2018传热传质学年会集

中国工程热物理学会学科类别学术会议论文编号：183295金属有机骨架吸附式热泵性能优化研究曹猛,夏潇潇,李松*（华中科技大学能源与动力工程学院煤燃烧国家重点实验室，武汉，430074）（Telsongli@）摘要：吸附式制冷可以由太阳能或工业废热等低温热源驱动，相比于电驱动的蒸汽压缩式制冷更具节能潜力。而寻找性能更好的吸附剂/制冷剂工质对一直是提高吸附式制冷系统的关键。本文以乙醇作为制冷剂，以两种金属有机骨架（MOFs）UiO-66和UiO-67作为吸附剂，探究了MOFs/乙醇吸附式制冷系统的性能。结果表明，UiO-67/乙醇性能优于UiO-66/乙醇，SCE最高可达442kJ/kg，COP最高可达0.65，这样的性能使UiO-67/乙醇拥有作为吸附式制冷工质对的潜力。关键词：吸附式制冷；吸附剂；金属有机骨架；SCE；COPPerformanceOptimizationofAdsorption-drivenCoolingbasedonMetal-OrganicFrameworksCAOMeng,XIAXiaoxiao,LISong*(StateKeyLaboratoryofCoalCombustion,SchoolofEnergyandPowerEngineering,HuazhongUniversityofScienceandTechnology,Wuhan,430074,China)AbstractComparedtoconventionalvaporcompressioncoolingsystems,adsorptioncoolingsystems(ACS)possessmoremeritssincetheycanbedrivenbylow-gradeheatsourcessuchassolarandindustrialwasteheat.ExplorationofmorecompetitiveworkingpairsisalwaysthekeytoimprovetheperformancesofACS.Inthiswork,theadsorptioncoolingperformancesoftwopreparedMOFadsorbentsUiO-66andUiO-67wereinvestigatedusingethanolasrefrigerant.TheresultsshowedthatUiO-67/ethanoloutperformedUiO-66/ethanolwithamaximumspecificcoolingeffect(SCE)of442kJ/kgandamaximumcoefficientofperformance(COP)of0.70,suggestingthecompetitivepotentialofUiO-67/ethanolworkingpairsinACS.Keywordsadsorptioncooling;adsorbent;specificcoolingeffect;coefficientofperformance0前言基金项目：国家科学基金资助项目（51606081）近年来，随着化石燃料趋近枯竭，能源安全日渐成为一个全球议题。而制冷耗能量一直在全球能源消耗中占有很大比例。目前，全球大约有15亿台家用和9千5百万台工业及运输领域的制冷设备在运行，它们分别占到了全球能源消耗的10%和30%，并且还有逐年增长的趋势ADDINEN.CITE<EndNote><Cite><Author>CoulombD</Author><Year>2015</Year><RecNum>34</RecNum><DisplayText>[1]</DisplayText><record><rec-number>34</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1528285339">34</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="Report">27</ref-type><contributors><authors><author>CoulombD,DupontJ-L,PichardA</author></authors></contributors><titles><title>TheRoleofRefrigerationintheGlobalEconomy</title><secondary-title>29thInformatoryNoteonRefrigerationTechnologies</secondary-title></titles><dates><year>2015</year></dates><pub-location>Paris</pub-location><urls></urls></record></Cite></EndNote>[1]，因此开发新型节能制冷系统成为了近年来的研究热点。与经典的电驱动蒸汽压缩式系统不同，吸附式制冷系统可以由太阳能、工业废热等未被有效利用的低温热源驱动ADDINEN.CITE<EndNote><Cite><Author>王健</Author><Year>2012</Year><RecNum>26</RecNum><DisplayText>[2]</DisplayText><record><rec-number>26</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1527725589">26</key></foreign-keys><ref-typename="Thesis">32</ref-type><contributors><authors><author>王健</author></authors></contributors><titles><title>CaCl_2/BaCl_2-NH_3两级吸附式制冷循环实验研究</title></titles><dates><year>2012</year></dates><publisher>上海交通大学</publisher><urls></urls></record></Cite></EndNote>[2]，且使用相对环境友好的制冷剂，比如水ADDINEN.CITE<EndNote><Cite><Author>Sapienza</Author><Year>2012</Year><RecNum>23</RecNum><DisplayText>[3]</DisplayText><record><rec-number>23</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1527724961">23</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Sapienza,A.