Study On Thermodynamic Optimization And Dynamic Operating Energy Consumption Of Seawater Source Heat Pump System

The open indirect system of seawater source heat pump(SWHP) used in the media center of Qingdao International Jalor Center is selected as the study object. And the study on thermodynamic optimization and dynamic operation energy consumption of SWHP system is carried out.Firstly, the experimental test is carried out to study the summer operating characteristic of SWHP system in the media center. The test data shows that the energy efficiency ratio(EER) of heat pump unit and SWHP system are separately 4.22 and 3.15. During the test, the number of the pumps is changed and the different operating conditions of the SWHP system are compared. After reducing the number of the operating pumps, the system refrigerating capacity reduce 1.7%, while the system EER increase 9.1%.Exergy and thermoeconomics analysis on open indirect system of SWHP are carried out in order to further promote the application of SWHP system. And the exergy loss expression and the thermoeconomic equation of uniform exergy loss cost pattern about SWHP system are obtained. Then the pure thermodynamic and thermoeconomic optimization programs are worked out on the base of the exergy loss expression and the thermoeconomic equation. The programs can separately obtain the system composition and operating parameters that makes the minimum of system exergy loss or system annual production costs at different seawater temperature. When the seawater temperature is 24℃, compared with the pure thermodynamic optimization results, the thermoeconomic optimization results increase 22.7% on exergy loss and reduce 13.9% on the EER of heat pump unit. But on the other hand, the thermoeconomic optimization results reduce 29.1% on the annual production costs and 35.9% on the initial investment. In the process, reference the Cleland model and utilize the method of multinomial function fit, the computing method about the thermodynamic property of refrigerant R410A is studied and the relevant program is worked out.Seawater temperature is the essential parameter to the design of SWHP system. And it plays the decisive role to the normal operation of SWHP system. The thesis fits the annual change curve of the seawater temperature and the air temperature in Qingdao in the form of second-order Fourier series. The result indicates that the change of seawater temperature in Qingdao is later a month around than air temperature and the rangeability of seawater temperature has some attenuation also. Air temperature can influence the air conditioning load of buildings and seawater temperature simultaneously. Then the variation of seawater temperature can change the performance of SWHP system. So the dynamic operating energy consumption of SWHP system is studied in which the change of air temperature and seawater temperature is considered.Based on the building's hourly load simulated by DeST, the media center is secelted as the object to study the dynamic operating energy consumption of SWHP system. The results indicate that seasonal EER of the SWHP system is separately 3.49 in summer and 2.38 in winter. Compared with air source heat pump system, the seasonal EER of heat pump unit and system in SWHP system are all higher than that of air source heat pump system. Furthermore, the effect of pump variable frequency drive on the operating energy consumption of SWHP system is studied. The results indicate that electricity saving ratio of pumps is 58.3% after pumps frequency conversion. At the same time, the seasonal EER of SWHP system separately increases 20.1% in summer and 15.1% in winter.The optimum design parameters and characteristic of operating energy consumption are obtained through the research on thermodynamic optimization and dynamic operation energy consumption of SWHP system. And this has some academic value and practical significance to the design and application of SWHP system.