共查询到19条相似文献,搜索用时 125 毫秒
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根据上海的气候条件,以上海地区某写字楼为对象,提出4种太阳能驱动的溴化锂吸收式与电动蒸汽压缩式热泵联合制冷与供暖系统。这4种系统分别由热管式真空管集热器或抛物面槽形聚光集热器,单效或双效溴化锂吸收式制冷机,以及风冷热泵或水源热泵构成。分析比较这4种系统的节能型和经济性的结果表明,采用抛物面槽形聚光集热器+双效溴化锂吸收式制冷机+风冷热泵组成的系统,同时具备较好的节能性与经济性,一次能源利用率可降低约50%。 相似文献
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太阳能空调系统特征方程的研究 总被引:2,自引:0,他引:2
通过对太阳能空调系统中能量转换过程的分析,运用一新无因次参数,建立了表征太阳能空调系统热性能特点的特征方程,揭示了系统日制冷量与吸收式制冷机的性能系数以及太阳辐射参数之间的线性关系,并通过将该特征方程用于计算-太阳能空调系统的年制冷量,介绍了特征方程的应用。 相似文献
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根据别墅建筑的特点,建立一套太阳能与小型溴化锂吸收式制冷机相结合的制冷/热泵系统。该系统可为别墅建筑实现夏季制冷、冬季供暖以及全年提供生活用热水多项功能。介绍了整个系统的形式及其工作原理以及如何选择太阳能集热器和吸收式制冷机,并指出了系统的初投资较高、系统效率较低等不足;建议了提高制冷机制冷系数的措施以提高系统的总效率。 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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小型太阳能溴化锂吸收式制冷系统的优化设计 总被引:2,自引:0,他引:2
小型太阳能溴化锂吸收式制冷机是当今制冷空调业中的研究重点,其中需要解决的关键问题是换热器的合理选择和优化设计,最终达到提高效率、减小体积和节约成本的多重目的。实验室设计的5 kW吸收式制冷机组为板式换热器和管壳式换热器的结合体,经过数值计算模拟,可达到理想效果。 相似文献
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进行溴化锂吸收式制冷机塑料换热装置及制冷机系统的结构设计,塑料换热装置的传热管采用聚四氟乙烯塑料管,传热管布置为阿基米德螺线状盘管,将实验传热系数与理论计算传热系数进行比较。比较结果表明:冷凝器、蒸发器实验传热系数低于理论计算值,吸收器的实验传热系数高于理论计算值。 相似文献
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《Applied Thermal Engineering》2007,27(8-9):1642-1652
In China, the application of small size gas-fired air-cooled absorption refrigeration systems as an alternative for electric compression air conditioning systems has shown broad prospects due to occurrence of electricity peak demand in Chinese big cities and lack of water resources. However, for conventional air-cooled absorption refrigeration systems, it is difficult to enhance the heat and mass transfer process in the falling film absorber, and may cause problems, for example, remarkable increase of pressure, temperature and concentration in the generators, risk of crystallization, acceleration of corrosion, degradation of performance, and so on. This paper presents a gas-fired air-cooled adiabatic absorption refrigeration system using lithium bromide–water solutions as its working fluid, which is designed with a cooling capacity of 16 kW under standard conditions. The system has two new features of waste heat recovery of condensed water from generator and an adiabatic absorber with an air cooler. Performance simulation and characteristic analysis are crucial for the optimal control and reliability of operation in extremely hot climates. A methodology is presented to simulate thermodynamic performance of the system. The influences of outdoor air temperature on operation performances of the system are investigated. 相似文献
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出了融除湿、蒸发冷却、压缩制冷及太阳能热水为一体的复合式太阳能空调的优化方案。分析比较了三种空气处理方案。结果表明 ,与常规空调相比 ,优化方案节电近 4 7%。 相似文献
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Two-stage air-cooled ammonia–water absorption refrigeration system could make good use of low-grade solar thermal energy to produce cooling effect. The system simulation results show that thermal COP is 0.34 and electrical COP is 26 under a typical summer condition with 85 °C hot water supplied from solar collector. System performances under variable working conditions are also analyzed. Circular finned tube bundles are selected to build the air-cooled equipment. The condenser should be arranged in the front to get an optimum system performance. The mathematical model of the two-stage air-cooled absorber considering simultaneous heat and mass transfer processes is developed. Low pressure absorber should be arranged in front of middle pressure absorber to minimize the absorption length. Configuration of the air-cooled equipment is suggested for a 5 kW cooling capacity system. Temperature and concentration profiles along the finned tube length show that mass transfer resistance mainly exists in liquid phase while heat transfer resistance mainly exists in cooling air side. The impacts on system refrigeration capacities related to absorption behaviors under variable working conditions are also investigated. Both cycle analysis and absorption performances show that two-stage air-cooled ammonia–water absorption chiller is technically feasible in practical solar cooling applications. 相似文献
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《Applied Thermal Engineering》2014,62(2):424-432
Large scale heat-driven absorption cooling systems are available in the marketplace for industrial applications but the concept of a solar driven absorption chiller for air-conditioning applications is relatively new. Absorption chillers have a lower efficiency than compression refrigeration systems, when used for small scale applications and this restrains the absorption cooling system from air conditioning applications in residential buildings. The potential of a solar driven ammonia–water absorption chiller for residential air conditioning application is discussed and analyzed in this paper. A thermodynamic model has been developed based on a 10 kW air cooled ammonia–water absorption chiller driven by solar thermal energy. Both energy and exergy analyses have been conducted to evaluate the performance of this residential scale cooling system. The analyses uncovered that the absorber is where the most exergy loss occurs (63%) followed by the generator (13%) and the condenser (11%). Furthermore, the exergy loss of the condenser and absorber greatly increase with temperature, the generator less so, and the exergy loss in the evaporator is the least sensitive to increasing temperature. 相似文献