</author><author>Glaznev,I.S.</author><author>Santamaria,S.</author></authors></contributors><titles><title>Adsorptionchillingdrivenbylowtemperatureheat:Newadsorbentandcycleoptimization</title><secondary-title>AppliedThermalEngineering</secondary-title></titles><periodical><full-title>AppliedThermalEngineering</full-title></periodical><pages>141-146</pages><volume>32</volume><number>1</number><dates><year>2012</year></dates><urls></urls></record></Cite></EndNote>[3]、甲醇ADDINEN.CITE<EndNote><Cite><Author>Schicktanz</Author><Year>2012</Year><RecNum>24</RecNum><DisplayText>[4]</DisplayText><record><rec-number>24</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1527725114">24</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Schicktanz,M.</author><author>Hügenell,P.</author><author>Henninger,S.K.</author></authors></contributors><titles><title>EvaluationofMethanolAdsorptiononActivatedCarbonsforthermallydrivenchillersPartI:Thermophysicalcharacterisation</title><secondary-title>InternationalJournalofRefrigeration</secondary-title></titles><periodical><full-title>InternationalJournalofRefrigeration</full-title></periodical><pages>543-553</pages><volume>35</volume><number>3</number><dates><year>2012</year></dates><urls></urls></record></Cite></EndNote>[4]、乙醇ADDINEN.CITE<EndNote><Cite><Author>El-Sharkawy</Author><Year>2014</Year><RecNum>25</RecNum><DisplayText>[5]</DisplayText><record><rec-number>25</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1527725253">25</key></foreign-keys><ref-typename="ConferenceProceedings">10</ref-type><contributors><authors><author>El-Sharkawy,IbrahimI.</author><author>Uddin,Kutub</author><author>Miyazaki,Takahiko</author><author>Saha,BidyutBaran</author><author>Koyama,Shigeru</author><author>Henninger,StefanK.</author></authors></contributors><titles><title>Characterizationofadsorbent/refrigerantpairsfordevelopinghighperformanceadsorptioncoolingsystems</title><secondary-title>AsianConferenceonRefrigerationandAirConditioning,Acra</secondary-title></titles><dates><year>2014</year></dates><urls></urls></record></Cite></EndNote>[5]和氨ADDINEN.CITE<EndNote><Cite><Author>El-Sharkawy</Author><Year>2014</Year><RecNum>25</RecNum><DisplayText>[5]</DisplayText><record><rec-number>25</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1527725253">25</key></foreign-keys><ref-typename="ConferenceProceedings">10</ref-type><contributors><authors><author>El-Sharkawy,IbrahimI.</author><author>Uddin,Kutub</author><author>Miyazaki,Takahiko</author><author>Saha,BidyutBaran</author><author>Koyama,Shigeru</author><author>Henninger,StefanK.</author></authors></contributors><titles><title>Characterizationofadsorbent/refrigerantpairsfordevelopinghighperformanceadsorptioncoolingsystems</title><secondary-title>AsianConferenceonRefrigerationandAirConditioning,Acra</secondary-title></titles><dates><year>2014</year></dates><urls></urls></record></Cite></EndNote>[5]，因而具有很大的节能潜力和应用前景。决定吸附式制冷系统性能优劣的关键因素是吸附剂/制冷剂工质对的性能。