共查询到19条相似文献,搜索用时 390 毫秒
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由于可以利用低品位热源制冷,氨水吸收式制冷系统得到了广泛的应用。氨水系统的精馏器要求很高的安装精度,限制了其应用范围。为了开发新型制冷器,将升膜理论应用到氨水吸收式制冷系统中,用一个冷凝发生器来实现精馏塔的作用。研究结果表明,本循环的热力系数比较高,这一成果可广泛应用于各种车、船等的制冷系统设计中。 相似文献
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介绍太阳能集热器和氨水吸收式制冷机的结构、原理和特点,对利用太阳能驱动氨-水吸收式制冷空调的可行性进行分析探讨,阐述研制开发太阳能氨水吸收式制冷空调对节能降耗保护环境的意义. 相似文献
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氨水喷射-吸收式制冷循环的研究 总被引:6,自引:0,他引:6
对喷射增压的氨水吸收式制冷循环进行分析和热力计算,分别与一般的氨水吸收式循环相比,前在相同的热源温度下,获取的最低蒸发温度能够降低10℃左右,单级喷射-吸收系统的COP一直保持在O.3左右,双级喷射-吸收系统的COP在O.2左右。虽然在较高的蒸发温度段该制冷循环的性能系数略有降低,但是它能够利用现实中许多低品位的热源获取更低的蒸发温度。 相似文献
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氨水吸收式制冷需要消耗很大的公用工程,其性能系数(COP)不是很高,引入夹点分析法分析氨水吸收式制冷系统,该方法能够确定可回收的系统最大内部循环热,优化后的系统性能系数为0.623,比优化前的系统性能系数高11.58%。该方法对氨水吸收式制冷设计具有一定的指导意义。 相似文献
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利用氨水吸收式循环将太阳能与地热两个热源结合,提出了一种新颖的制冷与供热系统。由于热源温差的协调配置,该系统具有更高的能量利用特性。还研究了热源温度以及重要内部操作条件对系统制冷、供热效率的影响规律,探讨了该系统的可行性。 相似文献
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由于我国节能减排政策的引导,工业余热氨水吸收式制冷系统以其节能减排、制冷效果好等优点越来越引起人们的关注。工业余热氨水吸收式制冷系统的研究主要集中在新型工质对的寻求、强化传热传质、优化制冷循环系统的研究等方面,特别是吸收器的吸收强化及活性剂的研究,成为工业余热氨水吸收式制冷系统的研究热点,通过对以上内容进行了详细分析,并指出今后的发展趋势。 相似文献
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《Applied Thermal Engineering》2003,23(13):1577-1593
In the absorption refrigeration system (ARS) working with aqua–ammonia, the ejector is commonly located at the condenser inlet. In this study, the ejector was located at the absorber inlet. Therefore, the absorber pressure becomes higher than the evaporator pressure and the system works with triple-pressure-level. The ejector has two main functions: (i) aiding pressure recovery from the evaporator, (ii) upgrading the mixing process and the pre-absorption by the weak solution of the ammonia coming from the evaporator. In addition to these functions, it can also act to lower the refrigeration and heat-source temperatures. Energy analyses show that the system’s coefficient of performance (COP) and exergetic coefficient of performance (ECOP) were improved by 49% and 56%, respectively and the circulation ratio (f) was reduced by 57% when ARS is initiated at lower generator temperatures. Due to the reduced circulation ratio, the system dimensions can be reduced; consequently, this decreases overall cost. The heat source and refrigeration temperatures decreased in the range of 5–15 °C and 1–3 °C, respectively. Exergy analyses show that the exergy loss of the absorber of ARS with ejector had a higher exergy loss than those of the other components. Therefore, a multiple compartment absorber can be proposed to reduce the exergy loss of the absorber of ARS with ejector. 相似文献
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Petro O. Kapustenko Leonid M. Ulyev Stanislav A. Boldyryev Andrey O. Garev 《Energy》2008,33(6):882-889
The food processing industry in Ukraine is widely developed and continues to develop. The majority of the enterprises of the food processing industry use the technological process with refrigerating cycles. Basically it uses ammonia refrigeration units. In existing ammonia refrigeration units waste energy from ammonia overheat after compression is not used. This waste energy can be used for heating of other technological streams. It can be achieved by detailed inspection of the technological streams system and further heat integration of the ammonia unit into a heating system of the enterprise. In this study an inspection of a cheese production plant has been conducted and the opportunity to heat integration of an existing ammonia refrigeration unit into technological process is considered. At present energy from ammonia superheating and condensation is not used and is expelled into the atmosphere through the cooling tower. There are two options for use of this heat: first without additional compression of ammonia and second with additional compression of ammonia stream. Both cases are considered. 相似文献
