OPTIMIZATION OF UNIQUAC INTERACTION PARAMETERS FOR ABSORPTION REFRIGERATION MACHINE WORKING FLUIDS.

Transcription

1 Sceces & Tecologe B N 46, (Décebre 17), pp OPTIMIZATION OF INTACTION PAAMTS FO ABSOPTION FIGATION MACHIN WOKING FLUIDS. Ile LOUA 1, Nardess BOUNAB et Abdesela Hasse MNIAI 1 Laboratore de l Igéere des Procédés de l vroeet, Metour Broters Uversty Costate, Alegra. Laboratore de l Igéere des Procédés de l vroeet, Costate 3 Uversty, Alegra. eçu le 18 Jullet 17 Accepté le 1 ovebre 17 Abstract To be able to pre-select ew worg fluds for absorpto refrgerato systes, t s ecessary to ave a good uderstadg te calculato or correlato of teropyscal propertes of worg fluds. Te coce of te ost approprate terodyac odel for te predcto or calculato of terodyscal propertes s a crucal tas. Cosequetly te preset study deals wt te deterato of excess propertes for refrgerat xtures wc are requred for te calculato of te varous volved etalpes ad ece te used refrgerato ace. Te preset study cosdered te pars (-cloro-1,1,1,-tétrafluoroetae) (14) as a refrgerat cobato wt a orgac absorbet (N, N - Detylacetade) DMAC ad (1,1,1,-tetrafluoroetae) (134a) as a refrgerat cobato wt a orgac absorbet detyleter tetraetyleeglycol (DMTG) by calculatg te olecular teracto paraeters for te odel usg te excess etalpy of xg at egt dfferet teperatures varyg fro C to 14 C by a step of C for te frst par ad varyg fro C to 14 C for te secod par. Te obtaed teracto paraeters values led to xg excess etalpy results very close to experetal values, cotrary to te odel wc sowed uge devatos. Terefore te optzato tecque based o te Splex etod proved to be very relable te deterato of teracto paraeters for te odel. Keywords: ; ; xcess etalpy; efrgerat; Absorbet. ésué Pour pouvor présélectoer de ouveaux fludes de traval pour les systèes de réfrgérato à absorpto, l est écessare de be copredre le calcul ou la corrélato des proprétés teropysques des fludes de traval. Le cox du odèle terodyaque le plus appropré pour la prédcto ou le calcul des proprétés terodyaques est ue tâce crucale. coséquece, la présete étude trate de la déterato des proprétés excédetares des élages de réfrgérats écessares au calcul des dfféretes etalpes plquées et doc de la ace frgorfque utlsée. La présete étude a exaé les pares (-cloro-1,1,1,-tétrafluoroétae) (14) e tat que frgorgèe e cobaso avec u absorbat orgaque (N, N'-détylacétade) DMAC et (1,1,1, -tétrafluoroétae) (134a) e tat que réfrgérat e assocato avec u détyléter éter tétraétylèeglycol (DMTG) absorbat orgaque e calculat les paraètres d'teracto oléculare pour le odèle e utlsat l'etalpe de élage e excès à ut tepératures dfféretes varat de C à 14 C par u pas de C pour la preère pare et varat de C à 14 C pour la deuxèe pare. Les valeurs des paraètres d'teracto obteues ot codut à élager les résultats d'excès d'etalpe très proces des valeurs expéretales, cotrareet au odèle qu présetat des écarts portats. Par coséquet, la tecque d'optsato basée sur la étode Splex s'est révélée très fable pour déterer les paraètres d'teracto du odèle. Mots clés: ; ; xcès d'etalpe; éfrgérat; Absorbat. ملخص لكي تكون قاد ار على تحديد سوائل عمل جديدة مسبق ا ألنظمة التبريد باالمتصاص من الضروري أن يكون لديك فهم جيد في حساب أو ت اربط الخصائص الح اررية الفيزيائية للسوائل العاملة. إن اختيار أنسب نموذج ديناميكا ح اررية للتنبؤ بالخصائص الح اررية أو حسابها هو مهمة حاسمة. وبناء على ذلك تتناول الد ارسة الحالية تحديد الخصائص ال ازئدة لمخاليط التبريد الالزمة لحسابات المستهلك المختلفة ومن ثم آلة التبريد المستخدمة. N'- نظرت الد ارسة الحالية في أزواج) مع الماصة العضويةN ) ( cloro tétrafluoroetae -كمبرد (14) (134a) ( tetrafluoroetae -كمبرد مع توليف عضوي ثنائي ميثيليثر رباعي إيثيلينجليكول ( Detylacetadeو) DMAC طريق حساب معلمات التفاعل الجزيئي لنموذج ( DMTG )عن باستخدام المحتوى الحراري الزائد لالختالط عند ثمانية درجات ح اررة مختلفة تت اروح من درجة مئوية إلى 14 درجة مئوية بخطوة مقدارها درجة مئوية للزوج األول وتت اروح من درجة مئوية إلى 14 درجة مئوية للزوج الثاني. أدت قيم معلمات التفاعل التي تم الحصول عليها إلى خلط نتائج المحتوى الح ارري الفائض قريبة جدا من القيم التجريبية على عكس نموذج الذي أظهر انح ارفات ضخمة. ولذلك ثبت أن تقنية التحسين القائمة على طريقة Splex الكلمات المفتاحية:.. المحتوى الح ارري ال ازئد التبريد. ماص. موثوقة للغاية في تحديد معلمات التفاعل لنموذج. Uversté des Frères Metour Costate, Algére, 17.

