climate difference effect so that the calculation from the cold climate U-value resulted in less insulation than cost-optimal in warmer climates. Parametric analyses revealed that the power value of 0.2 remarkably improved the accuracy as well as performance worked well in all cases and can be recommended as a default value. Sensitivity analyses with a broad range of energy costs and window parameters revealed that the developed equation resulted in maximum 5% underestimation and maximum 7% overestimation of an average area-weighted optimal U-value of building envelope in another climate. The developed method allows objectively to compare optimal insulation of the building envelope in different climates. The method is easy to apply for energy performance comparison of similar buildings in different climates and also for energy performance requirements comparison.https://www.mdpi.com/1996-1073/14/2/321conductanceclimate correctioneconomic insulation thicknessNZEB office building |
| spellingShingle | Kaiser Ahmed Jarek Kurnitski New Equation for Optimal Insulation Dependency on the Climate for Office Buildings Energies conductance climate correction economic insulation thickness NZEB office building |
| title | New Equation for Optimal Insulation Dependency on the Climate for Office Buildings |
| title_full | New Equation for Optimal Insulation Dependency on the Climate for Office Buildings |
| title_fullStr | New Equation for Optimal Insulation Dependency on the Climate for Office Buildings |
| title_full_unstemmed | New Equation for Optimal Insulation Dependency on the Climate for Office Buildings |
| title_short | New Equation for Optimal Insulation Dependency on the Climate for Office Buildings |
| title_sort | new equation for optimal insulation dependency on the climate for office buildings |
| topic | conductance climate correction economic insulation thickness NZEB office building |
| url | https://www.mdpi.com/1996-1073/14/2/321 |
| work_keys_str_mv | AT kaiserahmed newequationforoptimalinsulationdependencyontheclimateforofficebuildings AT jarekkurnitski newequationforoptimalinsulationdependencyontheclimateforofficebuildings |