Study of Natural Ventilation Flow in a Room Fitted With a Solar Chimney

2012 ◽  
Author(s):  
K. Goriel ◽  
V. Avakian ◽  
B. P. Huynh
Keyword(s):  
Technological Innovation ◽  
Software Package ◽  
Natural Ventilation ◽  
Considerable Change ◽  
Test Rig ◽  
Solar Chimney ◽  
Natural Processes ◽  
Design And Implementation ◽  
The Past ◽  
Chimney Test

The past few decades have seen a considerable change in terms of technological innovation. The recent technological trend is a shift towards the incorporation of natural processes such as hydro, solar and wind in design and implementation. For the purpose of this report, a miniaturised solar chimney test rig was constructed which utilises the principles of natural ventilation. Analysis of similar types of technologies was conducted and various ideas considered in the construction of the test rig. Computational fluid dynamics software was also used in conjunction with the experiment to see the similarities associated with the experiment and software package, taking into account the limitation of various instruments. A comprehensive experimental and theoretical approach was developed and reported.

Concussion, neuroethics, and sport: Policies of the past do not suffice for the future

2017 ◽  
Author(s):  
Brad Partridge ◽  
Wayne Hall
Keyword(s):  
Mental Health ◽  
Head Trauma ◽  
Mental Health Problems ◽  
Ethical Issues ◽  
Cognitive Impairments ◽  
Concussion Management ◽  
Design And Implementation ◽  
The Past ◽  
Management Policies

Concussion management policies have become a major priority worldwide for sports that involve frequent collisions between participants because repeated head trauma has been associated with long-term cognitive impairments, mental health problems, and some forms of neurological degeneration. A number of concussion management policies have been developed by professional bodies and subsequently adopted by various sporting leagues. These have offered little guidance on how to navigate ethical issues in identifying and managing concussion. This chapter discusses ethical issues that arise in the diagnosis of concussion, debates about the longer-term consequences of repeated concussion injuries, and the design and implementation of policies that aim to prevent and manage concussion injuries in sporting matches.

scholarly journals Solar Chimney Applications in Buildings

Encyclopedia ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 409-422
Author(s):  
Haihua Zhang ◽  
Yao Tao ◽  
Long Shi
Keyword(s):  
Natural Ventilation ◽  
Energy System ◽  
Assisted Ventilation ◽  
Building Envelope ◽  
Building Structures ◽  
Solar Chimney ◽  
Climate Conditions ◽  
And Performance ◽  
Modern Building ◽  
Ventilation Systems

A solar chimney is a renewable energy system used to enhance the natural ventilation in a building based on solar and wind energy. It is one of the most representative solar-assisted passive ventilation systems attached to the building envelope. It performs exceptionally in enhancing natural ventilation and improving thermal comfort under certain climate conditions. The ventilation enhancement of solar chimneys has been widely studied numerically and experimentally. The assessment of solar chimney systems based on buoyancy ventilation relies heavily on the natural environment, experimental environment, and performance prediction methods, bringing great difficulties to quantitative analysis and parameterization research. With the increase in volume and complexity of modern building structures, current studies of solar chimneys have not yet obtained a unified design strategy and corresponding guidance. Meanwhile, combining a solar chimney with other passive ventilation systems has attracted much attention. The solar chimney-based integrated passive-assisted ventilation systems prolong the service life of an independent system and strengthen the ventilation ability for indoor cooling and heating. However, the progress is still slow regarding expanded applications and related research of solar chimneys in large volume and multi-layer buildings, and contradictory conclusions appear due to the inherent complexity of the system.

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.

Changing Profile of Congenital Heart Disease

PEDIATRICS ◽  
1989 ◽  
Vol 83 (5) ◽  
pp. 790-791
Author(s):  
D. WOODROW BENSON ◽  
James Moller ◽  
Donald C. Fyler ◽  
David E. Fixler
Keyword(s):  
Congenital Heart Disease ◽  
Heart Disease ◽  
Surgical Treatment ◽  
Congenital Heart ◽  
Considerable Change ◽  
Diagnostic Methods ◽  
Younger Patients ◽  
The Past ◽  
Steady Improvement ◽  
Complex Lesions

In the past 20 years, considerable change has occurred in the profile of congenital heart disease regarding both diagnosis and treatment. The profile has changed from older to younger patients; the essence of this change has been from pediatric to infant to neonatal cardiology. There has been a shift from palliative to more definitive surgical procedures and a change from invasive (cardiac catheterization) to noninvasive (echocardiography) diagnostic methods. The profile has changed from definitive surgical treatment limited to simple lesions to surgical treatment of the most complex lesions. There has been steady improvement in the recognition of cases of congenital heart disease. Of all children admitted to hospitals for treatment of congenital heart disease, the portion less than three days of age has increased from 24% in 1969 to 1972 to 33% in 1982 to 1986.

Small and Full-Scale Modeling for the Application of Wall Solar Chimneys

2016 ◽  
Author(s):  
David Park ◽  
Francine Battaglia
Keyword(s):  
Natural Ventilation ◽  
Velocity Ratio ◽  
Thermal Conditions ◽  
Ambient Air ◽  
Full Scale ◽  
Scale Model ◽  
Small Scale ◽  
Solar Chimney ◽  
Window Position ◽  
Pi Theorem

A solar chimney is a natural ventilation technique that has a potential to save energy consumption as well as to maintain the air quality in the building. However, studies of buildings are often challenging due to their large sizes. The objective of the current study was to determine relationships between small- and full-scale solar chimney system models. In the current work, computational fluid dynamics (CFD) was utilized to model different building sizes with a solar chimney system, where the computational model was validated with the experimental study of Mathur et al. The window, which controls entrainment of ambient air, was also studied to determine the effects of window position. Correlations for average velocity ratio and non-dimensional temperature were consistent regardless of window position. Buckingham pi theorem was employed to further non-dimensionalize the important variables. Regression analysis was conducted to develop a mathematical model to predict a relationship among all of the variables, where the model agreed well with simulation results with an error of 2.33%. The study demonstrated that the flow and thermal conditions in larger buildings can be predicted from the small-scale model.

Development of a Predictive Equation for Ventilation in a Wall-Solar Chimney System

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
David Park ◽  
Francine Battaglia
Keyword(s):  
Mathematical Model ◽  
Relative Error ◽  
Natural Ventilation ◽  
Thermal Conditions ◽  
Ambient Air ◽  
Maximum Error ◽  
Scale Model ◽  
Small Scale ◽  
Maximum Relative Error ◽  
Solar Chimney

A solar chimney is a natural ventilation technique that has potential to save energy consumption as well as to maintain the air quality in a building. However, studies of buildings are often challenging due to their large sizes. The objective of this study was to determine the relationships between small- and full-scale solar chimney system models. Computational fluid dynamics (CFD) was employed to model different building sizes with a wall-solar chimney utilizing a validated model. The window, which controls entrainment of ambient air for ventilation, was also studied to determine the effects of window position. A set of nondimensional parameters were identified to describe the important features of the chimney configuration, window configuration, temperature changes, and solar radiation. Regression analysis was employed to develop a mathematical model to predict velocity and air changes per hour, where the model agreed well with CFD results yielding a maximum relative error of 1.2% and with experiments for a maximum error of 3.1%. Additional wall-solar chimney data were tested using the mathematical model based on random conditions (e.g., geometry, solar intensity), and the overall relative error was less than 6%. The study demonstrated that the flow and thermal conditions in larger buildings can be predicted from the small-scale model, and that the newly developed mathematical equation can be used to predict ventilation conditions for a wall-solar chimney.

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