Thermodynamic analysis of absorption refrigeration cycles using ionic liquids as absorbents

doi:10.11949/j.issn.0438-1157.20181093

Abstract

Abstract:

The thermodynamic performances of three working pairs (R161/[hmim] [Tf₂N], R32/[emim] [Tf₂N] and R290/[emim] [BF₄]) have been analyzed. Non-Random Two-Liquid (NRTL) model was used to correlate the vapor-liquid equilibrium data of refrigerants/ionic liquids. The effects of generator outlet temperature, evaporator outlet temperature, absorption temperature on the circulation ratio, COP and exergetic coefficient of performance (ECOP) have been discussed. The COP of R32/[emim] [Tf₂N] system is close to that of R161/[hmim] [Tf₂N] system and the COP of R290/[emim] [BF₄] is the lowest. When the evaporation temperature is 5℃ and the absorption temperature is 25℃, the COP of R32[emim] [Tf₂N] system reaches more than 0.59. However, the COP of R290 is always less than 0.1. Upon reducing the absorption temperature, it can expand the feasible temperature of the cycle and improve the COP. When the evaporation temperature is 5℃ and the absorption temperature is reduced from 30℃ to 25℃, the COP increases more than 1.4 times.

摘要：

分析了R161/[hmim][Tf₂N]、R32/[emim][Tf₂N]、R290/[emim][BF₄]三种工质对的热力学性能；采用NRTL模型对制冷剂/离子液体的汽液相平衡数据进行了关联；探讨了发生器出口温度、蒸发器出口温度及吸收温度对循环比、COP及?效率的影响。R32/[emim][Tf₂N]和R161/[hmim][Tf₂N]的COP相近，R290/[emim][BF₄]的COP最小；在蒸发温度、吸收温度分别是5、25℃时，R32/[emim][Tf₂N]系统的COP随着发生温度的变化可达到0.59以上，R290/[emim][BF₄]的COP低于0.1；降低吸收温度可以扩大循环的可行温度，提高COP；蒸发温度为5℃，吸收温度从30℃降低到25℃，COP可提高1.4倍以上。

CLC Number:

TK121

SUN Yanjun, DI Gaolei, XIA Juan, WANG Xiaopo, JIN Liwen. Thermodynamic analysis of absorption refrigeration cycles using ionic liquids as absorbents[J]. CIESC Journal, 2018, 69(S2): 38-44.

孙艳军, 邸高雷, 夏娟, 王晓坡, 金立文. 以离子液体为吸收剂的吸收式制冷循环热力学分析[J]. 化工学报, 2018, 69(S2): 38-44.

