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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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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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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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利用低位能的氨水吸收式制冷(AAR)系统设计软件的开发及应用 总被引:1,自引:0,他引:1
介绍了氨水吸收式制冷系统设计中的计算机软件化过程,利用Visual Basic集成编译环境,采用OOP(面向对象编程)技术,编制基于Windows操作系统的应用软件,实现氨水吸收式制冷系统设计计算的图形化,可视化,用户可以在良好的界面和操作演示帮助的引导下完成流程选择,参数计算,设备计算等操作,对多种状态参数组合的计算结果与实际计算数据进行分析对比,得到令人满意的结果。 相似文献
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本文介绍了以工业余热为热源的单级氨水吸收式制冷机在工业制冰(蓄冰)与冰藏申的应用。通过生产性实验,初步得出了该机在生产中的性能变化规律及效率。并将该机与压缩式制冷机进行了技术经济比较,阐明了其在工业余热升级利用及节能增效中所起的作用。 相似文献
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吸收式制冷技术的应用与发展 总被引:5,自引:1,他引:4
王长庆 《能源技术(上海)》2000,21(1):31-35
溴化锂吸收式制冷技术在我国得到了飞速发展和广泛应用。介绍了溴化锂吸收式制冷技术在我国应用情况,对单效机,双效机及直燃机的应用场合进行了分析,同时对溴化锂吸收式制冷技术将来的发展进行了展望。 相似文献
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A computational model is developed for the parametric investigation of single‐effect and series flow double‐effect LiBr/H2O absorption refrigeration systems. The effects of generator, absorber, condenser, evaporator and dead state temperatures are examined on the performance of these systems. The parameters computed are coefficient of performance (COP), exergy destruction rates, thermal exergy loss rates, irreversibility and exergetic efficiency. The results indicate that COP and exergetic efficiency of both the systems increase with increase in the generator temperature. There exist different optimum values of generator temperature for maximum COP and maximum exergetic efficiency. The optimum generator temperature is lower corresponding to maximum exergetic efficiency as compared to optimum generator temperature corresponding to maximum COP. The effect of increase in absorber, condenser and evaporator temperatures is to decrease the exergetic efficiency of both the systems. The irreversibility is highest in absorber in both systems. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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This paper describes the performance of an ammonia–water combine ejector–absorption cycle as refrigerator and heat pump. This combination brings together the advantages of absorption and ejector systems. Also, thermodynamic cycles on the temperature–enthalpy and temperature–entropy charts are shown. The thermodynamics of the combined ejector–absorption cycles are simulated by a suitable method and a corresponding computer code, based on analytic functions describing the behaviour of the binary mixture NH3–H2O. It is found that in the case of the refrigerator and heat pump, the theoretical coefficient of performance (COP) or the theoretical heat gain factor (HGF) vary from 1.6 to 90.4 per cent and 0.7 to 37.6 per cent, greater than those of the conventional absorption system, respectively. The operation conditions were: generator temperature (205.5 to 237.1°C), condenser temperature (25.9 to 37.4°C) and evaporator temperature (−8.4 to 5°C). Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
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Gorakshnath Takalkar 《国际能源研究杂志》2020,44(15):12269-12283
The combination of ionic liquid-refrigerant based [EMIM][DMP]-H2O as an alternative working pair for single effect vapor absorption cycles (VACs) is assessed and optimized by using energy and exergy based performances. Thermodynamics properties of binary mixture of [EMIM] [DMP]-H2O like Dühring's (P-T-x1) and h-T-X1 plots are computed from the activity coefficient based non-random two-liquid model (NRTL) model. Further modeling and simulation of VACs are accomplished in open source Scilab as mathematical programing software and used to ascertain the optimal generator temperature established on energetic and exergetic COP. Optimal results include an extensive range of temperatures like Te from 2.5 to 15°C and Ta and Tc from 30 to 45°C. Simulation of the single effect VAC with SHE by using [EMIM][DMP]-H2O mixture at Te = 10°C, Tg = 100°C, Ta = 30°C, and Tc = 40°C were evaluated and compared with the 5 working fluids. Simulation outcomes depicted greater COP of 0.82 for [EMIM][DMP]-H2O in comparison with NH3-H2O, EMISE-H2O, [EMIM][BF4]-H2O and nearly equal to LiBr-H2O (COP = 0.83). In addition, the effect of Tg on the COP, ECOP f , and composition are compared and optimized for the evaporation temperature range from 2.5 to 15°C, Ta/Tc from 30 to 45°C and cooling water (CW) flow in series and parallel. Additionally, the optimal Tg exhibited distinction based on energy and exergy analysis. Thus, it resulted in optimized performances of [EMIM] [DMP]-H2O that can be suitable to replace corrosive aqueous LiBr in VACs. 相似文献
