Effect of the solar roof chimney position on heat transfer in a room

Vazquez-Ruiz, A.; Navarro, Jorge; Hinojosa, J.F.; Xamán, J.

doi:10.1016/j.ijmecsci.2021.106700

Cited by 15 publications

(8 citation statements)

References 49 publications

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Section: Numerical Modelingmentioning

confidence: 99%

“…-The Boussinesq model for the variation of the air properties with temperature is utilized. Several studies showed that this approximation is valid for small-scale solar chimneys (Khanal and Lei, 2015;Vazquez-Ruiz et al, 2021;Zavala-Guille´n et al, 2018;Zhang and Yang, 2019) as the temperature rise in their cavities is not high. -For the turbulence closures of the Reynolds stress, ru i u j , and the turbulence heat flux, ru i t, in equations ( 3) and ( 4), the k À v model with the corrections for Low-Reynolds number effects was employed.…”

Section: Cfd Modelmentioning

confidence: 99%

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Characterizing the induced flow through the cavity of a wall solar chimney under the effects of the opening heights

Nguyen

2022

Journal of Building Physics

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Using solar chimneys in buildings can enhance the thermal insulation of the building envelope and provide sufficient ventilation and cooling. The performance of a solar chimney is strongly affected by its configurational factors. This work examines the effects of the opening heights on the flow field in the cavity of a wall solar chimney with a Computational Fluid Dynamics (CFD) model. Both cases of equal and unequal opening areas were considered. The results show that the induced flow rate increases with the opening height and gradually becomes constant as the opening height is about 2.0–3.0 and 5.0–6.0 times the air gap for heating the left wall (HLW) and the right wall (HRW) of the air cavity, respectively. Particularly, using equal inlet and outlet heights that are equal to the air gap reduces the flow rate of 27% for HLW and 85% for HRW compared to the maximum ones. The optimal design of a wall solar chimney to achieve maximum flow rate is proposed for two cases of heating, that is, (a) for HLW, equal opening heights which are twice the air gap, and (b) for RHW, the inlet height equal to the air gap, and the outlet height equal to five times the air gap.

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Section: Numerical Modelingmentioning

confidence: 99%

Section: Cfd Modelmentioning

confidence: 99%

Characterizing the induced flow through the cavity of a wall solar chimney under the effects of the opening heights

Nguyen

2022

Journal of Building Physics

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“…For assessing the ventilation performance of the configurations in Figure 1, the airflow rate in each case was computed with a model based on Computational Fluid Dynamics (CFD). CFD has been employed extensively for simulations of indoor air and ventilation [9,14,15,28,[32][33][34][35][36]. Following the CFD models for solar chimneys in the literature, a two-dimensional model was built with the following assumptions:…”

Section: Cfd Modelmentioning

confidence: 99%

“…Therefore, the RNG k − model was selected. Details of the formulations can be seen in [9,14,15,28,32,33,37].…”

Section: Cfd Modelmentioning

confidence: 99%

“…With a simple opening at the top of the room with one vertical wall heated, Marcias-Melo et al [27] showed that the most efficient case for removing heat was when the opening was on the top of the heated wall. To enhance the ventilation rate, Vazquez-Ruiz et al [28] added a solar chimney to the top of the room. Their results showed the highest ventilation rate was achieved with the chimney positioned nearest to the air inlet, which was on the wall perpendicular to the heated one.…”

Section: Introductionmentioning

confidence: 99%

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CFD Analysis of Different Ventilation Strategies for a Room with a Heated Wall

Nguyen

Tran

et al. 2022

Buildings

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Solar chimneys can help to reduce solar heat gain on a building envelope and to enhance natural ventilation. In this work, we proposed three configurations of two solar chimneys combined with a heated wall for the natural ventilation of a room: (I) the chimneys are connected serially, (II) the chimneys are parallel and exhaust air at two separate outlets, and (III) the chimneys are parallel, but the outlets are combined. The airflow rate achieved with each configuration was predicted with a Computational Fluid Dynamics model. The results show the effects of the heat flux in each channel and the geometries of the channels. Configuration (II) shows the highest flow rate. Particularly, the proposed configurations enhance the flow rate significantly and up to 40% when compared to the typical setup with a single channel solar chimney. The findings offer a novel design option for building façades for reducing solar heat gain and enhancing natural ventilation.

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