@AIR USER S MANUAL VERSION 4.0 COPYRIGHT NOTICE

Transcription

1 @AIR USER S ANUAL VERSION 4.0 COPYRIGHT NOTICE softre nd mnul re copyrighted nd licensed for use by one user per copy purchsed. This mnul nd the softre described in it re copyrighted ith ll rights reserved. Under the copyright ls, this mnul or the softre my not be copied, in hole or prt ithout ritten consent of Techre Engineering Applictions, Inc. Techre Engineering Applictions, Inc. grnts permission to the purchser to mke limited number of copies of the dd-in for bckup purposes only, provided tht the copies re not in use t the sme time s the originl. Additionl reproduction of the dd-in is violtion of copyright l. Violtors ill be prosecuted to the fullest extent of the l. Copyright Techre Engineering Applictions, Inc. All rights reserved TRADEARKS The folloing trdemrks re used throughout this mnul. They re registered trdemrks of the compnies shon. Lotus, nd 1--3 re trdemrks of Lotus Development Corportion. Excel, Windos, Visul C/C++ nd Visul BASIC re trdemrks of the icrosoft Corportion. thcd is trdemrk of thsoft, Inc.

2 Tble of Contents 1. INTRODUCTION Overvie Bit nd 64-bit versions Wht s Ne.... USING PROPERTY FUNCTIONS Generl Informtion Description Functions Vlid Operting Rnge Bsic Unit Sets Wet or Dry Bsis Alternte oisture Prmeters Reference Conditions from Excel Loding Functions into Excel (3-bit) Loding Functions into Excel (64-bit) Using Functions from from thcd from Visul BASIC With Progrmming Lnguges Version nd Seril Number USING DESKTOP AIR Overvie Bsic Opertion Entering Dt Unit Selection Clculting Stte Points Formtting Property Vlues Lbeling nd Storing Stte Points Printing Sving And Opening Dt Files... 18

3 3.10 Advnced Fetures Expnsion/Compression Tool Heting/Cooling Tool Exchnging Dt ith Other Progrms Getting Help essges Exiting DeskTop Air THEORETICAL BASIS FUNCTIONS Bsis of Clcultions Humidity Prmeters Trnsport Properties SPEED AND ACCURACY CHARACTERISTICS Speed of Clcultions Accurcy of Clcultions REFERENCES APPENDIX ERROR CODES

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5 Chpter 1 Introduction Pge 1 1. INTRODUCTION 1.1 is softre product tht provides ccurte thermodynmic, psychrometric nd trnsport properties of moist ir through functions contined in Dynmic Link Librry (DLL). pckge includes DeskTop Air, n interctive ir property clcultor nd vrious dd-ins, hich llo the functions to be used s if they ere built into 1--3 for Windos, icrosoft Excel nd thcd. In 1--3 nd Excel, you cn ccess the functions directly from ithin cell formuls. Progrmmers cn cll the functions in the DLL directly from mny Windos progrmming lnguges such s icrosoft's Visul Bsic, Visul C++ nd Access. The DLL provides librry of ccurte functions, hich re bsed on dt published by the Ntionl Bureu of Stndrds (NBS) in 1955 (1). The NBS dt is lso the bsis of the formultions used to develop the tbles published in the Americn Society of Heting, Refrigertion nd Air-Conditioning (ASHRAE) Fundmentls, All of the properties clculted re bsed on rel gs properties, not perfect gs pproximtions. As such, they include the effects of pressure nd interctions cused by the mixing of ter vpor nd dry ir components. For detils on the theory nd ccurcy of the functions, check the html version of the user s mnul. The psychrometric functions fcilitte conversion mong vrious moist ir prmeters such s bsolute humidity, reltive humidity, et bulb temperture nd degree of sturtion. The thermodynmic property functions provide forrd nd inverse reltionships using specific volume, specific enthlpy nd specific entropy. The trnsport property functions provide specific het, dynmic viscosity nd therml conductivity from pressure, temperture nd humidity rtio. Also included re severl functions, hich provide thermodynmic properties of ter hich re useful in clcultions involving ddition or removl of moisture from ir strems. functions re vlid over temperture rnge from 180 K, (-136 F) to 000 K, (3140 F) nd t pressures up to 5.0 P, (75 psi). The functions detect requests for clcultions outside tht rnge nd return n error vlue. The Setup progrm nd the instlltion instructions contined in pckge guide you through instlling the files you'll need for the pplictions you expect to use. Exmple files to help you get strted ill lso be instlled. The s creted to signify tht it functions tht ere comptible ith Lotus 1--3, the dominnt spredsheet progrm severl yers go. Tody, symbol is most recognized s prt of n internet e-mil ddress. Hoever, for continuity, e hve retined the even though the current product supports vriety of Windos pplictions.

6 Chpter 1 - Introduction Pge 1. 3-BIT AND 64-BIT VERSIONS pckge includes both 3-bit nd 64-bit instlltion files. The instlltion instructions you received ith pckge ill guide you through instlling the files you'll need for the pplictions you expect to use. Exmple files to help you get strted ill lso be instlled. 1.3 WHAT S 4.0 dds 64-bit versions of the TAir DLL, the DeskTop Air clcultor nd the Excel ddin. It lso hs converted ll help files to compiled HTL formt for comptibility ith neer operting 3. does not instll the help shortcut on the toolbr hen using Excel 007 or lter in order to operte more 3.1 dds seventh unit set, ETF, hich is similr to the ET unit set but uses kg/cm for pressure. This version lso improves the ccurcy of the trnsport 3.0 dds mny ne fetures over the previous These include the folloing: Extends the temperture rnge uprds from 00 C, (39 F) to 000 K, (3140 F). Adds trnsport property functions: o AirPTWC, hich clcultes specific het given pressure, temperture nd humidity rtio. o AirPTW, hich clcultes dynmic viscosity given pressure, temperture nd humidity rtio. o AirPTWK, hich clcultes therml conductivity given pressure, temperture nd humidity rtio. Includes DeskTop Air, n dvnced ir property clcultor ith mny improved fetures over the previous ir property clcultor. Adds four ne unit sets, EngG using psig for pressure insted of psi, SIF, hich uses the forml SI units, P for pressure insted of br nd K for temperture, insted of C, SIK using kp insted of br for pressure nd ET using the clorie insted of the joule for energy. Allos specific properties to be expressed on either dry or et bsis. Allos the humidity rtio prmeter to be input lterntely, s mole frction or mss frction. Added ne thermodynmic functions: o AirPTHs, hich clcultes sturted enthlpy given pressure nd temperture.

7 Chpter 1 Introduction Pge 3 o AirPHTs, hich clcultes sturtion temperture for given pressure nd enthlpy. o AirWX, hich clcultes either the mole or mss frction given the humidity rtio, o AirXW, hich clcultes the humidity rtio given either the mole or mss frction. Improved instlltion progrm tht llos distribution over the eb.

8 Chpter - Using Property Functions Pge 4. USING PROPERTY FUNCTIONS.1 GENERAL INFORATION All pplictions using the ir property functions use the sme set of functions. In most pplictions, the functions re clled by nme. In the DeskTop Air clcultor, the pproprite functions re clled utomticlly ccording to your on-screen selections. Ech user of spredsheets or progrms you rite using the ir property functions, must hve their on copy Spredsheets nd progrms clling the functions must ccess the dynmic link librries t run time. Since these files ill be clled by mny pplictions, they must be instlled on the computer in either the Windos directory or preferbly, in the Windos System directory. Normlly, the instlltion progrm ill set this up for you utomticlly. In Excel, 1--3, thcd, Visul BASIC nd your on Windos progrms, the functions provided cn be used ithin equtions just like ech ppliction's built-in mth functions. The functions cn even be nested. Ech function returns single, floting point result. The functions require up to three inputs nd unit set prmeter to identify the stte point. Subsequent sections of this chpter describe the clling syntx nd other considertions in using the functions ithin supported pplictions.. DESCRIPTION FUNCTIONS All of functions, hich re ccessible to the user, re summrized in the tble belo. Function Input(s) Output Equtions of Stte AirPTWV() Pressure, Temperture, HO Content Specific Volume AirPVWT() Pressure, Volume, HO Content Dry Bulb Temperture AirTVWP() Temperture, Volume, HO Content Pressure Thermodynmic nd Psychrometric Functions AirPTW() Pressure, Temperture Sturted Humidity Rtio AirPWD() Pressure, HO Content De Point Temperture AirPTF() Pressure, Temperture Enhncement Fctor AirPTRW() Pressure, Temperture, Reltive Humidity HO Content AirPTWR() Pressure, Temperture, HO Content Reltive Humidity AirPTWB() Pressure, Temperture, HO Content Wet Bulb Temperture AirPTBW() Pressure, Temperture, Wet Bulb HO Content AirPBWT() Pressure, Wet Bulb, HO Content Temperture AirPBRT() Pressure, Wet Bulb, Reltive Humidity Temperture AirPTWU() Pressure, Temperture, HO Content Degree of Sturtion AirPTUW() Pressure, Temperture, Degree of Humidity Rtio