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This paper presents the performance investigation of a shell and helical coil type of Solution Heat Exchanger (SHX) in an ammonia–water vapour absorption system. In an absorption system, SHX is one of the major heat recovery components. The main objective of any heat exchanger design is to achieve minimum heat transfer area required for a given heat duty, as it governs the overall fixed cost content of such a system. The required surface area is decided by the overall heat transfer coefficient. Hence, the heat transfer coefficient (HTC) correlation plays a major role in optimizing the heat exchanger. In this paper, shell and helical coil type of SHX is investigated with more emphasis on the dimensionless correlation of shell side co-efficient, which decides the overall HTC and the size of heat exchanger. From the experimental study, shell side heat transfer coefficient of 510–650 W/m2 K is obtained with the heat exchanger effectiveness of 0.84–0.9 for the tested conditions. A proposed Nusselt number correlation is compared with the experimental results. 相似文献
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José Fernández-Seara Alberto Vales Manuel Vázquez 《Applied Thermal Engineering》1998,18(12):1189-1205
This paper is concerned with the design, modelling and parametric analysis of a gas-to-thermal fluid heat recovery system from engine exhausts in a trawler chiller fishing vessel to power an NH3-H2O absorption refrigeration plant for onboard cooling production. Synthetic oil was used as heat transfer fluid and recirculated. The major components of the system are fluid-to-solution and gas-to-fluid heat exchangers. Both heat exchangers and the complete system have been modelled. Models are implemented in several computer programs. These models have been used to study the influence of geometric design parameters and thermal operating conditions on heat exchangers and system thermal performance. The analysis of the results allowed us to find the optimum thermal operating conditions that minimise total heat transfer area. Optimal design based on real data was performed and the operating function of exhaust gases by-pass control was obtained and is presented. 相似文献
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AbstractTernary Al2O3-ZrO2-Y2O3 samples with a eutectic composition were prepared by slow cooling. The microstructural evolution was observed with X-ray diffraction (XRD), scanning electron microscopy (SEM).The SEM observation of the ternary samples agreed with the XRD with a completion of crystallisation by slow cooling. The target materials commonly have ‘cantaloupe skin’ microstructures as shown in the previous studies by Han et al. The nanocomposite may have experienced different cooling rates with two different microstructures, near the surface having experienced optimal conditions for the eutectic reaction during their cooling and thus formed the eutectic microstructure, near the centre having experienced a slower cooling rate. The crystallised eutectic ternary Al2O3-ZrO2-Y2O3 system had three different phases with a 3Y2O3-5Al2O3 (yttrium-aluminium garnet phase), an alumina phase formed by the eutectic reaction, and a solid solution of ZrO2 and Y2O3. 相似文献
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The NH3 oxidation and reduction process are experimentally and kinetically studied in this paper. It is found that NH3 has contributions not only to N2O formation, but also to N2O destruction in certain conditions. The main product of homogeneous NH3 oxidation is found to be NO rather than N2O, but some bed materials and sulphur sorbents have catalytic contributions to N2O formation from NH3 oxidation. In reduction atmosphere, NH3 can promote the KC destruction. It is deduced that the ammonia injection into fluidized bed coal combustion flue gas can
decrease both NOx and N2O emissions. The ammonia injection process is kinetically simulated in this study, and the reduction rates of NOx and N2O are found to depend on temperature, O2 concentration, initial NOx and N2O concentrations, and amount of injected ammonia. 相似文献
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The present study exemplifies the comprehensive thermal analysis to compare and contrast ammonia‐lithium nitrate (NH3‐LiNO3) and ammonia‐sodiumthiocynate (NH3‐NaSCN) absorption systems with and without incorporation of nanoparticles. A well‐mixed solution of copper oxide/water (CuO/H2O) nanofluid is considered inside a flat‐plate collector linked to an absorption chiller to produce 15‐kW refrigeration at ?5°C evaporator temperature. Enhancements in heat transfer coefficient, thermal efficiency, and useful heat gain of the collector are evaluated, and the effect of these achievements on the performance of both absorption chillers have been determined for different source temperatures. A maximum 121.7% enhancement is found in the heat transfer coefficient with the application of the nanofluid at 2% nanoparticle concentration. The maximum coefficient of performance observed for the NH3‐NaSCN chiller is 0.12% higher than that for the NH3‐LiNO3 chiller at 0°C evaporator temperature. Contradictory to this, the average system coefficient of performance of the NH3‐LiNO3 absorption system has been found 5.51% higher than that of the NH3‐NaSCN system at the same evaporator temperature. Moreover, the application of the nanofluid enhanced the performance of the NH3‐NaSCN and NH3‐LiNO3 systems by 2.70% and 1.50%, respectively, for lower generator temperature and becomes almost the same at higher temperatures, which altogether recommends the flat‐plate collector–coupled NH3‐LiNO3 absorption system be integrated with a nanofluid. 相似文献