2 Ile LOUA, Nardess BOUNAB et Abdesela Hasse MNIAI 1. INTODUCTION Te vapor absorpto refrgerato syste s a d of portat eergy savg tecology ad esso reducto. It ca utlze reewable eergy suc as solar ad geoteral eergy or waste eergy fro dustral processes. I addto, te absorpto syste as o vbrato ad ose ad terefore, evroetally fredly ad becoes a copettve alteratve to te covetoal ecacal-drve vapour copresso refrgerato systes [1]. I spte of above advatages of te absorpto refrgerato syste, t s ot used for coercal purposes because of ts low perforace; so t eeds proveet. Te perforace of te absorpto refrgerato cycle depeds o ts cofgurato ad s crtcally depedet o te cecal ad terodyac propertes of te worg pars coposed of a refrgerat ad a absorbet [1, 13, 14, 18]. Accordgly, ay researcers ave attepted to develop ew worg pars for te absorpto refrgerato cycles to prove ter perforace [15, 16, 17 ] A wde varety of refrgerat-absorbet cobatos (bot orgac ad orgac) ave bee suggested for vapor absorpto coog systes lterature. A survey of absorpto fluds provded by Marcrss [19] suggests tat, tere are soe 4 refrgerat copouds ad absorbet copouds avalable. Most of tese are two copoet systes. Te two coo worg fluds absorpto refrgerato cycle are water-lbr ad aoa-water. Tese two worg fluds preset drawbacs wc drectly affect te perforace of tese refrgerato systes. Hece to overcoe te drawbacs assocated wt te covetoal worg pars, fdg a sutable xture s evtable. Furterore, to be able to evaluate te perforace of te cycle, oe ust ave at least te vapor lqud equlbru data of te worg flud xture. Obvously, te vapor lqud equlbru data of te worg flud ust be sold ad robust to prove te qualty of te results [1]. Te calculato of te absorpto systes requres te owledge of te etalpy of te lqud ad vapor pase xtures as a fucto of teperature, pressure ad cocetrato. However ost of te lqud systes devate fro dealty ad terefore te calculatos of specfc excess etalpes are ecessary. Tese are portat terodyac propertes are fuctos of te teperature ad te coposto of te cosdered solutos ad do ave a fluece o te usual ad ecessary etalpy-cocetrato dagras. Hece te terodyac calculato of te ey operatg paraeters of a absorpto cycle,.e. te coeffcet of perforace (COP) ad te crculato rato wt a possble varato of te order of 15% [1]. I addto, to ave sold etalpy-cocetrato dagras of te worg flud, t s ecessary to ave a good correlato of te specfc excess etalpy of te worg flud xtures usg ad to coose approprate terodyac odel to descrbe te actvty coeffcet, wc s a easure of te devato fro dealty of te lqud syste. Varous odels for te actvty coeffcet are avalable te lterature ad ost of te are based o te varato of te excess Gbb free eergy g wt coposto. Tey predct ore or less depedg o te type of te cosdered systes. Hece, te proble of te coce of te ost approprate terodyac odel s ot a easy tas. Tece, advace study o te terodyac odel to descrbe te vapor lqud equlbru propertes of te ew worg fluds xtures for te absorpto coog systes s udoubtedly ecessary before vestgatg te perforace of te absorpto cycle usg ew worg fluds. I te lterature, a uber of studes were carred out o tecques to prove te perforace of absorpto refrgerato systes drectly or drectly. I ay prevous wors, te No-ado two-lquds (NTL) actvty coeffcet odel was used to correlate te vapor lqud equlbru data of o