【作者】 王海涛；

【导师】 季杰；

【作者基本信息】 中国科学技术大学 ， 热能工程， 2007， 博士

【摘要】 随着全球人口的增长、能耗的增加，太阳能的开发利用正在加速发展。太阳能热泵SAHP系统（SOLAR-ASSISTED HEAT PUMP，SAHP）是太阳能利用的一种方式，SAHP系统将热泵装置和太阳能集热器结合在一起，同时提高热泵的性能系数和太阳能的热利用效率。本文将光伏发电与变频技术和直膨式SAHP系统有机结合在一起，提出了光伏-变频太阳能热泵PV／T-VFSAHP系统（Photovoltaic-Variable Quency Solar Assisted Heat Pump）的概念。结合系统数学模型对辐照强度、环境温度、蒸发器出口过热度三个参数对PV／T-SAHP系统性能的影响进行了模拟分析，根据分析的结果提出了使系统优化的控制策略。即电子膨胀阀——吸气过热度控制，机组无论在标准工况下、变工况、满负荷、变负荷运行维持较高的COP值和集热器效率η_coll。当变频压缩机恒定频率运行时，其性能相当于一个在相同频率下运行的定速压缩机。因此，光伏-变频太阳能热泵系统在实际运行时可以离散为无穷多个与不同频率相对应的定速压缩机，所以研究清楚定频下电子膨胀阀的开度对系统性能的影响是研究光伏-变频太阳能热泵系统的关键。所以本文主要从电子膨胀阀的开度对系统性能的影响进行研究。以PV／T-SAHP系统实验台为基础，开发了电子膨胀阀开度控制器。并对不同的电子膨胀阀开度下，PV／T-SAHP系统的动态性能进行了实验和分析，根据实验结果我们发现，系统的COP值随着冷凝水温的升高而降低，光电效率的峰值发生在工质蒸发对光伏模块的冷却作用和太阳辐照度和空气对集热／蒸发器表面的加热作用的平衡点，而并非太阳辐照度最高点。在电子膨胀阀开度一定时，随着太阳辐照度的升高，压缩机功率出现振动，当电子膨胀阀开度最大时，系统振动更加明显。振荡对运行经济性与安全性均不利，为确保运行稳定性，片面地增加蒸发器的运行过热度，这就大大降低了蒸发器的利用率，为获得一定的节能效益就减小蒸发器的运行过热度，但盲目地减少过热度，追求运行经济性而导致系统产生振荡．只有对蒸发器和膨胀阀本身的动态特性做出定量分析，并找出系统的临界稳定区（Minimum Stable Signal线，简称MSS线）与条件，找出影响系统稳定性的各种因素，才能在保证系统稳定性前提下，最大限度的利用蒸发器的有效传热面积，获得最高的经济性。由此本文提出了光伏-太阳能热泵（PV／T-SAHP）的系统稳定性原理。同时指出优化PV／T-SAHP系统的关键问题是找到系统集热／蒸发器的MSS线（Q—Tsh关系曲线）。最后，建立了变频PV／T-SAHP系统（PV／T-VFSAHP系统）的数学模型，就不同频率时的系统的性能进行了模拟和分析。得出压缩机转速过大和过小，都会影响系统的正常运行，对系统产生不利的影响。在实际运行时，这两种情况都要避免。并对频率分别是30hz、50hz、70hz时的系统性能进行了实验研究。更多还原

【Abstract】 With the rising of population and energy consuming on earth, the fossil energy on earth is stepping into exhaustion and the issues of environment are facing grimness . The utilization and development of solar energy are improving greatly. The Photovoltaic Solar Assisted Heat Pump (PV/T-SAHP) system which integrated heat pump and solar energy collector can heighten the COP (coefficient of performance) and the utility efficiency of solar energy simutaneous is a main way of utilization of solar energy.Based on the photovoltaic and the technology of variable frequency and the DXSAHP (direct expansion solar assisted heat pump),we proposed the idea of the PV/T-VFSAHP (Photovoltaic-Variable Quency Solar Assisted Heat Pump) .Combined the mathematical mode of the PV/T-SAHP system , system performance and optimization under the affecting factor of solar radiation, condensing water temperature, surrounding temperature , and the superheat of evaporator were studied. Based on the results ,the optimal control strategy of the system was put forward.viz.the control of the EXV-the superheat degree of the collector.By this way, the system can maintain more COP and more the efficient of the collector at no matter what status of the system,such as the standard status , the variable status, the full load and the variable load.When the variable frequency compressor run at a constant frequency ,its performance worthiness a fix velocity compressor move with a sameness frequency.So the PV/T-VFSAHP can disperse to a lot of fixed velocity compressor corresponding different frequency. Therefor the key of the study of the PV/T-VFSAHP is to probe the effecting of the opening of the EXV to the system.Basing on the test rig and mathematical mode of the PV/T-SAHP system ,we developed the controller of the openning the EXV (Electronic Expansion Valve).At the same frequency of compressor, under different opening of EXV, outdoor tests were conducted on the PV/T-SAHP system. The dynamic behavior of PV/T-SAHP was analyzed . The COP of the system reduced along with the raising of temperature of the condensing water .The peak value of the efficiency of the photovoltaic is occurred while the balance between the cooling influence of the vaporizing working material to the PV/T module and the heating influence of the air to the collector/evaporator, not the vertex of the solar radiation. The vibration of the power of the compressor appeared when the raising of the solar radiation at a fixing opening of EXV. when at the maximum opening of the EXV, the vibration is especially evident. The vibration is harmful to the economical and security of the system .Increasing and decreasing the superheat degree of the evaporator ex parte are all mistake.The only way to utilize the availity area of the evaporator and to gain the maximum economocal of PV/T-SAHP is to find the MSS of the system.So we brings forward the principal of the stability of the PV/T-SAHP system .At the same time point out the key of the study of the PV/T/T-SAHP is to discover the relation of the solar radiation and the superheat degree of collector/evaporator.At last , we simulation and analyzing the performance of the PV/T-SAHP system based on the mathetical mode of the PV/T-SAHP system under different frequency of compressor ,and carry through the experiment when the frequency is 30hz,50hz,70hz更多还原