A cycle model of the updated ocean thermal energy conversion system is proposed. The cycle system mainly consists of a compressor, a turbine, an evaporator, a condenser, and a regenerator and can absorb heat from high-temperature heat sources such as solar energy, waste heat produced in other equipments, or heat warm sea water. The effects of main irreversible losses on the performance of the system are considered. Expressions for the power output and efficiency of the system are analytically derived. The characteristic curves of the dimensionless power output versus the efficiency are obtained. The optimum values of some of the main parameters at the maximum power output are calculated. The results obtained here can provide some guidance for the optimum design and operation of real ocean thermal conversion systems.