About Humid Air Excel Add-In
The psychrometrics Excel Add-In library calculates 35 thermodynamic properties of humid (moist) air
in SI and English units.
It allows 21 different combinations of input variables to be used for calculations.
Input variables that can be used are:
- pressure,
- dry bulb temperature,
- wet bulb temperature,
- dew point tempertature,
- relative humidity,
- humidity ratio,
- enthalpy,
- entropy,
- and volume.
The library is fully integrated in Excel, and available functions can be used in the same way as any other Excel function.
Main features of the library:
- Professional quality, industrial strength software;
- Based on the most accurate formulation (Hyland and Wexler);
- Accurate and thoroughly tested;
- Create User Defined Functions (UDF) which use HumidAir functions;
- Call HumidAir functions from VBA (sample is included in the release version);
- Developed in C++ for maximum speed;
- Easy to install and easy to use;
- For installation and use of the library no administrator rights required;
- After installation no computer restart required;
- One year free technical support.
|
The following figure shows a sample spreadsheet included in the download package.
Humid Air Excel Add-In - Sample calculations in Excel
The psychrometrics library uses the most exact formulations of thermodynamic properties of moist air currently available.
Formulations are based on the study performed by Hyland and Wexler, and approved by ASHRAE (American Society
of Heating, Refrigeration and Air-conditioning Engineers) as documented in the 1997 ASHRAE Handbook "Fundamentals".
They presented the equation of state in:
- Formulations for the thermodynamic properties of the saturated phases of H2O from
173.15 K to 473.15 K, W. Hyland and A.Wexler, ASHRAE Transactions, 89(2A) 500-519, 1983.
- Formulations for the thermodynamic properties of dry air from 173.15 K to 473.15 K,
and of saturated moist air from 173.15 K to 372.15 K, at pressures to 5 MPa, R. W.
Hyland and A. Wexler, ASHRAE Transactions, 89(2A) 520-535, 1983.
System Requirements
Operating system Windows 2000/XP/Vista/Windows 7.
Excel 97 or better.
User privilages
Installation and use of the library requires standard user privilages or better.
Psychrometric Properties
The following termodynamic and transport properties can be calculated with Humid Air Excel Add-In:
| Calculable properties in SI or E units - HumidAir Excel Add-In v2.0 |
| 1 |
Dry bulb temperature [Tdb] |
| 2 |
Wet bulb temperature [Twb] |
| 3 |
Dew point temperature [Tdp] |
| 4 |
Pressure [P] |
| 5 |
Saturation water pressure [Ps] |
| 6 |
Saturation pressure at wet bulb temperature [Pwb] |
| 7 |
Saturation pressure at dew point temperature [Pdp] |
| 8 |
Mole fraction of water [Xw] |
| 9 |
Mole fraction of air [Xa] |
| 10 |
Weight fraction of water [Ww] |
| 11 |
Weight fraction of air [Wa] |
| 12 |
Humidity ratio [W] |
| 13 |
Saturation humidity ratio [Ws] |
| 14 |
Degree of saturation [DS] |
| 15 |
Relative humidity [RH] |
| 16 |
Specific volume of dry air [Va] |
| 17 |
Specific volume of saturated ice [Vi] |
| 18 |
Specific volume of saturated water [Vw] |
| 19 |
Specific volume of saturated vapor [Vv] |
| 20 |
Specific volume of moist air [Vm] |
| 21 |
Specific density of dry air [Da] |
| 22 |
Specific density of saturated ice [Di] |
| 23 |
Specific density of saturated water [Dw] |
| 24 |
Specific density of saturated vapor [Dv] |
| 25 |
Specific density of moist air [Dm] |
| 26 |
Specific enthalpy of dry air [Ha] |
| 27 |
Specific enthalpy of saturated ice [Hi] |
| 28 |
Specific enthalpy of saturated water [Hw] |
| 29 |
Specific enthalpy of saturated vapor [Hv] |
| 30 |
Specific enthalpy of moist air [Hm] |
| 31 |
Specific entropy of dry air [Sa] |
| 32 |
Specific entropy of saturated ice [Si] |
| 33 |
Specific entropy of saturated water [Sw] |
| 34 |
Specific entropy of saturated vapor [Sv] |
| 35 |
Specific entropy of moist air [Sm] |
Range of Validity
The entire set of equations used by the Humid Air Excel Add-In library,
is defined by the following temperature and pressure range:
- 173.15 K <= T < = 473.15 K
- 0.000001 MPa <= P < = 5 MPa
Reference Point
IMPORTANT:
In the used formulations for calculation of thermodynamic properties of moist air, reference state
(zero enthalpy) is set at 0 °C. On some psychrometric charts (especially in the US)
reference state (zero enthalpy) is set at 0 °F.
As a consequence, enthalpy and entropy values calculated by the library will be
shifted on these charts for the difference between reference points.
Since for any process calculation only enthalpy difference (in and out of a process)
is important, reference point doesn't really matter.
If you want to reproduce enthalpy values from such charts, you should find the enthalpy
difference for one point (doesn't matter which one), and then add that value for all
calculated enthalpies. The same applies for entropy values.
|
Screenshots
The following screenshots demonstrate how to use the library.
1.(a) Start Excel and press "Insert"->"Function" menu item.
1.(b) Alternatively, start Excel and press "Paste Function" toolbar button.
2. Select a function and press OK button.
3. Enter input parameters and press OK button.
NOTE: You don't have to put quotes around property ID they are inserted automatically.
That's it, result will be displayed in the selected cell.
Downloads
The setup program will automatically install the library in Excel.
Humid Air Excel Add-In library
IMPORTANT:
For the demo version input pressure is fixed to:
- p = 8 bar in SI Units and
- p = 116.029 psi in English Units.
These values will be used for calculation regardless of your input value for pressure.
To further evaluate the library, go to our Psychrometric Calculator web application, it uses the same calculation engine.
|
Quick reference documents
Price info
Prices subject to change without notice!
| HumidAir Excel Add-In v2.0 |
| 1-4 licenses |
US $ 179.95 per copy |
| 5-20 licenses |
US $ 164.95 per copy |
| 21 > licenses |
US $ 149.95 per copy |
| Company wide license |
US $ 5995.00 |
Note: when purchasing a license you receive one year subscription for free.
The subscription includes updates and e-mail technical support.
If you have any questions, please don't hesitate to contact our sales:
sales@megawatsoft.com
General Information
For immediate access to HumidAir Excel Add-In, you may purchase and download our product using automated and secure online
ordering system. After ordering, you will receive a notification mail with further instructions, your
password (required during installation) and the retail version download location.
The Registration includes a free subscription program. Each Registered user will be receiving bug
fixes and technical support for the registered version within one year.
Shipping by the postal mail is not available.
For software registration we employ the services of one of the leading American
registering firms RegSoft.com.
Details about the company you can find at the RegSoft.com's website
http://www.regsoft.com/.
How to order
Internet ordering
Available ordering options (open an order form to select):
- Credit Card
- PayPal
- FAX Ordering
- Phone
To view an order form, preview ordering options or buy specific number of licenses for
HumidAir Excel Add-In
click the button:
or to purchase a Company wide license click here:
.
|