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MoistAirTab™ Product Information


  • Do you still use those clumsy Windows based psychrometric calculators?
  • Are your eyes sore from reading those wall hanging psychrometric charts?
  • Are you bored form interpolating from rows and rows of numbers?
  • Do you ever do any calculations involving psychrometrics in spreadsheet?

Well, if you answered yes to even one question, you must explore how ChemicaLogic MoistAirTab™ can help you.

MoistAirTab™ brings you a comprehensive set of air, water, steam and ice properties - right in your spreadsheet - with "live" links to variable psychrometric conditions by cell reference. You never again have to copy or re-type any property values into your spreadsheet!

MoistAirTab™ is indispensable for professionals working in the field of air conditioning, power generation, paper and pulp, food processing, desiccant drying, compressor design and chemical process engineering.

Some of the unique features of MoistAirTab are:

  • Direct "live" links to variable psychrometric conditions by cell reference
  • Built-in MoistAirTab™ worksheet functions and user-interface dialog-boxes
  • Choice of Metric/SI or English units
  • Includes all standard psychrometric properties, as well as transport and dimensionless properties for steam, water and ice
  • Generate your own psychrometric charts and tables
  • Save property values for export to other applications – limited only by the spreadsheet’s file transfer capability
  • Spreadsheet simulators for moisture content expressions, streams mixing, heating, cooling, humidification, air dehydration, solids drying, multi-stage air compressor are included as examples
  • Allows multiple input specifications – up to 18 combinations of input variables. First independent variable can be either: Dry-bulb temperature (Tdb), Humidity Ratio (W), or Relative Humidity (RH). Second independent variable can be either: Dry-bulb Temperature (Tdb), Wet-bulb Temperature (Twb), Humidity Ratio (W), or Relative Humidity (RH), Enthalpy (H), Entropy (S), or Volume (V)
  • Calculation results using MoistAirTab can be freely formatted and charted for presentation


MoistAirTab uses an equation of state to compute all of the thermodynamic properties. MoistAirTab uses formulations that are approved by the American Society of Heating, Refrigeration and Air-Conditioning Engineers, Inc. (ASHRAE) as documented in the 1997 ASHRAE Handbook: Fundamentals. See the technical information section for additional references.


The range of validity for the properties of moist air are:

	Pressure: 0 <= P (bar) <= 50, or
          	  0 <= P (psi) <= 725
	Temperature: -100 <= T (C) <= 372, or
             	     -148 <= T (F) <= 701.6

Package Contents

The MoistAirTab add-in package contains:

  • Spreadsheet add-in files containing the MoistAirTab Functions and MoistAirTab user-interface consisting of dialog boxes.
  • A dynamic link library (DLL) containing the core moist air routines
  • On-line, context sensitive help files
  • A manual with a MoistAirTab Function Quick Reference card
  • Free technical support

System Requirements

You should not encounter any hardware or software problems in using SteamTab on any hardware that has one of the following spreadsheet applications pre-installed:

  • Windows Excel 2010 (32-bit and 64-bit are both supported)/2007/2003 running on Microsoft Windows 7/Vista/XP
  • Mac OSX Microsoft Excel 2011