吸收式制冷设备及其经济分析

本文着重分析吸收式制冷设备的特性、使用场合及其经济性,同时分析了利用低品位热能和工业余热作吸收式制冷设备的经济性,并给出了不同制冷设备经济指标的比较。     

低品位热能在制冷技术中的应用研究

分析了低品位热能在吸收式制冷、吸附式制冷以及蒸气喷射式制冷中的应用情况，提出以喷射式制冷为基础、以Ｒ１２３为工质的制冷装置是利用低品位热源比较理想的制冷装置。     

扩散吸收式制冷技术进展

扩散吸收式制冷（Diffusion Absorption Refrigeration,DAR）能够利用低品位能源如太阳能和余热等,是一种有利于环保和能源高效利用的技术,具有十分广阔的应用前景。结合国内外的最新研究动态,本文从工质选择、循环热力学分析、系统改进与优化研究三个方面介绍扩散吸收式制冷技术的主要研究成果,并对扩散吸收式制冷技术的发展趋势以及未来研究方向进行展望。同时,对本课题组关于扩散吸收式制冷所做的工作也进行了总结。     

单压吸收式制冷循环

单压吸收式制冷循环以道尔顿分压定律为理论基础 ,通过改变压力平衡剂在制冷剂蒸气中的浓度来改变制冷剂的分压力从而改变制冷剂的蒸发温度 ,实现蒸发制冷。该循环最大的特点是整个系统处于单一的压力状态 ,使用低品位热能就能实现制冷效果 ,因此 ,在小型吸收式制冷装置方面具有良好的发展前景。本文介绍了单压吸收式制冷循环的组成和制冷机理、可用工质组以及确定运行参数的基本原则。     

低品位热能制冷发电站

以低沸点工质为循环制冷作功工质,以低品位热能为热源,建设低品位热能制冷发电站,用以制冷、发电。     

低品位热能制冷发电站

以低沸点工质为循环制冷作功工质,以低品位热能为热源,建设低品位热能制冷发电站,用以制冷、发电。     

能源工业的可持续发展

利用低温工质制冷发电的方法，以低温工质为循环制冷作功工质，依托具有低品位热能的太阳能，地热能，工业余热与低污染的低品位工业热能为热源，建设发电站与制冷发电站，用以制冷与发电。以此来减少煤炭，石油，天然气的消耗量，抑制大气中ＣＯ２气体浓度的增加，减缓全球气候变暖。     

废汽制冷 效益可观

漠化及吸收式制冷机组是一种利用热能制冷的设备。其优点是耗电极少，在电力供应紧张、热能相对富裕的情况下具有推广价值。尤其是热水型漠化程吸收式制冷机组，可充分利用低位康热，为大中型抗生素企业有效利用发酵消毒废汽创造了条件。     

环境中的低品位热能利用研究

环境中的低品位热能储量巨大,但一般将其视为不可用能,主要是很难将其可用性体现出来。通过深冷制冷循环形成一个远低于环境温度的冷源,环境中的低品位热能的可用性就能充分显现出来。将低品位热能的可用性发挥出来用于此循环,能减少高等级能量的需要。为了达到此目的,需要一个能用低品位热能做功的设备。气动压缩机中动力源来自增压液体工质和增压气体混合的湿蒸气,做功后的湿蒸气一部分节流产生的深冷温度的冷量用于维持深冷制冷循环的需要;温度上升后的低压气体工质在对外输出冷量的同时吸收外部低品位热能,增压、增温后的高压气体工质经喷射器与液体工质混合。循环对外输出的冷量成为循环的收益,可以通过阶梯利用或复用等方式增加制冷的效益。     

带吸收式制冷的汽轮机热电联产

<正> 许多工业部门或其他部门既需要一定电力,也需要一部分热能。有些单位设置了背压式汽轮机进行热电联产以满足热和电这两方面的需求。为了提高热电联产的效率,足够的热负荷是很重要的。通常热负荷是用于干燥、蒸煮以及冬季供暖等等。在某种条件下,热电联产的热负荷往往不足。近年来,利用低品位蒸汽作为热源的吸收式制冷机在国外已得到普及,在我国的应用也越来越多。今后不但工业部门或者其他部门(如大型宾馆等)有条件的均可采用带吸收式制冷的热电联产,冷天可利用余热进行供暖,热天则由吸收式制冷机利用余热供空调,以及日常过程冷却和冷藏等用。这样就可以大大节省电力,使背压式汽轮机进     

