炭化活化温度对活性炭-CaCl2复合吸附剂性能的影响

为研究并开发高性能的吸附剂,本文以CaCl₂和杉木木屑为原料,采用炭化活化造孔的方法制备复合吸附剂,考察了炭化活化温度对复合吸附剂性能的影响,炭化活化温度分别选择400℃、500℃、600℃和700℃。扫描电镜照片和元素分布图表明,复合吸附剂具有发达的孔隙结构而且CaCl₂分布均匀。NH₃吸附性能实验表明,吸附剂4 h的NH₃吸附量随炭化活化温度的升高而增加。而对于吸附制冷而言,500℃炭化活化温度下制备的复合吸附剂具有最好的性能,其30 min的吸附量达到0.488 g/g。     

太阳能固体吸附式制冷的研究与进展

本文阐述子利用太阳能作为驱动热源的固体吸附式制冷系统的工作原理及循环过程。     

固体吸附式制冷／热泵系统理想基本循环的理论分析

本文简单介绍了固体吸附式制冷／热泵系统的研究进展。     

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。     

固体吸附式制冷系统中吸附剂粒径及吸附床总孔隙率对吸附床传热性能的影响研究

文章采用数值模拟方法研究了圆筒型吸附床的二维非稳态脱附传热过程,并基于综合导热系数和接触热阻分析了吸附剂的粒径和吸附床的总孔隙率对吸附床传热性能的影响,以及吸附床的总孔隙率与吸附剂粒径的最优组合。分析结果表明:当吸附床的总孔隙率较大时,吸附剂粒径对吸附床传热性能的影响更为明显,且吸附剂粒径越小,吸附床的传热性能越好;随着吸附剂粒径逐渐增大,吸附床总孔隙率对吸附床传热性能的影响呈现出不同的变化趋势;当吸附剂的粒径较小且吸附床的总孔隙率较大时,吸附床的传热性能最优。     

一种新颖的太阳能制冷管及其性能实验研究

一种新颖结构的太阳能吸附制冷管,其吸附床由一种具有高强度,高吸附性能和导热性能,并对太阳能具有高吸收率的复合吸附剂块组成,与已有的太阳能制冷系统相比,每根冷管生成一个制冷系统,结构简单,密封性好,同时吸附床可直接吸收太阳辐射,提高了对太阳能的有效利用。实验表明,在未采用专门的集热装置,吸附床向阳面温度仅为７５℃左右的情况下,冷管的性能,系数可达８％左右。     

吸附式制冷系统的常用工质对及其应用特点

总结了目前吸附式制冷系统常用的吸附工质对的性能及研究应用现状,提出了常用工质对的优缺点及使用范围,为设计吸附式制冷系统时选择不同的工质对提供理论与经验依据。     

太阳能吸附式制冷和供热的研究展望

本文介绍了近几年来太阳能吸附式制冷和供热系统的国内外研究与应用开发状况，并综 了该领域今后的研究重点。     

余热制冷用氯化钙_硅胶复合吸附剂的制备及性能研究

为了开发出利用余热进行吸附制冷的高性能吸附剂,采用浸渍法在真空下将氯化钙担载于粗孔硅胶上,制备了硅胶/氯化钙复合吸附剂,测试了复合吸附剂的吸附等温线和吸附速率,测试结果表明:浸渍法得到的复合吸附剂对水具有更大的吸附能力,在20%的湿度下,复合吸附剂在2h的吸附量为15.64 g/100 g吸附剂,是单一硅胶在相同条件下吸附量的8.06倍。用制备的复合吸附剂制作了一台小型吸附制冷机并进行了测试,当热源温度为90℃,冷却水温度为35℃时,在整个循环周期内(15 min),制冷功率为0.705kW,单位质量吸附剂的制冷功率(SCP)为70.51 W/kg,COP为0.25。     

吸附剂固化的发展与固化活性炭块的试验研究

吸附剂的固化成型被认为是增大吸附式制冷系统的制冷量一个可行的方法。本文一方面综述了吸附系统中吸附剂固化的发展现状，讨论各种固化技术和方法。另一方面总结了在我们实验室所涉及的活性炭固化研究工作，给出了以块状活性炭一甲醇为吸附工质对时比较合适的固化工艺参数。     

Investigation on adsorption refrigeration with a single adsorbent bed

This paper describes an experimental investigation of adsorption refrigeration with a single generator (adsorbent bed) in a basic cycle, which verifies the previous theoretical conclusions that the cycle time and the maximum desorption temperature (corresponding to the maximum temperature of external heat source) are key factors with various influences to the COP and the cooling capacity of a cycle on a prototype machine. Moreover, in order to investigate the difference between theoretical and real cycles, a new physical parameter, the packing coefficient, is introduced to the adsorption cycle © 1998 John Wiley & Sons Ltd.     

