For on-chip electronic cooling, a micromachined silicon LHP (Loop Heat Pipe) is being developed, with a Coherent Porous Silicon (CPS) wick as the central part. The present work is a lumped-element network analysis of the overall heat removal performance of such a device. A heat flux of more than 100 W/cm2 is predicted for a micromachined baseline LHP. Moreover, this system-level model shows that a higher performance could be achieved by optimizing the vapor-removing duct. This would be possible without severe microfabrication challenges. The predicted performance of an optimized LHP with reduced turbulent flow losses in the evaporator exceeds 1000 W/cm2.