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HowtoReadaPsychrometric Chart
Helping you make a better measurement.
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35 WET BULB TEM
PERATURE - °C
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10% RELATIVE HUMIDITY
20%
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40%
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70%
80%
90%
.76
.78
.80
.82
.84
.86
.88
.90
.92
.94 S
PE
CIF
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.96
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610 Meters above Sea LevelBAROMETRIC PRESSURE 707 mm of Mercury
Linric Company Psychrometric Chart, www.linric.com
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Download theexercisechart:bit.ly/1QiA5zb
BruceMcDuffee MichaelBoetzkes
WebinarPresenters&HumidityExperts
Agenda&TakeawaysAgenda1. WhatisaPsychrometric
Chart?2. Whyshouldyoucare?3. Reviewthechartanatomy4. Exercise1– Wetbulb5. Exercise2– GrowingPlants6. Exercise3- Evaporative
Cooling
Takeaways• Avisualrepresentationcanhelpyoubetterunderstandtheparametersandhowtheyinteractwithtemperaturechanges.
• Usingachartcanbequickerthananonlinecalculatororapp.
WhatisaPsychrometric Chart?
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35 WET BULB TEM
PERATURE - °C
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10% RELATIVE HUMIDITY
20%
30%
40%
50%
60%
70%
80%
90%
.76
.78
.80
.82
.84
.86
.88
.90
.92
.94 S
PE
CIF
IC V
OLU
ME
m³/k
g O
F D
RY
AIR
.96
.98
1.0
0
1.0
2
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RA
TIO
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RA
MS
OF
MO
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KIL
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610 Meters above Sea LevelBAROMETRIC PRESSURE 707 mm of Mercury
Linric Company Psychrometric Chart, www.linric.com
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• Mollier Diagram• Psychrometric Chart• Visualrepresentationofpropertiesofamoistgas
Whyshouldyoucare?
• Helpswithabetterunderstandingofthehumidityparameters• Abetterunderstandinghelpsyoumakeabettermeasurement• Visuallearningcanmeanbetterunderstanding• Quickconversionsinthefield
Parameter
Drybulb temperature
Humidity ratio
Saturationcurve(100%RH)
RelativeHumidity
Dewpointtemperature
VaporPressure
Enthalpy
Wetbulbtemperature
Specific volume (dryair)
Parameter
Drybulb temperature
Humidity ratio
Saturationcurve(100%RH)
RelativeHumidity
Dewpointtemperature
VaporPressure
Enthalpy
Wetbulbtemperature
Specific volume (dryair)
Parameter
Drybulb temperature
Humidity ratio
Saturationcurve(100%RH)
RelativeHumidity
Dewpointtemperature
VaporPressure
Enthalpy
Wetbulbtemperature
Specific volume (dryair)
Parameter
Drybulb temperature
Humidity ratio
Saturationcurve(100%RH)
RelativeHumidity
Dewpointtemperature
VaporPressure
Enthalpy
Wetbulbtemperature
Specific volume (dryair)
Parameter
Drybulb temperature
Humidity ratio
Saturationcurve(100%RH)
RelativeHumidity
Dewpointtemperature
VaporPressure
Enthalpy
Wetbulbtemperature
Specific volume (dryair)
Parameter
Drybulb temperature
Humidity ratio
Saturationcurve(100%RH)
RelativeHumidity
Dewpointtemperature
VaporPressure
Enthalpy
Wetbulbtemperature
Specific volume (dryair)
Parameter
Drybulb temperature
Humidity ratio
Saturationcurve(100%RH)
RelativeHumidity
Dewpointtemperature
VaporPressure
Enthalpy
Wetbulbtemperature
Specific volume (dryair)
Parameter
Drybulb temperature
Humidity ratio
Saturationcurve(100%RH)
RelativeHumidity
Dewpointtemperature
VaporPressure
Enthalpy
Wetbulbtemperature
Specific volume (dryair)
Parameter
Drybulb temperature
Humidity ratio
Saturationcurve(100%RH)
RelativeHumidity
Dewpointtemperature
VaporPressure
Enthalpy
Wetbulbtemperature
Specific volume (dryair)
Parameter
Drybulb temperature
Humidity ratio
Saturationcurve(100%RH)
RelativeHumidity
Dewpointtemperature
VaporPressure
Enthalpy
Wetbulbtemperature
Specific volume (dryair)
Comments&Questions
Ifwedon’tgettoyourquestion today,we’llrespondviaemailafterthewebinar.
Exercise1:Wetbulb– Drybulbconversions
MeasuredParameters:Tdry =80FTwet =65F
Task:Determinetheotherparameters
Exercise#1Dry bulb 80FWetbulb 65FRH
Dewpoint
Vapor pressure
Humidity ratio
Enthalpy
Saturationvaporpressure
Exercise#1Dry bulb 80FWetbulb 65FRH
Dewpoint
Vapor pressure
Humidity ratio
Enthalpy
Saturationvaporpressure
Exercise#1Dry bulb 80FWetbulb 65FRH 45%Dewpoint
Vapor pressure
Humidity ratio
Enthalpy
Saturationvaporpressure
Exercise#1Dry bulb 80FWetbulb 65FRH 45%Dewpoint 57FVapor pressure .47inHgHumidity ratio 69grainsEnthalpy
Saturationvaporpressure
Exercise#1Dry bulb 80FWetbulb 65FRH 45%Dewpoint 57FVapor pressure .47inHgHumidity ratio 69grainsEnthalpy 30BTU/lb
Saturationvaporpressure
Exercise#1Dry bulb 80FWetbulb 65FRH
Dewpoint
Vapor pressure
Humidity ratio
Enthalpy
Saturationvaporpressure
Exercise#1Dry bulb 80FWetbulb 65FRH 45%Dewpoint 57FVapor pressure .48inHgHumidity ratio 70gr/lbEnthalpy 30btu/lbSaturationvaporpressure 1.02inHg
Comments&Questions
Ifwedon’tgettoyourquestion today,we’llrespondviaemailafterthewebinar.