太阳能相变蓄热应用于吸收式制冷的分析

介绍了一种将太阳能相变蓄热技术应用于两级吸收式制冷的新型空调系统,简要分析了该系统的装置结构、工作原理和使用优点。对相变蓄热装置放热过程中放热盘管出水温度随放热时间的变化关系进行了实验测量,并对两级吸收式制冷系统效率进行了分析。通过研究可知,该太阳能空调系统有效解决了以往系统不稳定性和间断性问题;太阳能相变蓄热装置具有体积小、蓄热量大、放热速率大、连续放热温度均匀、便于控制热源加热温度等特点,适合储存太阳能并为吸收式制冷系统提供加热热源。综合考虑系统设备简单,加工要求低的制造特点,所以吸收式制冷以太阳能等低品位热源驱动有着良好的发展前景。     

降低吸附式制冷系统驱动热源温度的研究进展

吸附式制冷是一种环境友好的制冷方式,可以利用低品位热能提供冷量,因此具有重要的节能意义。目前,吸附式制冷技术在太阳能热利用、工业余热利用等中低温余热领域已有应用,但对低于60℃热源的利用实例较少。降低吸附式制冷系统所需的驱动热源温度是扩大吸附式制冷系统使用范围的重要手段。吸附式制冷系统所需驱动热源温度与系统循环方式、吸附剂性能等因素密切相关。从二级/多级吸附式制冷循环、表面酸性强度与孔结构等影响吸附剂再生温度方面阐述了降低吸附式制冷系统驱动热源温度技术的国内外研究现状。分析结果显示,多级循环吸附式制冷系统可以降低装置的驱动热源温度,但装置结构较为复杂;低再生温度吸附剂能够拓宽吸附式制冷装置的驱动热源温度范围,吸附剂的脱附温度与表面极性、酸性、孔结构等参数有关,对吸附剂进行改性,吸附剂极性弱、酸性低的表面特性有利于降低脱附温度。另外,还介绍了数据中心余热驱动的吸附式制冷技术。开展降低吸附式制冷系统驱动热源温度的研究为低温余热高效利用提供了技术参考。     

Simulation research on an EAX (Evaporator-Absorber-Exchange) absorption refrigeration cycle

There are some heat sources whose temperature is much higher than the limited generation temperature of conventional single effect absorption refrigeration cycle but lower than that of conventional double effect absorption refrigeration cycle. These heat sources can not be utilized efficiently by prior cycles. To make efficient use of these heat sources, this paper proposed an EAX (Evaporator-Absorber-Exchange) absorption refrigeration cycle. The proposed cycle can make use of the condensing heat of the vapor separated from high temperature generator to make additional refrigeration. Therefore, the COP (Coefficient of Performance) of the proposed cycle is much higher than that of the conventional single effect cycle. Simulation results show that the COP of the EAX cycle can be 40% higher than that of the conventional single effect cycle at some simulated conditions.     

新型太阳能吸收式制冷循环的性能分析

在两级溴化锂吸收式制冷循环的基础上,提出了一种由太阳能驱动的新型吸收式制冷循环,并对其进行性能分析。通过大量计算,分析结果表明,在现有太阳能集热器所能提供的热水温度范围内,新型太阳能吸收式制冷循环有较高的热力系数。该循环系统的中间压力、中间浓度对系统的热力系数和热源可利用温差有较大影响。     

喷射式氨-水吸收制冷系统的研究

在传统吸收制冷系统中引入喷射器,根据喷射器理论和吸收制冷循环理论,对新制冷系统的工作性能进行了模拟。分别探讨了冷凝温度、喷射器压缩比等参数对系统性能系数和发生温度的影响。结果表明,在原有吸收制冷系统结构变化不大的情况下,尽管系统性能系数有所下降,但系统发生温度却显著降低,因此,低品位的热源将有可能成为氨吸收制冷的加热热源,对于节能减排具有重要的意义。     