以水为制冷剂时常用的吸附剂有硅胶和沸石ADDINEN.CITE<EndNote><Cite><Author>Henninger</Author><Year>2009</Year><RecNum>35</RecNum><DisplayText>[6,7]</DisplayText><record><rec-number>35</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1528512607">35</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Henninger,S.K.</author><author>Habib,H.A.</author><author>Janiak,C</author></authors></contributors><titles><title>MOFsasadsorbentsforlowtemperatureheatingandcoolingapplications</title><secondary-title>JournaloftheAmericanChemicalSociety</secondary-title></titles><periodical><full-title>JournaloftheAmericanChemicalSociety</full-title></periodical><pages>2776-7</pages><volume>131</volume><number>8</number><dates><year>2009</year></dates><urls></urls></record></Cite><Cite><Author>Rezk</Author><Year>2012</Year><RecNum>36</RecNum><record><rec-number>36</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1528512732">36</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Rezk,Ahmed</author><author>Al-Dadah,Raya</author><author>Mahmoud,Saad</author><author>Elsayed,Ahmed</author></authors></contributors><titles><title>Characterisationofmetalorganicframeworksforadsorptioncooling</title><secondary-title>InternationalJournalofHeat&MassTransfer</secondary-title></titles><periodical><full-title>InternationalJournalofHeat&MassTransfer</full-title></periodical><pages>7366-7374</pages><volume>55</volume><number>25-26</number><dates><year>2012</year></dates><urls></urls></record></Cite></EndNote>[6,7]，醇类和氨常用的吸附剂主要是活性炭ADDINEN.CITE<EndNote><Cite><Author>Aristov</Author><Year>2009</Year><RecNum>37</RecNum><DisplayText>[8,9]</DisplayText><record><rec-number>37</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1528513112">37</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Aristov,YuriyI.</author></authors></contributors><titles><title>Optimaladsorbentforadsorptiveheattransformers:Dynamicconsiderations</title><secondary-title>InternationalJournalofRefrigeration</secondary-title></titles><periodical><full-title>InternationalJournalofRefrigeration</full-title></periodical><pages>675-686</pages><volume>32</volume><number>4</number><dates><year>2009</year></dates><urls></urls></record></Cite><Cite><Author>Tamainot-Telto</Author><Year>2009</Year><RecNum>38</RecNum><record><rec-number>38</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1528513418">38</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Tamainot-Telto,Z.</author><author>Metcalf,S.J.</author><author>Critoph,R.E.</author><author>Zhong,Y.</author><author>Thorpe,R.</author></authors></contributors><titles><title>Carbon–ammoniapairsforadsorptionrefrigerationapplications:icemaking,airconditioningandheatpumping</title><secondary-title>InternationalJournalofRefrigeration</secondary-title></titles><periodical><full-title>InternationalJournalofRefrigeration</full-title></periodical><pages>1212-1229</pages><volume>32</volume><number>6</number><dates><year>2009</year></dates><urls></urls></record></Cite></EndNote>[8,9]。