以硫化石墨为吸附剂基质的再吸附制冷性能分析
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摘要
相比于传统的吸附式制冷,再吸附制冷作为一种新型的制冷方式,其结构更加简单,并且其制冷性能系数也比相同条件下的吸附式制冷系统要高,故有较好的应用前景。但受到吸附剂的传热传质性能的限制,难以实现高效的再吸附制冷。本文利用硫化石墨作为吸附剂的基质,对其导热系数以及渗透率进行了测试比较,优选吸附剂。并且针对再吸附制冷系统建立了相关数学模型,分析不同工况条件下吸附剂工质对的性能。对整个再吸附制冷过程进行模拟仿真,从而得到不同工况下的制冷性能。结果表明,采用新型复合吸附剂的再吸附系统,COP最大可达到0.3以上,SCP最大可达到161 W/kg。
Compared with the conventional adsorption refrigeration cycle,resorption refrigeration cycle as a new cooling method has simpler structure and higher COP under the same operation condition. Therefore it has a good prospect. However,performance of the system is still greatly influenced by different adsorbents,temperature and pressure for adsorption. In this research,adsorbent with the matrix of expanded natural graphite treated with sulfuric acid is developed to study its thermal conductivity and permeability as well as select the superior one. Based on the basic physical properties of the adsorbent and refrigerant,simulation of whole resorption refrigeration process is set up to obtain the performance parameters under different conditions. According to the simulation results,the highest COP is more than 0. 3while the best SCP is 161 W / kg.
Compared with the conventional adsorption refrigeration cycle,resorption refrigeration cycle as a new cooling method has simpler structure and higher COP under the same operation condition. Therefore it has a good prospect. However,performance of the system is still greatly influenced by different adsorbents,temperature and pressure for adsorption. In this research,adsorbent with the matrix of expanded natural graphite treated with sulfuric acid is developed to study its thermal conductivity and permeability as well as select the superior one. Based on the basic physical properties of the adsorbent and refrigerant,simulation of whole resorption refrigeration process is set up to obtain the performance parameters under different conditions. According to the simulation results,the highest COP is more than 0. 3while the best SCP is 161 W / kg.
引文
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[2]Meunier F,Poyelle F,Le Van M D.Second-law analysis of adsorptive refrigeration cycles:the role of thermal coupling entropy production[J].Applied Thermal Engineering,1997,17(1):43-55.
[3]Yumrutas R,Kunduz M,Kanoglu M.Exergy analysis of vapor compression refrigeration systems[J].Exergy,an International Journal,2002,2(4):266-272.
[4]Wang D C,Xia Z Z,Wu J Y,et al.Study of a novel silica gel-water adsorption chiller.Part I.Design and performance prediction[J].International Journal of Refrigeration,2005,28(7):1073-1083.
[5]Wang J,Wang L W,Luo W L,et al.Experimental study of a two-stage adsorption freezing machine driven by low temperature heat source[J].International Journal of Refrigeration,2013,36(3):1029-1036.
[6]Vasiliev L L,Mishkinis D A,Antukh A A,et al.Resorption heat pump[J].Applied Thermal Engineering,2004,24(13):1893-1903.
[7]Bao H S,Wang R Z,Oliveira R G,et al.Resorption system for cold storage and long-distance refrigeration[J].Applied Energy,2012,93:479-487.
[8]Jiang L,Wang L W,Wang R Z.Investigation on thermal conductive consolidated composite Ca Cl2for adsorption refrigeration[J].International Journal of Thermal Sciences,2014,81:68-75.
[9]Maggio G,Freni A,Restuccia G.A dynamic model of heat and mass transfer in a double-bed adsorption machine with internal heat recovery[J].International Journal of Refrigeration,2006,29(4):589-600.
[10]Jin Z Q,Wang L W,Jiang L,et al,Experiment on the thermal conductivity and permeability of physical and chemical compound adsorbents for sorption process[J].Heat and Mass Transfer,2013,49(8):1117-1124.
[11]包华汕.低品位热源驱动的热化学再吸附制冷研究[D].上海:上海交通大学,2011.
[12]E A Moreira,M D M Innocentini,J R Coury.Permeability of ceramic foams to compressible and incompressible flow[J].Journal of European Ceramic Society,2004(10/11):3209-3218.
[13]R B Bird,W E Stewart,E N Lightfoot.Transport Phenomena[M].New York:John Wiley,1960.
[14]D J Krishna,T Basak,S K Das.Natural convection in a non-Darcy anisotropic porous cavity with a finite heat source at the bottom wall[J].International Journal of Thermal Sciences,2009,48(7):1279-1293.
[15]L W Wang,S J Metcalf,R E Critoph,et al.Thermal conductivity and permeability of consolidated expanded natural graphite treated with sulphuric acid[J].Carbon,2011,49(14):4812-4819.
[16]L W Wang,R Z Wang,R G Oliveira.A review on adsorption working pairs for refrigeration[J].Renewable and Sustainable Energy Reviews,2009,13(3):518-534.