dealty bary systes suc as HFCs ad orgac solvets xtures for absorpto refrgerato cycles [1,11,,1,]. Te (NTL), edlc-kwog-soave cubc equato of state (KS), Perturbed-ca Statstcal Assocatg flud Teory (PC- SAFT) ad odels were studed by Hf M Aryad [1] order to select te approprate odel to be used to correlate te teropyscal propertes eeded to vestgate te teral perforace of te absorpto systes based o aoa/oc lqud worg fluds. Te preset wor ca be regarded as a cotuato of a prevous oe [] were te bary syste 14-DMAC was cosdered a absorpto refrgerato ace ad te odeg of te perforace ad te recrculato rato was carred out by eas of te, wc s based o te cotrbutos of groups of atos o a structural bass,ad cosders te lqude soluto to be ade up of groups rater ta pure copoets as troduced by Fredeslud et al. [3]. Iteracto paraeters betwee te fuctoal groups ay be evaluated usg table I [7,8] Te results obtaed [] were ot always a reasoable agreeet wt experetal data ad ts ay certaly be due to errors duced by te approxatos upo wc s based te group cotrbuto cocept, partcularly te property addtvty. Terefore te a of te preset wor s to sow te fluece of te cose terodyac odel o te perforace of a absorpto refrgerato ace, rater usg te odel wc s te precursor of ad s based o olecular rater ta group teracto paraeters [4]. Two worg fluds were cosdered ts study, te frst oe s (-cloro-1,1,1,- tétrafluoroetae) (14) as a refrgerat cobato wt a orgac absorbet (N, N - Detylacetade) DMAC ad te secod oe s (1,1,1,-tetrafluoroetae) (134a) as a refrgerat cobato wt a orgac absorbet detyleter tetraetyleeglycol (DMTG). II. CALCULATION POCDU Te etalpy of te soluto te lqude pase ca be regarded as te su of te wegted cotrbutos of te two copoets,as a fucto of te teperature ad 38

3 OPTIMIZATION OF INTACTION PAAMTS FO ABSOPTION FIGATION MACHIN WOKING FLUIDS. cocetrato ad ca be calculated fro te specfc etalpy of te pure copoets ad te excess specfc etalpy of xg as follows: x r 1 x) (1) wt r s te specfc etalpy of te refrgerat, a te specfc etalpy of te absorbet, x s te wegt fracto of refrgerat te soluto ad te excess specfc etalpy of xg [J/g]. A. xcess terodyac propertes : Te excess olar Gbbs eergy of xg g of te soluto s te pot of departure for calculatg oter excess propertes. Te excess olar Gbbs eergy of xg s expressed ters of te olar cocetrato ad te actvty coeffcet as follows: g T ( x.( )) g S (3) T Fro equato () ad (3) te specfc excess etalpy ay be expressed as: g T g T T T x T x T B. Actvty coeffcet odels : a () x T (4) x T Varous odels for te calculatos of te actvty coeffcets γ are proposed te lterature. ac oe depeds o te aer, te expresso for te Gbbs eergy g s cose. Te ad odels were used to evaluate te actvty coeffcet γ te lqud pase. C. (Uversal Quas-cecal Actvty coeffcet) odel : Te coeffcet of actvty s ade of two ters as [5]: C Te frst ter s te cobatory ad te secod s te resdual oe ad are gve as follows: C Z q l x l (6a) x x l z q 1 (5) (6) 1 (6c) r q r (5) (6b) Were r ad q are te va der Waals olecular volue ad surface paraeters, respectvely, z s te coordato uber set equal to τ s te eergy paraeter. D. ( Fuctoal Actvty Coeffcet) odel : Slarly to te, te s also ade of two ters, cobatoral ad resdual as sow by quato 5. Te frst ter s te cobatoral wc s expressed by quato 6a ad te secod oe s te resdual ad s expressed as: (7a) v Were ad are te resdual actvty coeffcets of group te xture ad pure lqud, respectvely. Q 1 Q X q x X v v x x (7c) (7d) (7b) Te actvty coeffcet s a fucto of teperature ad s dfferetated as follows: c T T T C T (8) Ts ter does t deped o teperature Tus, we ave to dfferetate ts ter T Q T T a T a T K Te dervatve of T. T ( ) ( ) K T. T T ( ) a T ca be obtaed slarly to (9) (1)

