The Impact of Roof Pitch and Ceiling Insulation on Cooling Load of Naturally-Ventilated Attics
A 2D unsteady computational fluid dynamics (CFD) model is employed to simulate buoyancy-driven turbulent ventilation in attics with different pitch values and ceiling insulation levels under summer conditions. The impacts of roof pitch and ceiling insulation on the cooling load of gable-roof residen...
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| Format: | Article |
| Language: | English |
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MDPI AG
2012-07-01
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| Series: | Energies |
| Subjects: | |
| Online Access: | http://www.mdpi.com/1996-1073/5/7/2178 |
| _version_ | 1818038899347292160 |
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| author | Linxia Gu Zhigang Shen Shimin Wang |
| author_facet | Linxia Gu Zhigang Shen Shimin Wang |
| author_sort | Linxia Gu |
| collection | DOAJ |
| description | A 2D unsteady computational fluid dynamics (CFD) model is employed to simulate buoyancy-driven turbulent ventilation in attics with different pitch values and ceiling insulation levels under summer conditions. The impacts of roof pitch and ceiling insulation on the cooling load of gable-roof residential buildings are investigated based on the simulation of turbulent air flow and natural convection heat transfer in attic spaces with roof pitches from 3/12 to 18/12 combined with ceiling insulation levels from R-1.2 to R-40. The modeling results show that the air flows in the attics are steady and exhibit a general streamline pattern that is qualitatively insensitive to the investigated variations of roof pitch and ceiling insulation. Furthermore, it is predicted that the ceiling insulation plays a control role on the attic cooling load and that an increase of roof pitch from 3/12 to 8/12 results in a decrease in the cooling load by around 9% in the investigated cases. The results suggest that the increase of roof pitch alone, without changing other design parameters, has limited impact on attics cooling load and airflow pattern. The research results also suggest both the predicted ventilating mass flow rate and attic cooling load can be satisfactorily correlated by simple relationships in terms of appropriately defined Rayleigh and Nusselt numbers. |
| first_indexed | 2024-12-10T07:50:04Z |
| format | Article |
| id | doaj.art-4d90818847524690932a6e938aa7fa14 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-12-10T07:50:04Z |
| publishDate | 2012-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-4d90818847524690932a6e938aa7fa142022-12-22T01:57:04ZengMDPI AGEnergies1996-10732012-07-01572178219610.3390/en5072178The Impact of Roof Pitch and Ceiling Insulation on Cooling Load of Naturally-Ventilated AtticsLinxia GuZhigang ShenShimin WangA 2D unsteady computational fluid dynamics (CFD) model is employed to simulate buoyancy-driven turbulent ventilation in attics with different pitch values and ceiling insulation levels under summer conditions. The impacts of roof pitch and ceiling insulation on the cooling load of gable-roof residential buildings are investigated based on the simulation of turbulent air flow and natural convection heat transfer in attic spaces with roof pitches from 3/12 to 18/12 combined with ceiling insulation levels from R-1.2 to R-40. The modeling results show that the air flows in the attics are steady and exhibit a general streamline pattern that is qualitatively insensitive to the investigated variations of roof pitch and ceiling insulation. Furthermore, it is predicted that the ceiling insulation plays a control role on the attic cooling load and that an increase of roof pitch from 3/12 to 8/12 results in a decrease in the cooling load by around 9% in the investigated cases. The results suggest that the increase of roof pitch alone, without changing other design parameters, has limited impact on attics cooling load and airflow pattern. The research results also suggest both the predicted ventilating mass flow rate and attic cooling load can be satisfactorily correlated by simple relationships in terms of appropriately defined Rayleigh and Nusselt numbers.http://www.mdpi.com/1996-1073/5/7/2178atticnatural ventilationroof pitchinsulationcoolingturbulenceCFD |
| spellingShingle | Linxia Gu Zhigang Shen Shimin Wang The Impact of Roof Pitch and Ceiling Insulation on Cooling Load of Naturally-Ventilated Attics Energies attic natural ventilation roof pitch insulation cooling turbulence CFD |
| title | The Impact of Roof Pitch and Ceiling Insulation on Cooling Load of Naturally-Ventilated Attics |
| title_full | The Impact of Roof Pitch and Ceiling Insulation on Cooling Load of Naturally-Ventilated Attics |
| title_fullStr | The Impact of Roof Pitch and Ceiling Insulation on Cooling Load of Naturally-Ventilated Attics |
| title_full_unstemmed | The Impact of Roof Pitch and Ceiling Insulation on Cooling Load of Naturally-Ventilated Attics |
| title_short | The Impact of Roof Pitch and Ceiling Insulation on Cooling Load of Naturally-Ventilated Attics |
| title_sort | impact of roof pitch and ceiling insulation on cooling load of naturally ventilated attics |
| topic | attic natural ventilation roof pitch insulation cooling turbulence CFD |
| url | http://www.mdpi.com/1996-1073/5/7/2178 |
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