@AIR USER S ANUAL VERSION 3. COPYRIGHT NOTICE The @Air 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 etent of the l. Copyright 1995-009 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. Ecel, Windos, Visul C/C nd Visul BASIC re trdemrks of the icrosoft Corportion. thcd is trdemrk of thsoft, Inc.
Tble of Contents 1. INTRODUCTION... 1 1.1 Overvie... 1 1. Wht s Ne.... USING THE @AIR PROPERTY FUNCTIONS... 3.1 Generl Informtion... 3. Description of @Air Functions... 3..1 Vlid Operting Rnge... 5.. Bsic Unit Sets... 5..3 Wet or Dry Bsis... 6..4 Alternte oisture Prmeters... 6..5 Reference Conditions... 7.3 Using @Air from Ecel... 8.4 Using @Air from 1--3... 8.5 Using @Air from thcd... 10.6 Using @Air from Visul BASIC... 10.7 Using @Air With Progrmming Lnguges... 11.8 Version nd Seril Number... 11 3. USING DESKTOP AIR... 1 3.1 Overvie... 1 3. Bsic Opertion... 1 3.3 Entering Dt... 13 3.4 Unit Selection... 14 3.5 Clculting Stte Points... 15 3.6 Formtting Property Vlues... 15 3.7 Lbeling nd Storing Stte Points... 15 3.8 Printing... 16 3.9 Sving And Opening Dt Files... 16 3.10 Advnced Fetures... 17 3.10.1 Epnsion/Compression Tool... 17 3.10. Heting/Cooling Tool... 18 3.10.3 Echnging Dt ith Other Progrms... 19
3.11 Getting Help... 19 3.1 essges... 19 3.13 Eiting DeskTop Air... 19 4. THEORETICAL BASIS OF @AIR FUNCTIONS... 0 4.1 Bsis of Clcultions... 0 4. Humidity Prmeters... 3 4.3 Trnsport Properties... 4 5. SPEED AND ACCURACY CHARACTERISTICS... 7 5.1 Speed of Clcultions... 7 5. Accurcy of Clcultions... 7 6. REFERENCES... 36 APPENDIX - @AIR ERROR CODES
Chpter 1 Introduction Pge 1 1. INTRODUCTION 1.1 OVERVIEW @Air is softre product tht provides ccurte thermodynmic, psychrometric nd trnsport properties of moist ir through functions contined in Dynmic Link Librry (DLL). The @Air 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 Ecel nd thcd. In 1--3 nd Ecel, 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, 1993. All of the properties clculted by @Air re bsed on rel gs properties, not perfect gs pproimtions. As such, they include the effects of pressure nd interctions cused by the miing 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. The @Air 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 @Air pckge supports only 3-bit pplictions nd requires Windos 95 or lter. The Setup progrm nd the instlltion instructions contined in the @Air pckge guide you through instlling the files you'll need for the pplictions you epect to use. Emple files to help you get strted ill lso be instlled. The nme, @Air, s creted to signify tht it contins @ functions tht ere comptible ith Lotus 1--3, the dominnt spredsheet progrm severl yers go. Tody, the @ symbol is most recognized s prt of n internet e-mil ddress. Hoever, for continuity, e hve retined the nme @Air even though the current product supports vriety of Windos @Air for Windos Version 3. - User's nul
Chpter 1 - Introduction Pge pplictions. 1. WHAT S NEW @Air 3. does not instll the help shortcut on the toolbr hen using Ecel 007 or lter in order to operte more relibly. @Air 3.1 hs dded 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 properties. @Air 3.0 hs dded mny ne fetures over the previous version, @Air.0. These include the folloing: Etends 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 epressed 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. 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. @Air for Windos Version 3. - User's nul
Chpter - Using the @Air Property Functions Pge 3. USING THE @AIR 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 of @Air. 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 Ecel, 1--3, thcd, Visul BASIC nd your on Windos progrms, the functions provided by @Air 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 synt nd other considertions in using the functions ithin supported pplictions.. DESCRIPTION OF @AIR FUNCTIONS All of the @Air 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 @Air for Windos Version 3. - User's nul
Chpter - Using the @Air Property Functions Pge 4 Sturtion AirPTWH() Pressure, Temperture, HO Content Specific Enthlpy AirPHWT() Pressure, Enthlpy, HO Content Temperture AirPTHs() Pressure, Temperture Sturted Enthlpy AirPHTs Pressure, Enthlpy Sturted Temp AirPTWS() Pressure, Temperture, HO Content Specific Entropy AirPSWT() Pressure, Entropy, HO Content 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 pproimtions to the ctul properties. The perfect gs pproimtions re resonble t lo pressures but increse in error s the pressure is incresed. The formultions used in @Air re bsed on rel gs properties nd include the effects of pressure nd the miing of ir nd ter vpor. Refer to section! Reference source not found. 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. @Air for Windos Version 3. - User's nul
Chpter - Using the @Air Property Functions Pge 5 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 The @Air 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 0 1 3 4 5 6 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 Non-Dim @Air lets the user select the desired unit set ith ech function cll by the use of n etr 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 fleibility in entering the unit set prmeter is vilble hen using the ir property @Air for Windos Version 3. - User's nul
