Investigation on the Performance of a Trombe Wall Driven by Thermal Pressure

2012 ◽  
Vol 614-615 ◽  
pp. 200-203
Author(s):  
Jun Qin Hou ◽  
Yong Gang Lei ◽  
Fei Wang ◽  
Xun Wang
Keyword(s):  
Numerical Simulation ◽  
Heat Flux ◽  
Heat Flow ◽  
Natural Ventilation ◽  
Ventilation Rate ◽  
Thermal Pressure ◽  
Wall Width ◽  
Trombe Wall ◽  
Ventilation Performance

Numerical simulation was carried out for the ventilation performance of a Trombe wall driven by thermal pressure. The effect of heat flux, the wall width and height to the indoor ventilation were analyzed and discussed. The results show that the increase of heat flow and the height of wall cause the increase of natural ventilation rate while the increase of width cause the increase of ventilation and then deceasing.

Natural-Ventilation Flow in a 3-D Room Fitted With Solar Chimney

2012 ◽  
Author(s):  
B. P. Huynh
Keyword(s):  
Heat Flux ◽  
Flow Pattern ◽  
Natural Ventilation ◽  
Air Flow ◽  
Ventilation Rate ◽  
High Heat Flux ◽  
Solar Chimney ◽  
Solar Heat ◽  
Solar Heat Flux ◽  
Inlet Opening

Natural-ventilation flow induced in a real-sized rectangular-box room fitted with a solar chimney on its roof is investigated numerically, using a commercial CFD (Computational Fluid Dynamics) software package. The chimney in turn is in the form of a parallel channel with one plate being subjected to uniform solar heat flux. Ventilation rate and air-flow pattern through the room are considered in terms of the heat flux for two different locations of the room’s inlet opening. Chien’s turbulence model of low-Reynolds-number K-ε is used in a Reynolds-Averaged Navier-Stokes (RANS) formulation. It is found that ventilation flow rate increases quickly with solar heat flux when this flux is low, but more gradually at higher flux. At low heat flux, ventilation rate is not significantly affected by location of the inlet opening to the room. On the other hand, at high heat flux, ventilation rate varies substantially with the opening’s location. Location of the inlet opening to the room also affects strongly the air-flow pattern. In any case, ample ventilation rate is readily induced by the chimney.

scholarly journals Effects of Lateral Window Position and Wind Direction on Wind-Driven Natural Cross Ventilation of a Building: A Computational Approach

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
M. Z. I. Bangalee ◽  
J. J. Miau ◽  
S. Y. Lin ◽  
M. Ferdows
Keyword(s):  
Wind Direction ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Ventilation Rate ◽  
Experimental Investigations ◽  
Original Design ◽  
Lateral Direction ◽  
Window Position ◽  
Ventilation Performance ◽  
Moderate Range

Energy is saved when an effective natural ventilation system can provide comfort air to the occupants in a building by replacing a mechanical ventilation system. It also minimizes the risk of the environmental pollution and the global warming. A one story, full scale building was considered to carry out a comparative study of three different cases of wind-driven natural (WDN) cross ventilation with the help of computational fluid dynamics (CFD). In each case, the location of window was changed in lateral direction to predict the probable position for optimum ventilation performance and the angle of wind was varied to check the sensitivity of the wind direction on the flow field. After validating the current methodology through two satisfactory comparisons with the experimental investigations, the governing equations subjected to the corresponding boundary conditions were solved using commercial software and then the results were analyzed. A better location for the windows in each case was proposed. The ventilation purpose was served quite well even if the wind angle was changed in a moderate range from the original design. Furthermore, the velocity components, ventilation rate, surface pressure, ventilation time, and so forth in each case were investigated and compared extensively with those in other cases.

scholarly journals A Grey Box Modeling Method for Fast Predicting Buoyancy-Driven Natural Ventilation Rates through Multi-Opening Atriums

2019 ◽  
Vol 11 (12) ◽  
pp. 3239 ◽  
Author(s):  
Peng Xue ◽  
Zhengtao Ai ◽  
Dongjin Cui ◽  
Wei Wang
Keyword(s):  
Natural Ventilation ◽  
Simulated Data ◽  
Ventilation Rate ◽  
Modeling Method ◽  
Predictive Equation ◽  
Evaluation Time ◽  
Ventilation Performance ◽  
Ventilation Rates ◽  
Semi Empirical ◽  
Key Parameter

