Design parameter determination method and application of untreated sewage-source heat pump systems

There are many influencing factors in designing an untreated sewage-source heat pump system. When determining the user’s demand load and the temperature parameters of the supply and return water, the main influencing parameters include the inlet and outlet temperatures of the system and the evaporator of the heat pump unit. The above temperature parameters affect the selection and operation conditions of the equipment including heat pumps, sewage pumps, intermediate pumps and sewage heat exchangers. The investment and operating cost of the system are directly affected by the selection and operation parameters of the equipment. Taking annual total cost as the objective function, applies a complex method to optimize the determination of the above parameters and illustrates its application by an example.