【作者】 陈飞虎；

【导师】 龚光彩；

【作者基本信息】 湖南大学 ， 供热、供燃气、通风及空调工程， 2014， 博士

【摘要】 相比常规的制冷系统,复合冷凝空调系统可回收冷凝器排放的废热、增加了系统的制冷能力、降低了压缩机的排气压力。然而,复合冷凝空调系统在应用中仍有一些问题有待解决。这些问题包括：由于增加了热回收装置,系统运行参数发生改变,导致系统效率降低或不能平稳运行；冷热源设备匹配不合理,整体优化差而造成能量浪费；卫生热水装置与冷凝器联合工作的运行参数选择有盲目性；实际运行和测试中缺乏简便的评价和操作方法；替代制冷剂在复合冷凝系统中的运行特性不同于系统的运行制冷剂为R22。而这些研究方向对系统的稳定运行及提升系统的性能具有重要作用。针对上述出现的问题,本文研究了应用复合冷凝技术之后系统的运行特性。由于大温差变化所导致的传热过程随时间的变化,论文对几种典型复合冷凝过程开展了仿真研究：包括大型水冷离心式制冷机组、风冷热泵机组、多功能热泵热水机组实验装置和替代制冷剂复合冷凝过程的仿真。第一,应用(?)分析对大容量的离心式冷水机组水冷+水冷模式的复合冷凝过程建立了卫生热水水温上升的动态数学模型和机组的动态数学模型。提出将卫生热水水温从进口初始温度上升到用户要求温度所需的时间为一计算周期来评价和计算热回收系统的性能。提出了机组热回收效率(卫生热水生产效率)和机组效率的积分累积数学模型。为机组效率的计算提供了更合理的计算方法。应用SIMULINK仿真软件搭建了离心式冷水机组复合冷凝过程的仿真模型,并用实验数据进行了验证。得出了系统运行参数与时间的关系,然后利用该仿真模型求得系统优化参数。第二,应用(?)析对风冷热泵机组的复合冷凝过程建立了卫生热水水温上升的代数累积数学模型,并据此建立了风冷热泵机组复合冷凝过程的代数累积数学模型。提出了机组热回收效率(卫生热水生产效率)和机组效率的求和计算方法。然后运用SIMULINK软件建立了风冷热泵机组复合冷凝过程的仿真模型,并用实验数据进行了验证。第三,对多功能热泵热水空调机组进行了实验研究。分析了机组各部件性能参数随运行时间的变化情况。并将实验结果与风冷热泵复合冷凝热回收仿真结果进行了对比分析。验证了风冷热泵复合冷凝仿真模型的可靠性。然后,应用机组热回收效率(卫生热水生产效率)和机组效率的计算方法,结合风冷+水冷模式的热泵机组实例,提出了便于实际测量的测试方法。最后,分析了替代制冷剂在复合冷凝系统中应用的趋势。应用风冷热泵机组复合冷凝过程的代数累积数学模型,建立了氟系替代制冷剂R407C和R410A在风冷热泵复合冷凝系统中的SIMULINK仿真模型。对仿真模型在制冷模式下的可靠性进行了验证。然后将该仿真模型应用于氟系替代制冷剂R407C和R410A在风冷热泵系统复合冷凝过程中的运行特性计算,与R22系统的性能作了对比分析。并针对CO2制冷/热泵系统进行了仿真分析,应用风冷热泵机组复合冷凝过程的离散模型数学模型,建立了在制冷和复合冷凝过程的SIMULINK仿真模型。对CO2制冷/热泵系统制冷循环模式下的仿真模型进行了验证,然后对CO2制冷/热泵系统复合冷凝模式进行了计算,与R22系统的性能作了对比分析。并将CO2制冷/热泵系统应用复合冷凝模式前后机组的性能做了比较。为替代制冷剂在复合冷凝过程中的应用提供了理论基础。更多还原

【Abstract】 Compared to the conventional air conditioning system, the air conditioning system with compound condensation process can produce the sanitary hot water,it have the advantages of recovering the condensation heat, improving the refrigerate capability, reducing the exhaust temperature of the compressor. However, there are still some problems needed to be solved in the development process of air conditioning system with the compound condensation process. They are as follows: Due to the addition of the sanitary hot water supply equipment, the system operating parameter has been changed, the system may not operating smoothly; the system component may not match rationally, it lead to the energy waste; the blindness of choosing the operating parameter of the combined sanitary hot water supply system and the condenser; there are no simple and convenient method to evaluate and test the performance of the system; the system characteristic with alternative refrigerant is different to the R22system. And due to the big temperature gap change of the condensation process, the heat transfer process is vary with the operating time. In order to solve these problems, this paper separately analyzed the principle and characteristic of water condensing+water condensing mode and air condensing+water condensing mode of the compound condensing process. It include the performance exam of four aspects:the decentralized water-cooling chiller unit, the air cooling heat pump unit, the muti-function heat pump system and the substitute refrigerate in the compound condensation process.Firstly, the exergy analysis method has also been employed to analysis the two condensers condensation process. The dynamic models of the temperature improve of the sanitary hot water and the compound condensation process has been established based on the decentralized chiller unit. The calculation methods about the exergy efficiency of the sanitary hot water and the compound condensation unit have been given out. The period of the sanitary hot water temperature from the initial input temperature to the temperature the user demand was taken as a calculation circle. Then the performance of the system can be evaluated. The problem that the compound condensation process cannot described and simulated by the traditional thermodynamics is solved. The SIMULINK software is employed to build the simulation model. The experiment dates have been employed to exam the dynamic model. The relationship of the outlet temperature of sanitary hot water, the exergy efficiency of the system, and the outlet pressure of the compressor versus the operation time has been gotten. Then, the optimal mass flow of the sanitary hot water under the given condensation temperature and maximum exergy efficiency of the compound condensation process have been gotten.Secondly, the finite-time thermodynamics and the exergy analysis method have been employed to analysis the two condensers condensation process. The decentralized models of the temperature improve of the sanitary hot water and the compound condensation process has been established based on the air-cooling heat pump unit. The SIMULINK software is employed to build the simulation model. The experiment dates have been employed to exam the cumulative model.Thirdly, the performance of the unit muti-function heat pump system has been analysis. The experiment data has been used to exam the simulation model of the compound condensation process in the air-cooling heat pump unit. Then, the test method has been given out based on the cases about the air-cooling heat pump.Finally, the applying trend of the alternative refrigerant in the compound condensation process has been discussed. The decentralized simulation model of the alternative refrigerant in the air-cooling heat pump system has been build. It is based on the SIMULINK. The system operation characteristics with the R407C and R410A have been tested separately. And they were compared with the R22system. Following that, the AC/HP system model with nature refrigerant CO2is established according to the paper published. Then, the simulation model of the refrigerate cycle is built with SIMULINK. After the testify of the refrigerate cycle with CO2, the compound condensation process with CO2is established and tested, and theoretical basis is provided for the applying of the alternative refrigerate in the compound condensation process.更多还原