然而，这些传统的工质对普遍存在制冷剂吸附量不高、吸附速率较慢、需要高压才能达到较大吸附量等缺点，以至于吸附性能在正常工况下较低ADDINEN.CITE<EndNote><Cite><Author>Ilis</Author><Year>2017</Year><RecNum>39</RecNum><DisplayText>[10]</DisplayText><record><rec-number>39</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1528515142">39</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Ilis,GamzeGediz</author></authors></contributors><titles><title>InfluenceofnewadsorbentswithisothermTypeVonperformanceofanadsorptionheatpump</title><secondary-title>Energy</secondary-title></titles><periodical><full-title>Energy</full-title></periodical><pages>86-93</pages><volume>119</volume><dates><year>2017</year></dates><urls></urls></record></Cite></EndNote>[10]，因此，提高工质对的性能是发展高效吸附式制冷系统的关键。金属有机骨架（metal-organicframeworks，MOFs）是一种新型多孔材料，由于其比表面积大和吸附量高等优势而受到广泛关注。近年来，一些研究者探究了MOFs作为吸附剂应用于吸附式制冷系统的可行性。Rezk等人探究了HKUST-1对水蒸气的吸附性能，发现与常规硅胶材料RD-2060相比，HKUST-1对水的吸附量提高了95.7%，有助于提高系统的制冷性能，但是，HKUST-1的循环稳定性问题却制约了其应用ADDINEN.CITE<EndNote><Cite><Author>Rezk</Author><Year>2013</Year><RecNum>40</RecNum><DisplayText>[11]</DisplayText><record><rec-number>40</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1528516557">40</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Rezk,A.</author><author>Al-Dadah,R.</author><author>Mahmoud,S.</author><author>Elsayed,A.</author></authors></contributors><titles><title>Experimentalinvestigationofmetalorganicframeworkscharacteristicsforwateradsorptionchillers</title><secondary-title>ProceedingsofInstitutionofMechanicalEngineersPartCJournalofMechanicalEngineeringScience</secondary-title></titles><periodical><full-title>ProceedingsofInstitutionofMechanicalEngineersPartCJournalofMechanicalEngineeringScience</full-title></periodical><pages>992-1005</pages><volume>227</volume><number>5</number><dates><year>2013</year></dates><urls></urls></record></Cite></EndNote>[11]。Elsayed等人研究了CPO-27(Ni)和AluminiumFumarate对水蒸气的吸附性能，包括吸附量、吸附速率和循环稳定性，结果显示这两种MOFs吸附水的循环稳定性好，吸附量适中（相对压力为0.9时吸附量分别为0.47g/g和0.52g/g）ADDINEN.CITE<EndNote><Cite><Author>Elsayed</Author><Year>2016</Year><RecNum>13</RecNum><DisplayText>[12]</DisplayText><record><rec-number>13</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1526914560">13</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Elsayed,Eman</author><author>Al-Dadah,Raya</author><author>Mahmoud,Saad</author><author>Elsayed,Ahmed</author><author>Anderson,PaulA.</author></authors></contributors><titles><title>AluminiumfumarateandCPO-27(Ni)MOFs:Characterizationandthermodynamicanalysisforadsorptionheatpumpapplications</title><secondary-title>AppliedThermalEngineering</secondary-title></titles><periodical><full-title>AppliedThermalEngineering</full-title></periodical><pages>802-812</pages><volume>99</volume><dates><year>2016</year></dates><urls></urls></record></Cite></EndNote>[12]。