冰球式蓄冷空调系统热传递过程的数值模拟与研究
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摘要
冰蓄冷空调系统的运行理念是制冷机组在用电低谷时制取冷量,蓄冷系统在用电高峰时释放冷量,从而平衡电力的供求关系。该系统适用于存在用电差价的地区,目的在于节约用户的用电费用,减少高峰用电时的电耗。为优化蓄冷空调系统的结构,进一步达到单位用户既省电又省钱的效果,响应全社会对节能的呼声,本文分析了一个已投入使用的冰球式蓄冷空调系统的运行特性,借助ANSYS有限元分析软件,数值模拟了实际运行参数下的蓄冷空调系统的运行工况,同时通过设定不同的参数,探究了减少蓄冷时间的途径和影响释冷工况的因素。同时利用热力学第二定律,计算出蓄冷系统的各个部件(火用)损失情况。结果表明,蓄冰球的球壁厚度、球体的结构,载冷剂的流入温度与流量都影响着蓄冷系统的热传递速率,且球体几何结构对缩短蓄冷时间的效果最为明显;能量的耗损主要表现在压缩机与冷凝器两大部件上,在减少传热温差的基础上,提高换热器传热性能的途径是减少能耗、提高能效的有效方法。
Ice-storage air conditioning systems, which are often applied in regions where electricity is valued with different prices, are based on the refrigeration units producing cold in low demand of electricity, while ice-storage system melting phase-change materials to release cold energy in the peak price load. Thanks to this system, the quantity and the cost can be cut down to some extent. To improve this system and to make better use of energy, an ice-storage air conditioning having been put into operation is analyzed in this paper. One hand, the characters of the system are numerically modeled by software called ANSYS with the principle of finite element method analysis. Some ways to reduce freezing time and factors effecting PCM thaw have been found. The other hand, available-energy costing of every part of the system has been studied basis of second law analysis of thermal systems. It is concluded that the rate of heat transfer is influenced by wall thickness and structure of encapsulated ice storage, and inlet temperature and flux of refrigerant as well, while the structure of encapsulated ice storage taking first place among these factors. The energy loss from compressors and condensers almost take up the whole energy loss of this system. As temperature difference of heat transfer is decreased, performance of heat exchangers should be improved for controlling available-energy cost and increasing the efficient of the system.
Ice-storage air conditioning systems, which are often applied in regions where electricity is valued with different prices, are based on the refrigeration units producing cold in low demand of electricity, while ice-storage system melting phase-change materials to release cold energy in the peak price load. Thanks to this system, the quantity and the cost can be cut down to some extent. To improve this system and to make better use of energy, an ice-storage air conditioning having been put into operation is analyzed in this paper. One hand, the characters of the system are numerically modeled by software called ANSYS with the principle of finite element method analysis. Some ways to reduce freezing time and factors effecting PCM thaw have been found. The other hand, available-energy costing of every part of the system has been studied basis of second law analysis of thermal systems. It is concluded that the rate of heat transfer is influenced by wall thickness and structure of encapsulated ice storage, and inlet temperature and flux of refrigerant as well, while the structure of encapsulated ice storage taking first place among these factors. The energy loss from compressors and condensers almost take up the whole energy loss of this system. As temperature difference of heat transfer is decreased, performance of heat exchangers should be improved for controlling available-energy cost and increasing the efficient of the system.