The utilization of buoyancy-driven natural ventilation in atrium buildings during transitional seasons helps create a healthy and comfortable indoor environment by bringing fresh air indoors. Among other factors, the air flow rate is a key parameter determining the ventilation performance of an atrium. In this study, a grey box modeling method is proposed and a prediction model is built for calculating the buoyancy-driven ventilation rate using three openings. This model developed from Bruce’s neutral height-based formulation and conservation laws is supported with a theoretical structure and determined with 7 independent variables and 4 integrated parameters. The integrated parameters could be estimated from a set of simulated data and in the results, the error of the semi-empirical predictive equation derived from CFD (computational fluid dynamics) simulated data is controlled within 10%, which indicates that a reliable predictive equation could be established with a rather small dataset. This modeling method has been validated with CFD simulated data, and it can be applied extensively to similar buildings for designing an expected ventilation rate. The simplicity of this grey box modeling should save the evaluation time for new cases and help designers to estimate the ventilation performance and choose building optimal opening designs.

Modeling of Natural Ventilation in Built-in Photovoltaic-Trombe Wall

2013 ◽  
Vol 448-453 ◽  
pp. 1537-1541 ◽  
Author(s):  
Xiao Wei Xu ◽  
Ya Xin Su
Keyword(s):  
Solar Radiation ◽  
Natural Ventilation ◽  
Reverse Flow ◽  
Volume Flow Rate ◽  
Ventilation Rate ◽  
Volume Flow ◽  
Channel Width ◽  
Air Volume ◽  
Trombe Wall ◽  
Cfd Method

The natural ventilation in a novel built-in photovoltaic-Trombe wall (BiPV-TW) was numerically simulated by CFD method. The effect of solar radiation and channel width on the airflow pattern and ventilation rate was analyzed. Results showed that the solar radiation and channel width influenced the ventilation rate remarkably. As the solar radiation increased, the ventilation rate increased. As the channel width increased from 0.1m to 0.4m, the ventilation rate monotonously increased. However, when the channel width exceeded 0.5m, the reverse flow was formed in the tope zone and the ventilation rate decreased. A maximum air volume flow rate was achieved when the channel width was approximately equal to 0.4m in a 3m tall model.

scholarly journals Ventilation Characteristics and Performance Evaluation of Different Window-Opening Forms in a Typical Office Room

2021 ◽  
Vol 11 (19) ◽  
pp. 8966
Author(s):  
Yuanyuan Wang ◽  
Yanzhe Yu ◽  
Tianzhen Ye ◽  
Quan Bo
Keyword(s):  
Thermal Comfort ◽  
Natural Ventilation ◽  
Cfd Simulation ◽  
Thermal Sensation ◽  
Ventilation Rate ◽  
Window Opening ◽  
Ventilation Modes ◽  
Ventilation Performance ◽  
Scale Experiment ◽  
And Performance

As most existing office buildings in China lack fresh air systems for ventilation, natural ventilation with windows remains the main means of improving indoor air quality and adjusting indoor thermal comfort. However, knowledge of the ventilation characteristics of various window-opening forms in actual buildings is limited and current methods for evaluating ventilation performance lack a comprehensive consideration of ventilation rate and thermal comfort. In this study, the ventilation characteristics of different window-opening forms were systematically compared by conducting computational fluid dynamics (CFD) simulations. A full-scale experiment was conducted in a typical office room in a university in Tianjin to validate the CFD simulation. Two ventilation modes (wind-driven cross-ventilation and temperature-driven single-sided ventilation), three window-opening angles, and seven window types were investigated. Additionally, the ratio of the ventilation rate to the absolute value of thermal sensation was used to quantify the indoor natural-ventilation performance. The results showed that a sliding window with a full opening has the highest discharge coefficients of 0.68 and 0.52 under wind-driven cross-ventilation and temperature-driven single-sided ventilation, respectively, and top-hung windows opening both inwards and outwards have better ventilation performance than other window types under the two ventilation modes. This study is applicable to the design and practice of natural ventilation.

