Laboratory experiment and numerical analysis of a new type of solar tower efficiently generating a thermal updraft

Yuji Ohya, Masaki Wataka, Koichi Watanabe, Takanori Uchida

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

A new type of solar tower was developed through laboratory experiments and numerical analyses. The solar tower mainly consists of three components. The transparent collector area is an aboveground glass roof, with increasing height toward the center. Attached to the center of the inside of the collector is a vertical tower within which a wind turbine is mounted at the lower entry to the tower. When solar radiation heats the ground through the glass roof, ascending warm air is guided to the center and into the tower. A solar tower that can generate electricity using a simple structure that enables easy and less costly maintenance has considerable advantages. However, conversion efficiency from sunshine energy to mechanical turbine energy is very low. Aiming to improve this efficiency, the research project developed a diffuser-type tower instead of a cylindrical tower, and investigated a suitable diffuser shape for practical use. After changing the tower height and diffuser open angle, with a temperature difference between the ambient air aloft and within the collector, various diffuser tower shapes were tested by laboratory experiments and numerical analyses. As a result, it was found that a diffuser tower with a semi-open angle of 4° is an optimal shape, producing the fastest updraft at each temperature difference in both the laboratory experiments and numerical analyses. The relationships between thermal updraft speed and temperature difference and/or tower height were confirmed. It was found that the thermal updraft velocity is proportional to the square root of the tower height and/or temperature difference.

Original languageEnglish
Article number1077
JournalEnergies
Volume9
Issue number12
DOIs
Publication statusPublished - Dec 1 2016

Fingerprint

Diffuser
Towers
Numerical analysis
Numerical Analysis
Experiment
Experiments
Angle
Optimal Shape
Solar Radiation
Wind Turbine
Turbine
Energy
Electricity
Square root
Maintenance
Heat
Directly proportional
Vertical
Hot Temperature
Roofs

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Energy (miscellaneous)
  • Control and Optimization
  • Electrical and Electronic Engineering

Cite this

Laboratory experiment and numerical analysis of a new type of solar tower efficiently generating a thermal updraft. / Ohya, Yuji; Wataka, Masaki; Watanabe, Koichi; Uchida, Takanori.

In: Energies, Vol. 9, No. 12, 1077, 01.12.2016.

Research output: Contribution to journalArticle

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