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Tutorial for Psyc0226. Wei Fang, Ph.D., Professor Dept. of Bio-Industrial Mechatronics Engineering National Taiwan University Software last updated: 2002/02/26 Tutorial last updated: 2003/11/28. Capability of Psyc0226. Allow alteration on atmospheric pressure Provide handy PsyTables
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Tutorial for Psyc0226 Wei Fang, Ph.D., Professor Dept. of Bio-Industrial Mechatronics Engineering National Taiwan University Software last updated: 2002/02/26 Tutorial last updated: 2003/11/28
Capability of Psyc0226 • Allow alteration on atmospheric pressure • Provide handy PsyTables • Totally 11 tables are available • Provide PsyCharts • State calculation: besides AtmP, values of 2 independent states are required to calculate others • Process calculation: find differences between 2 states • More process calculation: • Evaporative cooling • Vapor pressure deficit on leaf
Abbreviations of thermodynamic properties of moist air used in Psyc0226 • Tdb: dry bulb Temp. • RH : relative humidity • Twb: Wet bulb Temp. • Tdp: dew point Temp. • AH : absolute humidity • SV : specific volume • Hfg: Saturated • DOS: degree of Saturation • Pws: saturated vapor pressure • Pw: vapor pressure More message of the selected cell
2. Set the intervals 3. List the values 1. Define the ranges User friendly 3-step design in PsyTable
Table 1: Twb = f(Tdb, RH) Twb RH (50 – 100%)and Tdb (20 – 44 oC)
Table 2: WBD = f(Tdb,RH) WBD Wet Bulb Depression is the limit of evaporative cooling methods.
Table 3: RH = f(Tdb,Twb) RH Twb (20 – 44 oC)and Tdb (20 – 44 oC)
VPD=Pws@Tdb – Pw@TdbAHD=Sat.AH@Tdb – Sat.AH@Tdp VPD/AHD of air
VPD’=Pw@Twb – Pw@TdbAHD’=Sat.AH@Twb – Sat.AH@Tdp VPD’/AHD’ of air
Besides atmospheric pressure, values of 2 independent states are required to derive others Evaporative cooling process calculation Vapor pressure deficit on leaf find differences between 2 states Psycharts
Independent Properties (IP) Any pair of IP can be the given values to derive others.
One click in Psychart window using left button of the mouse can define a state
Use mouse to define 2 states • To define 2nd state, change from ‘Inactive’ to ‘Active’ first. • Click in the Psychart window at the selected state or click on the crosshair region to move along constant lines or curves. • Click on ‘Cal.’ to calculate the difference.
Move along prefix lines or Curves Constant Tdb Constant Twb Constant RH Constant Tdp, Pw, AH Constant Tdp, Pw, AH Constant Tdb Constant RH Constant Twb
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)
Enter ‘Tdb after pad’ or ‘pad efficiency’ to derive others followed by a Click on ‘Draw’ icon. WBD
T T- ΔT Temperature drop after passing through pad (ΔT) ΔT = WBD of outdoor x Efficiency of the pad
Vapor pressure deficit (VPD) Enter Leaf temperature, then click on Draw icon. VPD
Lines and curves can be visible or hidden by (de)selecting related icons
Labels in Psychart window can be hidden by de-select the Unit label icon
The state user defined in the psychart window using left button of the mouse will be placed in the center of the psychart window if the Centralize icon was selected. This option is set inactive by default.
Enjoy playing with Digital Psychart Please send us information regarding found bugs. Mail to : weifang@ntu.edu.tw