in this paper, the pressure loss and heat transfer in bending and branching microchannels for Re numbers ranging from 10 to 3000 are investigated. Redirecting and splitting the fluid leads to an enhanced heat transfer, but at the same time the pressure loss is increased. The shape of the investigated bends and branchings has a significant influence on both, pressure loss and heat transfer. Fluid flow and heat transfer are simulated for single elements like L-bends and T-joints with different shapes. Test structures are fabricated in silicon and experimentally investigated. The aim of this work is to get an impression of the physical behavior in small elements that enable the development of new liquid cooling systems with higher cooling ability and higher effectiveness. (c) 2009 Elsevier Ltd. All rights reserved.