Temperature and Humidity Basics
We will provide an easy-to-understand explanation of the relationship between temperature, humidity, and saturated water vapor, and compare the amount of moisture contained in the air under general air conditioning and precision air conditioning.
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Here, we summarize the relationship between temperature and saturated water vapor amount, and compare the amount of moisture contained in the air under general air conditioning and precision air conditioning.
*The drying speed also varies depending on the moisture content of the object, but moisture content will not be discussed in this article.
Temperature changes, humidity, and dryness
In manufacturing, changes in the properties of an object due to changes in its moisture content (water content) have a significant impact on the quality of the product.
Humidity control is essential to maintain the drying speed and dryness.
When a wet object loses water, it dries. The less water vapor there is in the air, the easier it is for the water to evaporate and the easier it is for the object to dry.
What is humidity?
Humidity is the amount and percentage of water vapor in the air.
Humidity is broadly divided into absolute humidity and relative humidity, and it is the relative humidity that is generally used in weather forecasts.
What is relative humidity?
Relative humidity (RH) is the ratio of the amount of water vapor (mw) contained in the air at a certain temperature to the saturated amount of water vapor (mmax) at that humidity.
RH(%)=mw/mmax×100
When the relative humidity is 100%, the amount of water vapor in the air becomes saturated and condensation occurs.
The temperature at that time is called the dew point temperature.
What is absolute humidity?
There are two types of absolute humidity: volumetric absolute humidity and Weight absolute humidity, but Weight absolute humidity is generally used in the air conditioning field.
Air that contains water vapor is called humid air, and air that has had the water vapor removed from it is called dry air.
The ratio of Weight Weight of water vapor in moist air (mw (kg)) to the weight of dry air (mDA (kg)) is called absolute Weight (SH) (kg/kg).
SH(kg/kg)=mw/mDA
Temperature and humidity
For the same amount of moisture, lowering the temperature will increase the (relative) humidity.
To understand this, it will be helpful to know the "amount of saturated water vapor," which varies greatly depending on the temperature.
What is saturated water vapor?
The saturated water vapor amount a(T) (g/m³) is the amount of water vapor that can exist in 1 m³ of air, expressed in weight (g).
The amount of saturated water vapor is closely related to temperature; it increases as the temperature increases and decreases as the temperature decreases.
a(T)=(217×e(T))/(T+273.15)
e(T) is approximately
e(T)=6.1078×10^(7.5T/(T+237.3))
You can find it at:
*This time, calculations near the critical pressure (= 22.12 MPa) will be omitted.
*Critical pressure (force) is the pressure required to liquefy a gas near its critical temperature.
Saturated water vapor volume simulation
The following results are obtained by comparing the temperature under general environment, where the temperature varies from 5°C to nearly 35°C per year, with that under precision air conditioning, where the temperature is always controlled at 25°C ± 0.1°C.
If the temperature change is from 5°C to 35°C, we can see that there is a difference of about 6 times.
When controlled at 25°C ±0.1°C using precision air conditioner (TCU/ECU), there is almost no fluctuation in the amount of saturated water vapor.
Under precision air conditioning with a temperature difference of 5°C to 35°C and 24.9°C to 25.1°C, the difference in saturated water vapor volume is approximately 164 times.
By using precision air conditioning, it is possible to maintain humidity and saturated water vapor levels along with temperature.
This helps to stabilize the amount of saturated water vapor in the on-site environment throughout the year, and also stabilizes the amount of dried moisture.
*In the case of general air conditioning, due to reasons such as insufficient air conditioning capacity, the temperature difference as above (5℃ to 35℃) may occur throughout the year depending on the location of the air conditioning.
It is also possible to use wind to control the amount of moisture that dries.
This is because if air saturated with water vapor remains near the surface of an object, it prevents it from drying out.
By blowing "dry air" evenly onto the surface of an object, you can accelerate drying.
Are there any seasonal fluctuations in yield and measurement data?
Apiste, a manufacturer specializing in precision air conditioning, can provide a constant temperature and humidity environment year-round in a short delivery time.
- Changes in the viscosity of the material can cause uneven thickness and coating.
- Expansion and contraction of the workpiece is a problem
- Data varies due to fluctuations in measurement conditions
