Psychrometric Chart 2-Condition Calculator
RELATED CALCULATORS:
Instructions:
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Review the methodology below to ensure it aligns with your project's requirements.
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Select Metric or US units
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Select the first input parameter:
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Temperature,Dry Bulb, oF [oC]
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Temperature,Dew Point, oF [oC]
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Enter the Entering and Exiting values for the first selected input parameter
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Select the second input parameter:
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Temperature,Wet Bulb*, oF [oC]
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Relative Humidity, %
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Enter the Entering and Exiting values for the second selected input parameter.
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Enter the air flow rate to calculate the Total, Sensible, and Latent Cooling, Condensate Generated, and Air Flow Rate per ton.
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Enter the project's altitude.
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Click the Calculate button.
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The results are shown in the Results table
* Temperature, Wet Bulb, is only available as an input when the first input is Temperature,Dry Bulb
Methodology:
The following formulas are used in this calculator. They have been adapted from the 2021 ASHRAE Handbook -Fundamentals.
p = 14.696 (1-6.8754 x 10^(-6)Z)^5.2559
t = 59 - 0.00356620Z
For 32oF < t < 707.103oF:
p,ws = 145.03774 (2C / (-B + (B^2 - 4AC)^0.5))^4
See ASHRAE Handbook-Fundamentals for Coefficient Values, A, B, and C.
W = Mw / Mda
RH% = (p,w / p,s)
v = 0.370486 (t,db + 459.67)(1 + 1.607858) / p
h = 0.240 t + W(1061 + 0.444t)
p,w = p x W / (0.621945 + W )
where
h = specific enthalpy [Btu/lb,da]
p = barometric pressure [psia]
p,w = water vapor partial pressure [psia]
p,s = saturation water vapor pressure [psia]
p,ws = saturation pressure [psia]
t = temperature [oF]
T,d = dew point temperature [oF]
t,db = dry bulb temperature [oF]
t,wb = wet bulb temperature [oF]
v = specific volume [ft^3/lb,da]
W = humidity ratio [lb,w / lb,da]
Z = Altitude [ft]