Kummer等人报道了涂有聚硅氧烷基涂料的MIL-101(Cr)具有1.22g/g的饱和甲醇吸附量，并且在经历1000次吸附式制冷循环后，吸附量只减少了约10%，循环稳定性满足吸附式制冷的需求ADDINEN.CITE<EndNote><Cite><Author>Kummer</Author><Year>2016</Year><RecNum>15</RecNum><DisplayText>[13]</DisplayText><record><rec-number>15</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1526958303">15</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Kummer,Harry</author><author>Baumgartner,Max</author><author>Hügenell,Philipp</author><author>Fröhlich,Dominik</author><author>Henninger,StefanK.</author><author>Gläser,Roger</author></authors></contributors><titles><title>ThermallydrivenrefrigerationbymethanoladsorptiononcoatingsofHKUST-1andMIL-101(Cr)</title><secondary-title>AppliedThermalEngineering</secondary-title></titles><periodical><full-title>AppliedThermalEngineering</full-title></periodical><volume>117</volume><dates><year>2016</year></dates><urls></urls></record></Cite></EndNote>[13]。deLange等人则探究了以甲醇和乙醇作为制冷剂时一系列MOFs的吸附性能，发现与MOFs/水工质对相比，MOFs/乙醇工质对具有低压下能充分吸附和循环稳定性更好的优点ADDINEN.CITE<EndNote><Cite><Author>De</Author><Year>2015</Year><RecNum>30</RecNum><DisplayText>[14]</DisplayText><record><rec-number>30</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1528201286">30</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>De,LangeM</author><author>VanVelzen,B.L.</author><author>Ottevanger,C.P.</author><author>Verouden,K</author><author>Lin,L.C.</author><author>Vlugt,T.J.</author><author>Gascon,J</author><author>Kapteijn,F</author></authors></contributors><titles><title>Metal-OrganicFrameworksinadsorptiondrivenheatpumps:Thepotentialofalcoholsasworkingfluid</title><secondary-title>LangmuirtheAcsJournalofSurfaces&Colloids</secondary-title></titles><periodical><full-title>LangmuirtheAcsJournalofSurfaces&Colloids</full-title></periodical><pages>12783-96</pages><volume>31</volume><number>46</number><dates><year>2015</year></dates><urls></urls></record></Cite></EndNote>[14]。在众多MOFs系列中，包含有{Zr6O4(OH)4}金属团簇的锆基MOFs具有良好的热稳定性和化学稳定性ADDINEN.CITE<EndNote><Cite><Author>Liu</Author><Year>2018</Year><RecNum>42</RecNum><DisplayText>[15]</DisplayText><record><rec-number>42</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1528525684">42</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Liu,Shucheng</author><author>Xu,Jiao</author><author>Dai,Engao</author><author>Qiu,Junjie</author><author>Liu,Yi</author></authors></contributors><titles><title>SynthesisandpropertiesofferroceneconfinedwithinUiO-67MOFs</title><secondary-title>Microporous&MesoporousMaterials</secondary-title></titles><periodical><full-title>Microporous&MesoporousMaterials</full-title></periodical><dates><year>2018</year></dates><urls></urls></record></Cite></EndNote>[15]，符合吸附式制冷中对吸附剂的要求。