引文
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[10]I.S.Choi,J.D.Kim b,E.Kim,J.I.Yoon.Experimental characteristics of a storage tank on a harvest-type ice storage system.International Journal of Heat and Mass Transfer,2002(45):1407-1412
[11]Huei-Jiunn Chen,David W.P.Wang,Sih-Li Chen.Optimization of an ice-storage air conditioning system using dynamic programming method.Applied Engineering Thermal,2005(25):461-472
[12]胡鸣若,余国和.冰蓄冷空凋系统配置模式分析.上海理工大学学报,2000(4):315-319
[13]T.Kousksou,J.-P.Bedecarrats,J.-P.Dumas,A.Mimet.Dynamic modeling of the storage of an encapsulated ice tank.Applied Thermal Engineering,2005(25):1534-1547
[14]广州贝龙环保热力设备股份有限公司冰蓄冷系统电子样本
[15]张力君,田胜元.蓄冰球内金属蕊芯传热特性的理论研究.重庆建筑大学学报,1997年10月,第19卷第5期:1-5
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[18]Tackett,R.K.Case study:Office Building Uses Ice Storage,Heat and Cold Air Distribution.ASHRAE Transaction,1989,Vol.95(1):1139-1153
[19]J.M.Crane,C.Dunlop.Ice Storage System for a Department Store.ASHRAE Journal,1994,Vol.36(No.1):49
[20]赵庆珠,蒋久轶.冰球蓄冷过程的传热研究.第一部分:冰球蓄冰过程的数值模拟.1994年暖通空凋年会论文集
[21]张华.冰球蓄冷罐蓄冷过程的动态特性.真空与低温,2000年12月,第6卷第4期:221-224
[22]管建春,朱华,阿迪尔M.S.,屠传经.储冰球相变传热数值计算及分析.浙江大学学报(自然科学版),1999年1月,第33卷第1期:85-89
[23]鲁刚.冰球蓄冷器传热过程的数值模拟(硕士论文).大庆石油学院,2003年2月
[24]Amr O.Elsayed.Numerical study of ice melting inside rectangular capsule under cyclic temperature of heat transfer fluid.Energy Conversion and Management,2007(48):124-130
[25]Masayuki Tonino,Youshiyuki Kozawa.Ice-water two-phase flow behavior in ice heat storage systems.International Journal of Refrigeration,2001(24):639-651
[26]K.Cho,S.H.Choi.Thermal characteristics of paraffin in a spherical capsule during freezing and melting processes.Int.J.Heat Mass Transfer,2000(43):3183-3196
[27]A.M.Khudhair,M.M.Farid.A review on energy conservation in building applications with thermal storage by latent heat using phase change materials.Energy Convers.Manage,2004(45)263-275
[28]Prusa J,Maxwell GM,Timmer K.J.A mathematical model for a phase-change energy storage system utilizing rectangular containers.ASHRAE Trans,1991,97(2):245-261
[29]Hirata T,Makino Y,Nagano T,Kaneko Y.Analysis of natural convection melting inside isothermally heated horizontal rectangular capsule.Warme und Stoffeurtragung,1993(28):1-9
[30]滕敦朋,杨培毅.数值模拟中的一种特殊解法.青岛大学学报,2001年9月,第16卷第3期:35-37
[31]张维,方贵银,陈则韶.封装式冰蓄冷器融冰放冷过程动态特性研究.低温与特气,2000,No.1:24-28
[32]郭茶秀,张务军,熊辉东,Rainer Tamme.共晶盐蓄冷球凝固过程的数值模拟研究.暖通空调HV&AC,2006年第36卷第3期:17-21
[33]刘涛,杨凤鹏主编.精通ANSYS.北京:清华大学出版社,2002年9月第一版
[34]张朝晖主编.ANSYS8.0热分析教程与实例解析.北京:中国铁道出报社.2005年6月第一版
[35]小飒工作室编.最新经典ANSYS及Workbench教程.北京:电子工业出版社,2004年6月
[36]李开泰,黄艾香,黄庆怀编著.有限元方法及其应用.北京:科学出版社.2006年2月第一版
[37]林建忠,阮晓东,陈邦国,王建平,周洁,任安禄编著,流体力学,北京:清华大学出版社,2005年9月第一版:119-154
[38]李树林主编,制冷技术,北京:机械工业出版社,2003年8月第一版:286-288
[39]Bejan A,Lage I L.The Prandtl number effect on the transition in natural convection along a vertical surface.AMSE J Heat Transfer,1990,112:787-790
[40]金重,刘金环编著,大学物理实验教程(工科),天津:南开大学出版社,2000年11月第一版
[41]V.J.Lunardini.Some analytical methods for conduction heat transfer with freezing thawing.Proc.Conf.Int.Symp.On Cold Regions Heat Transfer,Edmonton,Canada:1987,June 4-6