4 Ile LOUA, Nardess BOUNAB et Abdesela Hasse MNIAI III. XPIMNTAL XCSS NTHALPY : xperetal excess etalpy s expressed as a fucto of teperature ad cocetrato for te 14- DMAC ad 134a-DMTG systes as a polyoal fucto expressed as [1,]: x T (11) s expressed [J/ g] ad x s te ole fracto of te refrgerat lqud pase. Te coeffcets for 14-DMAC ad for 134a-DMTG are gve [1,]. To be able to aalyse te results ad to copare wt te experetal data, te absolute average devato of te results s calculated. Te absolute average devato s calculated usg equato 1 AAD(%) 1 pts pts 1 exp exp calc IV. Optzato of teracto paraeters : (1) Te odel was used for te deterato of te actvty coeffcets of te costtuets 14 (-clor tetra-fluoroetae) ad DMAC (N' -N - detylacetade), ad te odel for te two cosdered worg pars(14-dmac,134a- DMTG. For te odel te requred teracto paraeters are obtaed usg te experetal data avalable te lterature [1,], by zg te obectve fucto F defed as follows: F N 1 (13),exp, cal Wt te excess etalpy, te subscrpts exp ad calc.deotg experetal ad calculated, respectvely ad N te uber of experetal data pots. Te adopted zato tecque was based o te Nelder-Mead verso Splex etod wc s extesvely descrbed detals te lterature [6]. For te odel te group teracto paraeters betwee te volved groups as well as te va der Waals volue ad surface area paraeters are avalable te lterature [7, 8] ad are as sow te followg Table I. Te decoposto to groups of te two cosdered costtuets s as follows: 14 (-cloro-1, 1, 1, -tétrafluoroetae): 1C, 1CH, 1Cl, 4F DMAC (N, N - Detylacetade): 1CH3, 1 CON(Me) V. SULTS : Te detal results of olecular teracto paraeters of te selected worg fluds obtaed after zato of te obectve fucto descrbed by quato 13 for te cosdered pars are sow te followg tables: TABL : MOLCULA INTACTION PAAMTS FO MODL FO 14(1) -DMAC () SYSTM Teperature ( C) a1 a TABL 3: MOLCULA INTACTION PAAMTS FO MODL FO 134A (1) -DMTG () SYSTM Teperature ( C) a1 a Te results of specfc excess etalpy wt ad odels at several teperatures are preseted fgures 1a- ad a -g. Aog te odels studed ts researc, bot ad odels sow ter ablty to calculate te actvty coeffcet ad tus specfc excess etalpy of te 14- DMAC wt relatve accuracy. Altoug, te calculato results usg odel were less accurate ta tose of odel for te 14-DMAC par. Subsequetly, odel s cose to evaluate te excess etalpy of te 134a-DMTG xture. Fg1a- sow te excess etalpy varatos wt te refrgerat (14) olar fracto at dfferet teperatures ters of olar fracto for te 14-DMAC par cosdered [1], te values of wc are copared wt te results obtaed te preset wor. TABL 1 GOUP VOLUM SUFAC AND INTACTION PAAMTS FO TH MODL / C CH CH 3 Cl F CON(Me) Q C CH CH Cl F CON(Me)

5 OPTIMIZATION OF INTACTION PAAMTS FO ABSOPTION FIGATION MACHIN WOKING FLUIDS. xcess etalpy (KJ/Kg) -1 - xperetal xcess etalpy (KJ/Kg) xperetal ,,1,,3,4,5,6,7,8,9 1, 14 olar fracto -,,1,,3,4,5,6,7,8,9 1, 14 olar fracto (a) (d) xcess etalpy (KJ/KG) -1 - xperetal,,1,,3,4,5,6,7,8,9 1, 14 olar fracto xcess etalpy (KJ/Kg) xperetal -,,1,,3,4,5,6,7,8,9 1, 14 olar fracto (e) (b) xcess etalpy (KJ/Kg) -1 - xperetal xcess etalpy (KJ/Kg) xperetal,,1,,3,4,5,6,7,8,9 1, 14 olar fracto,,1,,3,4,5,6,7,8,9 1, 14 olar fracto (c) (f) 41

