Application of a Wall-Solar Chimney for Passive Cooling of Dwellings

2015 ◽  
Author(s):  
David Park ◽  
Francine Battaglia
Keyword(s):  
Energy Consumption ◽  
Flow Regime ◽  
Thermal Condition ◽  
Natural Ventilation ◽  
Energy Use ◽  
Current Model ◽  
Numerical Data ◽  
Thermal Conditions ◽  
Air Gap ◽  
Solar Chimney

Energy consumption is an important issue and has become a great concern during last the few decades, where most energy consumption is utilized for conditioning buildings. The solar chimney is a natural ventilation technique that has the potential to save energy use in buildings as well as maintain comfortable indoor quality. The objective of the current study is to examine the effects of the wall-solar chimney on airflow distribution and thermal conditions in a room. In the current work, computational fluid dynamics was used to model a solar chimney. The time-dependent conservation equations for mass, momentum and energy were solved with the k-ε turbulence equations using ANSYS Fluent. Previous literature, that utilized numerical modeling to study the solar chimney for different dimensions of chimney geometry, only considered a two-dimensional solar chimney with one-directional heat transfer. In the current study, the solar chimney was modeled three-dimensionally for a more realistic simulation of actual flow and thermal condition of the room. Experimental and numerical data from literature were used to validate the current model, and the results agreed very well. The current study showed that the flow in the solar chimney system can be either laminar or turbulent depending on the parameters of the system, and that the effect of the chimney inlet is more significant than that of the air gap on the flow regime. This study also developed a new characteristic Rayleigh number Ra* relating the chimney inlet and the air gap, which showed good consistency with the prediction of the flow regime. The investigations on Ra* and the flow regime indicated that the flow becomes turbulent for Ra* ∼ 0.8 × 108. Lastly, the potential improvements of the designs were discussed by observing the flow and thermal condition of the room.

Application of a Wall-Solar Chimney for Passive Ventilation of Dwellings

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
David Park ◽  
Francine Battaglia
Keyword(s):  
Flow Regime ◽  
Natural Ventilation ◽  
Energy Use ◽  
Current Model ◽  
Numerical Data ◽  
Thermal Conditions ◽  
Solar Chimney ◽  
Airflow Distribution ◽  
Ventilation Technique ◽  
Save Energy

The solar chimney is a natural ventilation technique that has the potential to save energy use in buildings as well as maintain comfortable indoor quality. The objective of the current study was to examine the effects of the wall-solar chimney on airflow distribution and thermal conditions in a room. In the current work, computational fluid dynamics (CFD) was used to model a solar chimney. The solar chimney was modeled three-dimensionally for a more realistic simulation of fluid and thermal conditions. Experimental and numerical data from literature were used to validate the current model, and the results agreed very well. The current study showed that the flow in the solar chimney system can be either laminar or turbulent depending on the parameters of the system, and that the effect of the chimney inlet was more significant than that of the chimney width (air gap between the glass and absorber) on the flow regime. This study also developed a new characteristic Rayleigh number (Ra*) relating the chimney inlet and width, which showed good consistency with the prediction of the flow regime. The investigations of Ra* and the flow regime indicated that the flow becomes turbulent for Ra* ∼ 0.8 × 108. Finally, the potential improvements of the designs were discussed by observing the flow and thermal conditions of the room.

scholarly journals The Effect Of Outside Corridor’s Orientation to Interior Thermal Condition at Lawang Sewu Semarang.

2018 ◽  
Vol 73 ◽  
pp. 01011
Author(s):  
Benediktus Yosef Arya Wastunimpuna ◽  
Wahyu Setia Budi ◽  
Erni Setyowati
Keyword(s):  
Heat Stress ◽  
Relative Humidity ◽  
Thermal Condition ◽  
Natural Ventilation ◽  
Thermal Conditions ◽  
Standard Theory ◽  
Hot Wire ◽  
Air Movement ◽  
Dutch Colonial

The outside corridor of Dutch Colonial Building in Indonesia was made to make the temperature of the room more comfortable. Lawang Sewu Building in Semarang is one example of a building that has an outside corridor along the building and until now still use natural ventilation. This study focuses on finding out whether there is a difference on the thermal conditions of each room’s orientation, so after that we know the effect of orientation of the outdoor corridor to the temperature of the interior. In this study the experiment based on measurement using Heat Stress WBGT Meter for Wet Bulb Temperature, Dry Bulb Temperature, Relative Humidity, and KW0600653 Hot Wire Anemometer for the air movement. The data will be analysed using thermal standard theory to find out which point has the most comfortable thermal conditions.. At the end of this study will be found the effect of corridor’s orientation to thermal condition of the interior in Lawang Sewu Semarang.

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.

