Summary
A cheap rooftop-scale solar updraft prototype, using a polythene collector cover over a tarred concrete base and a PVC tower, was built and monitored in winter. Mean electrical output stayed between 3 and 20 W, with efficiency peaking around 0.11%; the authors blame weak winter irradiance and the small plant size, while stressing negligible build cost and zero running cost.
Description written by Solar Tower. The original abstract is available from the publisher via the link below.