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Numerical simulation of a solar-assisted ejector air conditioning system with cold storage 总被引:1,自引:0,他引:1
Indoor space cooling represents a large potential for solar energy use due to the relative coincidence between energy availability and cooling demand. Solar-assisted air conditioning (AC) applications emerged with the development of high efficiency solar collectors. Energy storage (hot or cold) must be implemented for solar-assisted AC applications when cooling demand is present during intervals without available solar energy and also for cooling capacity optimisation (“peak shaving”).The present paper analyses a solar-assisted ejector cooling system with cold storage. Simulations were carried out over one year considering climatic data for a hot location (Béchar, Algeria) and the performance of the system was assessed for a set of design conditions. Effects of cold storage upon comfort conditions and energy demand were evaluated. Maximum room temperature and overall interval of time during which the room temperature exceeded the set-point value were the parameters used to quantify system performance. It was found that cold storage improved comfort conditions compared to a system without storage. For some design conditions it was found that increasing the cold storage capacity did not result in improved comfort conditions. The control algorithm of the system was identified as the cause of this behaviour. 相似文献
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为了满足农村住宅清洁用能的需求,多种形式的能源系统逐渐开始应用于广大的农村地区。随着太阳能集热器集热效率的提高,热驱动机组各项性能不断改善,这样有利于太阳能吸收式空调系统在农村地区的应用。为了研究太阳能吸收式空调系统与农村住宅全年能耗的匹配问题,文章首先建立了DeST住宅模型,然后利用TRNSYS软件建立了太阳能吸收式空调系统模型,最后根据模拟结果对国内不同气候区内农村住宅供热季、供冷季的平均热负荷值,以及全年的能耗进行分析。此外,文章还分析了典型日太阳能吸收式空调系统的运行策略与效果。分析结果表明:在无辅助热源的条件下,太阳能集热器的集热温度会大于80℃,满足空调机组的热驱动温度,因此可以作为太阳能吸收式空调系统的的热源;当启动温度为85℃时,空调机组的制冷量可以达到8 kW,性能系数COP为0.733。 相似文献
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The present study deals with a small-scale solar-assisted absorption cooling system having a cooling capacity of 3.52 kW and was investigated experimentally under the climatic conditions of Taxila, Pakistan. Initially, a mathematical model was developed for LiBr/H2O vapor absorption system alongside flat-plate solar thermal collectors to achieve the required operating temperature range of 75°C. Following this, a parametric analysis of the whole system was performed, including various design and climate parameters, such as the working temperatures of the generator, evaporator, condenser, absorber, mass flow rate, and coefficient of performance (COP) of the system. An experimental setup was coupled with solar collectors and instruments to get hot water using solar energy and measurements of main parameters for real-time performance assessment. From the results obtained, it was revealed that the maximum average COP of the system achieved was 0.70, and the maximum outlet temperature from solar thermal collectors was 75°C. A sensitivity analysis was performed to validate the potential of the absorption machine in the seasonal cooling demand. An economic valuation was accomplished based on the current cost of conventional cooling systems. It was established that the solar cooling system is economical only when shared with domestic water heating. 相似文献
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B. Kundu P.K. Mondal S.P. Datta S. Wongwises 《International Communications in Heat and Mass Transfer》2010
An effort has been devoted to analyze the collector performance parameters of a solar-assisted LiBr/H2O vapor absorption cooling system with a flat-plate collector consisting of an absorber plate of different profiles. The effect of the collector fluid inlet temperature on the performance of solar collector, vapor absorption cycle, vapor absorption system and refrigerating efficiency has been studied for a wide range of design variables. A comparative study has also been made among the performance parameters of an absorber plate of different shapes with the variation of collector fluid inlet temperature. From the result, it can be highlighted that, at a particular collector fluid inlet temperature, the performances of a vapor absorption system attain a maximum value. Finally, an optimum collector fluid inlet temperature is determined by satisfying the minimization of volume of an absorber plate without affecting the cooling rate in the evaporator. 相似文献