Effects of wall proximity on the airflow in a vertical solar chimney for natural ventilation of dwellings

2020 ◽  
Vol 44 (3) ◽  
pp. 225-250
Author(s):  
Y Quoc Nguyen ◽  
John Craig Wells
Keyword(s):  
Heat Source ◽  
Natural Ventilation ◽  
Vertical Wall ◽  
Air Gap ◽  
Horizontal Plate ◽  
Solar Chimney ◽  
Horizontal Wall ◽  
Induced Flow ◽  
Air Channel ◽  
Wall Proximity

This study investigates performance of a vertical solar chimney, which absorbs solar energy and induces airflow for natural ventilation and cooling of dwellings, under effects of walls neighboring to its air channel. A computational fluid dynamics model was developed to predict induced flow rate and thermal efficiency of a vertical solar chimney with four types of nearby walls: a vertical wall to which the solar chimney was attached, a horizontal plate above the outlet of the air channel, a horizontal plate, and a horizontal wall below the inlet of the air channel. Examined factors included the heat flux in the air channel, the chimney height, the air gap, the distance of the walls, and the location of the heat source in the air channel. The results showed that effects of the wall proximity were modulated by the location of the heat source and the ratio G/ H between the air gap and the chimney height. Particularly, performance of the chimney was enhanced when the heat source was on the opposite side of the vertical wall and when G/ H was large.

scholarly journals KONDISI TERMAL PADA PENGHAWAAN ALAMI DI RUANG TUNGGU UTAMA STASIUN SEMARANG TAWANG

2018 ◽  
Vol 2 (3) ◽  
pp. 144
Author(s):  
Hana Faza Surya Rusyda ◽  
Erni Setyowati ◽  
Gagoek Hardiman
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Research Method ◽  
Thermal Condition ◽  
Natural Ventilation ◽  
Thermal Conditions ◽  
Field Measurements ◽  
Waiting Room ◽  
Train Station ◽  
State Of Mind

Abstract:. Thermal comfort is a state of mind that expresses a user's satisfaction with thermal conditions. This study focuses on the design of natural ventilation which is one of the efforts to reduce the heat that exists in the building, especially in maintaining the thermal conditions. Tawang Train Station, Semarang has a natural ventilation design that is still maintained especially in the waiting room. This study aims to determine the thermal conditions of the design of ventilation using the theory of Mom and Wiseborn, SNI 03-6572-2001, and Olgyay chart. This research method uses quantitative and field measurements were done for 14 hours to know the movement of air, temperature, humidity. The results were then compared with the standard and the theory. It was found that thermal comfort conditions that still utilize the movement of the wind from natural ventilation in the main waiting room of Tawang Semarang Station.Keyword: Thermal Condition, Natural Ventilation, Semarang Tawang Station.Abstrak: Kenyamanan termal merupakan suatu kondisi pikir seseorang yang mengekspresikan kepuasan pengguna terhadap kondisi termal.  Penelitian ini berfokus pada desain penghawaan yang merupakan salah satu upaya mengurangi panas yang ada dalam bangunan terutama dalam menjaga kondisi termal. Stasiun Tawang Semarang, mempunyai desain penghawaan alami yang masih dipertahannkan terutama pada ruang tungguya. Penelitian ini  bertujuan untuk mengetahui kondisi termal dari desain penghawaan dengan menggunakan teori mom dan wiseborn, SNI 03-6572-2001, serta grafik olgyay. Metode penelitian ini menggunakan kuantitatif dan pengukuran dilapangan dilakukan selama 14 jam untuk mengetahui pergerakan udara, temperature, kelembaban. Hasil penelitian kemudian di bandingkan dengan standar SNI, Mom & Wiseborn dan Diagram Olgyay. Ditemukan bahwa kondisi kenyamanan termal yang masih memanfaatkan pergerakan angin dari ventilasi alami pada ruang tunggu utama Stasiun Semarang Tawang.Kata Kunci: Kondisi Termal, Ventilasi Alami, Ruang tunggu, Stasiun Semarang Tawang

Effects of Entrance Geometry on Solar Chimney’s Performance

2016 ◽  
Author(s):  
B. P. Huynh
Keyword(s):  
Energy Consumption ◽  
Turbulence Model ◽  
Energy Demand ◽  
Natural Ventilation ◽  
Computational Modelling ◽  
Good Health ◽  
Economic Benefits ◽  
Solar Chimney ◽  
Total Energy Consumption ◽  
3 Dimensional