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《Applied Thermal Engineering》2007,27(11-12):2059-2065
Absorption strengthen is an effective way to improve the coefficient of performance (COP) of ammonia–water absorption refrigeration system. A mathematical absorption model for ammonia–water falling film absorption in magnetic field was built in this paper to study the influence of magnetic field on the absorption process. Macroscopic magnetic field force was introduced to the mathematical model. Changes in physical properties of ammonia–water solution while absorbing, the variation of falling film thickness along falling and the convection in the direction of thickness of liquid film have been considered in modeling. Numerical results showed that magnetic field have positive effect on the ammonia–water falling film absorption to some degree. When the magnetic induction intensity at the solution’s inlet is 3 Tesla (T), the increment in concentration of ammonia–water solution at outlet is 1.3% and the absorbability increased by 5.9%. The COP of a simple ammonia–water absorption refrigeration system increased by 4.73% and the decrement in circulation ratio is 8.3%. 相似文献
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对采用氨水溶液的变质量能量转换及储存系统的工作原理、工作循环和流程进行介绍。由于蓄能系统的能量转换过程是一个与时间有关的动态过程,常规的稳态制冷/热泵循环热力计算方法已不再适用,需给出一种新的动态热力计算方法。通过数值模拟来了解先进蓄能系统的工作特性,为进一步研究、开发该蓄能系统奠定理论基础。 相似文献
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Cogeneration has improved sustainability as it can improve the energy utilization efficiency significantly. In this paper, a novel ammonia-water cycle is proposed for the cogeneration of power and refrigeration. In order to meet the different concentration requirements in the cycle heat addition process and the condensation process, a splitting /absorption unit is introduced and integrated with an ammonia–water Rankine cycle and an ammonia refrigeration cycle. This system can be driven by industrial waste heat or a gas turbine flue gas. The cycle performance was evaluated by the exergy efficiency, which is 58% for the base case system (with the turbine inlet parameters of 450 °C/11.1 MPa and the refrigeration temperature below −15 °C). It is found that there are certain split fractions which maximize the exergy efficiency for given basic working fluid concentration. Compared with the conventional separate generation system of power and refrigeration, the cogeneration system has an 18.2% reduction in energy consumption. 相似文献
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Exergy analysis of industrial ammonia synthesis 总被引:4,自引:0,他引:4
Exergy consumption of ammonia production plants depends strongly on the ammonia synthesis loop design. Due to the thermodynamically limited low degree of conversion of hydrogen–nitrogen mixture to ammonia, industrial ammonia synthesis is implemented as recycle process (so-called “ammonia synthesis loop”). Significant quantities of reactants are recycled back to reactor, after the removal of ammonia at low temperatures. Modern ammonia synthesis plants use well-developed heat- and cold recovery to improve the reaction heat utilisation and to reduce the refrigeration costs. In this work, the exergy method is applied to estimate the effect of the most important process parameters on the exergy efficiency of industrial ammonia synthesis. A specific approach, including suitable definitions of the system boundaries and process parameters, is proposed. Exergy efficiency indexes are discussed in order to make the results applicable to ammonia synthesis loops of various designs. The dependence of the exergy losses on properly selected independent process parameters is studied. Some results from detailed exergy analysis of the most commonly used ammonia synthesis loop design configurations at a wide range of selected parameters values are shown. 相似文献