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夏季太阳辐射强度大,光照时间长,沼气池产气量也大,因此太阳能和沼气是农家致冷空调系统的理想替代能源。本文介绍一种以太阳能和沼气为能源,利用热动力驱动的致冷空调系统。该系统自控性好,适应性强,致冷空调效果佳,并且能在低温差下自行 相似文献
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研究了一种太阳能喷射/压缩复合制冷循环,由太阳能集热子系统、喷射制冷子系统及压缩制冷子系统组成,系统充分利用热电两种能源以及两种制冷方法各自的优点,优化喷射制冷子系统工作性能的同时,改善压缩式子系统的工作条件,从而提高复合制冷循环性能的同时节约高品位电能。采用性能较好的高蒸发温度式喷射制冷带走压缩机排气余热具有实际意义。通过数值模拟的手段分析系统性能及其主要影响因素,并优化工作条件。研究表明,与相同工作条件下的单压缩制冷循环相比,复合制冷循环工作日全天候运行时电力性能系数提升约为31.5%,节电优势显著。存在一个最佳的喷射子系统蒸发温度使得复合制冷循环性能系数达到运行工况的最大值。 相似文献
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本文研究一种以太阳能为动力的溶液再吸收与稀溶液增压的喷射吸收制冷循环,建立了相应的物理模型,以NH3-LiNO3做工质对进行了热力计算。结果表明,相地于传统吸收式制冷循环,该循环具有明显的优点;(1)高压稀溶液引射低压制冷剂蒸气,使吸收过程处于较高的压力状态,从而提高了吸收效果和循环的制冷效率;(2)在经济合理利用电能的前提下,通过增加泵功输入,可以大幅度提高制冷量,为低品位不稳定热源--太阳能的 相似文献
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介绍了结构简单、工作可靠的太阳能喷射式制冷系统的原理和工作过程,给出了一个模拟计算。采用R134a为制冷剂,在发生器温度90℃、冷凝器温度20~38℃和蒸发器温度 6~14℃时,对系统效率进行了模拟计算。结果表明,该系统具有一定的可行性。本文还对理想状况下水作为制冷剂的系统效率进行了讨论。 相似文献
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太阳能喷射式制冷系统性能的实验研究 总被引:4,自引:0,他引:4
对太阳能喷射式制冷系统进行了实验研究,采用电加热模拟太阳能辐射的方法,研究了冷凝器、发生器和蒸发器温度对制冷系统COP的影响,给出了太阳能喷射式制冷系统制冷能力与COP随时刻的变化关系。系统在80℃热源条件下,全天提供16℃的冷水,系统最大制冷量为0.43 kW。 相似文献
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利用?分析法对太阳能喷射制冷系统?损失随太阳辐射值的变化情况进行分析,了解系统各部件的?损失情况,给出系统总?损失随太阳辐射值变化的规律和系统各部件?损失占系统总?损失的比例随太阳辐射值变化的规律。结果表明:集热器?损失占系统总?损失的比例最大且随太阳辐射值的增加而减小,在太阳辐射值为500~1 100 W/m~2时,集热器?损失占系统总?损失的比例为79.28%~81.94%,因此提高集热器效率对降低系统?损失有着至关重要的影响。另外,由于喷射器固有结构的限制,随着发生温度的升高,喷射系数EER、系统性能系数COP并非一直增大,系统存在一个最佳的发生温度;控制发生温度在75℃时,随着太阳辐射值的增大,系统性能系数COP逐渐增大,在太阳辐射值达到600 W/m~2时逐渐变小。 相似文献
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Energy and exergy balances were done on a novel solar bi‐ejector refrigeration system with R123, whose circulation pump is replaced by an injector. The analysis result of the novel system was compared with that of the original one. The effect of operation condition on system energy efficiency, exergy efficiency and exergy loss was analyzed, and the dynamic performance of a designed solar bi‐ejector refrigeration system was also studied. The comparative results indicate that under the same operating condition, the novel system and the original system have equal energy efficiency, exergy efficiency and exergy loss, and the only difference between them is the exergy losses of the generators and the added injector. The other conclusions mainly include: the solar collector has the largest exergy loss rate of over 90% and for the bi‐ejector refrigeration subcycle, the ejector has the largest exergy loss rate of about 5%; the total exergy loss changes inversely proportional to the evaporation temperature and positively proportional to the condensation temperature; when the other parameters are fixed, there exists an optimum generation temperature, at which the overall energy and exergy efficiencies are both the maximum and the total exergy loss is the minimum. The study points out the direction for optimizing the novel solar bi‐ejector refrigeration system. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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《Applied Thermal Engineering》2001,21(2):157-168
This paper describes the development of an ejector refrigeration system that is powered by solar thermal energy. The cooling system contains no active parts and is therefore deemed passive. Water is used as the refrigerant though other natural refrigerants could be used for lower temperature operation. A prototype system was built with a nominal cooling capacity of 7 kW. This system was laboratory tested and then installed in an existing office in Loughborough, UK. The system has operated with a COP of up to 0.3 at this location. The system is also able to provide up to 20 kW of heating to the building during the winter. 相似文献