9 Chpter - Using Property Functions Pge 5 Sturtion AirPTWH() Pressure, Temperture, HO Content Specific Enthlpy AirPHWT() Pressure, Enthlpy, HO Content Temperture AirPWHT() Pressure, HO Content, Enthlpy Temperture AirPTHs() Pressure, Temperture Sturted Enthlpy AirPHTs Pressure, Enthlpy Sturted Temp AirPTWS() Pressure, Temperture, HO Content Specific Entropy AirPSWT() Pressure, Entropy, HO Content Temperture AirPWST() Pressure, HO Content, Entropy Temperture Trnsport Property Functions AirPTWC() Pressure, Temperture, HO Content Specific Het AirPTW() Pressure, Temperture, HO Content Dynmic Viscosity AirPTWK() Pressure, Temperture, HO Content Therml Conduct Vpor nd Liquid Wter Property Function AirVpTP() Wter Vpor Temperture St Pressure AirVpPT() Wter Vpor Pressure St Temperture. AirCondPTH() Pressure, Wter Temperture Specific Enthlpy AirCondPTS() Pressure, Wter Temperture Specific Entropy iscellneous Functions AirWX() Humidity Rtio ss or ole Frction AirXW() ss or ole Frction Humidity Rtio AirVer() None Version/seril no. Theoreticlly, n ir property stte point cn be uniquely identified by specifying ny to thermodynmic properties nd mesure of the rtio of ter vpor to dry ir. In most prcticl pplictions, pressure is one of the knon vribles. Therefore, most of the functions described bove ssume tht pressure is one of the knon vribles. If this is not the cse, one of the equtions of stte my be used to obtin the pressure. You my be fmilir ith psychrometric chrts or ir property tbles in hich pressure is not one of the vribles. There re couple of resons for this. Typiclly, psychrometric chrts nd ASHRAE tbles re vlid only t tmospheric pressure. In these cses, the pressure vrible is implied s stndrd tmospheric pressure. In other references, ir is sometimes treted s perfect gs in hich properties such s enthlpy, entropy nd specific het re not dependent upon pressure. Treting ir s perfect gs produces only rough pproximtions to the ctul properties. The perfect gs pproximtions re resonble t lo pressures but increse in error s the pressure is incresed. The formultions used re bsed on rel gs properties nd include the effects of pressure nd the mixing of ir nd ter vpor. Refer to section 4 for more informtion bout the model used nd its ccurcy. The property oisture Content refers to the humidity rtio by defult. You cn chnge it to refer to mole frction of ter vpor by dding C to the unit set rgument or mss frction by dding n. If some other mesure of moisture is knon such s Reltive Humidity, Wet Bulb Temperture, Degree of Sturtion or De Point Temperture, use one of the functions provided to obtin the oisture Content. As long s the stte point is defined, you should be ble to find the property you need in most cses, by using vrious combintions of the functions.

10 Chpter - Using Property Functions Pge 6 A function, AirPTW is provided to obtin the sturted moisture content for knon pressure nd temperture. The Dry Bulb Temperture t sturtion is synonymous ith the De Point Temperture. Therefore, this function cn be used ith pressure nd the De Point Temperture to obtin the moisture content. The inverse of this function is AirPWD, hich returns the De Point or Dry Bulb Temperture t hich the ir becomes sturted bsed on the level of ter vpor specified. The function AirPTHs clcultes the enthlpy of moist ir sturted ith ter t given pressure nd temperture. It is equivlent to clling the AirPTW function to get the sturted moisture content nd then clling the AirPTWH function ith the clculted moisture content. The function AirPHTs is used to nlyze process of simultneous heting nd humidifiction or cooling nd evportion hen the output strem is in sturted stte...1 Vlid Operting Rnge functions re vlid over temperture rnge from 180 K, (-136 F) to 000 K, (3140 F) nd t pressures up to 5.0 P, (75 psi). The functions detect requests for clcultions outside tht rnge nd return n error vlue... Bsic Unit Sets Input to ll the functions nd ll results cn be in ny of the vilble unit sets. The tble belo summrizes the units used for ech unit set. English SI English Guge SI Forml SI kp etric etric Forml Unit Set Number Unit Set Nme "ENG" "SI" ENGG SIF "SIK" "ET" ETF Temperture F C F K C C C Pressure psi Br psig P kp br kg/cm Entropy Btu/lbm/ F kj/kg/ C Btu/lbm/ F kj/kg/ C kj/kg/ C kcl/kg/ C kcl/kg/ C Enthlpy Btu/lbm kj/kg Btu/lbm kj/kg kj/kg kcl/kg kcl/kg Specific Volume ft 3 /lbm m 3 /kg ft 3 /lbm m 3 /kg m 3 /kg m 3 /kg m 3 /kg Specific Het Btu/lbm/ F kj/kg/ C Btu/lbm/ F kj/kg/ K kj/kg/ C kcl/kg/ C kcl/kg/ C Viscosity lbm/ft-hr Centipoise lbm/ft-hr P-sec Centipoise Centipoise Centipoise Conductivity Btu/hr/Ft/ F tt/m/ C Btu/hr/Ft/ F tt/m/ K tt/m/ C tt/m/ C tt/m/ K Humidity Rtio Non-Dim Non-Dim Non-Dim Non-Dim Non-Dim Non-Dim Non-Dim Reltive Humidity Non-Dim Non-Dim Non-Dim Non-Dim Non-Dim Non-Dim Non-Dim Degree of St. Non-Dim Non-Dim Non-Dim Non-Dim Non-Dim Non-Dim lets the user select the desired unit set ith ech function cll by the use of n extr function rgument, the unit set prmeter. The unit set prmeter selects bsic units, Eng, SI, etc. nd optionl unit set modifiers. The ir property functions ithin the function librry contin the conversion fctors for the bsic unit sets nd the set modifiers. When clling ir property functions from Visul Bsic or ny other Windos progrmming lnguge, the unit set prmeter is required nd must be n integer vlue. Additionl flexibility in entering the unit set prmeter is vilble hen using the ir property

11 Chpter - Using Property Functions Pge 7 dd-in functions from Excel or The spredsheet dd-ins llo the unit set prmeter to be entered either s chrcter string or n integer vlue. For most users, the chrcter string method is preferble becuse the chrcters representing the unit sets nd their options re mnemonic. For thcd, the unit set cn only be entered s number, hoever, you cn chieve the sme effect by defining mnemonics for the bse unit sets nd the options right on your thcd orksheet..3 Wet or Dry Bsis All mss-dependent properties (specific volume, enthlpy, entropy, specific het, viscosity nd conductivity) cn be bsed on either dry or et bsis. The defult for ll bsic unit sets expresses the properties per mss of dry ir. This is consistent ith ASHRAE conventions nd is quite useful hen deling ith processes tht involve evportion or condenstion of ter vpor. In some cses, you my ish to express these properties on et bsis, tht is, per mss of et ir (dry ir plus ter vpor). You cn ccomplish this by dding the letter W to the unit set nme or dding 16 to the unit set number. Remember tht the choice of et or dry bsis ffects both input nd output properties. For exmple in Excel, you cn clculte the enthlpy of moist ir on et bsis t pressure of 15 psi, temperture of 150 F nd humidity rtio of s follos: =AirPTWH(15,150,0.015, EngW )..4 Alternte oisture Prmeters The mount of moisture in the ir cn be expressed in severl ys, including humidity rtio, mole frction nd mss frction. Humidity rtio is defined s the rtio of the mss of ter vpor to the mss of dry ir. This method of expressing moisture is prticulrly useful hen deling ith evportion of condenstion becuse the flo of dry ir remins constnt ith either of these processes. ole frction, hich is equivlent to volume frction, is the rtio of the moles of ter vpor to the totl moles of ter vpor plus dry ir. ss frction is the rtio of the mss of ter vpor to the mss of ter vpor plus the mss of dry ir. The moisture content prmeter W, refers to humidity rtio by defult. This is nturl choice if properties re expressed on dry bsis. If you choose to express properties on et bsis, you my find it more convenient to express the moisture prmeter s mole or mss frction. You cn substitute mole frction herever humidity rtio is used, by dding C to the unit set nme or 3 to the unit set number. Similrly, you my substitute mss frction of ter vpor herever Humidity Rtio is used, by dding n to the unit set nme or 64 to the unit set number. If C is dded to the unit set nme or 96 is dded to the unit set number, the mss frction lterntive is selected. For exmple in Excel, you cn clculte the enthlpy of moist ir t pressure of 5 psig, temperture of 180 F nd moisture content of 1.5% by volume s follos: =AirPTWH(5,180,0.015, EngGC )

