Electrohydrodynamic (EHD) devices show many advantages over classical ones and have found wide application in various fields of engineering, in particular, for the heat transfer enhancement. The paper studies numerically the flow-type electroconvective heat exchanger that bases on both EHD pumping and mixing near the heater. The problem of the computer simulation of a realistic EHD heat exchanger is resolved by virtue of reduced model resource intensity—a technique for 3D/2D model substitution for a novel streamlined electrode configuration is proposed. The integral characteristics of EHD heat exchanger at hand are presented.