Calculation result: dt, wb, ah, and hr, 1 what is dt – KANOMAX 2211 Handheld IAQ Monitor User Manual
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10. Calculation Result: DT, WB, AH, and HR
10.1 What is DT
DT -- Dew Point Temperature
Air with higher temperature contains more water vapor, and the air reaches a saturation point as
temperature lowered （Relative humidity: 100％）. Then continuously lowered temperature causes water
vapor to start condensing -- this temperature is called Dew Point Temperature.
There are many formulas to calculate the Dew Point Temperature; however, this manual uses calculation in
conformity with JIS standard Z8806.
ln(e
w
）
=-6096.9385ЧT
-1
+21.2409642-2.711193Ч(10
-2
) ЧT
+1.673952Ч(10
-5
) ЧT
2
+2.433502Чln(T)
e=U/100×e
w
ｙ＝
ln（ｅ／611.213）
When y≧0;
td=13.715Чy+8.4262Ч(10
-1
) Чy
2
+1.9048Ч(10
-2
) Чy
3
+7.8158Ч(10
-3
) Чy
4
When y＜0;
td=13.7204Чy+7.36631Ч(10
-1
) Чy
2
+3.32136Ч(10
-2
) Чy
3
+7.78591Ч(10
-３
) Чy
4
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
Td: Dew point temperature （℃）