12 Chpter - Using Property Functions Pge 8..5 Reference Conditions Enthlpy nd entropy vlues re lys expressed reltive to prticulr reference conditions. ny people forget tht the vlues of enthlpy nd entropy tht re found in published tbles re not bsolute vlues but insted, re reltive to prticulr reference conditions. Engineering clcultions lys del ith enthlpy or entropy differences, typiclly beteen in-floing nd out-floing strems. For this reson, it does not mtter ht you select s the reference conditions, s long s you use them llos you to select reference conditions consistent ith ASHRAE or n lternte set of conditions bsed on bsolute zero temperture. In SI units, ASHRAE uses reference condition of 0 C nd one tmosphere of pressure for dry ir. For ter vpor, ASHRAE used reference condition of liquid ter t the triple point temperture of 0.01 C. In English units, hoever, ASHRAE uses reference condition of 0 F t one tmosphere of pressure for dry ir properties hile mintining the convention of using the triple point s reference temperture for ter properties. functions ill use reference temperture of 0 F if n English unit set is selected or 0 C if n SI unit set is selected. If you try to convert enthlpy (or entropy) vlues from English to SI units using stndrd conversion fctors, you ill find difference equl to the difference in dry ir enthlpy (or entropy) beteen 0 F nd F. You cn void this problem by converting the input prmeters (e.g. pressure nd temperture) to either English or SI units before clling the function. As n lterntive, you cn set the reference temperture for the dry ir portion to bsolute zero, (0 K) by dding n A to the unit set nme or dding 8 to the unit set number. In this cse the 0 K reference temperture ill be used for ny of the English or SI unit sets. For exmple in Excel, you cn clculte the enthlpy of moist ir ith 0 K reference temperture t pressure of 15 psi, temperture of 150 F nd humidity rtio of s follos: =AirPTWH(15,150,0.015, EngA ) Plese note tht in ll cses, the enthlpy nd entropy of the ter portion re set to zero for liquid ter t the triple point temperture. Some publictions, hich re bsed on perfect gs ssumptions, ssign the zero point for enthlpy nd entropy to ter in the vpor stte t the triple point or some other specified temperture. We believe tht setting the zero point for enthlpy nd entropy to ter in the liquid stte rther thn in the vpor stte hs to mjor dvntges. First, the vlues re numericlly equivlent to stndrd interntionl stem tbles (nd Techre s WinStem product). This fcilittes the hndling of processes tht include both moist ir nd liquid ter strems ithout orrying bout reference tempertures. Second, It gretly simplifies nlysis of processes in hich ter is either condensed from or evported to the ir strem. All reference conditions use the Interntionl Temperture Scle of 1990 (ITS-90) described in reference (5) s the bsis of temperture.

13 Chpter - Using Property Functions Pge 9.3 FRO 4.0 supports 3-bit nd 64-bit versions of icrosoft Excel. If you folloed the guidelines in the Instlltion Instructions, you should hve the proper version of the Excel dd-in instlled. Before you cn use functions in Excel, you hve to lod the dd-in using the Excel Add-in nger. The procedure for ctivting the dd-in is slightly different for 3-bit nd 64- bit versions nd so seprte instructions re provided..3.1 Loding Functions into Excel (3-bit) Once you hve strted Excel, use the Tools, Add-ins menu to strt Excel s Add-In nger. (In Office 007, click the Office button, then click the Excel Options button, then select the Add-ins tb nd click the Go button t the bottom. In Office 010, you cn get to the Addins tb by clicking the File menu nd then the Options item.) You should see n for Excel in the list box. If you did not for Excel in the Add-in nger list box, click the Brose button nd look for the file XLAir3.xll. It should be in the C:\Progrm Files\icrosoft Office\OfficeXX\Librry directory, here OfficeXX is the ltest Office version instlled. When you find it, click for Excel should no pper in the list box. If you re running Windos 7, look in the C:\Progrm Files (x86)\icrosoft Office\OfficeXX\Librry directory for the file. Click the check box next for Excel nd press OK. copyright notice should be displyed on the sttus br t the bottom of Excel. dd-in is no loded into Excel nd ill relod every time you strt Excel. If you do not nt the Add-in to lod ech time you strt Excel, go bck to the Add-in nger nd uncheck box before closing Excel. Once selected this y using the Add-in nger, the functions ill be loded utomticlly, ech time you strt Excel. If you ish to unlod the functions, use the Add-In nger nd uncheck the box for Excel. for Excel ill not lod until you select it gin using the Add-In nger s described bove..3. Loding Functions into Excel (64-bit) Once you hve strted Excel, click the File enu, then click the Options button, then select the Add-ins tb nd click the Go button t the bottom. Click the Brose button nd look for the file XLAir64.xll. It should be in the C:\Progrm Files\TechreEng\@Air (x64) directory. When you find it, click for Excel 010 should no pper in the list box. Click the check box next for Excel 010 nd press OK. copyright notice should be displyed on the sttus br t the bottom of Excel. dd-in is no loded into Excel nd ill relod every time you strt Excel. If you do not nt the Add-in to lod ech time you strt Excel, go bck to the Add-in nger nd uncheck box before closing Excel. Once selected this y using the Add-in nger, the functions ill be loded utomticlly, ech time you strt Excel. If you ish to unlod the functions, use the Add-In nger nd uncheck the box for Excel 010. for Excel ill not lod until you select it gin using the Add-In nger s described bove.

14 Chpter - Using Property Functions Pge Using Functions Once the dd-in is loded, the ir property functions re vilble in the sme ys s Excel's built-in functions. Tht is, they cn be typed into cell formuls or they cn be inserted by pressing the f x button hile creting cell eqution or using the Formul Pste Function menu selection. When using either of the to ltter methods, the ir property functions ill be sorted lphbeticlly in function ctegory clled Engineering. Generlly, you cn use ny of the functions listed in section. in ny cell formul. Be sure to prefix the function nme ith n "=" chrcter if it is the first or only item in formul. The line belo presents n exmple of cll to n ir property function from Excel ssuming tht the pressure is in cell A1, the temperture is in cell B1, the humidity rtio is in cell C1 nd ll vlues re in English units: =AirPTWH(A1,B1,C1, Eng ) pckge includes smple Excel spredsheet file nmed EXAPLE.XLS, hich demonstrtes the ir property functions using vrious unit set rguments. You cn find this file in Smples folder in progrm folder. Since property functions mke mny floting-point clcultions, they cn dd to spredsheet's reclcultion time. You my find it desirble to set the spredsheet to mnul reclcultion rther thn utomtic. functions cn use ny of severl unit sets nd vriety of options, ll of hich re ccessed using the unit set rgument. This llos different unit sets nd options to be mixed in the sme spredsheet. Plese see section. for instructions regrding the use of these fetures..4 FRO orks ith 3-bit versions of 1--3 including nd 1--3 illennium. You must lod the dd-in file nmed 13AIR.1A to ccess the ir property functions from When the dd-in is loded into memory it estblishes links beteen 1--3 nd dynmic link librry. Use the File, Add-Ins, nge Add-ins menu selections to strt the Add-In mnger. Before you cn use dd-in for the first time, you must register the dd-in by pressing the 'Register..' push-button. If instlled using the defult vlues, the file 13AIR.1A should be in the \LOTUS\13\ADDINS directory nd ill be shon in the Register Add-Ins indo. If you instlled the file elsehere, you ill hve to use the 'Look in' indo to serch for the file. When you hve locted the 13AIR.1A file, select it nd press the 'Open' push-button. The dd-in is no registered ith To lod the dd-in fter it is registered, click on the pth nme tht hs the 13AIR.1A file. A check mrk ill pper to the left of the pth nme indicting tht the dd-in is selected. Press the 'Done' push-button to complete the tsk. Therefter, ech time you strt 1--3, the functions ill be loded utomticlly. If you ish to unlod the functions, use the Add-In mnger to un-check the dd-in. Therefter, the 13AIR.1A dd-in ill not lod until you select it gin using the Add-In mnger s described bove but it should be unnecessry to go through the registrtion process gin.

