Investigation of buoyancy air flow inside solar chimney using CFD technique

2010 ◽  
Author(s):  
P Somsila ◽  
U Teeboonma ◽  
W Seehanam
Keyword(s):  
Air Flow ◽  
Solar Chimney

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.

Enhancement of Gravity Ventilation in Buildings

2017 ◽  
Author(s):  
Magdalena Nakielska ◽  
Krzysztof Pawłowski
Keyword(s):  
Natural Ventilation ◽  
Air Flow ◽  
Electrical Energy ◽  
Climatic Conditions ◽  
Demand Systems ◽  
Solar Chimney ◽  
Correct Operation ◽  
Research Results ◽  
Heat Demand ◽  
Flow Through

Nowadays, people are looking for solutions related to ventilation, cooling or heat demand systems, which would be energy efficient and, at the same time, would not cause the degradation of the surrounding environment. As far as ventilation is concerned, an good solution is a natural ventilation, which improves thermal comfort rooms without increasing the consumption of electrical energy in the building. In order to improve the mode of action of the natural ventilation in the building, one can mount various elements supporting the air flow. One of them is a solar chimney. In order to check the correct operation of a gravity ventilation installation in Poland’s climatic conditions, the measurements was carried out on a test stand on the 3.1 building of UTP University of Science and Technology in Bydgoszcz. The received results show the intensification of the air flow through the room the value between 50% and 150%, depending on a measuring hour (Chen et al. 2003). These research results were compared with the research results received before the installation of the solar chimney on the ducts of the gravity ventilation.

Virtual Height Aided Solar Chimney: A New Design

2011 ◽  
Author(s):  
Khaled I. E. Ahmed ◽  
Ali K. Abdel-Rahman ◽  
Mahmoud Ahmed ◽  
Wael M. Khairaldien
Keyword(s):  
Electric Power ◽  
Co2 Emissions ◽  
Conversion Efficiency ◽  
Numerical Study ◽  
Air Flow ◽  
Flow Speed ◽  
Numerical Results ◽  
Solar Chimney ◽  
Virtual Height ◽  
Wide Range

Renewable energy source deployment is growing rapidly as it reduces CO2 emissions and increases diversity and security of supply. Solar chimney (SC) is a promising large-scale power technology, which absorbs solar radiation and converts parts of solar energy into electric power free of CO2 emissions. A major problem of Solar Chimney Power Plant (SCPP) is its low conversion efficiency as determined by the thermal performance of the system. However, the conversion efficiency of SCPP significantly increases with the SC height increase. The current paper proposes a new design of a virtual height aided solar chimney. In this new system the solar chimney is aided with a passive cooling system at the top of the chimney and a passive solar heater at its base to virtually mimic larger heights of the chimney. The new design has been simulated numerically for development and optimization. The numerical study is done in two stages to examine this concept. In the first stage, numerical results are obtained for the effect of the chimney height on the inside air flow speed. Then, in the second stage, the effect of decreasing the temperature at the chimney exit and the effect of increasing the temperature at the chimney base on the air flow speed are examined separately for small chimney heights. Then the combined effect of the two actions is investigated at a wide range of chimney heights. The numerical results have shown that the localized base heating and exit cooling have significantly enhanced the chimney performance for chimney heights up to 500m. A chimney with height of 300m gains an increase in the air velocity more than 25% due to the heating and cooling actions. Virtual height aided Chimney with original height of 300m acts similarly to a conventional chimney with height of 500m due to the effect of base heating and exit cooling actions. This air flow velocity increase reflects 100% increase in the expected generated electric power. Further detailed results are presented and discussed.

Effect of the number of turbine blades on the air flow within a solar chimney power plant

2017 ◽  
Vol 232 (4) ◽  
pp. 425-436 ◽  
Author(s):  
Ahmed Ayadi ◽  
Zied Driss ◽  
Abdallah Bouabidi ◽  
Mohamed Salah Abid
Keyword(s):  
Power Plant ◽  
Kinetic Energy ◽  
Power Plants ◽  
Turbulent Viscosity ◽  
Air Flow ◽  
Turbine Blades ◽  
Electrical Power ◽  
Thermal Characteristics ◽  
Solar Chimney ◽  
Solar Chimney Power Plant

Solar chimney power plants generate thermal heat and electrical power using the radiation from sun. These systems are characterized by their high costs. In fact, it is required to optimize the components of the solar system such as the collector, the chimney, the absorber, and the turbine. This paper focuses on the effect of the number of turbine blades on the air flow within a small prototype of a solar chimney power plant. Four configurations with different turbine blades are proposed to study the effect of the turbine blades number on the thermal characteristics of a solar chimney power plant. For each configuration, the distribution of the magnitude velocity, the air temperature, the pressure, the turbulent kinetic energy, and the turbulent viscosity are presented and discussed. This paper is identified to be of interest for engineers and designers for increasing the power output of a solar chimney power plant.

