Abstract: A two dimensional numerical model is developed to simulate the dynamic and thermal behavior and to estimate the performance of the evaporator of a CPL. The vaporization problem of the working fluid is handled with using enthalpy equation, which avoids using time consuming selfadaption mesh techmique but is easy to track and maintain the liquid vapor interface, so it is convenient to handle with the capillary force in porous medium. The introducing source term in the momentum equations, which acts different capillary force is calculated at different liquid vapor fronts. Numerical results under different working conditions are presented.