15 Chpter - Using Property Functions Pge 11 Once the dd-in is loded, the ir property functions cn be used in ny cell formul by typing the function nme in the sme ys s 1--3's built-in functions. If you need help, use the Help menu nd select the '@Air Help' item. This ill lunch n interctive help indo, hich provides informtion regrding the functions nd their usge. Generlly, you cn use ny of the functions listed in section.1 in ny cell formul simply by prefixing the function nme ith n "@" chrcter. pckge contins smple spredsheet file nmed EXAPLE.13 hich mkes severl typicl clls to the ir property functions. The line belo presents n exmple of cll to n ir property function from SI ) The rgument "A1" is for the ir pressure nd cn be cell reference or n ctul pressure vlue. In similr mnner, "B1" is for temperture nd "C1" is for the humidity rtio. The lst rgument selects the units set nd ny options. This syntx ctully clls n dd-in function in the 13AIR.1A dd-in. These dd-in functions perform error checking nd return n pproprite 1--3 error vlue hen necessry - typiclly hen input rguments re out of rnge or hen too mny rguments re supplied to the function ill not ccept cell formul tht contins function reference ith too fe input rguments. The 13AIR dd-in functions themselves, cll functions in TAIR3.DLL to ctully perform the clcultions. functions cn use ny of severl unit sets nd vriety of options, ll of hich re ccessed using the unit set rgument. This llos different unit sets nd options to be mixed in the sme spredsheet. Plese see section. for instructions regrding the use of these fetures..5 FRO ATHCAD dd-in for thcd is self-registering DLL. All tht is required for thcd to ccess the functions is tht the dd-in file, CDAIR3.DLL, be locted in the WINCAD\USEREFI directory. function is used, thcd ill utomticlly lod nd register the function. dd-in for thcd llos the use of ny of the unit sets. thcd, hoever, llos only pure numbers (ithout units) to be pssed to nd from user-defined functions. The lst rgument in ech function cll is the unit set designtor nd cn hve vlue from 0 to 17 depending upon the selection of bse unit set nd the unit set options. The other rguments to the function must be numbers ithout units hose vlues re consistent ith the selected unit set. pckge contins smple thcd file nmed EXAPLE.CD, hich mkes typicl clls to the ir property functions nd illustrtes the use of the unit set designtor. Although on-line help is not directly vilble from ithin thcd, the Choose function feture does recognize functions nd ssists the user ith the functions. Use the th, Choose Function menu selections to open the Choose Function indo. Scroll

16 Chpter - Using Property Functions Pge 1 don the 'Function nme is' box to find ll of the ir functions listed in lphbeticl order. The 'Returns' box ill describe the input rguments nd the return vlue for the function tht is selected. Pressing the 'Insert' push-button ill copy the function to your orksheet ith plceholders for ech function rgument..6 FRO VISUAL BASIC The ir property functions cn be used directly in your Visul Bsic progrms just like the builtin functions. Before the functions cn be used, hoever, they must be declred s functions nd Visul BASIC must be told here to find them. This cn ll be ccomplished by including DECLARE sttement for ech of the ir property functions in either the Form code or in the Globl code. The DECLARE sttement must include the nme of the function, the dynmic link librry here it cn be found (TAIR3.DLL) nd the list of rguments (hich must ll be pssed by vlue, 'ByVl'). A smple DECLARE sttement is s follos: Declre Function AirPTW Lib "TAIR3.DLL" (ByVl P As Double, ByVl T As Double, ByVl UnitSet As Integer) As Double If you re using 64-bit version of Office, the DLL nme is TAir64.dll insted of TAir3.dll nd you must include the term PtrSfe fter the keyord Declre, for exmple: Declre PtrSfe Function AirPTW Lib "TAIR64.DLL" (ByVl P As Double, ByVl T As Double, ByVl UnitSet As Integer) As Double A text file, TAIRVBDEC.TXT, hich lists declrtions for ll of functions is included in pckge in the \Progrmming subdirectory. If you re using functions in n Excel Visul Bsic module to crete dditionl functions, you should use different nme to declre the functions or else they ill conflict ith the functions in the XlAir.xll dd-in. In this cse, you must use the ALIAS keyord in the declrtion to identify the true nme in the DLL. For exmple, Declre Function yairptwh Lib "TAIR3.DLL" ALIAS "AirPTWH" (ByVl P As Double, ByVl T As Double, ByVl W As Double, ByVl Unitset As Integer) As Double If you re using 64-bit version of Office, the DLL nme is TAir64.dll insted of TAir3.dll nd you must include the term PtrSfe fter the keyord Declre, for exmple: Declre PtrSfe Function yairptwh Lib "TAIR64.DLL" ALIAS "AirPTWH" (ByVl P As Double, ByVl T As Double, ByVl W As Double, ByVl Unitset As Integer) As Double A text file, TAIRVBADEC.TXT, hich lists declrtions using the Alis formt is included in pckge in the \Progrmming subdirectory. With ech TAIR3 function cll, your code should check to ensure tht the vlues returned re greter thn Return vlues of or smller indicte error conditions. See the Appendix for listing of error codes nd their menings.

17 Chpter - Using Property Functions Pge 13.7 WITH PROGRAING LANGUAGES The ir property functions in TAIR3.DLL or TAIR64.DLLcn lso be clled from ithin C/C++ progrms compiled to run under Windos. Prototypes for ll functions re provided in the file nmed TAIRPROTO.H. All files needed to support your progrmming pplictions cn be found in the \Progrmming directory if you choose to instll progrmming support during instlltion. You my lso find it convenient to include the file nmed AIRERR.H. It defines mnemonic constnts for the vrious error vlues returned by ir functions. The compiled code should lso be linked ith the import librry nmed TAIR3.LIB or TAIR64.LIB s pproprite. With ech ir property function cll, your code should check to ensure tht the vlues returned re smller (more negtive) thn Return vlues of or smller indicte error conditions. See the Appendix for listing of error codes nd their menings..8 VERSION AND SERIAL NUBER There my be ne releses to dd fetures or to support ne pplictions. Ech ne relese ill hve version number tht is printed on the diskette lbel. The TAIR3.DLL file hs its on version number, hich my differ from version number. Every copy sold is provided ith unique seril number. You cn identify the version of the DLL nd seril numbers of your copy by using the AirVer function, hich tkes no rguments. In Excel, n empty pir of prentheses is needed. In 1--3 no prentheses is needed. The AirVer function returns floting-point number contining the informtion (e.g., ). The first to digits indicte the DLL version number. The next five digits mke up your copy's seril number. The seril number lso cn be found by selecting About on the Help menu of DeskTop Air.

18 Chpter 3 - Using DeskTop Air Pge USING DESKTOP AIR 3.1 OVERVIEW DeskTop Air is Windos ppliction, hich clcultes the thermodynmic nd trnsport properties of moist ir. It cn be used s n interctive replcement for ir property tbles nd psychrometric chrts but does much more thn tht. It utomticlly clcultes ll unknon properties hen stte point is defined by knon properties. The progrm is flexible, nd designed to minimize keystrokes for common clcultions. DeskTop Air llos you to enter ny number of stte points, lbel them nd store the collection of points for lter reference. You cn print tble of stored points or copy them to the clipbord nd pste them into your fvorite spredsheet or ord processor. jor fetures of this progrm include: vlidity s full rnge of pressures nd tempertures flexible interctive design lrge choice of units for ech property tools for heting, cooling, expnsion nd compression processes instnt response time extensive help screens If instlled properly, DeskTop Air is strted by simply double clicking on its nme/icon in subgroup of the TechreEng Group ppering in the Windos Strt enu. 3. BASIC OPERATION The DeskTop Air disply is rrnged in tbulr formt tht remins constnt lthough the progrm indo cn be re-sized. You my sometimes find it convenient to mke the progrm indo smller. Ech of the ros is dedicted to one of the ir properties (pressure, dry bulb temperture, specific volume, enthlpy, entropy, et bulb temperture, de point, reltive humidity, humidity rtio, degree of sturtion, HO mole frction, HO mss frction, moleculr mss, specific het, dynmic viscosity nd therml conductivity). There is column tht displys the property vlues for the ctive point nd column tht displys dt for one of the stored points. The key properties tht cn be used to define the ir stte point re: pressure, temperture, specific volume, enthlpy, entropy, nd one of the moisture indictors. Theoreticlly, stte point cn be uniquely identified by specifying the moisture content nd ny to of the other five properties. On Psychrometric chrt, the stte point is normlly determined s the intersection of to lines, hich represent to vribles. Only to vlues re required on the Psychrometric chrt becuse the chrt is vlid for only single ir pressure. In most prcticl pplictions, pressure is usully one of the knon vribles. ost of the clcultions require