[42]M.Salcudean,Z A bdullah.On the numerical modeling of heat transfer during solidification process.Int.J.Num.Meth.Eng.1988,25:445-473
[43]Thakur S,Shyy W.Some implementational issues of convection schemes for finite volume formulation.Numer Heat Transfer,Part B,1993,24:31-55
[44]Wark K.Thermodynamics.New York:Mcgraw -Hill Book Co,1977,3th ed
[45]Chang K C,Payne U J.Numerical treatment of diffusion coefficients at interfaces.Numer Heat Transfer,Part A,1992.21(3):363-376
[46]Chamber B,Lee T Y T.A numerical study of local and average natural convection Nusselt numbers for simultaneously convection above and below a uniformly heated horizontal thin plate.ASME J Heat Transfer,1997,119:102-108
[47]Wark K.Jr.Advanced Thermodynamics for Engineers.New York:McGraw-Hill,1995
[48]Reistad G M,Fabrycky W J.Available-Energy Costing,Thermodynamics:Second Law Anslysis.ACS Symposium Series,1980,122:143-159
[49]Steco S S,Manfrida G.The Exergy and Capital Cost factors:A New Approach to Energy Conversion Economics,Second Law Analysis of Thermal Systems,ASME,New York,1987
[50]傅秦生编著,能量系统的热力学分析方法,西安:西安交通大学出版社,2005年7月第一版
[2]B.Zalba,J.M.Marin,L.F.Cabeza,H.Mehling.Review on thermal energy storage with phase change:materials,heat transfer analysis and applications.Appl.Therm.Eng.2003,23:251-283
[3]Braun.J.E.A comparison of chiller-priority,storage-priority,and optimal control of an ice-storage system.ASHRAE Transaction,1992,v82 nl:893-902
[4]Beggs,Clive.Economics of ice thermal storage.Building Research and Information,1991,19(6):342-355
[5]俞炳丰主编.中央空调新技术及其应用.北京:化学工业出版社,2004.379-471
[6]EPRI.Commercial cool storage design guide.Hemispher Publishing Corporation,USA,Washington,1987
[7]Carslaw H S,Jaeger J C.Conduction of Heat in Solids.2~(nd)ed.London.Clarendon Press 1986.283-296
[8]陈光明.日本蓄热现状.暖通空调.1998
[9]Yasuhiro Hamada,Makoto Nakamura,Hideki Kubota.Field measurements and analyses for a hybrid system for snow storage/melting and air conditioning by using renewable energy.Applied Energy 2007(84):117-134
[10]I.S.Choi,J.D.Kim b,E.Kim,J.I.Yoon.Experimental characteristics of a storage tank on a harvest-type ice storage system.International Journal of Heat and Mass Transfer,2002(45):1407-1412
[11]Huei-Jiunn Chen,David W.P.Wang,Sih-Li Chen.Optimization of an ice-storage air conditioning system using dynamic programming method.Applied Engineering Thermal,2005(25):461-472
[12]胡鸣若,余国和.冰蓄冷空凋系统配置模式分析.上海理工大学学报,2000(4):315-319
[13]T.Kousksou,J.-P.Bedecarrats,J.-P.Dumas,A.Mimet.Dynamic modeling of the storage of an encapsulated ice tank.Applied Thermal Engineering,2005(25):1534-1547
[14]广州贝龙环保热力设备股份有限公司冰蓄冷系统电子样本
[15]张力君,田胜元.蓄冰球内金属蕊芯传热特性的理论研究.重庆建筑大学学报,1997年10月,第19卷第5期:1-5
[16]任秀宏.冰蓄冷空调系统的研究与技术经济分析(硕士论文).河北工业大学.2006
[17]T.B.Jekel et al.Modeling of Ice-storage Tanks.ASHRAE Transaction,1993
[18]Tackett,R.K.Case study:Office Building Uses Ice Storage,Heat and Cold Air Distribution.ASHRAE Transaction,1989,Vol.95(1):1139-1153
[19]J.M.Crane,C.Dunlop.Ice Storage System for a Department Store.ASHRAE Journal,1994,Vol.36(No.1):49
[20]赵庆珠,蒋久轶.冰球蓄冷过程的传热研究.第一部分:冰球蓄冰过程的数值模拟.1994年暖通空凋年会论文集
[21]张华.冰球蓄冷罐蓄冷过程的动态特性.真空与低温,2000年12月,第6卷第4期:221-224
