| In recent years the research and application of sewage source heat pump system are increasing year by year in our country. Sewage source heat pump technology is a renewable resource utilization way that can extract urban sewage in the area of low-temperature heat, which is an effective way achieving urban wastewater. The paper designs energy storage sewage source heat pump system, which is a new type of heat pump system with the combination of phase change energy storage technology, using phase change storing energy technology in the night sewaging the cold/heat energy stored in a storage device in the "power low time", again releasing energy stored in the accumulator in the peak, carrying on air conditioning cooling/heating, rising to "remove peak and valley" action.Take a building in Beijing for an example, this design applies phase change storing energy technology to sewage source heat pump system, and use this kind of new sewage source heat pump machine set as the cold/heat source of the building. The matched storing energy heat exchange devices are also designed. This kind of storing energy sewage source heat pump system has many operation mode, they are separate cooling/heating, separate accumulation of cold/heat, using cold storage cooling and using heat storage heating, combined heating/cooling, and their thermal dynamics in different operation mode are analyzed. Based on the features of the building load, operating principles and thermal performances of the storing energy sewage-source heat pump system, and the plans of the heat/cold storage are analyzed, so as to meet the requirement of the building load of a year. In order to investigate the operation characteristics of the storing energy sewage-source heat pump system, numerical models are built for the compressor, condenser, evaporator, thermostatic expansion valve in the storing energy storing sewage-source heat pump system, and integrate the above models to build a simulation model of the whole system. Solve the model system, and make simulating analysis to the operation characteristics of the storing energy devices under the cold/heat storage condition, cold/heat release condition, combined cooling/heating condition and so on, together with the winter and summer operation conditions of the system. The calculation results show that, this storing energy heat exchange device could satisfy the building load, and provides reference for the later design. In order to evaluate application effect of the storing energy sewage-source heat pump system, calculations about the economics, energy consumption, and environment indices are made to the sewage-source heat pump system, energy storage type sewage-source heat pump system, urban piping+water chillers system, air source heat pump system, ground-source heat pump system, and comprehensive evaluation researches are made using entropy weight analytic hierarchy process to these five kinds of cold and heat source schemes. Research results show that the comprehensive performance of energy storage type sewage-source heat pump system is superior to other four kinds of cold and heat source scheme. And based on the evaluation indices, further calculations are made to determine the economic distance between the sewage treatment plant and building, in this economic distance range, the sewage-source heat pump system had the obvious advantages of saving energy and environmental protection. This research has an important meaning for providing theoretical basis of application and extension of a new kind of storing energy sewage-source heat pump system. |
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