Abstract：

In terms of the characteristics of the urban sewage-source heat pump system, puts forward an integrated optimal mathematical model with the objective function of total annual costs, and prepares the calculation programme. On condition that the units meet the building heating and cooling requirements, performs the optimization of key design parameters based on different sewage temperature. With an actual case, presents the optimal value of design parameters, and analyses the influences of several parameters on the annual total costs and the system performance. This method achieves a better balance between reliable and economical system operation and realizes the optimal matching of each part of the system.