汽车余热吸收式溴化锂制冷系统的研究

发布时间：2018-10-21 15:49

【摘要】：汽车空调是现代汽车舒适性的重要保障,但由于大部分汽车都是采用机械压缩式空调,其系统的运行明显增加了汽车的能耗,同时也影响了汽车的整体动力性能。针对以上问题,本文研究了一种余热吸收式溴化锂制冷系统,将压缩式制冷系统与吸收式溴化锂系统结合起来,不但有效地利用了发动机冷却水的余热,而且能节省汽车的油耗,大大减少汽车空调对汽车动力性能的影响。本文的主要工作及结论如下:(1)结合传统压缩式和吸收式溴化锂空调的优缺点,提出了一种新的余热吸收式溴化锂制冷系统,用于改善目前普遍使用的压缩式汽车空调制冷循环。通过将压缩式制冷与吸收式溴化锂制冷方式相结合,有效地利用了发动机冷却水所产生的余热,同时还克服了传统吸收式溴化锂制冷效率低的难题;(2)对该余热吸收式溴化锂汽车空调系统进行了热力计算,包括了传热面积、介质流量等计算;并对发生器、冷凝器等关键部件进行了结构设计。通过对发生器的设计,将其与发动机冷却水箱结合起来,有效地利用了它的余热;通过对冷凝器的设计,用双层平行流换热器代替单层平行流换热器,不仅增加了散热面积,也提高了制冷效率;(3)对该平行流换热器空气侧的流场进行仿真,以压降和换热系数的实验值作为参考,分析了迎面风速从1.5m/s~5.5m/s变化时,其空气侧换热性能的变化情况。通过正交实验,用极差法对平行流换热器的结构参数进行分析,总结出当翅片间距A=2mm,翅片长度B=30mm,,翅片高度C=9mm和百叶窗角度D=25°时,也即是第25组水平组合,此换热器的换热性能相对较好;(4)搭建本文所研究的余热吸收式溴化锂制冷系统的简易实验平台,验证了该系统的可行性;同时将其与传统压缩式制冷系统进行比较,分析得出在相同制冷量条件下该系统的耗电量明显减少。
[Abstract]:Automobile air conditioning is an important guarantee for the comfort of modern automobile. However, because most of the vehicles use mechanical compression air conditioning, the operation of the system obviously increases the energy consumption of the vehicle, and also affects the overall dynamic performance of the vehicle. In order to solve the above problems, a waste heat absorption lithium-bromide refrigeration system is studied in this paper. By combining the compression refrigeration system with the absorption lithium bromide refrigeration system, the residual heat of engine cooling water is utilized effectively. Moreover, it can save the fuel consumption of the automobile and greatly reduce the influence of automobile air-conditioning on the power performance of the vehicle. The main work and conclusions of this paper are as follows: (1) combining the advantages and disadvantages of traditional compression and absorption lithium bromide air conditioners, a new waste heat absorption lithium bromide refrigeration system is proposed to improve the refrigeration cycle of compressed automobile air conditioners. By combining the compression refrigeration with the absorption lithium bromide refrigeration, the residual heat produced by the cooling water of the engine is utilized effectively. At the same time, it overcomes the problem of low refrigeration efficiency of traditional absorption lithium bromide; (2) the thermal calculation of the residual heat absorption lithium bromide automobile air conditioning system, including the calculation of heat transfer area, medium flow rate, etc. The key components such as condenser are designed. Through the design of the generator, combining it with the engine cooling tank, the waste heat of the generator is effectively utilized, and by the design of the condenser, the double-layer parallel flow heat exchanger is used instead of the single-layer parallel flow heat exchanger, which not only increases the heat dissipation area, The refrigeration efficiency is also improved. (3) the flow field of the parallel flow heat exchanger is simulated and the change of the heat transfer performance of the air side is analyzed with the experimental values of pressure drop and heat transfer coefficient as the reference. By orthogonal experiment, the structural parameters of parallel flow heat exchanger are analyzed by the range method. It is concluded that when the fin spacing is 2mm, the fin length is 30 mm, the height of the fin is C=9mm and the shutter angle is 25 掳, it is the 25th horizontal combination. The heat transfer performance of the heat exchanger is relatively good. (4) the simple experimental platform of the waste heat absorption lithium-bromide refrigeration system studied in this paper is built to verify the feasibility of the system, and at the same time, the feasibility of the system is compared with the traditional compression refrigeration system. The analysis shows that the power consumption of the system is obviously reduced under the same refrigerating capacity.
【学位授予单位】：广州大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U463.851

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