This paper presents a new compact modeling technique to describe the convective heat transfer realized by a flow of coolant in integrated microchannels used for thermal management of IC chips. This model works only in case of laminar flow and straight microchannels. The compact model represents the convective heat transfer with alternating resistors in the flow path. The implementation of this model in a successive node reduction (SUNRED) algorithm based thermal filed solver is also presented. A simulation example for a simplified geometry with one channel situated in the center of a pyramidal stack of silicon dice is presented, though, the final target application is in the thermal simulation engine of a logi-thermal simulation system. The errors have been calculated as the difference of the results of the alternating resistor and modified SUNRED model and the result of a detailed CFD simulation. The error of our new compact model was below 2 % for both modeling techniques.