In this study, total pressure drop changes for all components of a loop heat pipe (LHP) have been investigated. A mathematical model to calculate the steady state performance of the LHP has been examined, as related to pressure drops considering a certain temperature range and applied heat flow rate. The calculations have been given for the evaporator, the vapor line, the liquid line, the condenser, and the subcooler. The energy transported by the LHP system is evaluated as a function of operating temperature. For the calculation Maple V mathematical problem solving and visualization system has been used.