Chpter - Using the @Air Property Functions Pge 6 dd-in functions from Ecel or 1--3. 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 The dd-in for Ecel cn be configured to llo the unit set rgument to be optionl. This is done during the instlltion process. The defult selection is to mke the unit set mndtory. We recommend ccepting this option unless you hve eisting spredsheets tht ere set up ithout using unit set rgument. In ny cse, e recommend tht you specify the unit set rgument ith ll ne ork. If the unit set rgument is omitted, the functions ill use the ENG unit set ith no dditionl set modifiers...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 epresses 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 epress 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 emple in Ecel, you cn clculte the enthlpy of moist ir on et bsis t pressure of 15 psi, temperture of 150 F nd humidity rtio of 0.015 s follos: =AirPTWH(15,150,0.015, EngW )..4 Alternte oisture Prmeters The mount of moisture in the ir cn be epressed 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 epressing 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 epressed on dry bsis. If you choose to epress properties on et bsis, you my find it more convenient to epress 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. @Air for Windos Version 3. - User's nul
Chpter - Using the @Air Property Functions Pge 7 For emple in Ecel, 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 )..5 Reference Conditions Enthlpy nd entropy vlues re lys epressed 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 consistently. @Air 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. The @Air 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 3.018 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 desired @Air 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 emple in Ecel, 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 0.015 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. @Air for Windos Version 3. - User's nul
Chpter - Using the @Air Property Functions Pge 8 All reference conditions use the Interntionl Temperture Scle of 1990 (ITS-90) described in reference (5) s the bsis of temperture..3 USING @AIR FRO EXCEL You must lod the XLAIR3.XLL dd-in to ccess the ir property functions from Ecel. Loding this dd-in brings the functions into memory nd links them to Ecel. You cn lod the @Air property functions into Ecel using the Add-in nger. The @Air dd-in orks ith ll 3-bit versions of Ecel, including Office 000 nd XP. Use the Tools Add-Ins menu in Ecel to strt the Add-In nger. If instlled using the defult settings, the file XLAIR3.XLL should be in either the EXCEL or OFFICE\LIBRARY subdirectory nd the Add-In nger ill sho tht @Air for Ecel is vilble. Click the check bo net to @Air for Ecel nd press OK. A messge ill disply the Techre copyright notice ech time the dd-in is loded. Ech time you strt up Ecel, the @Air functions ill be loded utomticlly. If you ish to remove the functions, use the Add-In nger nd uncheck the bo net to @Air for Ecel to remove the dd-in. @Air ill not lod the net time you strt Ecel unless you dd it using the Add-In nger s described bove. Once the dd-in is loded, the ir property functions re vilble in the sme ys s Ecel's built-in functions. Tht is, they cn be typed into cell formuls or they cn be inserted by pressing the f 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 prefi the function nme ith n "=" chrcter if it is the first or only item in formul. The line belo presents n emple of cll to n ir property function from Ecel 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 ) The @Air pckge includes smple Ecel 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 the @Gs progrm folder. Since the @Air 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. The @Air 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 mied in the sme spredsheet. Plese see section. for instructions regrding the use of these fetures..4 USING @AIR FRO 1--3 @Air orks ith 3-bit versions of 1--3 including 1--3 97 nd 1--3 illennium. You must @Air for Windos Version 3. - User's nul
Chpter - Using the @Air Property Functions Pge 9 lod the dd-in file nmed 13AIR.1A to ccess the ir property functions from 1--3. When the dd-in is loded into memory it estblishes links beteen 1--3 nd the @Air dynmic link librry. Use the File, Add-Ins, nge Add-ins menu selections to strt the Add-In mnger. Before you cn use the @Air 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 1--3. 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. 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 1-- 3 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 prefiing the function nme ith n "@" chrcter. The @Air pckge contins smple 1-- 3 spredsheet file nmed EXAPLE.13 hich mkes severl typicl clls to the ir property functions. The line belo presents n emple of cll to n ir property function from 1--3: @AirPTXH(A1,B1,C1, 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 synt 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. 1--3 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. The @Air 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 mied in the sme spredsheet. Plese see section. for instructions regrding the use of these fetures. @Air for Windos Version 3. - User's nul