Theoretical and experimental investigation of an ammonia–water power and refrigeration thermodynamic cycle

A combined thermal power and cooling cycle proposed by Goswami is under intensive investigation, both theoretically and experimentally. The proposed cycle combines the Rankine and absorption refrigeration cycles, using a binary ammonia–water mixture as the working fluid. This cycle can be used as a bottoming cycle using waste heat from a conventional power cycle or an independent cycle using low temperature sources such as geothermal and solar energy. Initial parametric studies of the cycle showed the potential for the cycle to be optimized for first or second law efficiency, as well as work or cooling output. For a solar heat source, optimization of the second law efficiency is most appropriate, since the spent heat source fluid is recycled through the solar collectors. The optimization results verified that the cycle could be optimized using the generalized reduced gradient method. Theoretical results were extended to include realistic irreversibilities in the cycle, in preparation for the experimental study. An experimental system was constructed to demonstrate the feasibility of the cycle and to compare the experimental results with the theoretical simulation. Results showed that the vapor generation and absorption condensation processes work experimentally. The potential for combined turbine work and refrigeration output was evidenced in operating the system. Analysis of losses showed where improvements could be made, in preparation for further testing over a broader range of operating parameters.     

An experimental comparison between LPG and engine exhaust gas as energy source for an absorption refrigeration system

This paper presents an experimental analysis of an absorption refrigeration system, comparing two different energy sources. The exhaust gas from an internal combustion engine was evaluated against the original energy source, liquefied petroleum gas (LPG). The experiments were performed in a domestic refrigerator, monitoring the air temperature and humidity inside the equipment. A production engine was tested with 25% and wide‐open throttle valve (WOT), mounted on a bench dynamometer. The energy demand, cooling capacity and coefficient of performance (COP) were determined for both energy sources. The results showed that engine exhaust gas is a potential source for absorption refrigeration systems. When the engine exhaust gas was used as energy source, the energy available for the refrigerator was higher with 25% throttle valve opening. Copyright © 2011 John Wiley & Sons, Ltd.     

Experimental investigation of integrated refrigeration system (IRS) with gas engine,compression chiller and absorption chiller

An integrated refrigeration system (IRS) with a gas engine, a vapor-compression chiller and an absorption chiller is set up and tested. The vapor-compression refrigeration cycle is operated directly by the gas engine. The waste heat from the gas engine operates the absorption refrigeration cycle, which provides additional cooling. The performance of the IRS is described. The cooling capacity of the IRS is about 596 kW, and primary energy ratio (PER) reaches 1.84 at air-conditioning rated conditions. The refrigerating capacity of the prototype increased and PER of prototype decreased with the increase of the gas engine speed. The gas engine speed was preferably regulated at part load condition in order to operate the prototype at high-energy efficiency. The refrigerating capacity and PER of the prototype increased with the increase of the outlet temperature of chilled water or the decrease of the inlet temperature of cooling water. The integrated refrigeration chiller in this work saves running costs as compared to the conventional refrigeration system by using the waste heat.     

Study on a solar-driven ejection absorption refrigeration cycle

This paper deals with a solar-driven ejection absorption refrigeration (EAR) cycle with reabsorption of the strong solution and pressure boost of the weak solution. The physical model is described and the corresponding thermodynamic calculation is performed with the working pair NH₃–LiNO₃. It is demonstrated that the EAR cycle has obvious advantages as compared with the conventional absorption refrigeration cycle: (1) the controllable high absorption pressure allows for substantially high coefficients of performance by the action of a liquid–gas ejector in which the low-pressure refrigerant vapour is injected and pressurized as a result of the ejection of high-pressure solution; (2) internal steady operation can be realized for refrigeration cycles driven by unsteady heat sources, especially for solar energy, by adjusting the power input consumed by solution pumps under the condition of economical and reasonable utilization of electric energy. © 1998 John Wiley & Sons, Ltd.