Ideal Gas Mixture and Psychrometric Applications

1
Chapter 12
Cooling Towers, 2000MW coal-fired Cottam Power
Station, Nottinghamshire. Photo courtesy of
FreeFoto.com

• Ideal Gas Mixture and Psychrometric Applications

2
Mixture Composition
Describing mixture composition
For Gases
Daltons Model
Amagats Model
3
Mixture Composition
Describing mixture composition
For Gases
Daltons Model
Amagats Model
4
Ideal Gas Properties for Mixtures
Evaluated at the mixture temperature
Evaluated at the mixture temperature, and
appropriate partial pressure, pi
5
Mixture Analysis (non-reacting)
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Ideal Gas Cases
For Ideal Gases using Tables A-22, A-23
Assuming Constant Specific Heats
7
Psychrometric Principles
Dry air Water vapor Moist Air
Humidity Ratio
Relative Humidity
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Psychrometric Properties
Mixture Enthalpy
Water Vapor Enthalpy
Water Vapor Entropy
Dew Point Temperature
Sling Psychrometer picture courtesy of USA Today
9
Psychrometric Charts
10
Relative Humidity f
Mixture Enthalpy
Wet Bulb Temp.
Humidity Ratio w
ASHRAE Comfort Zone
HUMID
HOT
COLD
DRY
Dry Bulb Temp.
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Dehumidification
12
Humidification
13
Evaporative Cooling
14
Adiabatic Mixing
15
Cooling Towers