A porous combustor-heater (PCH) with cyclic flow reversal combustion (CFRC) was investigated on the basis of simulation for practical applications. Emphasis was placed on determination of the optimal switching period under which the system will offer a high thermal efficiency with low emissions. It was shown that by using the CFRC thermal performance, emissions are strongly affected by the switching period through the interaction of the hot zone movement within the reactor and by heat transfer to the tube bank. An optimal switching period of about 120-180 s was found with maximum thermal efficiency to be as high as 85% with low emissions of CO and NO(x) of 200 and 20 ppm, respectively. The CFRC system yields higher thermal efficiency with higher combustion efficiencies than the unidirectional steady state regime at the same experimental conditions. (C) 2008 Elsevier Ltd. All rights reserved.