Based on the cooling

heating and power load profile and the ways to meet the cooling load

the operation space of the combined cooling

heating and power(CCHP)is divided into four states

each with three operational strategies. The condition as an optimal operation strategy is obtained by the KT condition of the optimal operation model. A new operational strategy that meets the cooling heating and power load only by primal generation and heat recovery system is proved to be an optimal operation strategy. It is shown that the optimal operation strategy of CCHP is related to the electricity price

gas price

load composed of cooling

heating and power

and the efficiency of CCHP. The optimal strategy can be obtained by the proposed discriminator by considering those factors. The calculation results based on cooling

heating and power load and the actual system show the correctness of the conditions for the proposed optimal operation strategy.