The impacts of introducing voids combinations on indoor ventilation performance in high-rise residential buildings

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hamza Laloui ◽  
Noor Hanita Abdul Majid ◽  
Aliyah Nur Zafirah Sanusi
Keyword(s):  
Architectural Design ◽  
Natural Ventilation ◽  
Residential Buildings ◽  
Design Feature ◽  
Field Measurements ◽  
Ventilation Rate ◽  
Content Type ◽  
High Rise ◽  
Building Models ◽  
Ventilation Performance

PurposeThe paper aims to investigate and evaluate the impacts of the voids combination as a passive design feature on wind-driven ventilation performance in high-rise residential building units. It proposes a series of building models and thereon indoor ventilation performance and outlining why and how these building models designed with architectural design features are important. This study aims to provide a comprehensive understanding of how natural ventilation as a passive cooling strategy in living units of high-rise residential buildings can be applied through improving the provision of the architectural design feature of voids configurations.Design/methodology/approachThe study was carried out through field measurements experiment and the computational fluid dynamics methods. A series of numerical simulations were carried out to calculate the indoor ventilation rate inside the case studies of the generated building models based on various variables such as horizontal voids type, size and wind directions.FindingsThe results indicate that the provision of a single-sided horizontal voids in building models can improve the indoor ventilation rate in units with cross ventilation mode up to 4 times, depending on wind direction and living unit location. The indoor ventilation performance in units located in models with single-sided horizontal voids is 17.54% higher than the units located in models without voids configuration. Furthermore, higher indoor ventilation performance was achieved in the case scenarios located at higher levels compared to the middle and lower levels in both horizontal voids types.Originality/valueThis study explores the application of voids combinations for natural ventilation performance, investigates the numerical simulation results and validates field measurements experiment data using CFD simulation.

Analysis of Natural Ventilation Efficiency of a Passive Solar Chimney in a Conference Hall of the Magic School of Green Technology

2013 ◽  
Vol 368-370 ◽  
pp. 603-606 ◽  
Author(s):  
Chun Han Chien ◽  
Hsien Te Lin
Keyword(s):  
Natural Ventilation ◽  
Ventilation Rate ◽  
Green Technology ◽  
Solar Chimney ◽  
Air Exchange Rate ◽  
Ventilation Efficiency ◽  
Air Ventilation ◽  
Passive Solar ◽  
Ventilation Performance ◽  
Air Exchange

This study focuses on the efficiency of passive solar chimney in natural ventilation performance of the conference hall at the Magic School of Green Technology (MSGT) in Tainan, Taiwan. The air exchange rate in the conference hall was between 5.73 ACH and 9.11 ACH, which exceeded the minimum air ventilation rate required in Taiwan. This shows that a passive solar chimney can effectively applied to the conference hall to meet indoor ventilation and air exchange requirements without using air conditioning.

scholarly journals EVALUATION OF NATURAL VENTILATION RATE BY FIELD MEASUREMENT AND NUMERICAL SIMULATION DURING PRE-ACCEPTANCE PHASE

2012 ◽  
Vol 77 (678) ◽  
pp. 681-688
Author(s):  
Ryuichi YASUNAGA ◽  
Yumi ASHITANI ◽  
Yasuyuki SHIRAISHI ◽  
Yoshie UCHIKAWA ◽  
Yasushi NAKAMURA
Keyword(s):  
Numerical Simulation ◽  
Field Measurement ◽  
Natural Ventilation ◽  
Ventilation Rate

scholarly journals Contrastive Analysis on the Ventilation Performance of a Combined Solar Chimney

2021 ◽  
Vol 12 (1) ◽  
pp. 156
Author(s):  
Huifang Liu ◽  
Peijia Li ◽  
Bendong Yu ◽  
Mingyi Zhang ◽  
Qianli Tan ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Indoor Air ◽  
Natural Ventilation ◽  
Optimal Operation ◽  
Solar Chimney ◽  
Temperature Ranges ◽  
Trombe Wall ◽  
Ventilation Performance ◽  
Heating Mode ◽  
Better Than

A combined solar chimney is proposed in this paper that integrates an inclined-roof solar chimney with a traditional Trombe wall. The ventilation performance of the combined solar chimney is analyzed numerically and then compared with the Trombe wall and the inclined-roof solar chimney. The feasibility of different operation modes and the ventilation effect under different environment conditions are also discussed. The results show that when the ambient temperature ranges from 298 to 303 K in the summer, a natural ventilation mode is appropriate. Otherwise, an anti-overheating mode is recommended. When the ambient temperature is lower than 273 K in the winter, a space heating mode has a better heating effect. A preheating mode can be employed to improve the indoor air quality when the ambient temperature is higher than 278 K. The simulation results indicates that the ventilation effect of the combined solar chimney is better than that of the Trombe wall and the inclined-roof solar chimney, and the problem of overheating can be avoided. The study provides guidance for the optimal operation of a combined solar chimney.

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