19 Chpter 3 - Using DeskTop Air Pge 15 tht the pressure be knon. In the rre cse hen pressure is not knon, it cn be clculted from the eqution of stte if the dry bulb temperture, specific volume nd humidity rtio is knon. Ech of the key properties hs check box ssocited ith it. When checked, it signifies tht this property is to be used in clculting the stte point. In generl, to thermodynmic properties nd one other property, hich indictes the moisture content, must be selected before DeskTop Air ill llo computtion. There re some combintions of only to properties tht llo computtion in the sturted stte. In these cses, you ill notice tht the Compute Sturted button is enbled. Once you select one property, DeskTop Air ill disble ll the other check boxes hose properties re not lloed in combintion ith the first selected property. You my chnge your selections by un-checking one or ll of the check boxes nd selecting ne combintion. To compute n ir property stte point, begin by selecting the input properties nd set the corresponding check boxes s described bove. Enter vlues for those properties in the boxes to the right of the property nmes. (The next section describes vrious methods for entering dt.) When you enter vlue for ny of the key properties, red X ppers next to the property vlue to indicte tht ne vlue hs been entered. This is rning tht the vlue being displyed is not consistent ith the current stte point. After compute commnd is completed successfully, ll property vlues re reclculted nd the red X s re clered. Be sure to enter the vlues in units consistent ith the unit displyed to the right of the vlue box. If you ish to chnge units, select the desired units before entering the vlue. If you chnge units fter the vlue is entered, the vlue entered ill be converted to the ne units. Next, click the 'Compute' button to find ll the unknon properties. If the Compute button is gryed, you hve not checked enough properties to define the stte point. Fields ithout check boxes re output only. These include moleculr mss, specific het, viscosity nd therml conductivity. After reclcultion, ll fields contin property vlues for moist ir t prticulr stte point. The box lbeled Reference identifies the reference conditions for the property vlues. It indictes hether the vlues re on et or dry bsis, the reference pressure for entropy nd the reference temperture for dry ir enthlpy nd entropy. 3.3 ENTERING DATA Numeric dt is entered in specilly designed edit box clled n IO Box, hich behves like stndrd Windos edit box but includes some dditionl fetures. To enter ne dt, double click the IO Box nd ll the dt ill be highlighted. As you enter ne dt, the old dt ill be replced. To edit dt, hold the left mouse button don nd drg the mouse over the chrcters tht you ish to replce, thereby highlighting them. Relese the mouse button nd type ne chrcters to replce the highlighted ones. The IO Box hs to modes of opertion, input nd output. When ne dt is entered, the IO Box is plced in the input mode nd red X ppers to the left of the box. After ne stte point is computed, ll IO Boxes re plced in the output mode nd the red X s re removed.

20 Chpter 3 - Using DeskTop Air Pge 16 The IO Box ccepts either numericl vlues or rithmetic expressions tht cn be evluted to numeric vlue. A number cn be entered in either deciml or scientific nottion. The expression cn be ny vlid rithmetic expression using the folloing opertors: + dd - subtrct * multiply / divide ^ exponent ( ) prentheses Arithmetic clcultions cn be nested to ny level using prentheses. An exmple of vlid expression is: ((1004^ + 997^) / )^.5 hich evlutes to Expressions re evluted henever you tb to or click on nother control or press the Enter button. Only the resulting vlue is shon in the box. If you enter n incorrect expression, your computer ill beep nd the edit cursor ill highlight the offending chrcter. You must fix the error before DeskTop Air ill llo you to continue. If the expression you re entering is too long to fit in the box, the box ill temporrily increse in length so tht you my vie more of the expression. When you re finished editing, the box returns to its originl length. To recll the lst expression used in n input box, use the 'Recll Expression' commnd on the 'Edit' menu. You ll then hve the opportunity to edit the expression nd let the IO Box reevlute it. Note tht the box retins the lst number or expression entered even fter compute commnd is issued. As result, the vlue in the box ill not reflect the vlue of the reclled expression if compute commnd hs ltered the vlue. You my use the Cut, 'Copy' nd 'Pste' commnds on the 'Edit' menu or the toolbr to exchnge numeric dt beteen DeskTop Air s IO Boxes nd ny other ppliction tht supports the clipbord. If you strt entering dt in n IO Box nd ish to go bck to the originl dt you my use the 'Undo' commnd on the 'Edit' menu. Hoever, once the IO Box loses the focus, the 'Undo' commnd is no longer vilble. 3.4 UNIT SELECTION DeskTop Air llos you to use ny combintion of units for input nd output properties. The units for ech property cn be set independently by using its ssocited combo box. To chnge unit, select its combo box nd scroll through the list of vilble units using either the keybord cursor rros or the mouse. Whenever ne unit is selected, the progrm converts the vlues displyed for tht property to the ne units. Therefore, hen entering dt you should first select the units nd then key in the input vlues. Otherise, the vlues ill be converted to the ne units nd you ill hve to re-enter them. The first time the progrm is strted, the properties ill be displyed in SI units. You cn chnge ll of the units to either stndrd English or SI units by issuing the 'English Units' or 'SI

21 Chpter 3 - Using DeskTop Air Pge 17 Units' commnd from the 'Formt' menu or pressing the Eng or SI toolbr button. When you chnge to English units in this mnner, the reference temperture for dry ir is chnged to 0 F. Similrly, hen chnging to SI units, the reference temperture is chnged to 0 C. You my choose ny combintion of vilble units for your defult unit set. Simply select the units you desire for ech property nd issue the 'Use Settings As Defult' commnd from the 'Formt' menu. The next time you strt DeskTop Air, your defult unit set ill be used. If you chnge units nd then sve file, those selected units ill be restored henever the file is opened. If you ish to chnge the units bck to your defult unit set, issue the commnd 'Restore Defult Settings' from the 'Formt' menu. Unit system chnges in DeskTop Air do not ffect use from ny other pplictions (e.g., Excel, 1--3, etc.). 3.5 CALCULATING STATE POINTS When you hve finished entering vlues for the selected input vribles, click the on-screen button lbeled 'Compute' to clculte ll of the stte point properties. If the Compute button is gryed, you hve not checked enough properties to define the stte point. You my lso compute the stte point by pressing the 'Enter' key on your keybord. Note tht the 'Enter' key serves to purposes in DeskTop Air. Pressing the 'Enter' key just fter entering dt in n IO Box, tells DeskTop Air to evlute the expression in the IO Box. Pressing the 'Enter' key second time tells DeskTop Air to compute the stte point. If you move the focus to ny other control fter entering dt in n IO Box, the expression is evluted utomticlly nd you only hve to press the 'Enter' key only once to compute the stte point. The Enter key ill not compute stte point if the Compute button is gryed. 3.6 FORATTING PROPERTY VALUES DeskTop Air normlly displys ll property vlues in fixed deciml nottion. You my increse or decrese the number of deciml plces in selected property IO Box by selecting Add Deciml Plces or Decrese Deciml Plces from the Formt menu or by clicking either of the toolbr buttons, respectively. If you ish to chnge the selected property to scientific nottion, select the 'Scientific Nottion' commnd from the Formt' menu or press the EE toolbr button. The Formt menu mny be used to chnge the number formt to 'Fixed Deciml' or 'Percent' s ell. Corresponding toolbr buttons re Fix nd % respectively. Of course, the percent formt only mkes sense for the non-dimensionl properties. The formtting commnds re only enbled hen the focus is on n IO Box. 3.7 LABELING AND STORING STATE POINTS DeskTop Air gives you the option of lbeling nd storing ny number of stte points for future reference. After computing the stte point, DeskTop Air ill utomticlly suggest unique

22 Chpter 3 - Using DeskTop Air Pge 18 nme for the ne stte point such s Point 1 or Point, but you ill probbly nt to enter something more descriptive. Just enter ne nme in the Point Lbel box. To store this point, press the 'Store Point' button. (The Store button ill not be enbled if the displyed dt is not correctly clculted stte point.) DeskTop Air requires ll stored points to hve unique lbel. If you try to store to points ith the sme lbel, DeskTop Air ill query hether you ish to replce the stored point, hich hs the sme lbel, ith the current point. If not, you should renme the point nd try to store it gin. After storing the point, the stte point vlues for the ctive point ill be copied into storge rry nd given the nme you selected. The point ill be displyed in the stored points column in sme units s the ctive point. After stte point is stored, its nme is dded to the point nme combo box in the upper right hnd corner of the min indo. You cn vie stored point by pressing the rro on the point nme combo box nd selecting point from the drop don list. If you ish to use stored point ith ny of the specil tools or s the bsis for clculting ne point, you must recll the stored point to the ctive point. Begin by selecting the point from the point nme combo box s dropdon list. Next, press the Recll Point button to copy the stored point to the ctive point. You my no use the ctive point for ne clcultions. If you chnge ny input dt nd press 'Compute', the ctive point ill be chnged but the stored point from hich you copied the vlues ill remin intct. You cn delete stored point by first selecting it from the Point Nme combo box nd then select 'Delete Point' from the 'Edit' menu. This collection of stte points cn be sved s DeskTop Air file. In ddition, you cn copy stte points to the clipbord, here they cn be trnsferred to nother ppliction such s spredsheet progrm or ord processor. 3.8 PRINTING You cn print tble consisting of ll of the stored points by selecting the Print commnd from either the file menu or the toolbr. The tbles ill include column for ech of the stored points ith ech of its properties listed in ro. A lbel for ech ro includes the property nme nd the current units selected. The printing utility ill ttempt to fit s mny points on pge s possible, bsed on the pper size nd orienttion tht you specify using the Print Setup commnd. You cn previe the output by selecting the Print Previe commnd from the File enu. 3.9 SAVING AND OPENING DATA FILES When you strt DeskTop Air or open ne file, it ill be untitled. You my sve collection of stored stte points long ith your selections of units nd formts to DeskTop Air file. Select 'Sve' from the 'File' menu or click the disk icon on the toolbr, hich ill open the Sve As dilog box. You should enter nme for the file; the file extension.ir ill be dded utomticlly. You my choose folder in hich to sve the file or ccept the defult folder. If you hve sved the file t lest one time during the session, you cn sve the ork under