作为最早被报道的一批锆基MOFs，UiO(UniversityofOslo)系列便是锆基MOFs中的典型代表ADDINEN.CITE<EndNote><Cite><Author>Nickerl</Author><Year>2014</Year><RecNum>45</RecNum><DisplayText>[16]</DisplayText><record><rec-number>45</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1528526746">45</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Nickerl,Georg</author><author>Leistner,Matthias</author><author>Helten,Stella</author><author>Bon,Volodymyr</author><author>Senkovska,Irena</author><author>Kaskel,Stefan</author></authors></contributors><titles><title>IntegrationofaccessiblesecondarymetalsitesintoMOFsforH2Sremoval</title><secondary-title>InorganicChemistryFrontiers</secondary-title></titles><periodical><full-title>InorganicChemistryFrontiers</full-title></periodical><pages>325-330</pages><volume>1</volume><number>4</number><dates><year>2014</year></dates><urls></urls></record></Cite></EndNote>[16]。本文以两种UiO系列MOFs即UiO-66和UiO-67作为吸附剂，以乙醇作为制冷剂。相比于水，乙醇可以应用于摄氏零度以下的制冷工况（制冰、低温冷冻），是廉价的工业原料，毒性低于甲醇和氨，是比较理想的制冷剂，并且MOFs/乙醇工质对具有比MOFs/水工质更快的吸附速率，更好的稳定性ADDINEN.CITE<EndNote><Cite><Author>De</Author><Year>2015</Year><RecNum>30</RecNum><DisplayText>[14]</DisplayText><record><rec-number>30</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1528201286">30</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>De,LangeM</author><author>VanVelzen,B.L.</author><author>Ottevanger,C.P.</author><author>Verouden,K</author><author>Lin,L.C.</author><author>Vlugt,T.J.</author><author>Gascon,J</author><author>Kapteijn,F</author></authors></contributors><titles><title>Metal-OrganicFrameworksinadsorptiondrivenheatpumps:Thepotentialofalcoholsasworkingfluid</title><secondary-title>LangmuirtheAcsJournalofSurfaces&Colloids</secondary-title></titles><periodical><full-title>LangmuirtheAcsJournalofSurfaces&Colloids</full-title></periodical><pages>12783-96</pages><volume>31</volume><number>46</number><dates><year>2015</year></dates><urls></urls></record></Cite></EndNote>[14]。本研究通过实验获得了两种MOFs的乙醇吸附曲线，分别计算了不同工况下以UiO-66/乙醇和UiO-67/乙醇作为制冷工质对时的单位吸附剂制冷量（SCE）和性能系数（COP），为其在吸附式制冷领域的应用提供了科学依据。1研究方法 1.1实验方法UiO-66和UiO-67的制备分别参照文献ADDINEN.CITE<EndNote><Cite><Author>S</Author><Year>2016</Year><RecNum>28</RecNum><DisplayText>[17]</DisplayText><record><rec-number>28</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1528081323">28</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Øien-ØdegaardS</author><author>Bouchevreau,B</author><author>Hylland,K</author><author>Wu,L.</author><author>Blom,R</author><author>Grande,C</author><author>Olsbye,U</author><author>Tilset,M</author><author>Lillerud,K.P.</author></authors></contributors><titles><title>UiO-67-typeMetal-OrganicFrameworkswithEnhancedWaterStabilityandMethaneAdsorptionCapacity</title><secondary-title>InorganicChemistry</secondary-title></titles><periodical><full-title>InorganicChemistry</full-title></periodical><pages>1986</pages><volume>55</volume><number>5</number><dates><year>2016</year></dates><urls></urls></record></Cite></EndNote>[17]和ADDINEN.CITE<EndNote><Cite><Author>Schaate</Author><Year>2011</Year><RecNum>27</RecNum><DisplayText>[18]</DisplayText><record><rec-number>27</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1528080044">27</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Schaate,Andreas</author></authors></contributors><titles><title>ModulatedSynthesisofZr‐BasedMetal–OrganicFrameworks:FromNanotoSingleCrystals</title><secondary-title>Chemistry</secondary-title></titles><periodical><full-title>Chemistry</full-title></periodical><pages>6643-6651</pages><volume>17</volume><number>24</number><dates><year>2011</year></dates><urls></urls></record></Cite></EndNote>[18]的方法。