Chpter - Using the @Air Property Functions Pge 10.5 USING @AIR FRO ATHCAD The @Air 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. Whenever @Air function is used, thcd ill utomticlly lod nd register the function. The @Air 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. The @Air 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 for @Air is not directly vilble from ithin thcd, the Choose function feture does recognize the @Air functions nd ssists the user ith the functions. Use the th, Choose Function menu selections to open the Choose Function indo. Scroll don the 'Function nme is' bo to find ll of the ir functions listed in lphbeticl order. The 'Returns' bo 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 USING @AIR 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 A tet file, TAIRVBDEC.TXT, hich lists declrtions for ll of the @Air functions is included in the @Air pckge in the \Progrmming subdirectory. If you re using the @Air functions in n Ecel 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.ll dd-in. In this cse, you must use the ALIAS keyord in the declrtion to identify the true nme in the DLL. For emple, 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 A tet file, TAIRVBADEC.TXT, hich lists declrtions using the Alis formt is included in the @Air for Windos Version 3. - User's nul
Chpter - Using the @Air Property Functions Pge 11 @Air pckge in the \Progrmming subdirectory. With ech TAIR3 function cll, your code should check to ensure tht the vlues returned re greter thn -1000. Return vlues of -1000 or smller indicte error conditions. See the Appendi for listing of error codes nd their menings..7 USING @AIR WITH PROGRAING LANGUAGES The ir property functions in TAIR3.DLL cn lso be clled from ithin C/C progrms compiled to run under Windos (3-bit only). 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. With ech ir property function cll, your code should check to ensure tht the vlues returned re smller (more negtive) thn -1000. Return vlues of -1000 or smller indicte error conditions. See the Appendi for listing of error codes nd their menings..8 VERSION AND SERIAL NUBER There my be ne releses of @Air to dd fetures or to support ne pplictions. Ech ne relese of @Air ill hve version number tht is printed on the diskette lbel. The TAIR3.DLL file hs its on version number, hich my differ from the @Air version number. Every copy of @Air 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 Ecel, 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., 3.01345). The first to digits indicte the DLL version number. The net 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. @Air for Windos Version 3. - User's nul
Chpter 3 - Using DeskTop Air Pge 1 3. 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 fleible, 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 over @Air s full rnge of pressures nd tempertures fleible interctive design lrge choice of units for ech property tools for heting, cooling, epnsion nd compression processes instnt response time etensive help screens If instlled properly, DeskTop Air is strted by simply double clicking on its nme/icon in the @Air3 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 @Air for Windos Version 3. - User's nul
Chpter 3 - Using DeskTop Air Pge 13 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 bo 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 boes 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 boes nd selecting ne combintion. To compute n ir property stte point, begin by selecting the input properties nd set the corresponding check boes s described bove. Enter vlues for those properties in the boes to the right of the property nmes. (The net section describes vrious methods for entering dt.) When you enter vlue for ny of the key properties, red X ppers net 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 bo. 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. Net, 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 boes 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 bo 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 bo clled n IO Bo, hich behves like stndrd Windos edit bo but includes some dditionl fetures. To enter ne dt, double click the IO Bo 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 Bo hs to modes of opertion, input nd output. When ne dt is entered, the IO Bo is plced in the input mode nd red X ppers to the left of the bo. After ne stte point is computed, ll IO Boes re plced in the output mode nd the red X s re removed. @Air for Windos Version 3. - User's nul
Chpter 3 - Using DeskTop Air Pge 14 The IO Bo ccepts either numericl vlues or rithmetic epressions tht cn be evluted to numeric vlue. A number cn be entered in either deciml or scientific nottion. The epression cn be ny vlid rithmetic epression using the folloing opertors: dd - subtrct * multiply / divide ^ eponent ( ) prentheses Arithmetic clcultions cn be nested to ny level using prentheses. An emple of vlid epression is: ((1004^ 997^) / )^.5 hich evlutes to 1000.506. Epressions re evluted henever you tb to or click on nother control or press the Enter button. Only the resulting vlue is shon in the bo. If you enter n incorrect epression, your computer ill beep nd the edit cursor ill highlight the offending chrcter. You must fi the error before DeskTop Air ill llo you to continue. If the epression you re entering is too long to fit in the bo, the bo ill temporrily increse in length so