29_ properties of air and water 61294_27
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Properties of Air and Water
27PA RT27
H VA C E Q U AT I O N S , D ATA , A N D R U L E S O F T H U M B
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384 PART 27
27.01 Properties of Air/Water Vapor Mixtures
A. Psychrometric Definitions:
1. Dry Bulb Temperature. The temperature of air read on a standard thermometer. Units:° F.DB. Symbol: TDB or DB.
2. Wet Bulb Temperature. The wet bulb temperature is the temperature indicated by athermometer whose bulb is covered by a wet wick and exposed to air moving at a veloc-ity of 1,000 feet per minute. Units: ° F.WB. Symbol: TWB or WB.
3. Humidity Ratio. The weight of water vapor in each pound of dry air; also known as spe-cific humidity. Units: Lb.H 2O/Lb.DA or Gr.H 2O/Lb.DA. Symbol: W.
4. Enthalpy. A thermodynamic property which serves as a measure of the heat contentabove some datum temperature (Air 0 ° F.DB and Water 32 ° F.). Units: Btu/Lb.DA orBtu/Lb.H 2O. Symbol: h.
5. Specific Volume. The cubic feet of air/water mixture per pound of dry air. Units:Cu.Ft./Lb.DA. Symbol: SpV.
6. Dew Point Temperature. The temperature at which moisture will start to condensefrom the air. Units: ° F.DP. Symbol: T DP or DP.
7. Relative Humidity. The ratio of water vapor in the air/water mixture to the water vaporin saturated air/water mixture. Units: %RH. Symbol: RH.
8. Sensible Heat. Heat that causes a rise in temperature. Units: Btu/Hr. Symbol: H S.9. Latent Heat. Heat that causes a change in state (i.e., liquid water to gaseous water).
Units: Btu/Hr. Symbol: H L.
10. Total Heat. Sum of sensible heat and latent heat. Units: Btu/Hr. Symbol: H T.11. Sensible Heat Ratio. The ratio of the sensible heat to the total heat. Units: None. Sym-bol: SHR.
12. Vapor Pressure. Pressure exerted by water vapor in the air. Units: In.Hg. Symbol: P W.13. Standard Barometric Pressure. Pressure at Sea Level (29.921 InHg. = 14.7 Psi).
B. Thermodynamic Properties of Air/Water Mixtures are given in the followingtables:
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Properties of Air and Water 385
Thermodynamic Properties of Moist Air @ 14.696 PSIA
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386 PART 27
Thermodynamic Properties of Moist Air @ 14.696 PSIA
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Properties of Air and Water 387
Thermodynamic Properties of Moist Air @ 14.696 PSIA
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388 PART 27
Thermodynamic Properties of Moist Air @ 14.696 PSIA
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Properties of Air and Water 389
Thermodynamic Properties of Moist Air @ 14.696 PSIA
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390 PART 27
Thermodynamic Properties of Moist Air @ 14.696 PSIA
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Properties of Air and Water 391
Thermodynamic Properties of Moist Air @ 14.696 PSIA
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392 PART 27
27.02 Properties of Air
Barometric Pressures at Various Altitudes at 70 ° F.
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Properties of Air and Water 393
Air Equation Constants for Altitude
Notes:
1. Equation Constants Units: BTU/Hr. CFM ° F.2. Equation Constants Units: BTU LbDA/Hr. Gr.H 2O CFM.3. Equation Constants Units: BTU LbDA/Hr. Lb.H 2O CFM.4. Equation Constants Units: Lb.DA/Hr. CFM.5. Use table values in lieu of constants in equations in Part 5, Equations.
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394 PART 27
Air Equation Constants for Temperature
Notes:
1. Equation Constants Units: BTU/Hr. CFM ° F.2. Equation Constants Units: BTU LbDA/Hr. Gr.H 2O CFM.3. Equation Constants Units: BTU LbDA/Hr. Lb.H 2O CFM.4. Equation Constants Units: Lb.DA/Hr. CFM.5. Use table values in lieu of constants in equations in Part 5, Equations.
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Properties of Air and Water 395
Air Equation Factors for Density
Notes:
1. Multiply constants in equations in Part 5, Equations, by values in the table.
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396 PART 27
Air Equation Factors for Density
Notes:
1. Multiply constants in equations in Part 5, Equations, by values in the table.
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Properties of Air and Water 397
Air Equation Factors for Density
Notes:
1. Multiply constants in equations in Part 5, Equations, by values in the table.
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398 PART 27
Physical Properties of Gases
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Properties of Air and Water 399
27.03 Properties of Water
Boiling Points of Water
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400 PART 27
Thermodynamic Properties of Water
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Properties of Air and Water 401
Thermodynamic Properties of Water
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402 PART 27
Thermodynamic Properties of Water
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Properties of Air and Water 403
Thermodynamic Properties of Water
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404 PART 27
Thermodynamic Properties of Water
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Properties of Air and Water 405
Thermodynamic Properties of Water
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406 PART 27
Thermodynamic Properties of Water
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Properties of Air and Water 407
Thermodynamic Properties of Water
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408 PART 27
Thermodynamic Properties of Water
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Properties of Air and Water 409
Thermodynamic Properties of Water
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410 PART 27
Thermodynamic Properties of Water
Properties of Water
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Properties of Air and Water 411
Water Equation Factors
Notes:
1. Water equation corrections for temperature, density, and specific heat.2. For glycol system equation factors, see Section 27.04, Glycol Systems, below.
27.04 Glycol Systems
Ethylene Glycol
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Note:
1. Specific gravity with respect to water at 60 ° F.
412 PART 27
Propylene Glycol
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