粉末X射线衍射（PXRD）所用仪器为荷兰帕纳科公司生产的X’PertPRO型X射线衍射仪，测试温度为室温，步长为0.013°，测试范围为5-50°。气体（蒸汽）吸附所用仪器为康塔克默仪器贸易（上海）有限公司生产的Autosorb-iQ2全自动气体吸附分析仪，77K条件下测得的氮气吸附等温线用于计算样品的BET比表面积和总孔容，293K条件测得的乙醇蒸汽吸附用来表征样品的蒸汽吸附性能。1.2吸附曲线模型本文中我们采用由Ng等人ADDINEN.CITE<EndNote><Cite><Author>Ng</Author><Year>2017</Year><RecNum>21</RecNum><DisplayText>[19]</DisplayText><record><rec-number>21</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1527578137">21</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Ng,K.C.</author><author>Burhan,M</author><author>Shahzad,M.W.</author><author>Ismail,A.B.</author></authors></contributors><titles><title>AUniversalIsothermModeltoCaptureAdsorptionUptakeandEnergyDistributionofPorousHeterogeneousSurface</title><secondary-title>SciRep</secondary-title></titles><periodical><full-title>SciRep</full-title></periodical><volume>7</volume><number>1</number><dates><year>2017</year></dates><urls></urls></record></Cite></EndNote>[19]提出的通用吸附曲线模型来预测MOFs在不同温度下的乙醇平衡吸附量。W=i=1nα式中，W是温度为T，压力为p下MOFs对乙醇的平衡吸附量；ps为乙醇在温度T下的饱和压力；αi是为描述非均匀表面的吸附位点能量分布特性而引入的概率系数，并且所有概率系数之和为1，即i=1nαi=1；εoi表示最大概率出现的吸附能量位点；而n值则由吸附曲线的特征决定，在这里对于UiO-66/乙醇和UiO-67/乙醇n值均为表1通用吸附曲线模型中的参数Table1Parametersinthefittingofuniversaladsorptionmodel制冷工质对nαεo(J/mol)m(J/mol)UiO-66/乙醇UiO-67/乙醇33α1=0.2α2=0.06α3=0.73α1=0.29α2=0.46α3=0.25εo1=6.22×103εo2=1.20×104εo3=2.06×10-19εo1=6.72×103εo2=4.89×10-12εo3=5.98×103m1=1.54×103m2=1.5×102m3=6.57×101m1=1.78×102m2=4.46×101m3=2.90×1031.3吸附式制冷循环分析图1基本吸附式制冷循环Fig.1Basicadsorptioncoolingcycle典型的基本吸附式制冷循环主要由四部分组成，其中吸附和脱附各占两部分。图1是一个基本吸附循环的示意图，I-Ⅱ为平衡吸附量不变的预加热过程，加热到脱附开始温度T2；Ⅱ-Ⅲ为定压脱附过程，此时吸附床与冷凝器相连，吸附床压力保持为冷凝压力Pcon不变，平衡吸附量从最大Wmax减小到最小Wmin；Ⅲ-Ⅳ为平衡吸附量不变的预冷却过程，冷却到吸附开始温度T3；Ⅳ-I为定压吸附过程，此时吸附床与蒸发器相连，吸附床压力保持为蒸发压力Peva不变，平衡吸附量从最小Wmin增加到最大Wmax。Teva和Tcon分别表示蒸发温度和冷凝温度，Tdes表示脱附完成时的脱附温度，在这里近似等于低温驱动热源温度，T1表示吸附完成时的吸附温度Tads，在计算中与Tcon相等。评价吸附式制冷系统的两个重要指标是单位吸附剂制冷量（SCE）和性能系数（COP），前者代表系统的制冷能力大小，后者则反映了系统的能量利用效率。根据图1中所描述的热量与质量平衡，系统的COP为SCE与系统的总热投入Qh的比值ADDINEN.CITE<EndNote><Cite><Author>El-Sharkawy</Author><Year>2008</Year><RecNum>22</RecNum><DisplayText>[20]</DisplayText><record><rec-number>22</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1527650843">22</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>El-Sharkawy,I.I.</author><author>Saha,B.B.</author><author>Koyama,S.</author><author>He,J.</author><author>Ng,K.C.</author><author>Yap,C.</author></authors></contributors><titles><title>Experimentalinvestigationonactivatedcarbon–ethanolpairforsolarpoweredadsorptioncoolingapplications</title><secondary-title>InternationalJournalofRefrigeration</secondary-title></titles><periodical><full-title>InternationalJournalofRefrigeration</full-title></periodical><pages>1407-1413</pages><volume>31</volume><number>8</number><dates><year>2008</year></dates><urls></urls></record></Cite></EndNote>[20]，即COP=SCEQh上式中，SCE等于制冷剂在蒸发器的蒸发吸热量减去制冷剂从冷凝器到蒸发器冷却所消耗的冷量，SCE=(Wmax-上式中，Wmax和Wmin分别是最大和最小循环制冷剂吸附量；LHTeva为制冷剂在蒸发温度下的蒸发潜热；Qads=TconT和制冷剂的吸热量，Qref=Wmax上式中，Cpads为吸附剂的定压比热容，T2表示预加热结束，开始脱附时的温度；W表示脱附过程中随温度变化的平衡吸附量；qst表示单位吸附量的等量吸附热。