脱附制冷系统的试验研究

根据CaCl2-NH3脱附过程的热力学原理,对脱附制冷循环的可行性进行了分析,对脱附循环中产生的冷量进行了计算,得出了系统的性能系数COP,通过试验测定了床层在脱附和吸附过程中的壁面温度,并建立了脱附制冷的数学模型,对管内的温度分布进行了模拟计算,得到了管内的温度分布图。研究表明,CaCl2-NH3脱附制冷循环具有较高的COP值和较大的制冷量输出能力。     

柴油机余热吸附式制冷系统的动力学实验研究

提出了一种发动机排气余热驱动的以氯化钙－氨为工质对的吸附式制冷机的设计方法，在实际工况下对该系统进行了测试，得出了系统的工作特性曲线，并采用吸附制冷单管实验台，对制冷系统单元吸附床在解吸和吸附过程中的传热传质特性进行了研究，结果表明，在恒定蒸发压力下，制冷能力随进入发生器的热流变化，吸附床内的传质过程主要受传热过程影响。     

基于平行流铝扁管吸附床传热性能的模拟研究

吸附床是吸附式制冷系统的关键部件。吸附床的换热能力对吸附式制冷系统的各项性能有显著影响。文章针对应用于吸附床的传统换热器和扁管换热器的不足之处,设计出一种新型平行流铝扁管吸附床,并建立了该吸附床的二维传热模型,以温度随时间的变化情况为分析指标,分析翅片的间距、高度、厚度,以及吸附剂体积分数等因素对吸附床传热性能的影响,从而优化调整吸附床的结构,提高其换热性能。分析结果表明:当翅片高度约为70 mm时,吸附床的换热能力达到峰值;当翅片厚度大于1.5 mm时,翅片厚度的增加对吸附床传热性能的影响比较微弱;当吸附剂体积分数由0.25逐渐增大至0.45时,吸附剂的等效传热系数约增加了50%。     

Comparative study on adsorbent characteristics for adsorption thermal energy storage system

The adsorption performance of the thermal energy storage (TES) system changes depending on the material properties of the adsorbent itself, but the change of the hardware structure can also substantially change the adsorption characteristics. In this study, a laboratory‐scale adsorption‐based TES system was constructed, and the adsorption performance of three adsorbents was evaluated in the same system to compare the adsorption performance between adsorbents. The adsorption characteristics of silica gel, zeolite 13X, and 4A, which are the most preferred adsorbents in the physical adsorption‐based TES system, were selected for evaluation. Experiments with each adsorbent were performed, including heat recovery to evaluate the heat transfer effect and the amount of heat recoverable in the actual TES system. Experimental results have identified several key characteristics of the adsorption and performance of each adsorbent in the TES system, as well as operating parameters that determine the influence of adsorption performance on the TES system. The actual energy storage density of the adsorbent is affected not only by the enthalpy of adsorption of the material itself but also by other factors. These factors include the difference in thermal conductivity that causes a difference in temperature distribution and the magnitude of mass transfer resistance due to the shape of the adsorbent particle and the actual TES system reactor structure. If the reaction heat generated during the adsorption reaction cannot be effectively released, the adsorption performance is significantly lowered due to the increased temperature of the reactor inside. This phenomenon was commonly observed in adsorbents examined in the present study. The uptake amount, X [g/g], was increased by allowing the inside of the reactor to be maintained at a lower temperature through heat recovery. In case of silica gel, the temperature rise during adsorption reaction is not high due to the difference of isotherm characteristics compared with zeolites, but it is possible to absorb more amount of adsorbate and to recover heat for a longer time. The energy storage density is affected by the temperature increase effect and the uptake amount of adsorbate during the adsorption reaction. The experimental results show that the energy storage density of zeolite 13X is 15% and 28.7% higher than that of silica gel and 4A, respectively, and the temperature rise due to heat generation during adsorption reaction is also high, which is advantageous in adsorption TES system performance.     

太阳能吸附式制冷关键技术的研究

介绍了太阳能吸附式制冷技术，指出了其存在的问题，并对太阳能吸附式制冷的关键技术的研究现状进行深入的分析和探讨，进一步明确其研究方向.     

吸附式制冷系统吸附床内非平衡态热力学分析

从非平衡态热力学角度，对以氯化钙—氨为工质对的固体吸附式制冷系统吸附床内传热传质过程进行了分析，建立了吸附床内热质耦合模型，并通过对模型的数值模拟，探讨了解吸／吸附过程中各热力学流之间的作用关系及其对吸附床熵产率的影响。     

Composite adsorbents of CaCl2 and sawdust prepared by carbonization for ammonia adsorption refrigeration

Composite adsorbents of CaCl₂ and sawdust prepared by carbonization for adsorption refrigeration with NH₃ as refrigerant are tested, and the effects of carbonization temperature on the sorption capacity and rate are analyzed. The results show that the amount of pores in the sawdust of the composite adsorbents carbonized, apart from the content of CaCl₂, is the most dominant factor influencing the NH₃ sorption on composite adsorbents. The optimum carbonization temperature is 700°C, which gives the maximal NH₃ sorption capacity as high as 0.774 kg of NH₃ per kg of the composite, and the specific cooling power is approximately between 338 and 869 W/kg with the cycle duration varying from 5 to 20 minutes. The present study demonstrates that the composite absorbent of CaCl₂ and sawdust prepared by carbonization is more promising and competitive for adsorption refrigeration application.     

Adsorption mechanism and improvements of the adsorption equation for adsorption refrigeration pairs

An improved adsorption model for adsorption refrigeration pairs such as activated carbon–methanol and zeolite–water is suggested based upon normal Dubinin adsorption equations. This model has been verified by various experimental results. Copyright © 1999 John Wiley & Sons, Ltd.     

太阳能固体吸附式制冷技术应用的一些探讨

总结了自行设计的太阳能固体吸附式制冷装置所取得的一些成果,对太阳 能固体吸附式制冰机系统的实际应用从工艺上、操作上、成本上作了分析与说明,并对 进一步开展太阳能固体吸附式制冷装置的研究作出了展望。