6 Ile LOUA, Nardess BOUNAB et Abdesela Hasse MNIAI xcess etalpy (KJ/Kg) xperetal xcess etalpy (KJ/Kg) ,,,4,6,8 1, xperetal ,,1,,3,4,5,6,7,8,9 1, 14 olar fracto,,,4,6,8 1, 134a Molar fracto (g),,,4,6,8 1, xcess etalpy (KJ/Kg) - -1 xperetal xcess etalpy (KJ/Kg) xperetal ,,,4,6,8 1, 134a Mole fracto,,,4,6,8 1, 14 olar fracto () Fg1. Coparso of experetal, ad specfc excess etalpes at: a) C; b) C; c) 4 C; d) 6 C; e) 8 C; f) 1 C; g) 1) C; 14 C. Slar wt tose of 14 ad DMAC xture Fga - sow te excess etalpy varatos wt te refrgerat (134a) olar fracto at dfferet teperatures ters of olar fracto for te 134a-DMTG par cosdered [], te values of wc are copared wt te results obtaed te preset wor. Fro te calculated excess etalpy for te vestgated worg xtures at teperature varyg fro C to 14 C for 134a-DMTG, It s terestg to see at te fgure a,g tat te results of te specfc excess etalpy ave good agreeet wt te experetal data. It s also terestg to observe tat at ger teperature beyod 1 C te excess etalpy was postve wc eas tat te xg process s edoterc. O cotrary, at lower teperature below 1 C, te excess etalpy was egatve wc eas tat te xg process s exoterc. xcess etalpy (KJ/Kg) ,,,4,6,8 1,,,,4,6,8 1, 134a Molar fracto xperetal

7 OPTIMIZATION OF INTACTION PAAMTS FO ABSOPTION FIGATION MACHIN WOKING FLUIDS. xcess etalpy (KJ/Kg),,,4,6,8 1,, -,5-1, -1,5 -, -,5 xcess etalpy (KJ/Kg) xcess etalpy (KJ/Kg),,,4,6,8 1, 134a Molar fracto xperetal,,,4,6,8 1,,4,4,3,,1, -,1 -, -,3 -,4 -,5,, 1,8 1,6 1,4 1, 1,,8,6,4,,,,4,6,8 1, 134a Molar fracto xpretal,,,4,6,8 1, xperetal,,,4,6,8 1, 134aMolar fracto Fg. Coparso of experetal, ad specfc excess etalpes at: a ) C; b ) 4 C; c ) 6 C; d ) 8 C; e ) 1 C; f ) 1 C; g ) 14 C. Fro te prevous fgures, t ca be see tat qualtatvely bot te ad te odels led to slar sapes of te correspodg curves of versus te refrgerat olar fracto for 14-DMAC bary syste. For 14-DMAC ad for 134-DMTG systes, calculatos reproduce correctly te experetal data altoug values gve always a better correlato Fg1a- ad Fga -. Bot odels gve acceptable results everteless, -,5-1, -1,5 -, -,5,3,,1, -,1 -, -,3 -,4 -,5,, 1,8 1,6 1,4 1, 1,,8,6,4, reproduces better te experetal data ad ca be used wt ore cofdece to predct te actvty coeffcets, tus specfc excess etalpy. VI. CONCLUSION Troug ts optzato study t as bee clearly sow tat te group cotrbuto cocept based odels le te for te actvty coeffcets ave serous ltatos as llustrated by te obtaed results were te correspodg curves are far away fro tose of te experetal ad te wc tur were a excellet agreeet. To ave sold etalpy-cocetrato dagras of te worg flud used absorpto refrgerato systes, t s ecessary to ave a good correlato of te specfc excess etalpy of te worg flud xtures usg ad to coose approprate terodyac odel to descrbe te actvty coeffcet. Tey predct ore or less depedg o te type of te cosdered systes. Hece, te proble of te coce of te ost approprate terodyac odel s ot a easy tas. Also te a results s tat olecular teracto paraeters becoe avalable for te 14-DMAC ad for te 134a-DMTG systes wc are ot avalable. Wt powerful zato tecques le Nelder-ead verso Splex etod, te