Owner manual

46
10.2 What is WB
Wet Bulb Temperature -- WB
Wet-bulb temperature is measured with a wet-bulb thermometer, which is a regular thermometer with a wet
muslin wick cover.
To calculate wet-bulb temperature without using a wet-bulb thermometer, existing dry-bulb temperature and
relative temperature are used on the aspirated psychrometer humidity table that is JIS standard Z8806
compliant. In this manual; however, we uses Newtonian approximation based on the assumption of a
temperature measured on a wet-bulb thermometer being lower than a dry-bulb thermometer.
ln(e
tw
）=-6096.9385×T
w
-1
+21.2409642-2.711193×(10
-2
) × T
w
+1.673952×(10
-5
) × T
w
2
+2.433502×ln(T
w
)
A= e
tw
ｆ’（tw）=4030.183/((235+tw)
2
)×A+P/2/755
tw1=tw-(A-P
×
(t-tw)/2/755-E
×
U/100)/
ｆ’（
tw
）
tw: Wet bulb temperature （℃）
e
tw
: Saturated water vapor pressure at tw （Pa）
T
w
: Absolute temperature （k）＝（tw＋273.15）
P: Barometric pressure (Pa)
E: Saturated water vapor pressure at t （Pa）
U: Relative humidity
T: Dry bulb temperature （℃）
10.3 What is AH
Absolute Humidity -- AH
Absolute humidity represents an amount of water vapor contents per 1kg of dry air.
To calculate absolute humidity, apply temperature and relative humidity on below formula.
ln(e
w
）=-6096.9385×T
-1
+21.2409642-2.711193×(10
-2
) ×T
+1.673952×(10
-5
) ×T
2
+2.433502×ln(T)
e=U/100×eW
D(g/m3)＝0.794×(10
-2
) ×ｅ/（1＋0.00366×ｔ）
e
w
: Saturated water vapor pressure （Pa）
T: Absolute temperature
（
K
）＝
t(
℃
)
＋
273.15
t: Dry bulb temperature （℃）
e: Water vapor pressure （Pa）
U: Relative humidity
D: Absolute humidity (g/m3)