PropertiesTdb175FTdb2100FTwb163FTwb275FElevation11ft.AtmPress14.69psiaAPinHg29.91in HgHRatio10.0095lbw/lbaHRatio20.0129lbw/lba66.8Grains90.4GrainsRelHum151.6%RelHum231.4%SpHt10.244Btu/lb-FSpHt20.246Btu/lb-FEnal128.4Btu/lbEnal238.3Btu/lbSpVol113.69cu.ft./lbSpVol214.41cu.ft./lbDewPt156.0FDewPt264.4FlbpCuFt0.0006966673lbw/ft3lbpCuFt0.0008963857lbw/ft3

This Psychrometric Processes Program follows equations provided in the 2005 ASHRAE Handbook of Fundamentals, Chapter 6. The program can replace the Psychrometric chart and users are encouraged to compare values. It permits the quick calculation of basic HVAC air mixing, cooling, heating and heat recovery processes. Thanks are extended to Dr. Jim Richardson (CE Department @ UA) and Barbara McCrary of Hattemer, Hornsby & Bailey, Pratteville, AL for assistance in learning the use of Visual Basic macros in Excel that permit the calculation of psychrometric values using functions.See HVAC Simplified (Kavanaugh, 2006) available from ASHRAE for additional details.Note 1: In these programs, required input values are in yellow cells. Output values are in blue or green.The Psychrometric ChartNote 2: If Macro security level is set at high, this program will result in errors in the cells [NAME?]. To reset the security level,1. Close the PsychProcess program.2. Click on "Tools" on the main tool bar, select "Macro", select "Security.3. Reset security level to Medium (recommended) or Low4. Exit Excel5. Re-Open Excel 6. Run programFor 2007 Office products, the terminology "trust" has replaced "security" and the procedure has been changed (as you might expect). To change the "trust" settings:

Open Excel Click the Office Button (top left corner of screen) Click on "Excel Options" button @ the bottom of the pop-up window Click on "Trust Center" Click on "Trust Center Settings" Click on " Enable all macros.." Open and Run the programs An option would be to reset the trust setting by repeating steps 1 thru 5 and, Click on " Disable macros with notification"

MixingQair15000cfmQair21000cfmQSair14869scfmQSair2925scfmStream 1Stream 2mflow121912lb/hrmflow24164lb/hrStream 3(mixed)mflow326077lb/hrQair36000cfmTdb379.0FHRatio30.0101lbw/lba70.5GrainsTwb365.2FRelHum347.9%SpHt30.244Btu/lb-FEnal330.0Btu/lbSpVol313.80cu.ft./lbDewPt357.5F

Mixing - This Worksheet computes the resulting properties of air (stream 3) when streams 1 and 2 are mixed. Flow rates are entered below but properties for streams 1 and 2 are entered on the "Properties" Worksheet.Note: Input values (Qair1 and Qair2) are in cubic feet per minute. For additional information purposes, these values are corrected to air at standard conditions of =0.075 lb/cu.ft. (QSair1 and QSair2).Stream 2 @Qair2(cfm), Tdb2(F),& Twb2(F)Stream 1 @Qair1(cfm), Tdb1(F),& Twb1(F)Stream 3 @Qair3(cfm), Tdb3(F),& Twb3(F)123

Heat Rec'ryHRUEffectivenessRoom AirSenEff70%TdbRm75LatEff65%TwbRm63FOutdoorOutdoor AirFQairOut10000cfmTdbOut96QSairOut9307scfmTwbOut75FmflowOut41883lb/hrElev.600ft.SupFankW0kWHRU OutletOALoadsExFankW0kWCapacitiesMBtu/hTonsTemps.MBtu/hTonsExhaust(not req'd)qTotalHru280.123.3TdbHru81.3FTotal413.734.5QairEx2000cfmqSenHru151.512.6TwbHru67.3FSensible216.518.0QSairEx1851scfmSHRHru0.54Room AirOutdoor AirHRU OutletHRatioRm0.0095lbw/lbaHRatioOut0.0138lbw/lbaHRatioHru0.0110lbw/lba66.8Grains96.9Grains77.3GrainsRelHumRm51.6%RelHumOut38.0%RelHumHru48.6%SpHtRm0.244Btu/lb-FSpHtOut0.246Btu/lb-FSpHtHru0.245Btu/lb-FEnalRm28.4Btu/lbEnalOut38.3Btu/lbEnalHru31.6Btu/lbSpVolRm13.69cu.ft./lbSpVolOut14.33cu.ft./lbSpVolHru13.89cu.ft./lbDewPtRm56.0FDewPtOut66.3FDewPtHru60.0F