obtaed results are very relable ad ca be used to perfor coputer experets at wll. Fro ts aalyss, t ca be cocluded tat te use of default bary teracto paraeter s ot be able to calculate te specfc excess etalpy of 14 ad DMAC also of 134a ad DMTG xtures wt g accuracy. Fally troug ts study oe ca see tat te coce of te ost adequate etod of optzato s a crucal tas upo wc wll deped te relablty of te results. FNCS [1] I. Borde, M. Jee et N. C. Dalptrope. "Worg fluds for a absorpto syste based o 14 (-cloro-1, 1, 1,, tetrafluoroetae) ad orgac absorbets".it. J. efrg. Vol.. N 4. pp [] I. Borde, M. Jee et N. C. Dalptrope. "Absorpto syste based o te refrgerat 134a".It. J. efrg. Vol.18.N 6.pp [3] Louaer, A.-H. Mea, O. Larece ad M. Bece-Leoce, Coputer-aded desg ad test of ew refrgerats for absorpto cycle usg group cotrbuto etods, Desaato Joural 6 (7) 63, lsever [4] Fredeslud A., Joes.L., Praustz J.M., 1975, Groupcotrbuto estato of actvty coeffcets odeal lqud xtures, AIC J., 1, [5] Maurer G., Praustz J.M., O te dervato ad exteso of te equato, Flud Pase qulbra, (1978)91-99 [6]. C. ed, J. M. Praustz, B.. Pog. "Te propertes of gases ad lquds", 4t dto Mc Graw Hll Boo Copay, [7] H Nelder J. A., Mead. A., 1965, Splex etod for fucto zato, Coput. J., 7, [8] I. Louaer, Cocepto et test de ouveaux réfrgérats pour ue ace frgorfque à cycle d absorpto utlsat la étode de cotrbuto de groupes, Tése de Magstère, souteue e 4, uversté Costate, Algera 43

8 Ile LOUA, Nardess BOUNAB et Abdesela Hasse MNIAI [9]. Jadot, G. Juet, qulbre lqude-vapeur de élages d éters fluorés, Hg teperatures-hg pressures, vol. 6, [1] M. Hf, Teodyac study o absorpto refrgerato systes usg aoa/oc lqud worg pars, Doctoral tess defeded 16, ovra I Vrgl, Spa. [11]. Deg, X. g, D.Zeg, X.L Vapor-lqud equlbru easureets ad assesets of fluoroetae+detyeter detylee glycol systes for te ybrd refrgerato cycle Iteratoal Joual of efrgerato 43 (14),1766, lsever. [1] P. Srr, S.Aporrataa, S.Cugpabulpataa A revew of absorpto refrgerato tecologes eewable ad Sustaable ergy evews 5 (1), , lsever.. [13] K. Merdad, P.Kya, At. Ugur overvew of oc lquds used as worg fluds absorpto cycles (13) Adv. Mec. g. Artcle ID 659, 7 pages. [14] J.Su, SG. Zag A revew of worg fluds of absorpto cycles eewable ad Sustaable ergy 16 (1), [15] BJ. sa Wy refrgerat sould be favored for absorpto refrgerato ASHA J 1 (1959), [16] M. Jee, A. Levy, I. Bord Desty of bary xtures fro equlbru easureets Iteratoal Joual of efrgerato 3 (8), [17] X. L,. Zeg, D.X. Se, Y.S. Meg, X.L. L, B.Y Vapor lqud equlbraofdfluoroetae+n,n-detylacetade, dfluoroetae+detyleter detylee glycol ad 1,1- dfluoroetae+detyleter detylee glycol systes Flud Pase qulb 347 (13), [18] H. Perez-Blaco Absorpto eat pup perforace for dfferet types of soluto Iteratoal Joual of efrgerato 7(1984), [19] A. Marcrss, JM. Gutra, TS. Zawac Absorpto flud data survey Ist.Gas Tec (1988), fal report o world wde data. [] X.H. Ha, Z.J. Gao, Y.J. Xu Solublty of refrgerat1,1,1,- tetrafluoroetae te N,N-detyl forade te teperature rage fro (63.15 to ) K. J. Ce.g.Data 56(11), [1] X.L. Meg, D.X. Zeg, X.. L,Y.S. Se, soteral vapor lqud equlbru easureets of 1,1-dfluoroetae+N,Ndetylforade ad N,N-detylacetade J.Ce..data 58(13a), [] X.L. Meg, D.X.Zeg, J.Z. Wag, X.. L ergy savg ecas aalyss of te absorpto-copresso ybrd refrgerato cycle eew.ergy 57(13b),