Anew micro heat spreader (MHS) concept for efficient transport of large, concentrated heat loads is introduced. The MHS is a single-phase, closed microfluidic system, which utilizes reciprocating flow forced convection. This microfluidic device has the potential to control transient heat loads by active control strategies. Hence, it can be utilized in various thermal management applications, mainly in electronic cooling. The MHS concept is validated by numerical solutions of two-dimensional Navier-Stokes and heat transport equations via a recently developed arbitrary Lagrangian Eulerian spectral element algolithm. Analytical relations for power consumption and heat removal capacities of the MHS are presented.