Exercise2:ControlledEnvironments
MeasuredParameters:• Greenhousemaintainedat40%RHat80°F• Outdoorairis60%RHat40°F
Questions:• Iftheoutdoorairinbroughtinsideandheatedto80°Fwhathappenstothehumidity?• Willtherebecondensationonthegreenhouseglass?
Exercise#2 OutsideDry bulb 40°FWetbulb
RH 60%Dewpoint
Vapor pressure
Humidity ratio
Enthalpy
Saturationvaporpressure
Exercise#2 Outside WarmedDry bulb 40°F 80°FWetbulb 35°F 54°F
RH 60% 14%Dewpoint 27.3°F 27.3°F
Vapor pressure 0.15inHg 0.15inHg
Humidity ratio 21.8grains/lb
21.8grains/lb
Enthalpy 13BTU/lb 23BTU/lb
Saturationvaporpressure
0.25in Hg 1.03in Hg
Exercise#2 Ambient GlassDry bulb 80°F 40°FWetbulb
RH 40%Dewpoint
Vapor pressure
Humidity ratio
Enthalpy
Saturationvaporpressure
Exercise#2 Ambient GlassDry bulb 80°F 40°FWetbulb
RH 40%Dewpoint
Vapor pressure
Humidity ratio
Enthalpy
Saturationvaporpressure
Comments&Questions
Ifwedon’tgettoyourquestion today,we’llrespondviaemailafterthewebinar.
Exercise3:EvaporativeCoolingEfficiency
MeasuredParameters:Denver– 90FTdry,65FTwetNYC– 90FTdry,80FTwet
Task:ProvewhyevaporativecoolingismoreefficientinDenvercomparedtoNYC
Howitworks
Exercise#3 NYC DENDry bulb 90F 90FWetbulb 80F 65FRH
Dewpoint
Exercise#3 NYC DENDry bulb 90F 90FWetbulb 80F 65FRH 65%Dewpoint 77F
Exercise#3 NYC DENDry bulb 90F 90FWetbulb 80F 65FRH
Dewpoint
Exercise#3 NYC DENDry bulb 90F 90FWetbulb 80F 65FRH 65% 25%Dewpoint 77F 50F
Comments&Questions
Ifwedon’tgettoyourquestion today,we’llrespondviaemailafterthewebinar.
SummaryofthePsychrometric Chart
1. WhatisaPsychrometric Chart?2. Whyshouldyoucare?3. Reviewthechartanatomy4. Exercise1– Wetbulb5. Exercise2– Florist6. Exercise3- EvaporativeCooling
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0 0
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15
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20
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35 WET BULB TEM
PERATURE - °C
35
10% RELATIVE HUMIDITY
20%
30%
40%
50%
60%
70%
80%
90%
.76
.78
.80
.82
.84
.86
.88
.90
.92
.94 S
PE
CIF
IC V
OLU
ME
m³/k
g O
F D
RY
AIR
.96
.98
1.0
0
1.0
2
HU
MID
ITY
RA
TIO
- G
RA
MS
OF
MO
IST
UR
E P
ER
KIL
OG
RA
M O
F D
RY
AIR
610 Meters above Sea LevelBAROMETRIC PRESSURE 707 mm of Mercury
Linric Company Psychrometric Chart, www.linric.com
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HumidityAcademy
• Resourcesformakingabettermeasurement• Psychrometric charts• Technicalnotes• Humiditycalculator• Applicationnotes• more
www.rotronic-usa.com/humidity-academy
NextWebinarInterpretingHumidityInstrumentSpecificationsThursday,December10th1:00PMEST• Registeratwww.rotronic-usa.com/humidity-webinars
Takeaways• Learnhowtointerprettheterm"Accuracy". Aspecificationtitled“Accuracy”fromonemanufacturermaynotbecomparabletotheAccuracyspecificationfromasecondmanufacturer.
• Explorethedifferencesinspecificationmethodologiesofseveralmanufactures
• Learnhowtoapplyamethodologythatcanbeusedtoobjectivelycomparethespecifiedperformanceoftheinstruments.
Helpingyoumakeabetterhumiditymeasurement– andmore.
Transmitters,portablemetersandloggersfor:
• Humidity• CarbonDioxide• LowDewPoint• WaterActivity• DifferentialPressure• MonitoringsystemsforcGMP• ISO17025calibrations(humidityandtemperature)
Postwebinarsurvey
Thankyou!email:[email protected]:www.rotronic-usa.comCanada:www.rotronic.caOutsideAmericas:www.rotronic.com
Futurewebinarregistrations:www.rotronic-usa.com/humidity-webinars
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