2. Product information
  3. Precision air conditioning equipment Precision air conditioners PAU Series
  4. Precision air conditioners Technical Information
  5. 1-2. About air conditioning

Precision air conditioning equipmentPrecision air conditioners Technical Information

PAU Series

1-2. About air conditioning

This section describes what air conditioning is, and the elements, types and characteristics of air conditioning.

(1)About air conditioning

AC stands for air conditioning.
The main components of the air around us are nitrogen, oxygen, argon, and nitrogen in descending order, but it also contains other components such as carbon dioxide generated by breathing, water vapor as represented by the humidity, and so on.
It also contains hazardous chemicals and other substances that are harmful to us, such as dust, refuse, pollen, mold spores, viruses, cigarette smoke, formaldehyde given off by volatile building materials, and so on.
There are many indicators to quantitatively represent the characteristics of such air, such as temperature, humidity, volume, specific gravity, atmospheric pressure, air flow, cleanliness level, and so on, which are known as air conditions.
Air conditioning adjusts these air conditions to the appropriate states according to the application and purpose of the space.

(2) 4 elements of air conditioning

Air conditions can be broadly divided into 4 types, namely temperature, humidity, cleanliness, and airflow. These four conditions are called the four elements of air conditioning, and these four elements are controlled to achieve the appropriate indoor environment.

(3) Types of air conditioning

Air conditioning can be divided into the following two types according to the target purpose.
○Health air conditioning (general air conditioning, comfort air conditioning) ⇒ Air conditioning for humans
○Industrial air conditioning ⇒ Air conditioning for products handled

○Health air conditioning (general air conditioning, comfort air conditioning)

The purpose of the air conditioning is to maintain the health and improve the comfort of the people living in the space.
It covers general households where people live and reside in, offices, commercial facilities, hotels, and other public facilities etc.

Since people have a certain degree of environmental adaptability, the temperature and humidity that they feel comfortable in vary according to the season. In general, the range in the table below is said to be a comfortable temperature and humidity range.

  Temperature Humidity
Summer 25~28℃ 50~60%
Winter 18~22℃ 40~50%

Moreover, the temperature sense of a person also varies depending on the humidity. Air conditioning air that has a lower humidity feels more comfortable in summer even if the temperature is the same. In winter, heated air feels more comfortable when it is humidified to raise the humidity even if the temperature is somewhat lower.
In order to avoid heat shock, controlling the humidity in the room and minimizing the temperature difference between the inside and outside of the room as much as possible is said to be good for health.

Heat shock

If the temperature difference between the inside and outside of the room is large during air conditioning, a burden is imposed on the human body, making it feel uncomfortable. This is known as heat shock, which is classified as a cold shock when the air is cooled and a hot shock when the air is heated. To prevent this, the difference between the outside air temperature and room temperature needs to be kept to 7 to 10 °C (goes up and down due to differences in the air conditioning and air temperature).

○Industrial air conditioning

Air conditioning is used to foster the growth of flora and fauna besides humans, maintain the quality of goods, and improve production efficiency.
The most optimal temperature and humidity conditions vary depending on the type of industry and target, but the difference between industrial air conditioning and healthy air conditioning is that the same temperature and humidity is maintained throughout the year regardless of the season in order to keep the condition of the goods constant.

Example 1) Computer room

As electronic equipment generates heat, air conditioning is required throughout the year. Humidity control is also important, and if the humidity is too high, condensation and short-circuiting may occur. If the humidity is too low, static electricity may be generated, possibly leading to the suspension or damage of electronic devices.

Example 2: Semiconductor manufacturing

In order to prevent staining by dust, it is necessary to maintain a high level of cleanliness. Humidity control is also important to prevent circuit corrosion, condensation on microchip circuit surfaces, and degradation of equipment.

Example 3: Printing plant

Paper contains around 5 to 7% moisture. Humidity control is necessary to prevent paper from stretching, warping, and cracking due to the evaporation of moisture, and also to prevent static electricity which results in paper clogging.


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