Combined cooling heating and power system (CCHPs) has been widely installed in many buildings due to its efficient, economic and environmental performances. This study focuses on optimizing the capacity and electric cooling ratio of CCHPs under uncertainties of demands (cooling, heating and electricity), solar radiation and prices (electricity from grid and natural gas). To solve this problem, a new bi-stage stochastic model considering the annual total cost saving, primary energy saving, and carbon dioxide emission reduction comprehensively is proposed. Three operation strategies, namely following the thermal load (FTL), following the electric load (FEL) and following the hybrid electric-thermal load (FHL) are usually adopted in CCHPs. In this study, an improved version of FHL, denoted by IFHL, is proposed. The effects of these four operation strategies to the optimal design of CCHPs are contrasted in a hypothetic hotel. The optimization work is implemented in Matlab, and the results indicate that the capacities of all facilities except photovoltaic are increased while the integrated performance and electric cooling ratio are decreased due to the uncertainties. Moreover, the performance of IFHL is always superior to those of other three operation strategies whether the uncertainties are considered or not. (C) 2019 Elsevier B.V. All rights reserved.