Possible configurations of loop heat pipe evaporators have been analyzed, and the current state of experimental and theoretical studies on the choice of their capillary structures with a real pore size distribution function has been presented. On this basis, a methodology for selecting capillary structures for the primary and secondary loop heat pipe wicks with various operational parameters has been proposed. The operating conditions of loop heat pipes and the method of analytical calculation of the temperature field for a model with pseudoconvection in capillary structures have been formulated. The calculated and experimental data have been compared.