Building cooling heating & power (BCHP) system has advantages of energy saving and environment protection. Accurate feasibility evaluation and rational match between energy supply and energy demands are necessary for the realization of advantages of BCHP system. The influence of energy demands on the optimal facility scheme and feasibility of BCHP system needs especially to be studied. Mixed-integer nonlinear programming model is established with integrated optimization of facility scheme and operation strategy of BCHP system. A series of energy demands with different heat-electricity ratio and cooling-electricity ratio are achieved based on the energy demands of a hotel. Sensitivity analysis about energy demands ratios is carried out in this paper to study their influence on optimal capacity of facilities and feasibility indices. And the reason of the results is analyzed. Indices of feasibility evaluation include annual cost, annual cost saving rate and annual natural gas saving rate. It is shown in result that energy demands of different type have different weight in optimal capacities. Optimal capacities of facilities should be designed with consideration of all three kinds of energy demands. Different feasibility evaluation are achieved with different indices. The BCHP system is preferable for buildings with high heat demand. (C) 2008 Elsevier B.V. All rights reserved.