People spend most of their time indoors. A comfortable indoor environment is thus essential for the occupants’ good health and productivity. Buildings are responsible for about half of a modern society’s total energy consumption. HVAC (Heating, Ventilation and Air-Conditioning) which is often used to provide thermal comfort to the occupants, in turn accounts for a major proportion of this energy demand. Minimising HVAC energy consumption will thus result in great economic benefits. It also contributes beneficially to the issue of sustainable future and climate change, by reducing fuel burning. Natural ventilation can be used to help reduce significantly HVAC energy demand. Solar chimney (thermal chimney) is a device which absorbs solar radiation to heat the air. The heated air, becoming buoyant, rises through the chimney’s passage and induces further air currents. When fitted to a building, solar chimney can thus induce fresh outside air to flow through it for ventilation. As a very useful ventilation device, solar chimney has been the subject of many studies. However, due to the complex non-laminar, non-isothermal flow and heat transfer involved, there are still many factors affecting a solar chimney’s performance (measured by the induced flow rate of air, for instance) not yet considered, especially regarding 3-dimensional computational modelling in real-sized building settings. This work thus investigates computationally natural ventilation induced by a roof-mounted solar chimney through a real-sized 3-dimensional room, using a commercial CFD (Computational Fluid Dynamics) software package which employs the Finite Volume Method. Chien’s turbulence model of low-Reynolds-number K-ε is used in a Reynolds Averaged Navier-Stokes (RANS) formulation. Thus, the full set of Reynolds-Averaged governing equations pertaining to non-isothermal, buoyancy induced, incompressible, steady, turbulent flow of air near standard conditions at sea level, coupled with equations describing the Chien’s turbulence model, are solved, with appropriate boundary conditions. No further simplifying assumptions are made. Grid convergence tests are conducted to make sure that the grid patterns used are appropriate. Adequate numerical convergence is allowed; this often requires that relative changes in the successive iterated solutions be less than 0.0001. Accumulation errors resulting from massive or lengthy computation are also carefully monitored and minimized. 64-bits precision is used throughout. It is found that entrance geometry to the chimney’s channel affects significantly the ventilation rate, especially at higher solar heat flux, with rounded entrance resulting in higher rate. But these entrance-geometry effects also vary significantly with location of the room’s inlet-opening which in its turn affects the flow path before the chimney’s entrance.

The Numerical Simulation of Using the Solar Chimney Strengthen Natural Ventilation

2012 ◽  
Vol 512-515 ◽  
pp. 307-310 ◽  
Author(s):  
Han Bing Qi ◽  
Qiu Shi Wang ◽  
Dong Li ◽  
Hao Ran Bai
Keyword(s):  
Energy Consumption ◽  
Indoor Air ◽  
Time Use ◽  
Natural Ventilation ◽  
Building Energy ◽  
Practical Application ◽  
Solar Chimney ◽  
Energy Saving Potential ◽  
Fluent Software ◽  
Building Ventilation

Our country building energy consumption is amazing, building ventilation energy consumption is about more than 20% of the whole energy consumption , its energy saving potential is very great, How to reduce ventilation energy consumption and still keep good indoor air quality, makes the indoor natural ventilation ways becoming the focus of attention. This paper studies the solar chimney，one of ways of solar strengthening natural ventilation，strengthening natural ventilation；At the same time use FLUENT software simulate solar chimney model，Analysis the calculated results, get a reasonable solar chimney thickness and the air flow to meet the indoor ventilated requirements, so as to provide theoretical basis for the practical application.

scholarly journals Energy use in Building Envelope of a Residential Apartment Building in the Warm and Humid Climate of Guwahati, Assam

2020 ◽  
Vol 9 (11) ◽  
pp. 119-126
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Inner City ◽  
Urban Design ◽  
Urban Growth ◽  
Natural Ventilation ◽  
Energy Use ◽  
Building Envelope ◽  
Apartment Building ◽  
Heat Gain

In recent years, Guwahati city is witnessing a rapid urban growth due to ever-increasing human population sacrificing existing green pockets. This constant increase of built form is resulting in environmental imbalances and microclimate changes, contributing in a rise of indoor air temperature and that ultimately results a gradual increase in the energy consumption to maintain indoor thermal comfort in the inner-city areas. Although the urban growth pattern of Guwahati is controlled by prevailing GMDA building bye-laws, these building parameters are unable to control the organic growth of the city since there is no climate-sensitive approach available in the GMDA bye-laws. This paper aims to discuss the energy use in the building envelope by analysing the energy efficiency of a residential apartment building of Guwahati and reviews most common energy efficient codes that influences the heat gain or loss, natural ventilation, and day lighting, which, in turn, determines indoor temperatures, thermal comfort, and sensible cooling or heating demand inside urban residential buildings. Four relationships of building parameters are studied and analysed their impact on energy use. The amount of heat gain or loss, natural ventilation and day lighting that are allowed by building envelop will be calculated for each relationships and compared. All the relationships specify building envelope design that helps to improve the energy efficiency in residential building, but none suggested a basis for its proportion. This paper analyses the use of daylight and natural ventilation within a building envelope helps to minimise the energy consumption. A climate conscious urban design approach associating common energy codes such as window to floor area (WFR) ratio, Visual light transmittance (VLT) and residential envelope transmittance value (RETV) against average daylight and natural ventilation can be utilised as preliminary urban design techniques in development control regulations especially in the residential zones in the inner-city areas of Guwahati metropolitan development authority (GMDA).

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