【作者】 李斌；

【导师】 万珍平； 谭军毅；

【作者基本信息】 华南理工大学 ， 机械工程（专业学位）， 2016， 硕士

【摘要】 随着社会能源消耗的增加和气候的变暖,以太阳能作为驱动能源的太阳能吸收式制冷系统由于其环保和节能的特点而受到广泛的关注。相比于传统压缩式制冷系统,太阳能吸收式制冷系统在低品位的太阳能热水驱动下,其发生器内溴化锂溶液中的冷剂水蒸发分离能力存在不足,进而影响系统的制冷能力,使得能量转换效率不高。基于此,本文以太阳能吸收式制冷系统在低品位太阳能热水驱动下实现高效制冷为目标,提出一种应用超声强化太阳能热源驱动的吸收式制冷系统。本文首先研究超声强化发生器中溴化锂溶液的热质传递过程,从超声强化传质和超声强化传热两个方面研究了超声对于冷剂水蒸发分离能力的提升作用:一是超声在气液界面的雾化效应能有效降低气液分界面处溶液的粘度,减小传质层的液膜厚度,使得传质阻力下降,从而加速了溴化锂溶液中冷剂水的分离传质过程;二是超声空化及声流效应能强化发生器中换热管表面的对流传热,以及提升传热表面的沸腾相变换热,从而有效降低换热管固液界面的传热热阻,增强了溴化锂溶液中冷剂水分离传质的热驱动力。在上述研究的基础上,设计制造一台太阳能单效溴化锂吸收式制冷机组,机组设计的目标制冷量为10kW、额定热力系数为0.64。太阳能单效溴化锂吸收式制冷实验机组的设计包括机组的结构设计、机组的管路设计以及机组的控制系统设计。机组的结构设计首先计算系统的热力参数,然后依据热力参数对机组各换热部件进行传热计算、力学计算,再根据实验研究的结果和机组测试的要求完成结构设计。机组结构设计包括低压腔和高压腔各部件传热及结构设计、冷却塔设计以及机架设计。其中高压腔要结合实验研究来完成其结构设计,使腔内的发生器可以实现超声强化作用。然后依据设计完成机组结构制造成型。在机组腔体和冷却塔布置位置确定的基础上,依据机组测试需求的调节量和监测量,对机组系统的各管路进行设计,管路设计包括溴化锂溶液流路设计、冷剂水流路设计、冷却水循环流路设计、供热以及冷媒水流路设计。然后结合管路设计完成机组系统的制造成型。最后根据系统所需的热源热量完成太阳能集热器和蓄热水箱的选型。机组的控制系统设计主要包括了硬件设计以及相应的软件设计。硬件系统基于PLC来进行控制设计。软件设计基于机组的硬件设计,设计了系统的启动程序、停机程序以及故障保护程序,完善了机组的控制系统。更多还原

【Abstract】 With the continuous increasing energy consumption and the successive warming of the Global climate,solar absorption refrigeration system gets more extensive research, because of its environmental friendly and energy saving. However, though the solar energy absorption refrigeration system has the advantages of environmental protection and energy saving, its COP value is relatively low, compared to the compression refrigeration system. Because when solar energy absorption refrigeration system is drived by low grade solar hot water, the separation capability of refrigerant water within generator is weak. So this paper puts forward a solar absorption refrigeration system which used ultrasound to strengthen the driving force of low grade solar water.This paper firstly investigated the heat and mass transfer strengthening of lithium bromide solution in generator via ultrasound. This experiment includes mass transfer enhancement induced by ultrasound and heat transfer enhancement induced by ultrasound. To mass transfer enhancement, the atomizing effect of ultrasound can reduce the viscosity of solution in gas-liquid interface and the film thickness of mass transfer layer, which accelerates separation and mass transfer process of the refrigerant water in lithium bromide solution. To heat transfer enhancement, the ultrasonic cavitation and acoustic streaming effect can strengthen the convection of the heated tubes in generator and strengthen the boiling heat transfer, which incleases the driving force to separation and mass transfer process of the refrigerant water in lithium bromide solution.Based on the experimental study, this article designed and manufactured a solar single effect lithium bromide absorption chiller. The designed target refrigeration of the chiller was 10 kW and the rated thermal coefficient was 0.64. The design of solar single effect lithium bromide absorption chiller included structural design, piping system design and control system design.In structural design, the parameters of state points of absorption chiller were computed by software of solar Li-Br absorption chiller which is developed our research group. Based on the result of state point parameters, the paper calculates the heat transfer load of internal component of chiller and then designs its structure parameters. The structural design included the design of each component in low pressure chamber, the design of each component in high pressure chamber, the design of cooling tower, and the design of frame. Then the structures of the chiller would be manufactured by structural design.After positions of the pressure chambers and the cooling tower are determined, the piping system would be designed, basing on regulating values and monitoring values of the system. The piping system design of absorption chiller included the design of lithium bromide solution circulation circuit, the design of refrigerant water pipeline, the design of cooling water circuit, the design of heating water circuit and chilled water loop. Then the chiller would be manufactured combined the piping system design. Finally, the solar collectors and the heat storage tank selections would be completed based on the system heat source required.The control system design of absorption chiller included the design of hardware and the corresponding software. The design of hardware system was based on PLC. The software design included the start-up procedure, stop procedure and fault protection procedure.更多还原