Improving thermal performance and air flow inside the solar chimney by CFD simulation

Document Type : Original Article

Authors

Department of Architecture, Faculty of Engineering, Assiut University, Assiut 71515, Egypt

Abstract

 University buildings require a study environment prepared for students that
helps improve student concentration and academic achievement, as the most
important thing that may help improve thermal comfort is sufficient ventilation of
the space and an appropriate temperature. Solar chimneys play a major role in
improving thermal comfort for university spaces. The research dealt with the design
of eight Solar chimneys on the southern facade of a classroom in the university
campus in Sohag, Arab Republic of Egypt, to achieve the maximum indoor air
velocity and the lowest temperature during the summer, with a special focus on
thermal comfort for students, as the ANSYS program was used to simulate and
analyse air movement, fluid flow, temperature distribution, and electromagnetic
efficiency, and the study of other effects over time. A 3D model of the hall was
created using Solid Work, and a solar chimney was proposed using PCM panels to
achieve the best passive ventilation. First, the CFD numerical analyses were
performed within the ANSYS program to test the best solar chimney dimensions
and compare the results with field measurements. (DOE) experiments were
conducted on two fixed dimensions with chimney widths 20 cm and 40 cm, with
testing the chimney entrance openings of 20 cm x 20 cm and 40 cm x 40 cm and
testing the internal temperature and air velocity in the hall over the study months in
summer and winter and understanding the mechanism. The physical phenomenon
of atmospheric buoyancy. The experiments also included the design of a solar
chimney with a 45-degree inclined roof attached to a runway without considering
the humidity factor. for the effect of wind speed in a vacuum with a deviation (RMS)
of 0.8% between the two values. Runway temperatures were reduced by 2.5°C by  a solar chimney and results of an improved solar chimney design to enhance indoor
air movement, optimization results also showed that maximum indoor air velocity
in the runway area is achieved by using a 20x80 chimney with 20x20 void and
opening western windows in this case study. A solar panel with a height of 4 meters,
a width of 0.8 meters, an inclination of 45 degrees, and an air gap of 0.2 meters.
The proposed solar chimney and its advantages deserve further research. Based on
this innovative concept, the solar chimney on the south façade can be redesigned,
PCM panels assembled, the chimney width changed and the number of air intake
holes in the chimney increased to form an efficient solar chimney, to serve as
passive ventilation without much cost and make full use of solar energy., then
reaching the maximum internal wind speed of the vacuum achieving thermal
comfort by changing several parameters of the chimney.

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MSA Engineering Journal
Volume 2, Issue 2 - Serial Number 6
Special issue for Artificial Intelligence & Sustainable Engineering
March 2023
Pages 1245-1277

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