23 Chpter 3 - Using DeskTop Air Pge 19 different filenme by choosing the Sve As commnd from the File menu. To open sved file, select 'Open' from the 'File' menu or click the open file icon on the toolbr. This ill open dilog box tht lists ll of your DeskTop Air dt files in the current folder. You my select different folder to vie other files. Select the file you nt to open nd press the Open button to lod the file. To strt ne file, select the 'Ne' button from the Toolbr. If you hve stored ny points nd hve not sved the file, you ill be prompted to do so ADVANCED FEATURES DeskTop Air includes specil tools tht fcilitte the clcultion of some common ir processes. These tools include n expnsion/compression tool nd heting/cooling tool Expnsion/Compression Tool The Expnsion/Compression tool is used to evlute performnce of n ir turbine or n ir compressor. If you re predicting the performnce nd kno the efficiency of the turbine or compressor, the tool cn be used to clculte the stte point conditions t the expnsion or compression end point. If you re nlyzing the performnce of turbine or compressor nd kno the conditions t the end point, the tool cn be used to clculte the efficiency. The tool lso computes the energy converted to shft ork generted by the turbine or used by the compressor. To use the tool, first select the ctive stte point representing the strt of the expnsion or compression pth. Next, select 'Expnd/Compress' from the 'Tools' menu or click the turbine icon on the toolbr, hich ill open the Expnsion/Compression tool dilog box. In the tool dilog box, select the conditions you ill use the compute the end point from the combo box ner the top of the screen. Select Pressure & Efficiency if you kno the pressure nd efficiency. If you re checking n ctul mchine you ill need to kno the exiting ir temperture or enthlpy. Check either the Pressure, Enthlpy or Pressure, Temperture buttons s required. The to vribles you hve chosen ill hve their vlue fields enbled; ll others ill be gryed. Enter the pproprite vlues nd click the 'Compute' button. The Air Flo In column displys the stte point properties entering the equipment, hich ere copied from the ctive point. The Totl Flo Out box hs three columns tht disply the stte point properties t the end of the expnsion. The first column identifies the thermodynmic properties for the mixture of moist ir nd liquid ter exiting the equipment. The second column displys the thermodynmic properties for the moist ir exiting nd the third column shos the properties for the liquid ter if ny condenstion occurs. The units displyed re those currently in use on DeskTop Air s min indo. If you ish to use different units, you should select those units on the min indo before opening the expnsion tool. Belo the stte point properties, you ill find the shft poer bsed on the entering ir flo rte tht you entered. The units for these results ill be consistent ith your input units. You my chnge ny of the dt nd repet the clcultion s required. When you re

24 Chpter 3 - Using DeskTop Air Pge 0 stisfied ith the result, you my copy tht stte point bck to the ctive point on DeskTop Air s min indo by pressing the 'OK' button. Note tht the vlues of moist ir in the second column ill be copied bck to the ctive point. If no condenstion hs occurred, these vlues ill be the sme s in the first column lbeled mixture. If condenstion hs occurred, then the vlues in the second column ill be t sturted conditions. If you do not ish to replce the current point on the min indo ith the expnsion end point clculted, just press the 'Cncel' button Heting/Cooling Tool The Heting/Cooling tool is used to nlyze n ir strem in hich het is either dded or removed. If you kno the quntity of het tht is being dded to or removed from the ir strem, you cn use the tool to clculte the resulting stte point temperture nd other conditions. If you kno the temperture or enthlpy of the ir leving the heting or cooling device, you cn use the tool to clculte the quntity of het exchnged. To use the tool, first mke sure tht the ctive stte point represents the conditions of the ir entering the heting or cooling device. Next, select 'Het/Cool Tool' from the 'Tools' menu or click the flme icon on the toolbr, hich ill open the Heting/Cooling tool dilog box. In the tool dilog box, select the conditions you ill use to compute the end point from the combo box ner the top of the screen. Select Pressure, Het Flo if you kno the pressure nd het dded or removed. If you re mesuring performnce on n existing device you ill need to kno the exiting ir temperture or enthlpy. Check either the Pressure, Enthlpy or Pressure, Temperture buttons s required. The to vribles you hve chosen ill hve their vlue fields enbled; ll others ill be gryed. Enter the pproprite vlues nd click the 'Compute' button. The Air Flo In column displys the stte point properties entering the equipment, hich ere copied from the Active Point in the min screen indo. The Totl Flo Out box hs three columns tht disply the stte point properties t the end of the expnsion. The first column identifies the thermodynmic properties for the mixture of moist ir nd liquid ter exiting the equipment. The second column displys the thermodynmic properties for the moist ir exiting nd the third column shos the properties for the liquid ter if ny condenstion occurs. The units displyed re those currently in use on DeskTop Air s min indo. If you ish to use different units, you should select those units on the min indo before opening the Heting/Cooling tool. Belo the stte point properties, you ill find the het dded bsed on the entering irflo rte tht you entered. The units for these results ill be consistent ith your input units. You my chnge ny of the dt nd repet the clcultion s required. When you re stisfied ith the result, you my copy tht stte point bck to the Active Point on DeskTop Air s min indo by pressing the 'OK' button. Note tht the vlues for moist ir in the second column ill be copied bck to the ctive point. If no condenstion hs occurred, these vlues ill be the sme s in the first column lbeled mixture. If condenstion hs occurred, then the vlues in the second column ill be t sturted conditions. If you do not ish to replce the Active Point on the min indo ith the heting/cooling stte point clculted, just press the 'Cncel' button.

25 Chpter 3 - Using DeskTop Air Pge Exchnging Dt ith Other Progrms DeskTop Air includes to ys to shre dt ith other pplictions running on your PC such s Excel. Both methods use the Windos clipbord. In the first dt shring method, DeskTop Air's 'Edit / Copy' commnd copies htever text is highlighted in n IO Box (e.g., number or prt of number) to the Windos clipbord. From there, tht text cn be psted into other pplictions running on your PC. This is typiclly done using those pplictions 'Edit / Pste' commnd). The second dt shring method lso plces text on the clipbord but uses n extended formt tht is especilly useful for clcultions involving ir properties. This method is ccessed using the 'Copy Point' commnd on the 'Edit' menu. Regrdless of hether ny text is selected, this commnd copies tble of text vlues to the clipbord using either the Active Point or ll of the stored points. The tble includes one column for ech point. You cn optionlly direct DeskTop Air to lso include property nd unit lbels in hich cse they pper s the first column in the tble. The tble includes one ro for ech property in the sme order s they re displyed on DeskTop Air s min indo. All vlues re copied to the clipbord using the sme formt displyed on the screen. So, if you need more ccurcy in your Excel clcultions, set the DeskTop Air disply ccurcy ccordingly, before issuing the 'Copy Point' commnd GETTING HELP The Help menu offers extensive on-line help for DeskTop Air. The 'About' item in the Help menu presents the version nd seril numbers of your copy 3.1 ERROR ESSAGES When input vlues re out of rnge or ny other errors occur, messge box is displyed describing the error. The clculted fields ill not be updted until the error condition is resolved EXITING DESKTOP AIR You my exit DeskTop Air by using ny of the stndrd methods for closing Windos pplictions. These include the folloing: Click the upper left corner of its progrm indo nd select close from the menu. Select Exit from the File menu. Press Alt + F4 keys. Click the X button in the upper right corner of the progrm indo

26 Chpter 4 Theoreticl Bsis Functions Pge 4. THEORETICAL BASIS FUNCTIONS 4.1 BASIS OF CALCULATIONS The formultions used in developing the ir property functions tret moist ir s mixture of to rel gses, nmely, dry tmospheric ir nd ter vpor. Furthermore, dry tmospheric ir is ssumed to be homogeneous, single-component gs ith n pprent moleculr eight of g/mol. The P-V-T behvior of the mixture is described by viril eqution of stte: here, Pv RT Bm Cm = L v v P = Totl pressure T = Absolute Thermodynmic Temperture v = Totl volume of gs R = Universl Gs Constnt B m = second order viril coefficient of the mixture = third order viril coefficient of the mixture C m For the rnges of pressure nd temperture used in these functions, the higher order coefficients cn be ignored. It cn be shon for the ir-ter mixture tht nd here, B = x B + x x B + x B m 3 3 C = x C + 3x x C + 3x x C + x C x x B m = mole frction of ir in the mixture = mole frction of ter in the mixture, C = viril coefficients of ir

