Power devices such as IGBTs dissipate very large heat flux densities. Therefore the thermal environment is a main issue in their performance and reliability. In order to improve heat transfer, materials with high thermal conductivity seem to be very useful. Because of their high cost, we suggest replacing them with a groove wick and sintered metal powder wick heat pipes. Thermal simulations are provided to show the interest of these structures in power electronics. Heat spreaders composed of heat pipe or plain material are compared. A 40% decrease of the thermal resistance between the heat source and the ambient is expected. Then an experimental study on a brass-water heat pipe is described. Results are compared with thermal simulations.