Heat transfer enhancement of natural convection inside the inclined solar chimneys is investigated using electrohydrodynamic technique. The interactions between electric field, flow field, and temperature field are analyzed. The ranges of parameters considered are 10(4)<= Ra <= 10(7), 7.5kV <= V-0 <= 17.5 kV, 30 degrees <=theta <= 120 degrees, and 2 <= aspect ratio <= 14. Flow and heat transfer enhancements are significantly influenced at low Rayleigh number. The optimum inclined angle which obtains maximum volume flow rate and heat transfer is found to be at theta = 60 degrees. A maximum volume flow rate enhancement is expressed in relation with the number of electrodes. The relation between aspect ratio of chimney and number of electrodes that performs the optimum condition between efficiency and economy is analyzed incorporating with all concerning parameters. (C) 2007 Elsevier Ltd. All rights reserved.