A Study of Solar Panel Chimney for House Ventilation

2013 ◽  
Vol 422 ◽  
pp. 118-122 ◽  
Author(s):  
Song Hao Wang ◽  
Chih Sheng ◽  
Huann Ming Chou ◽  
Edgar J. Tobias Corado
Keyword(s):  
Solar Power ◽  
Physical Mechanism ◽  
Air Flow ◽  
Ventilation System ◽  
Solar Panel ◽  
Solar Panels ◽  
Solar Chimney ◽  
Flow Rates ◽  
Dimensional Parameters ◽  
Innovative Concept

A concept of solar chimney utilizing solar panels for building passive ventilation is proposed in this paper. First, CFD Numerical analyses were conducted to test the feasibility. Major dimensional parameters were considered in the simulation and meaningful air flow rates were observed under normal conditions. Experiments were conducted to confirm the concept and to understand the physical mechanism of the phenomenon by air buoyancy. Based on the results of the study, the proposed solar panel chimney and its advantages are worth of further investigation. Based on this innovative concept, the rooftop solar panel could be re-arranged, grouped and boxed to form an effective solar panel chimney, to serve as passive ventilation system without much cost and fully utilize the solar power.

Design, Construction, and Testing of a Small Scale Solar Chimney for Nomadic Herdsmen

2012 ◽  
Author(s):  
Ryan D. Chappell ◽  
Michael J. Congdon ◽  
Jesse J. French
Keyword(s):  
Air Flow ◽  
Electrical Power ◽  
Peak Performance ◽  
Small Scale ◽  
Solar Chimney ◽  
Performance Variables ◽  
Northern Mongolia ◽  
Nomadic People ◽  
Published Research ◽  
Design Construction

The basic solar chimney concept remains largely unchanged since being proposed nearly a century ago. The air inside a collector heats up, and becomes less dense and begins rising toward the center of the collector as the covering is sloped upward towards a centrally located chimney. Heat and air flow increases as it moves toward the chimney. When a turbine is placed in this chimney, electricity can be generated from the air flow. Using previously published research [1] on small scale solar chimneys, the authors designed and fabricated a small scale solar chimney. Performance variables were optimized to achieve peak performance and theoretical electrical output. The solar chimney was designed to achieve low material cost, and minimal maintenance effort without the use of heavy machinery. The solar chimney designed by the authors was constructed and tested for implementation in remote regions where land space is practically unrestricted and electrical power is desired for lighting and communication. The project team conducted an assessment of one likely location for this solar chimney in Northern Mongolia during the summer of 2011. There are nomadic people groups who do not have electrical power but have vast amounts of land at their disposal. The solar chimney is a potential source of electricity for these people groups, as it was also designed to be transportable, lightweight, and inexpensive.

Effect of Inlet Location on Ventilation Flow Through a Room Fitted With Solar Chimney

2018 ◽  
Author(s):  
Kashif Nazir ◽  
B. P. Huynh
Keyword(s):  
Solar Radiation ◽  
Flow Pattern ◽  
Natural Ventilation ◽  
Air Flow ◽  
Ventilation Rate ◽  
Navier Stokes ◽  
Computational Domain ◽  
Solar Chimney ◽  
Flow Through ◽  
Inlet Opening

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 the building for ventilation. Because only natural means (solar radiation here) are involved to cause the air flow, solar chimney is considered a natural-ventilation device. This work 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. Computational domain that includes regions outside the room’s inlet opening and chimney’s exit allows for employing realistic boundary conditions for the computational model. Ventilation rate and air-flow pattern through the room are considered in terms of the location of the room’s inlet opening. It is found that while ventilation flow-rate through the room is higher with the room-inlet opening being located high on the wall opposite to the chimney’s entrance, a room-inlet opening being located near the ground results in better flow pattern with more flow through the living area in the lower part of the room.

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