References 29

[1]	张国辉,刘万龙,石文星.我国办公建筑用多联机空调系统能耗调研分析[J].暖通空调,2018,48(8):17-21.ZHANG G H, LIU W L, SHI W X.Energy consumption of multi split air conditioning system for office building in China[J].HV&AC, 2018, 48(8):17-21.
[2]	李星,徐士鸣,李见波.基于R124-DMAC为工质对的余热吸收式制冷[J].化工学报,2015,66(5):1883-1890.LI X, XU S M, LI J B.Absorption refrigeration cycle driven by waste heat using R124-DMAC as working fluids[J].CIESC Journal, 2015, 66(5):1883-1890.
[3]	王刚,解国珍,王亮亮.溴化锂吸收式循环的内外热物理参数与机组制冷特性耦合[J].化工学报,2012,63(S2):1-7.WANG G, XIE G Z, WANG L L.Coupling of lithium bromide absorption cycle inside and outside thermal physical parameters and refrigerantion unit characteristics[J].CIESC Journal, 2012, 63(S2):1-7.
[4]	孙欢,陈萨如拉,申江,等.机械振动强化吸收式制冷系统实验研究及节能潜力分析[J].建筑节能,2018,46(324):1-6.SUN H, CHEN S R L, SHEN J, et al. Experimental study and energy-saving potential analysis on enhancing absorption refrigeration system with mechanical vibration[J].Building Energy Efficiency, 2018, 46(324):1-6.
[5]	贾炯,王辉涛,刘泛函,等.基于R124/DMAC为工质的压缩吸收式制冷系统的性能分析[J].制冷学报,2017,36(7):2436-2442.JIA J, WANG H T, LIU F H, et al. Performance study of compressive energy absorption refrigeration system based on R124/DMAC mixture[J].Journal of Refrigeration, 2017, 36(7):2436-2442.
[6]	陈光明,石玉琦.吸收式制冷(热泵)循环流程研究进展[J].制冷学报,2017,38(4):1-22.CHEN G M, SHI Y Q.State-of-the-art absorption refrigeration and heat pump cycles[J].Journal of Refrigeration, 2017, 38(4):1-22.
[7]	卞宜峰,何国庚,蔡德华,等.吸收式制冷工质对的研究进展[J].制冷学报,2015,36(6):17-23.BIAN Y F, HE G G, CAI D H, et al. Research progress of absorption refrigeration working pairs[J].Journal of Refrigeration, 2015, 36(6):17-23.
[8]	武卫东,吴俊,王振,等.新型离子液体-CO2吸收制冷工质对选择及吸收特性[J].制冷学报,2016,37(3):22-27.WU W D, WU J, WANG Z, et al. Selection of ionic liquids and absorption properties of ionic liquids-CO2 working pairs[J].Journal of Refrigeration, 2016, 37(3):22-27.
[9]	FONG K F, LEE C K.Performance advancement of solar air-conditioning through integrated system design for building[J].Energy, 2014, 73(9):987-996.
[10]	WU W, WANG B L, SHI W X, et al. Absorption heating technologies:a review and perspective[J].Applied Energy, 2014, 130(5):51-71.
[11]	WANG K, ABDELAZIZ O, KISARI P, et al.State-of-the-art review on crystallization control technologies for water/LiBr absorption heat pumps[J].International Journal of Refrigeration, 2011, 34(6):1325-1337.
[12]	郭媛媛,朱磊,赵竟全.以[mmim]DMP-甲醇为工质对的吸收式制冷循环研究[J].制冷与空调,2013,13(3):57-60.GUO Y Y, ZHU L, ZHAO J Q.Research on absorption refrigeration cycle with[mmim]DMP-methanol[J].Refrigeration and Air-conditioning, 2013, 13(3):57-60.
[13]	王建召.吸收式循环构型及含咪唑类离子液体工质对的研究[D].北京:北京化工大学,2009.WANG J Z.Study on configurations of absorption cycle and imidazole-based ionic liquids contenting working fluids[D].Beijing:Beijing University of Chemical Technology, 2009.
[14]	SHIFLETT M B, YOKOZEKI A.Solubility and diffusivity of hydrofluorocarbons in room-temperature ionic liquid[J].AIChE Journal, 2006, 52(3):1205-1219.
[15]	SHIFLETT M B, YOKOZEKI A.Binary vapor-liquid and vapor-liquid-liquid equilibria of hydrofluorocarbons (HFC-125 and HFC-143a) and hydrofluoroethers (HFE-125 and HFE-143a) with ionic liquid[emim] [Tf2N] [J].Journal of Chemical and Engineering Data, 2008, 53(2):492-497.
[16]	SHIFLETT M B, YOKOZEKI A.Gaseous absorption of fluoromethane, fluoroethane, and 1,1,2,2-tetrafluoroethane in 1-butyl-3-methylimidazolium hexafluorophosphate[J].Industrial & Engineering Chemistry Research, 2006, 45(18):6375-6382.
[17]	LI D, ZHENG D X, SUN G M, et al.Vapor-liquid equilibrium measurements of difluoromethane +[emim]OTf, difuoromethane +[bmim]OTf, difluoroethane +[emim]OTf, and difluoroethane +[bmim]OTf systems[J].Journal of Chemical and Engineering Data, 2011, 56(9):3663-3668.
[18]	KATO R, GMEHLING J.Measurement and correlation of vapor-liquid equilibria of binary systems containing the ionic liquids[emim](CF3SO2)2N,[bmim](CF3SO2)2N,[mmim](CH3)2PO4 and oxygenated organic compounds respectively water[J].Fluid Phase Equilibria, 2005, 231(1):38-43.
[19]	FALLANZA M, ORTIZ A, GORRI D, et al.Propylene and propane solubility in lmidazolium, pyridinium and tetralkylammonium based ionic liquids containing a silver salt[J].Journal of Chemical and Engineering Data, 2013, 58(8):2147-2153.
[20]	LIU X Y, BAI L H, LIU S Q, et al.Vapor-liquid equilibrium of R1234yf/[hmim]Tf2N and R1234ze(E)/[hmim]Tf2N working pairs for the absorption refrigeration cycle[J].Journal of Chemical and Engineering Data, 2016, 61(11):3952-3957.
[21]	KIM S, KIM Y J, JOSHI Y K, et al. Absorption heat pump/refrigeration system utilizing ionic liquid and hydrofluorocarbon refrigerants[J].Journal of Electronic Packaging, 2012, 134(3):0310091-0310099.
[22]	KIM S, PATEL N, KOHL P A.Performance simulation of ionic liquid and hydrofluorocarbon working fluids for an absorption refrigeration system[J].Industrial & Engineering Chemistry Research, 2013, 52(19):6329-6335.
[23]	KIM S, KOHL P A.Theoretical and experimental investigation of an absorption refrigeration system using R134/[bmim] [PF6] working fluid[J].Industrial & Engineering Chemistry Research, 2013, 52(37):13459-13465.
[24]	RENON H, PRAUSNITZ J M.Local compositions in thermo-dynamic excess functions for liquid mixtures[J].AIChE Journal, 1968, 14(1):135-144.
[25]	LIU X Y, QI X T, LÜ N, et al.Solubility of R161 and R143a in 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfony-l)imide[J].Fluid Phase Equilibria, 2015, 25(388):37-42.
[26]	SHIFLETT M B, YOKOZEKI A.Solubility and diffusivity of difluoromethane in room-temperature ionic liquid[J].Journal of Chemical and Engineering Data, 2006, 51(2):483-495.
[27]	GARDAS R L.A group contribution method for heat capacity estimation of ionic liquids[J].Industrial & Engineering Chemistry Research, 2008, 47(15):5751-5757.
[28]	JACQUEMIN J, HUSSON P, MAYER V, et al.High-pressure volumetric properties of imidazolium-based ionic liquids:effect of the anion[J].Journal of Chemical and Engineering Data, 2007, 52(6):2204-2211.
[29]	WU W, YOU T, ZHANG H Y, et al. Comparisons of different ionic liquids combined with trans-1,3,3,3-tetrafluoropropene (R1234ze(E)) as absorption working fluids[J].International Journal of Refrigeration, 2018, 88:45-57.