Although Computational Fluid Dynamics method has solved the impact on the building space environment of collaborative working air-condition in theory, the actual air distribution can't fully meet the boundary conditions due to the influence of these factors such as furniture, equipment and decoration. Therefore, the results of theoretical simulation cannot be directly applied to practical engineering. Not all the working condition can be covered by the theoretical calculation since the building load is changing. So a concise and effective model that can be used in practical engineering is needed to reduce energy consumption of collaborative working air-conditions. Based on the concept of single energy utilization efficiency, we come up with a method of calculating the efficiency of collaborative working air-conditions and propose an optimization strategy in energy usage. Experiments had proved that the method of energy efficiency optimization can improve the system energy efficiency of air-condition though reducing the entirety energy consumption. (C) 2016 Elsevier B.V. All rights reserved.