HRURoom AirOutdoor AirHRU Outlet Air to room or HVAC UnitExhaust AirThis Worksheet computes the properties of air leaving Heat Recovery Units (HRU) used to adsorb or remove heat (and in some units moisture) from room air that is being exhausted. The heat and moisture are transfered to or from the fresh outdoor air make-up air. The capacity of the HRU is also computed. The effects of the HRU supply fan heat are considered.Dt(o)t(r)t(hru)SummerDDWintert(hru)t(o)

Htg CoilInletConditionsOutletConditionsOutletConditionsWithoutHumidificationWithHumidification*QairHin2000cfmTdbOutAir20FqFurn75MBtu/hTwbOutAir15FQSairHin1983scfmOAVentInfil20% of supplymflowHin8924lb/hrTdbHout102.6FHRatioOA0.0007lbw/lbaTwbHout68.2F5.1GrainsTdbHin68FRelHumOA32.2%TwbHin56FSpHtOA0.240Btu/lb-FElevH0ft.HRatioHout0.0068lbw/lbaEnalOA5.6Btu/lbAPpsia14.70psia47.6GrainsSpVolOA12.11cu.ft./lbAPHg29.92in HgRelHumHout15.6%DewPtOA-6.8FSpHtHout0.243Btu/lb-FEnalHout32.1Btu/lbFluidTypeSat SteamHRatioHin0.0068lbw/lbaSpVolHout14.33cu.ft./lbFluidTemp212F47.6GrainsDewPtHout47.0FEnalFluid1150Btu/lbRelHumHin46.8%mfluid10.8lb/hrSpHtHin0.243Btu/lb-FqHumid0.5MBtu/hEnalHin23.7Btu/lbTdbHumOut102.8FSpVolHin13.45cu.ft./lbqNet75.5MBtu/hDewPtHin47.0F

t(in)WaterSteamt(out)t(in)t(out)*Assumption:Sufficient moisture is added in the form of water or saturated steam to replace the moisture lost via the exhaust air, which is replace with dryer outdoor air.

Clg-CoilInlet AirConditionsFan HeatNeglectedFan HeatIncludedQairIn4000cfmTotalPress2In. of WaterTC120MBtu/hFanEff65%SC100MBtu/hMotorEff82%QSairIn3897scfmBHP1.89hpSHR0.83qFan5.9TdbIn75FmflowIn17537lb/hrqTotNet114.1MBtu/hTwbIn63FQairOut3819cfmqSenNet94.1MBtu/hElevIn0ft.QSairOut3897scfmSHRNet0.82AtmPressIn14.70psiaAPinHgIn29.92in HgTdbOut51.7FTdbNet53.0FTwbOut51.7FTwbNet52.9FHRatioIn0.0095lbw/lbaHRatioOut0.0085lbw/lbaHRatioNet0.0085lbw/lba66.7Grains59.2Grains59.2GrainsRelHumIn51.6%RelHumOut100.0%RelHumNet99.4%SpHtIn0.244Btu/lb-FSpHtOut0.244Btu/lb-FSpHtNet0.244Btu/lb-FEnalIn28.4Btu/lbEnalOut21.6Btu/lbEnalNet21.9Btu/lbSpVolIn13.69cu.ft./lbSpVolOut13.07cu.ft./lbSpVolNet13.10cu.ft./lbDewPtIn56.0FDewPtOut52.8FDewPtNet52.8F

InOutFan Heat IncludedFan Heat NeglectedNet

Clg Coil-BPBy-Pass (BP)FactorMethodQairRet4000cfmmflowRet17326lb/hrTadp47FQairSup3757cfmBPFactor0.1QAairSup3850scfmQSairRet3850scfmTdbSup50.3FTdbRet79.8FTwbSup49.5FTwbRet67.1FHRatioadp0.0068lbw/lbaElev0ft.AtmPress14.70psiaqTotal201.0MBtu/hAPinHg29.91in HgqSensible125.3MBtu/hSHRcoil0.62HRatioRet0.0113lbw/lbaHRatioSup0.0073lbw/lba79.1Grains50.8GrainsRelHumRet52.0%RelHumSup94.7%SpHtRet0.245Btu/lb-FSpHtSup0.243Btu/lb-FEnalRet31.5Btu/lbEnalSup19.9Btu/lbSpVolRet13.85cu.ft./lbSpVolSup13.01cu.ft./lbDewPtRet60.7FDewPtSup48.7F

T(dbRet)T(wbRet)T(dbSup)T(wbSup)T(adp)Q(airRet)Q(airSup)BPFactor = 1-(TdbRet-TdbSup)/(TdbRet-Tadp)t(ret)t(sup)t(adp)