tht you my vie more of the epression. When you re finished editing, the bo returns to its originl length. To recll the lst epression used in n input bo, use the 'Recll Epression' commnd on the 'Edit' menu. You ll then hve the opportunity to edit the epression nd let the IO Bo reevlute it. Note tht the bo retins the lst number or epression entered even fter compute commnd is issued. As result, the vlue in the bo ill not reflect the vlue of the reclled epression if compute commnd hs ltered the vlue. You my use the Cut, 'Copy' nd 'Pste' commnds on the 'Edit' menu or the toolbr to echnge numeric dt beteen DeskTop Air s IO Boes nd ny other ppliction tht supports the clipbord. If you strt entering dt in n IO Bo nd ish to go bck to the originl dt you my use the 'Undo' commnd on the 'Edit' menu. Hoever, once the IO Bo 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 bo. To chnge unit, select its combo bo 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 @Air for Windos Version 3. - User's nul
Chpter 3 - Using DeskTop Air Pge 15 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 'ke Current Settings Defult' commnd from the 'Formt' menu. The net 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 of @Air from ny other pplictions (e.g., Ecel, 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 Bo, tells DeskTop Air to evlute the epression in the IO Bo. 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 Bo, the epression 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 fied deciml nottion. You my increse or decrese the number of deciml plces in selected property IO Bo 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 'Fied Deciml' or 'Percent' s ell. Corresponding toolbr buttons re Fi 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 Bo. 3.7 LABELING AND STORING STATE POINTS DeskTop Air gives you the option of lbeling nd storing ny number of stte points for future @Air for Windos Version 3. - User's nul
Chpter 3 - Using DeskTop Air Pge 16 reference. After computing the stte point, DeskTop Air ill utomticlly suggest unique 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 bo. 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 bo in the upper right hnd corner of the min indo. You cn vie stored point by pressing the rro on the point nme combo bo 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 bo s dropdon list. Net, 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 bo 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 bo. You should enter nme for the file; the file etension.ir ill be dded utomticlly. You my choose folder in hich to sve the file or ccept the defult folder. @Air for Windos Version 3. - User's nul
Chpter 3 - Using DeskTop Air Pge 17 If you hve sved the file t lest one time during the session, you cn sve the ork under 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 bo 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. 3.10 ADVANCED FEATURES DeskTop Air includes specil tools tht fcilitte the clcultion of some common ir processes. These tools include n epnsion/compression tool nd heting/cooling tool. 3.10.1 Epnsion/Compression Tool The Epnsion/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 epnsion 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 epnsion or compression pth. Net, select 'Epnd/Compress' from the 'Tools' menu or click the turbine icon on the toolbr, hich ill open the Epnsion/Compression tool dilog bo. In the tool dilog bo, select the conditions you ill use the compute the end point from the combo bo 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 eiting 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 bo hs three columns tht disply the stte point properties t the end of the epnsion. The first column identifies the thermodynmic properties for the miture of moist ir nd liquid ter eiting the equipment. The second column displys the thermodynmic properties for the moist ir eiting 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 epnsion 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. @Air for Windos Version 3. - User's nul
Chpter 3 - Using DeskTop Air Pge 18 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 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 miture. 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 epnsion end point clculted, just press the 'Cncel' button. 3.10. 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 echnged. To use the tool, first mke sure tht the ctive stte point represents the conditions of the ir entering the heting or cooling device. Net, select 'Het/Cool Tool' from the 'Tools' menu or click the flme icon on the toolbr, hich ill open the Heting/Cooling tool dilog bo. In the tool dilog bo, select the conditions you ill use to compute the end point from the combo bo 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 eisting device you ill need to kno the eiting 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 bo hs three columns tht disply the stte point properties t the end of the epnsion. The first column identifies the thermodynmic properties for the miture of moist ir nd liquid ter eiting the equipment. The second column displys the thermodynmic properties for the moist ir eiting 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 miture. 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 @Air for Windos Version 3. - User's nul