1. Engineering Fundamentals：part I Related to moist air and water
Thermodynamic properties of moist air
State
Process
Pad and Fan system
Pad efficiency at various facing velocity
Pad efficiency and pressure drop at various thickness
Fan curves
Efficiency of the nozzle in misting/fogging system
Psychrometric related Tables generated by Psychart software

2. Thermodynamic properties of moist air
dry bulb T
wet bulb T
dew point T
relative humidity
absolute humidity
(humidity ratio)
specific volume
enthalpy
vapor pressure
saturated vapor pressure

3. With 2 independent properties and the given atmospheric pressure
The state of the moist air can be defined.

4. Psychrometric Chart

5. Independent Properties
Twb rh
Tdp AH SV H
Pws
hfg Pv
Tdb P I

6. Digital Psychrometric Chart

7. Zoom in & Zoom out

8. Process: between states
Sensible Heating (3->4)
Sensible Cooling (4->3)
Humidification (4->5)
Dehumidification (5->4)
Heating (3->5, 3->1)
Cooling (5->3, 1->3)
Air Mixing (1, 2->3)
Evaporative Cooling，Drying (1->2, 1->3)
Combination of above (1->2->3->4->5)

9. A process with sensible heat gain

10. Move along prefix lines & Curves
Constant Twb
Constant RH
Constant Tdp, Pw, AH
Constant Tdp, Pw, AH
Constant RH
Constant Twb

11. Efficiency of a Pad and Fan system

12. Pad efficiency at various facing velocity
Eff = – * V * V2
Kool-Cel pad
Eff = – * V * V2
CELdek pad
Eff = * V – * V2
Excelsior pad
Trumbull, et al. (1986)
Thickness of the pads were not mentioned. 10 cm ?

13. Pad efficiency at various facing velocity and thickness
10 cm pad
20 cm pad

14. Pressure drop at various facing velocity and pad thickness
10 cm pad
20 cm pad

15. Fan curves of various models of

16. Blow-off of water from the pad
at 1 m/s for the Excelsior pad,
at 1.6 m/s for the Kool-Cel pad and
at 2 m/s for the CELdek pad
Trumbull, et al. (1986)

17. Efficiency of nozzle (misting/fogging system)
β = * 10-4 * P
Bottcher et al. (1991)
P = ATM  β= 100%
Considering some head loss and friction loss, 70 ATM (70 kg/cm2) was used in my research.

18. Handy Tables

19. User friendly 3-step design in PsyTable
1.Define the ranges
2.Set the intervals
3.list the values

20. Twb = f(Tdb, RH)
Twb
RH (50 – 100%)and Tdb (20 – 44 oC)

21. RH = f(Tdb,Twb) RH
Twb (20 – 44 oC) and Tdb (20 – 44 oC)

22. Wet Bulb Depression is the limit of evaporative cooling methods.
WBD = f(Tdb,RH)
WBD
Wet Bulb Depression is the limit of evaporative cooling methods.

23. Evaporative cooling Methods
Pad and Fan system
Spraying
Misting
Fogging
Multi-Net Fogging and Fan system