[22]管建春,朱华,阿迪尔M.S.,屠传经.储冰球相变传热数值计算及分析.浙江大学学报(自然科学版),1999年1月,第33卷第1期:85-89
[23]鲁刚.冰球蓄冷器传热过程的数值模拟(硕士论文).大庆石油学院,2003年2月
[24]Amr O.Elsayed.Numerical study of ice melting inside rectangular capsule under cyclic temperature of heat transfer fluid.Energy Conversion and Management,2007(48):124-130
[25]Masayuki Tonino,Youshiyuki Kozawa.Ice-water two-phase flow behavior in ice heat storage systems.International Journal of Refrigeration,2001(24):639-651
[26]K.Cho,S.H.Choi.Thermal characteristics of paraffin in a spherical capsule during freezing and melting processes.Int.J.Heat Mass Transfer,2000(43):3183-3196
[27]A.M.Khudhair,M.M.Farid.A review on energy conservation in building applications with thermal storage by latent heat using phase change materials.Energy Convers.Manage,2004(45)263-275
[28]Prusa J,Maxwell GM,Timmer K.J.A mathematical model for a phase-change energy storage system utilizing rectangular containers.ASHRAE Trans,1991,97(2):245-261
[29]Hirata T,Makino Y,Nagano T,Kaneko Y.Analysis of natural convection melting inside isothermally heated horizontal rectangular capsule.Warme und Stoffeurtragung,1993(28):1-9
[30]滕敦朋,杨培毅.数值模拟中的一种特殊解法.青岛大学学报,2001年9月,第16卷第3期:35-37
[31]张维,方贵银,陈则韶.封装式冰蓄冷器融冰放冷过程动态特性研究.低温与特气,2000,No.1:24-28
[32]郭茶秀,张务军,熊辉东,Rainer Tamme.共晶盐蓄冷球凝固过程的数值模拟研究.暖通空调HV&AC,2006年第36卷第3期:17-21
[33]刘涛,杨凤鹏主编.精通ANSYS.北京:清华大学出版社,2002年9月第一版
[34]张朝晖主编.ANSYS8.0热分析教程与实例解析.北京:中国铁道出报社.2005年6月第一版
[35]小飒工作室编.最新经典ANSYS及Workbench教程.北京:电子工业出版社,2004年6月
[36]李开泰,黄艾香,黄庆怀编著.有限元方法及其应用.北京:科学出版社.2006年2月第一版
[37]林建忠,阮晓东,陈邦国,王建平,周洁,任安禄编著,流体力学,北京:清华大学出版社,2005年9月第一版:119-154
[38]李树林主编,制冷技术,北京:机械工业出版社,2003年8月第一版:286-288
[39]Bejan A,Lage I L.The Prandtl number effect on the transition in natural convection along a vertical surface.AMSE J Heat Transfer,1990,112:787-790
[40]金重,刘金环编著,大学物理实验教程(工科),天津:南开大学出版社,2000年11月第一版
[41]V.J.Lunardini.Some analytical methods for conduction heat transfer with freezing thawing.Proc.Conf.Int.Symp.On Cold Regions Heat Transfer,Edmonton,Canada:1987,June 4-6
[42]M.Salcudean,Z A bdullah.On the numerical modeling of heat transfer during solidification process.Int.J.Num.Meth.Eng.1988,25:445-473
[43]Thakur S,Shyy W.Some implementational issues of convection schemes for finite volume formulation.Numer Heat Transfer,Part B,1993,24:31-55
[44]Wark K.Thermodynamics.New York:Mcgraw -Hill Book Co,1977,3th ed
[45]Chang K C,Payne U J.Numerical treatment of diffusion coefficients at interfaces.Numer Heat Transfer,Part A,1992.21(3):363-376
[46]Chamber B,Lee T Y T.A numerical study of local and average natural convection Nusselt numbers for simultaneously convection above and below a uniformly heated horizontal thin plate.ASME J Heat Transfer,1997,119:102-108
[47]Wark K.Jr.Advanced Thermodynamics for Engineers.New York:McGraw-Hill,1995
[48]Reistad G M,Fabrycky W J.Available-Energy Costing,Thermodynamics:Second Law Anslysis.ACS Symposium Series,1980,122:143-159
[49]Steco S S,Manfrida G.The Exergy and Capital Cost factors:A New Approach to Energy Conversion Economics,Second Law Analysis of Thermal Systems,ASME,New York,1987
[50]傅秦生编著,能量系统的热力学分析方法,西安:西安交通大学出版社,2005年7月第一版