Experimental and numerical investigation of a roof-scale solar chimney

This paper reports on an experimental investigation of the flow through the collector of a solar chimney power plant which has been constructed on the roof of the Aerospace and Mechanical Engineering building at the University of Arizona. This model contains a central chimney which is a long tubular structure located in the center, and a circular collector that employs the greenhouse effect to heat up the air under it. The chimney is 5.9m high and the collector radius measured from the center of the chimney is 4.13m. Measurements were carried out from April to June 2019. Several types of J thermocouples were mounted inside the collector at various radial locations to measure the air temperature both near the ground and the ceiling of the collector. A hot-wire probe (anemometer) was employed to measure the airflow velocity under the collector near the chimney inlet. A traverse system was designed and constructed, which allows the anemometer to be moved in the radial and circumferential direction under the collector. The height of the probe position above the collector ground can be adjusted by rotating the probe support along its longitudinal axis. A digital analog conversion system was used to convert the thermocouple and hot-wire readouts into binary data for processing via a LabVIEW interface. In parallel to the experiments, high-fidelity numerical simulations are being carried out for the conditions of the experiments. The simulations show longitudinal flow structures near the collector outflow that likely result from a buoyancy driven instability.