27 Chpter 4 Theoreticl Bsis Functions Pge 3 B, C B, C, C = viril coefficients of ter vpor = viril coefficients of the mixture ASHRAE uses polynomil equtions for estimting the viril coefficients of ir nd ter vpor s presented by Hylnd nd Wexler [8]. These equtions re derived from the dt presented by the NBS [1]. While these equtions produce resonble results, they re limited in temperture rnge from bout -100 C to 00 C nd re clerly indequte for this ppliction, hich supports tempertures up to 000 K. Insted of using polynomil equtions, Techre hs developed gs property dtbse from the NBS [1] dt. The dtbse includes viril coefficients s ell s idel gs properties for enthlpy, entropy nd specific het tht spn the rnge of tempertures from 180 K to 000 K. Coefficients re extrcted from the dtbse t ny desired temperture using nonliner interpoltion. The molr enthlpy of moist ir, h m cn be described by the eqution here, o ( ) ( ' o ' h = x h + h + x h + h ) + m RT B T db m dt m C T dc m m 1 v dt v h o h o h ' = idel gs molr enthlpy for ir = idel gs molr enthlpy for ter = constnt to djust reference stte for ir h ' = constnt to djust reference stte for ter The molr entropy of moist ir, s m cn be described by the eqution o ' o ' Pv sm = x( s + s) + x( s + s) Rln P+ xrln + x RT Pv x R R B T db C T dc m m m m x RT dt 1 v ln dt v here, s o = idel gs molr entropy for ir s o s ' s ' = idel gs molr entropy for ter = constnt to djust reference stte for ir = constnt to djust reference stte for ter

28 Chpter 4 Theoreticl Bsis Functions Pge 4 The molr specific het t constnt pressure of moist ir, c m, cn be described by the eqution: here, c m = c o x + c o x R RT Bm B RT m C T v + T T v T Bm Cm T Bm T Cm R v v v T v T Bm 3C m 1+ + v v o c o c m C + T T m + = idel gs molr specific het of dry ir t constnt pressure = idel gs molr specific het of ter vpor t constnt pressure For combintions of pressure nd temperture belo the boiling point of ter, there is mximum quntity of ter tht cn exist t tht temperture in the vpor stte. In this condition, the ir is sid to be sturted. For the cse here moist ir exists in sturted stte, the mole frction of ter vpor, x s is given by fp xs = P nd the mole frction of ir, x s is given by x here, p = f = s = x sidel = P fp P the pressure of sturted vpor over pure condensed phse ice or ter. dimensionless quntity introduced by Goff (1949) clled the enhncement fctor or excess solubility, hich is equl to x s / x sidel. the rtio of the vpor pressure of the pure ter, to the totl pressure of the mixture. ASHRAE uses equtions for estimting the enhncement fctor s ell s the viril coefficients of dry ir nd ir/ter mixture developed by Hylnd nd Wexler [8]. While erlier versions used these sme formultions, this current version uses nother method for clculting the enhncement fctor presented by Rbinovich [3]. We believe tht this method produces better correltion ith the originl experimentl dt developed by Goff. Even so, the differences beteen the to methods re generlly smll.

29 Chpter 4 Theoreticl Bsis Functions Pge 5 Assuming tht the condensed phse is pure ter, the vlue of x s cn be found by equting the chemicl potentil of pure condensed ter ith the chemicl potentil of its vpor in the gs solution. Since the equtions describing chemicl potentils re non-liner nd difficult to nlyze, phse equilibrium is often described in terms of thermodynmic function clled fugcity. The equlity of chemicl potentils cn be replced by equting the logrithms of the fugcity of pure condensed ter ith tht of its vpor in the gs mixture solution. The eqution of solubility bsed on this concept is derived by Rbinovich [3] nd cn be expressed s follos: x ln s ( p, T, x ) p z s 1 = ln + p v B dp + 3C + cond '' p (, ) p '' s z ps T RT s v ( v ) 3 ( B + ( B B ) x ) ( C + ( C C ) x + ( C C + C ) x ) s s g s v v here, B C z = 1+ + the compressibility of the ir mixture or the ter vpor s required. v v p s = sturtion pressure of ter vpor t temperture T. v cond = the volume of the condensed ter. The solubility eqution cn be solved for x s by itertion. The vlue of x s is used to find the de point temperture of gs mixture, to determine the mount of condenstion tht occurs in cooling process nd to verify tht the vlue of x input by the user does not exceed x s. 4. HUIDITY PARAETERS In determining the thermodynmic properties of moist ir, it is required to kno the reltive quntities of ter vpor nd dry ir in the mixture. The formultions described bove use the mole frctions of ir nd ter for this purpose. In prctice, it is common to use other prmeters s ell to define the proportions of ir nd ter vpor in the mixture. The most common of these prmeters include humidity rtio, reltive humidity, degree of sturtion, et bulb temperture nd de point temperture nd mss frction of ter includes number of functions hose purpose is to relte the vrious prmeters for determining the level of moisture in the ir. The functions use key chrcter to indicte ech humidity prmeter. The key chrcters nd the definitions of ech prmeter re s follos: Humidity Rtio = here, = mss of ter vpor in smple

30 Chpter 4 Theoreticl Bsis Functions Pge 6 = mss of dry ir in smple As described in section on lternte moisture prmeters, mole frction or mss frction of ter vpor cn be substituted for humidity rtio through the unit set rgument. Reltive Humidity = x x s here, x = mole frction of ter vpor x s = mole frction of ter vpor sturted t the sme temperture nd pressure W Degree of Sturtion = W s here, W = humidity rtio W s = humidity rtio of sturted ir t the sme temperture nd pressure De Point Temperture (D) is defined s the solution to the eqution: W P, D = W s ( ) s It represents the temperture to hich smple of moist ir t given unchnging pressure cn be cooled before condenstion begins. Thermodynmic Wet Bulb Temperture (B) is the temperture t hich ter, by evporting into moist ir t given dry-bulb temperture nd humidity rtio, cn bring the ir to sturtion dibticlly t the sme temperture B hile the pressure is mintined constnt. It is defined s the solution to the eqution: [ s ] ( ) s( ) ( ) ( ) ( ) hptw,, + W PB, WPT, h B = h PB, here, h(p,t,w) = h = h s (P,B) = enthlpy of the moist ir smple t given pressure, dry bulb temperture nd humidity rtio. enthlpy of ter dded t the et bulb temperture. enthlpy of sturted ir t the et bulb temperture. 4.3 TRANSPORT PROPERTIES Vlues for viscosity nd therml conductivity of dry ir t tmospheric pressure cn be found in

31 Chpter 4 Theoreticl Bsis Functions Pge 7 mny references lthough there does not pper to be ny definitive stndrd of ccepted vlues s there re for stem nd ter. We found the most complete coverge by Vssermn, Kzvchinskii, nd Rbinovich [] ho hve surveyed the vilble literture nd presented tbles of vlues over rnge of tempertures nd pressures. We hve used their tbulr vlues of viscosity nd therml conductivity s the bsis of our dtbse for dry ir. We hve lso used their recommended polynomil djustment fctors s function of density to ccount for vritions ssocited ith pressure. We hve used the equtions recommended by ASE (6) to compute the viscosity nd therml conductivity properties for ter vpor. These re the sme equtions used in our WinStem product. There is little informtion vilble regrding the viscosity nd conductivity of moist ir. In most prcticl cses, the reltively smll quntity of ter vpor in ir hs smll effect on the overll trnsport properties, unlike the thermodynmic properties, hich re gretly ffected by moisture. Nonetheless, e hve selected method to ccount for the effects of moisture bsed on kinetic theory s presented by Hirshfelder, Curtis nd Bird [4]. The eqution for viscosity of binry mixture is s follos: η η η η Z Y X + + = 1 / 1 here = η viscosity of the mixture x x x x X η η η η + + = ( ) = x x x x A Y η η η η η η η * ( ) = x x x x A Z * η η η η η = η viscosity of dry ir t the specified pressure nd temperture = η viscosity of ter vpor t the specified pressure nd temperture ( ) ( ) ( ) * *, 1 1 / T T C Ω + = σ η nd C 1 = 66.93E-7 = σ potentil function prmeter for mixture djusted for one polr molecule trnsport property integrl s function of T*, the reduced temperture ( ) = Ω *, 1 A 1 * = function of reduced temperture

