【作者】 刘雪玲；

【导师】 由世俊；

【作者基本信息】 天津大学 ， 供热、供燃气、通风及空调工程， 2011， 博士

【摘要】 以海水作为热泵机组的热源(汇)对于解决沿海建筑的冬季供暖和夏季空调、缓解日趋紧张的能源压力有重要意义。直接式和间接式海水源热泵系统的运行模式不同,系统效率和经济性也会随之改变。本文主要对两种模式的海水源热泵系统相关设备的传热性能进行了研究。为防止海水对热泵机组的腐蚀,间接式海水源热泵系统通常在海水与热泵机组之间增加中间换热器。目前海水源热泵系统的中间换热器采用的是价格较高的钛板换热器,为减少系统投资,本文对间接式海水源热泵系统中间换热器的传热性能进行了研究,设计并加工了普通钢制的中间换热器。通过搭建实验台,对管、内外流体流速对换热器传热性能的影响进行了研究,得到了管、内外流体的对流换热实验关联式;在实验基础上建立了换热器传热数学模型,对中间介质乙二醇溶液的出口温度和换热量随热源温度的变化进行了模拟计算。末端供水温度直接影响海水源热泵系统的效率,尤其当冬季海水温度较低时,供水温度的高低直接影响海水源热泵运行的经济性。本文通过标准散热器实验台对新型采暖地板传热性能进行了测试,结果表明供水温度为30℃即可满足供暖舒适性要求。供水温度的降低使得热泵的冷凝温度随之降低,从而提高了热泵系统的效率。当蒸发温度为-5℃,供水温度分别为30℃和45℃时,热泵系统的COP分别为4.76和3.52,增加了1.24。为减少中间换热环节,提高海水源热泵热源的温度条件,本文对直接式海水源热泵系统防腐蒸发器的传热性能进行了实验研究和理论分析。通过对防腐蒸发器和无防腐蒸发器传热性能的对比研究,得到实验用防腐涂料的导热系数为3.23 W/(m? K);管内流速小于1.5m/s时,喷涂防腐涂料后表面粗糙度强化了传热,蒸发器的传热系数略大于无防腐涂层的蒸发器;当管内流速大于1.64m/s,流动进入湍流状态,表面粗糙度的影响减弱,此时无防腐蒸发器的传热系数略大于防腐蒸发器。喷涂防腐涂料可解决海水的腐蚀问题,但对蒸发器传热性能影响不大。本文建立了直接式和间接式海水源热泵系统能耗模型,针对天津渤海湾的海水温度条件,对两种模式的海水源热泵空调系统的COP和能耗进行了模拟计算。结合实际工程,比较了直接式和间接式海水源热泵系统运行的经济性,结果表明:当海水温度为5.1℃时,直接式海水源热泵系统的COP为4.31,比间接式海水源热泵系统高1.02,在一个供暖季内可节约电量6496 kWh,减少运行费用5132元。更多还原

【Abstract】 Seawater source heat pumps are used for building heating and cooling, which is helpful to solve energy shortage problems. Efficiency of seawater source heat pump systems is different in direct and indirect application modes. Heat transfer performance of associated equipment of seawater source heat pump is studied in this thesis.Titanium heat exchangers were added between seawater and evaporator in indirect seawater source heat pumps to avoid corrosion. Because of the high price of titanium heat exchangers, antiseptic steel heat exchanger was designed and heat transfer performance was studied in order to decrease system investment. Experiment table was set up and the impact of inner and outer fluid velocity on heat transfer performance of heat exchangers was analyzed, convective heat transfer correlations of inner and outer tube were obtained. Mathematical model of heat transfer in heat exchanger was established based on the experiment results, outlet temperature of glycol solution and heat output with the change of seawater temperature were calculated.COP of heat pump are directly affected by supply water temperature, especially when the seawater temperature is low. Thermal performance of new type radiant floor was tested based on the standard radiator experiment table, the results indicated that the supply water temperature of 30℃could satisfied the comfort requirements, which is 15℃lower than that of normal floor heating. The decreasing of supply temperature lowered the condensing temperature, thus improving COP of heat pump system. When the evaporating temperature is -5℃and supply temperature dropped from 45℃to 30℃, COP of the heat pump system would increase from 3.52 to 4.76.In order to improve the evaporating temperature and system efficiency, experimental study and theoretical analysis on thermal performance of antiseptic evaporator of direct seawater source heat pump systems were done. According to the contrastive study of heat transfer in antiseptic and normal evaporator, it can be concluded that the thermal conductivity of the antiseptic dope is 3.23 W/(m? K).When seawater velocity is less than 1.5m/s, surface roughness enhanced heat transfer, heat transfer coefficient of the antiseptic evaporator is more than that of the non spray-painted evaporator; When sea water velocity is bigger than 1.64m/s, turbulent flows occurred, heat transfer coefficient of the antiseptic evaporator is less than that of the non spray-painted evaporator. Spray-painting antiseptic dope could solved seawater corrosion and have little influence on thermal performance of evaporator.Energy consumption model of direct and indirect seawater source heat pump system was set up, COP and energy consumption of direct and indirect system was simulated. Combined with one practical project, economical efficiency of the two modes of seawater source heat pump systems was compared, the results show that COP of direct system is 4.31 with the seawater temperature of 5.1℃, which is 1.02 higher than that of indirect system, 6,496 kWh and 5,132 RMB would be saved during a heating period.更多还原