【作者】 李从玖；

【导师】 戴汝平；

【作者基本信息】 华中科技大学 ， 供热、供燃气、通风与空调工程， 2005， 硕士

【摘要】 风冷热泵在我国应用越来越广泛,如何对风冷热泵系统进行设计才能获得良好的经济性是一个值得研究的问题。本文分析了影响风冷热泵系统设计的因素,提出了最经济平衡点的概念,即按此平衡点温度设计风冷热泵系统其生命周期费用最小。建立了风冷热泵生命周期成本的数学模型,给出了模型中各个参数的计算方法或者取值。通过对数学模型中影响平衡点的因素的分析,得到了风冷热泵平衡点主要是热泵设备价格和能源价格的函数的结论。之后用LccWare3.0软件计算了我国几个主要城市最经济平衡点的温度,并分析了各个参数对风冷热泵年成本的影响。运用热经济学优化方法对空调系统进行设计可以使空调系统生命周期费用具有良好的经济性。早期热经济学优化主要着眼于直接计算输入到系统的火用。但是,这么做通常是很困难的,因为空气侧换热器电机功耗和压缩机的功率难以确定。本文提出一种观点就是输入到系统的火用可以由火用守恒方程利用系统循环火用损失和系统输出的火用得到。为了进行热经济学优化,首先在Martin-Hou状态方程的基础上建立了制冷剂R22的热力学计算模型。从热力学关系式、能量平衡方程和换热器特性得到了热经济学优化的目标方程和约束方程。通过模拟计算得到了热力学和热经济学优化条件下的运行参数。结果表明在热力学优化条件下风冷热泵系统产生的总的不可逆损失和能源消耗费用最小,但是在热经济学优化条件下风冷热泵系统的年投资和运行费用最小。由此可见,热经济学优化可以使风冷热泵系统获得最好的经济性。更多还原

【Abstract】 Air-source heat pump is wider and wider used in our country. How to design an air-source heat pump system can achieve well economic interests is worth researching. This paper analyses the effecting factors in air-source heat pump design, putting forward a concept of economic balance point, i.e. based on this point the LCC of the air-source heat pump system will be minimized. Author developed mathematic equation of LCC, and provided values or calculations for each parameter in the LCC equation. By analyzing, author achieved a conclusion: balance point is a function of heat pump equipment and energy price. Later, author uses LccWare3.0 to calculate the balance point temperature of several cities in China,and analyzes effect of each parameter on the annual cost of air-source heat pump. The application of the thermo economic optimization design in an air-source heat pump system is important in achieving economical life cycle cost. Previous works on thermo economic optimization mainly focus on directly calculating exergy input into the system. However, it is usually difficult to do so because of the uncertainty of input power of fan on the air side of the heat-exchanger and that of pump in the system. This paper introduces a new concept that exergy input into the system can be substituted for the sum of exergy destruction and exergy output from the system according to conservation of exergy. In order to perform thermo economic optimization, a program is firstly developed to evaluate the thermodynamic property of R22 on the basis of Martin-Hou state equation. From the thermodynamic relations and equations derived from the energy balance and heat ex-changer characteristics, an objective function and constraining equations are obtained. Optimum values of the operating variables are identified at thermodynamic and thermo economic optimum conditions. Results show that the total irreversibility produced in the system and the cost of energy consumption are minimum at thermodynamic optimum conditions, but the annual cost of owning and operating the system is minimum at the thermo economic optimum condition. So, under thermo economic optimization condition, the air-source heat pump can achieve the most economical interest.更多还原