32 Chpter 4 Theoreticl Bsis Functions Pge 8 In sim ilr mnner, the equtions for therml conductivity of moist ir is s follos: here, X λ + Y 1 / λ = 1+ Z λ λ λ = therml conductivity of the mixture X Y λ x x x = + λ λ x x x x + λ () 1 ( Y ) ( ) = U + U + U λ Z U U U U λ λ = x λ x λ () 1 ( Y ) ( ) U + x xu + x U () 4 1 * 1 1 * 1 ( ) = A B ( ) 4 * 1 1 * 1 ( ) = A B ( Y) 4 * ( + ) λ 1 1 * 5 1 * ( ) = A B1 B1 5 * 4 λλ 1 5 3A 1 5 ( ) Z * ( + ) 4 λ λ 1 1 * = A B λ λ 1 5 λ = Therml conductivity of dry ir t the specified pressure nd temperture λ = Therml conductivity of ter vpor t the specified pressure nd temperture ( ) T + / λ = C nd C = E-7 σ Ω (, ) * * ( T ) 1 B 1 * = function of reduced temperture

33 Chpter 5 Speed nd Accurcy Pge 9 5. SPEED AND ACCURACY CHARACTERISTICS 5.1 SPEED OF CALCULATIONS This section ddresses clcultion speed s mesured ithin icrosoft Excel. Performnce ithin other pplictions is similr. The time required to reclculte spredsheet is function of mny fetures of the computer system hrdre nd the nture of the spredsheet. Since the supported spredsheets use double precision mth exclusively, clcultion time is sensitive to the number nd complexity of numericl equtions used. The time required to perform the clcultions lso vries depending on the specific functions. Some clcultions re more complex thn others. Some require itertions. The simplest functions run the fstest hile those tht re more complex nd require itertions run sloer. The tble belo lists times required to clculte some functions from icrosoft Excel. Function Clcultion Time AirPTRW AirPTWH AirPWD AirPHWT Typicl clcultion times in seconds per clcultion. A clcultion returns one property t one stte point. These times ere mesured on computer using 33 Hz Pentium II processor. Clcultion times ill vry depending on your prticulr computer. Note tht the reclcultion options selected ill lso ffect perceived clcultion time. 5. ACCURACY OF CALCULATIONS Thermodynmic properties for dry ir clculted hve been checked ginst the vlues published by NBS [1]. As shon on Exhibits 5.1 through 5.4, the clculted vlues

34 Chpter 5 Speed nd Accurcy Pge 30 sho excellent greement ith the source dt throughout most of the vlid rnge. Some smll differences cn be observed t lo tempertures nd high pressures. This is due to the limittions of using third order viril eqution of stte. Even so, the mximum error is less thn 0.3% for thermodynmic properties nd 3.17% for specific het. Another smller difference is shon in the compressibility fctor beteen 1500 K nd 000 K. This is due to the dissocition of Nitrogen nd Oxygen t these tempertures. This error is less thn 0.0%. The tbles sho some differences in enthlpy, entropy nd specific het occurring t 850 K nd groing ith temperture. This initilly, s thought to be ttributed to dissocition, but this s dismissed for to resons. First, dissocition effects ere not included belo 1500 K in reference 1. Second, the error is much greter thn ht cn be ttributed to dissocition bove 1500 K. Further exmintion of the dt tbles suggests tht the tbles in reference 1 re in error. One ould expect the thermodynmic properties to pproch the idel gs properties s the pressure is reduced to zero. While this is the cse for tempertures up to 800 K, it is not the cse bove 800 K. Curiously, t 800 K, the tbles in reference 1 chnge from temperture increment of 10 K to 50 K t the point here the error begins. Perhps this chnge of temperture increment s not hndled properly. Comprison of dt from Vssermn et l [] in the temperture rnge from 850 K to 1300 K supports the conclusion tht the tbles from NBS [1] re in error. Unfortuntely, the tbles from Vssermn et l [] does not contin dt for tempertures bove 1300 K. oist ir properties re compred ginst vlues published by ASHRAE [9] in Exhibits , hich sho excellent greement. It should be noted tht there re smll differences in the sturted humidity rtio nd ASHRAE, hich re ttributed to the different models used s explined in the section on bsis of clcultions. Exhibit 5.8 plots the enhncement fctors nd ASHRAE ith the originl experimentl dt from Goff. This clerly shos tht the model used provides better greement ith the originl experimentl dt thn the model used by ASHRAE. Since the enhncement fctor is the bsis for clculting sturted humidity rtio, e plce higher confidence on the sturted humidity rtio clculted

35 Chpter 5 Speed nd Accurcy Pge 31 COPARISON OF RESULTS WITH NBS [1] DATA EXHIBIT COPRESSIBILITY OF DRY AIR Temperture Rnge Pressure From To 1 tm 10 tm 40 tm deg K deg K Avg x Avg x Avg x % 0.00% 0.019% 0.08% 0.15% 0.79% % 0.001% 0.005% 0.008% 0.009% 0.014% % 0.001% 0.003% 0.003% 0.009% 0.013% % 0.001% 0.003% 0.004% 0.00% 0.004% % 0.001% 0.003% 0.004% 0.010% 0.013% % 0.001% 0.00% 0.003% 0.01% 0.013% % 0.001% 0.001% 0.00% 0.008% 0.010% % 0.001% 0.00`% 0.001% 0.004% 0.006% % 0.001% 0.001% 0.00% 0.00% 0.004% % 0.016% 0.004% 0.006% 0.004% 0.010% COPARISON OF RESULTS WITH NBS [1] DATA EXHIBIT 5. - ENTHALPY OF DRY AIR Temperture Rnge Pressure From To 1 tm 10 tm 40 tm deg K deg K Avg x Avg x Avg x % 0.01% 0.03% 0.1% 0.13% 0.6% % 0.00% 0.00% 0.01% 0.04% 0.07% % 0.00% 0.00% 0.01% 0.01% 0.01% % 0.00% 0.01% 0.01% 0.01% 0.01% % 0.00% 0.00% 0.01% 0.01% 0.01% % 0.00% 0.00% 0.00% 0.01% 0.01% % 0.00% 0.00% 0.00% 0.01% 0.01% % 0.00% 0.00% 0.00% 0.01% 0.01% * 0.03% * 0.09% * 0.03% * 0.09% * 0.03% * 0.10% ** ** ** ** ** **

36 Chpter 5 Speed nd Accurcy Pge 3 COPARISON OF RESULTS WITH NBS [1] DATA EXHIBIT ENTROPY OF DRY AIR Temperture Rnge Pressure From To 1 tm 10 tm 40 tm deg K Deg K Avg x Avg x Avg x % 0.00% 0.01% 0.0% 0.0% 0.05% % 0.00% 0.00% 0.00% 0.00% 0.01% % 0.00% 0.00% 0.00% 0.00% 0.01% % 0.00% 0.00% 0.00% 0.00% 0.00% % 0.00% 0.00% 0.00% 0.00% 0.00% % 0.00% 0.00% 0.00% 0.00% 0.00% % 0.00% 0.00% 0.00% 0.00% 0.00% % 0.00% 0.00% 0.00% 0.00% 0.00% % 0.01% 0.00% 0.00% 0.01% 0.01% ** ** ** ** ** ** COPARISON OF RESULTS WITH NBS [1] DATA EXHIBIT SPECIFIC HEAT OF DRY AIR Temperture Rnge Pressure From To 1 tm 10 tm 40 tm deg K deg K Avg x Avg x Avg % 0.11% 0.35% 1.04% 1.05% 3.17% % 0.00% 0.05% 0.06% 0.9% 0.38% % 0.01% 0.0% 0.03% 0.10% 0.17% % 0.00% 0.00% 0.01% 0.0% 0.03% % 0.00% 0.01% 0.01% 0.04% 0.06% % 0.00% 0.01% 0.01% 0.03% 0.04% % 0.00% 0.00% 0.01% 0.01% 0.0% % 0.00% 0.00% 0.0% 0.01% 0.04% x * 0.47% * 0.07% * 0.47% * 1.37% * 0.49% * 1.40% ** ** ** ** ** ** Notes: *, ** - Questionble reference dt.

37 Chpter 5 Speed nd Accurcy Pge 33 COPARISON OF RESULTS WITH ASHRAE [9] & NBS [1] EXHIBIT SPECIFIC VOLUE Temp º F Dry Air t 1 tm ft 3 /lbm Sturted oist Air t 1 tm ft 3 /lbm of Dry Air ASHRAE

38 Chpter 5 Speed nd Accurcy Pge 34 COPARISON OF RESULTS WITH ASHRAE [9] & NBS [1] EXHIBIT ENTHALPY Temp º F Dry Air t 1 tm Btu/lbm Sturted oist Air t 1 tm Btu/lbm of Dry Air ASHRAE

39 Chpter 5 Speed nd Accurcy Pge 35 COPARISON OF RESULTS WITH ASHRAE [9] & NBS [1] EXHIBIT 5.7 ENTROPY Temp º F Dry Air t 1 tm Btu/lbm/ºF Sturted oist Airt 1 tm Btu/lbm/ºF of Dry Air ASHRAE

40 Chpter 5 Speed nd Accurcy Pge 36 COPARISON OF RESULTS WITH ASHRAE [9] EXHIBIT ENHANCEENT FACTORS