In the present work we design, model and experimentally characterize a two-phase vapor venting parallel microchannel heat exchanger capped with a 220 nm pore, hydrophobic PTFE membrane that vents the vapor phase into separate vapor transport channels. We compare the performances of a traditional non-venting heat exchanger and the vapor-separating version operating at heat fluxes of up to 820 kW/m(2) and water mass fluxes of between 102 and 420 kg/s m(2). We find similar to 60% improvement in the normalized pressure drop and up to 4.4 degrees C reduction in the average substrate temperature between the control and vapor venting device under similar operating conditions. (C) 2011 Elsevier Ltd. All rights reserved.