Work Condition Research And Optimizational Design Of The Sewage Source Heat Pump System

With the fact that environmental protection and energy saving of sustainable development deeply increased, various low-temperature heat source brought into city heat source, such as underground water, solar, soil energy, excess heat, waste heat and urban sewage; especially, the urban sewage has strong developmental potential ability. The key of system design is the selection of heat transfer working condition of sewage heat pump system. The selection of these parameters is supposed to be assure the effect of system, and simultaneous satisfy the economical efficiency, including first cost and operating cost.The paper has tested the winter operation parameter of sewage heat pump system in a real project; according to the relevance data that practice measuring, the effect of matching between one-stage and two-stages pumps to clog proof machine has analyzed; and also the impact of the entrance temperature and entrance temperature difference to system function, the proportion of pump energy consumption in general energy consumption of system have been shown in the paper. Based on these analyses the selection principle and basis have been given. The system setting method provides the theory basis of sewage heat pump system engineering design and operation administration.Taking the dynamic year calculates cost as target function, and design parameters of every circle pipe in sewage heat pump system as optimize parameters, first invest and operating cost optimization target function of system have been deduced. According to testing data in actual project constraint condition in optimizing process is perfect. MATLAB procedure has been worked out to optimize the system design parameter. Combination with an example the system design parameters have been given; and also the effect of individual parameters to system year cost and system unit performance is analyzed.Based on the determination of circle pipes optimization parameters and combination with an actual project, the design procedures and principle of design the sewage-clear water heat exchanger have been introduced. The mathematic model of system heat transfer area and unit performance have been established based on finite-time thermodynamics theory, and the specific optimization design has been shown combination with an actual project.