Computational and experimental studies on solar chimney power plants for power generation in Pacific Island countries

Abstract

Computational and experimental studies were performed on solar chimney power plants (SCPP). The first part of the work was optimization of the geometry of the major components of an SCPP of 10m height and 8m collector diameter using a computational fluid dynamics (CFD) code ANSYS-CFX to study and improve the flow characteristics inside the SCPP. The collector inlet opening, the collector outlet height, the collector outlet diameter, the chimney divergence angle, chimney inlet opening and the diameter of the chimney were varied and optimum values that give the highest power were obtained. Based on the best configuration achieved for the 10m high SCPP, a scaled down model of 1:2.5 was modeled and simulated. The 4m tall SCPP had a collector diameter of 3.2m. The collector outlet height was kept constant while the collector outlet diameter and the chimney throat diameter were varied in the second part. The collector inlet opening was also varied. The best configuration was then fabricated and extensive experiments were carried out on days of different solar insolations with and without water bags including the effect of atmospheric wind as the third and main part of this work. Detailed measurements of temperature variations along the collector and along the chimney height were performed. The air velocity at the location of turbine was measured and the power available to the turbine was estimated. It was found that, at higher wind speeds, the temperatures along the collector and along the chimney height drop a little; however, the air velocity and available power increase. Water bags were placed under the collector to obtain round-the-clock power. A 100m SCPP was later modeled and simulated to predict the power available for bigger sized towers at different solar insolations. Such SCPP plants will be very appropriate for Pacific Island Countries; most of these countries have islands with populations of only a few hundred people. Also, the solar insolation is very high in these countries.