Psychrometric Properties Excel

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Psychrometrics

Humid Air Excel Add-In

For Excel 97 or better

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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;
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.
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 v1.2.1
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]