Numerical simulation of buoyancy-driven turbulent ventilation in attic space under winter conditions

Wang, Shimin; Shen, Zhigang; Gu, Linxia

doi:10.1016/j.enbuild.2011.12.012

Numerical simulation of buoyancy-driven turbulent ventilation in attic space under winter conditions

Journal Article · Mon Dec 19 00:00:00 EST 2011 · Energy and Buildings

DOI:https://doi.org/10.1016/j.enbuild.2011.12.012· OSTI ID:1765174

Wang, Shimin ^[1]; ^[2]; Gu, Linxia ^[2]

Univ. of Nebraska, Lincoln, NE (United States); University of Nebraska-Lincoln
Univ. of Nebraska, Lincoln, NE (United States)

Attic design and construction have significant impacts on residential buildings’ energy performance. In order to understand how passive ventilation rates affect ridge-vent attic's performance, a two-dimensional steady-state finite volume model is employed to simulate the buoyancy-driven turbulent ventilation and heat transfer in a triangular attic space of a gable-roof residential building under winter conditions. The modeled attic has a pitch of 5/12 and a passive ventilation system, consisting of continuous ridge and soffit vents. The v2f model is used to analyze the turbulent air flow and natural convection heat transfer inside the attic. The effects of ambient air temperature, vent size, and ceiling insulation on heating load and ice dam formation are investigated. The thermal performance of the vented attic is compared with a sealed attic as well. Here, the simulation results reveal that symmetrical air flow patterns exist in a vented attic, in contrast to the asymmetrical air flow patterns found in a sealed attic. In addition, it is suggested that increasing vent size results in higher ventilation air flow rate but barely affects the attic heating load, and that both sufficient ventilation and insulation are needed to ensure the proper functions of the attic and its energy efficiency.

View Accepted Manuscript (DOE)

Research Organization:: Univ. of Nebraska, Lincoln, NE (United States)

Sponsoring Organization:: USDOE Office of Energy Efficiency and Renewable Energy (EERE)

Grant/Contract Number:: EE0003866

OSTI ID:: 1765174

Journal Information:: Energy and Buildings, Journal Name: Energy and Buildings Vol. 47; ISSN 0378-7788

Publisher:: ElsevierCopyright Statement

Country of Publication:: United States

Language:: English

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32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
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Turbulence
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Numerical simulation of buoyancy-driven turbulent ventilation in attic space under winter conditions

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