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.TT pocketEngineer softDesign

... pocketEngineer software for mobile design

pocketEngineer software  animated gif (free)  email me  buy now  Rethink, Reinvent apps   
...Ductulator Plus+
...aDuctulator (And)
...aBattMV (And)
...aKitchenExhaust (And)
...tRod Sizer (free)
...pocketPipe Sizer
...aPipeSizer (And)
...multi Pipes PD (And)
...aPocketGas (And)
...rhoAIR (free)
...aRhoAIR (free) (And)
...aPsychroAC (And)
...AirTAB superEZ
...Qcool Check
...aCriticalVel (And)
...aPocketPool (And)
ePF Loop Pdrop
...hydrant pressure drop
...Pumping Mainline
the new home of .TT pocketEngineer softDesign - where pocketEngineer software lives...
 a rhoAIR (free) (Android)

the cousin of Windows rhoAIR - air density + Cp + psychrometric air properties calculator on Android




To take a glance at all pocketEngineer software and OS requirements, click Overview.

For Windows Mobile & Windows, see rhoAIR free


 aRhoAIR: air density + Cp + pyschrometric air properties calculator 

aRhoAIR is a state point psychrometric air properties calculator to find air density, specific heat capacity, vapour pressure, dew point temperature, moisture content, enthalpy, etc. It is specially developed by a professional engineer to replace the psychrometric chart. aRhoAIR will change the way you normally find air properties, air density and specific heat by using conventional psychrometric chart.

Aim: creating a mobile design environment
for the practising engineers & designers in today's mobile world.

Results: Instant solutions at your fingertips.



- calculate Air Density, Specific Heat, DewPoint Temperature, various Pressure, Moisture Content, Specific Volume, Enthalpy, etc.
- input options - RH or Wet Bulb Temperature.

- input options - Z (altitude) or P (pressure) with units selection.

- calculation formulation based on ASHRAE guidelines.
- alternative on-the-move method to using conventional Psychrometric Chart.
- in SI & IP units.

- save result function with built-in result file viewer.


 Did you know? . . .about Enthalpy Units 


It is incorrect to directly convert Enthalpy from SI unit (kJ/kg) to IP unit (Btu/lb), and vice versa. Hard to believe! Test it yourself.


 Did you know? . . .the definition of Standard air density = 1.204 kg/m3 ?  


The value is of course valid only for what is termed standard air conditions.


In the International Standard Atmosphere (ISA), standard temperature and pressure is 15 oC and 101325 Pa respectively. This gives the air density of 1.225 kg/m3 at sea level and the air does not contain water vapour, i.e. dry air.


At 20 oC, the dry air has a density of 1.204 kg/m3. At 20 oC and 101325 Pa, it may be referred to as Normal temperature and pressure conditions.


In AMCA 210 Standard for fan performance testing, standard air is defined as air with a density of 1.2 kg/m3 (at 20 oC, 50% RH and 101325 Pa approximately). 


ASHRAE 37 Standard for unitary air-conditioning testing defines standard air as dry air having a mass density of 1.204 kg/m (at 20 oC and 101325 Pa).


SMACNA 126 Standard for HVAC duct testing defines density of standard air equals 1.204 kg/m3.


Note that there are many definitions of standard temperature and pressure. To avoid confusion, it is  often necessary to state the standard reference conditions.



 Calculation Exapmle (in IP units)


At 90 oF Dry Bulb and 70% RH, find air density, specific heat capacity, dewpoint temperature, moisture content, enthalphy, etc?


rhoAIR Calculation



Z (ft) = 0


Tdb (oF) = 90.0

Twb (oF) = 81.5

Tdp (oF) = 78.9

RH (%) = 70.0


rho (lb/ft3) =0.071

Cp (Btu/lb.F) = 0.250

W (lb/lb) = 0.0214

W (gr/lb) = 149.92

v (ft3/lb) = 14.334

h (Btu/lb) = 45.18 


p (in.Hg) = 29.9213

Pws (in.Hg) = 1.4230

Pw (in.Hg) = 0.9961



Z = altitude

Tdb = Dry bulb temperature

Twb = Wet bulb temperature     

Tdp = Dew point temperature

RH = Relative humidity

rho = Air density

Cp = Specific heat capacity

W = Humidity ratio

v = Specific volume

h = Enthalpy

p = Atmosphere pressure

Pws = Saturation vapour pressure

Pw = Partial water vapour pressure                                          




 aRhoAIR free ?

yes, it is free for all engineers and designers. Available in both SI & IP units, it is for world-wide users. If you need duct sizing, buy  aDuctulator.












 Price   free download @ Android Market



OS requirements: Android 




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