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  • App Store Info


• Professional quality psychrometric calculator quickly calculates highly accurate thermodynamic properties of moist air in I-P (English) or SI (metric) units or both – no more psychrometric charts!
• Application in meteorology, and heating, ventilation, and air-conditioning
• Uses industry standard ASHRAE equations
• Results and input can be e-mailed for later use, sharing, or documentation, in either table format (HTML), or plain text format. Optionally, a .csv file may be attached. This file can then be imported into a spreadsheet.

What makes PsychroCalc unique:
• Custom units: do your calculations in I-P, or SI units, or set (and save) your own unique combination
• Calculations for up to 2 different states and automatically show the delta (differences between them)
• Input two states and calculate delta, or one state and delta to calculate the secondstate
• Set altitude and select from 19 different combinations of 2 input variables to instantly view the calculated results
• PsychroCalc handles input combinations others do not, such as specific volume with any other variable
• Input values, see all results, and change units all on one screen
• Help screen includes detailed instructions and definitions of terms

Input and Output thermodynamic properties:
1. Tdb (dry-bulb temperature) in °F, °R, °C or Kelvins
2. Twb (wet-bulb temperature) in °F, °R, °C or Kelvins
3. Tdp (dew point temperature) in °F, °R, °C or Kelvins
4. ω (humidity ratio) in lbm of water vapor per lbm of dry air, or grains of water per lbm of dry air, or grams of water per kg of dry air, or kg of water per kg of dry air
5. φ (relative humidity) percent
6. h (specific enthalpy) in BTU per lbm of dry air, J per kg of dry air, or kJ per kg of dry air
7. v (specific volume) in cubic feet per lbm of dry air, or cubic meters per kg of dry air, or cubic centimeters per gram of dry air

Range of validity:
• IP units:
0 ft <= altitude <= 30,000 ft
32.0 °F <= Tdb <= 116.0 °F
11.2 °F <= Twb <= 115.9 °F
-51.5 °F <= Tdp <= 115.9 °F
0.0 lbm-v/lbm-da <= ω <= 0.3293 lbm-v/lbm-da
1.0% <= φ <= 99.0%
7.7 BTU/lbm-da <= h <= 394.3 BTU/lbm-da
12.4 ft^3/lbm-da <= v <= 77.77 ft^3/lbm-da

• SI units:
0 m <= altitude <= 9144 m
0.0 °C <= Tdb <= 46.67 °C
-11.54 °C <= Twb <= 46.61 °C
-46.38 °C <= Tdp <= 46.61 °C
0.0 kg-v/kg-da <= ω <= .3293 kg-v/kg-da
0.1 kJ/kg-da <= h <= 899.3 kJ/kg-da
0.774 m^3/kg-da <= v <= 4.855 m^3/kg-da

• If you have a question or suggestion, please email [email protected]

What's New in Version 1.1

• Added the option to email in HTML (table) format, and to attach .csv files.
• Changed the input of variables to use a custom numerical keyboard, rather than sliders.
• Fixed minor bugs


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