公式（5）等号右边第一项表示预加热过程制冷剂的吸热量，第二项表示脱附过程中制冷剂升温吸收的显热热量，第三项表示吸附热。表2列出了计算中所用的表2计算中所用的物性参数值Table2Thephysicalparametersinthecalculation参数 具体数值乙醇的蒸发潜热(kJ/kg) -1.642·(Teva-273)+985.7吸附剂的定压比热(kJ/(kg·K))1 制冷剂的定压比热(kJ/(kg·K))2.7等量吸附热可由Clausius-Clapeyron方程结合不同温度的吸附曲线得出，qst=-R∙∂lnP∂在计算中，使用实验所测得的293K和303K温度下的两条吸附曲线计算吸附热，吸附量每隔0.2mol/kg分一等份，则每一个相同吸附量下的两条吸附曲线对应的绝对压力可以得出；以所得绝对压力的对数ln(P)为纵坐标值，以吸附曲线的温度的倒数1/T为横坐标值，则在直角坐标系中，每一个吸附量下得出两个数据点，过这两个点的直线的斜率则可以算得。根据公式（6），吸附热qst可以由此斜率算得ADDINEN.CITE<EndNote><Cite><Author>Fröhlich</Author><Year>2016</Year><RecNum>8</RecNum><DisplayText>[21]</DisplayText><record><rec-number>8</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1526223833">8</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Fröhlich,Dominik</author><author>Pantatosaki,Evangelia</author><author>Kolokathis,PanagiotisD.</author><author>Markey,Karen</author><author>Reinsch,Helge</author><author>Baumgartner,Max</author><author>Veen,MoniqueA.VanDer</author><author>Vos,DirkE.De</author><author>Stock,Norbert</author><author>Papadopoulos,GeorgeK.</author></authors></contributors><titles><title>WateradsorptionbehaviourofCAU-10-H:athoroughinvestigationofitsstructure–propertyrelationships</title><secondary-title>JournalofMaterialsChemistryA</secondary-title></titles><periodical><full-title>JournalofMaterialsChemistryA</full-title></periodical><volume>4</volume><number>30</number><dates><year>2016</year></dates><urls></urls></record></Cite></EndNote>[21]。2结果分析与讨论2.1实验结果UiO-66和UiO-67的PXRD结果如图2所示，蓝色线是模拟得到的理论PXRD曲线，红色线是实验所得材料的PXRD曲线。对比实验和理论的PXRD结果，可以发现特征峰出现的位置几乎完全相同，说明实验成功合成了UiO-66和UiO-67。并且实验得到的PXRD曲线基线较平、几乎不存在杂峰，说明实验合成的UiO-66和UiO-67纯度较高。图2样品PXRD，(a)UiO-66模拟与实验结果（蓝色为模拟结果，红色为实验结果），(b)UiO-67模拟与实验结果（蓝色为模拟结果，红色为实验结果）Fig.2PXRDofthesamples,(a)UiO-66,(b)UiO-67,bluelinesrepresentsimulationresultsandredlinesrepresentexperimentresults由UiO-66和UiO-67在77K下的氮气等温吸附曲线计算得到的BET比表面积和总孔容如表3所示。UiO-66和UiO-67具有相同的拓扑结构和金属离子，由于UiO-67的配体链长较UiO-66大，因此UiO-67的BET比表面积和孔容积均较UiO-66大。表3MOFs的BET比表面积和总孔容Table3BETsurfaceareaandtotalporevolumeoftheMOFs样品 UiO-66UiO-67BET比表面积 (m2/g)15082466总孔容(cm3/g)0.9871.0282.2乙醇吸附曲线我们使用通用公式拟合了293K下两种MOFs对乙醇的吸附曲线数据（图3），从图中可以看到，UiO-66和UiO-67均在低压下就达到了对乙醇很高的吸附量。参考Canivet等人的工作，我们定义吸附量达到0.5倍饱和吸附量时所对应的相对压力值为αADDINEN.CITE<EndNote><Cite><Author>Canivet</Author><Year>2014</Year><RecNum>46</RecNum><DisplayText>[22]</DisplayText><record><rec-number>46</rec-number><foreign-keys><keyapp="EN"db-id="5z5sww0vqfzww8ewdawvzz9hva2xzet9wpaa"timestamp="1528529720">46</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Canivet,Jérôme</author><author>Bonnefoy,Jonathan</author><author>Daniel,Cécile</author><author>Legrand,Alexandre</author><author>Coasne