A/C EQUIPMENT

What is air-conditioning system?

“Air-conditioning” is generally perceived as making air cooler. But its true meaning covers temperature control inside the room where air-conditioning is involved. Temperature control is enabled through cooling coil and refrigerant to keep comfortable temperatures for people in the room. Air-conditioning also involves control of relative humidity, ventilation of dirty air, circulation of clean air, and air purification.

How air chiller system differs from home air-conditioner

Home air-conditioners work in the same way as an air chiller system for large buildings. But the difference is that in an air-conditioner, refrigerant runs through the cooling coil to generate cool air. In an air chiller system, refrigerant is used to chill water and the chilled water is then sent through the air handling unit (AHU) to produce cool air in chosen parts of the building. The selection of air-conditioning system for a building, office or home depends largely on the size of area that requires cooling.

Types of air-conditioning

Here are the currently popular air-conditioning systems:

Direct Expansion System, with 1-25 tons of refrigeration
- Mainly used at home, residential condominium, and small office
Packaged Unit, with built-in compressor, condenser, cooling coil, and fan unit
- Cooling with air (15 - 30 tons of refrigeration)
- Cooling with water (15 - 45 tons of refrigeration)
- Mainly used in office condominiums, with centralized cooling tower and heat pump. Each condominium has its own unit, and the tenant is responsible for its electricity bill.
- Commonly used in office condominium which can separate owners for each unit. Juristic person will provide cooling tower and pump to reduce heat from Packaged Unit. The electric bill will be separated.
Chilled water system
- Air-cooled chiller (40-200 tons of refrigeration)
- Water-cooled chiller (100-1,500 tons of refrigeration)
- Mainly used in large buildings like hotel, shopping mall or office establishment where the property owners are responsible for the electricity cost
- Commonly used with the owners who want to pay the electric bills by themselves such as hotels, departments stores, offices

How air-conditioning system distributes cooled air

There are two systems of cooled air distribution in an air-conditioning system.

System with no air duct for air circulation: This system uses split-type air-conditioner for specific areas. Air from the covered areas is drawn by fan through the cooling coil before being released back to the air-conditioned room. Air ventilation is done by exhaust fan that draws air out of the room while fresh air enters the room through openings, such as ventilation blocks, window frames, or door gaps.
System with air duct for air circulation: This system is mainly used in a large air-conditioning system. Air from areas that require air-conditioning is drawn by fan into the cooling coil through air duct. During the air circulation, fresh air from outside the room is brought in to improve the air quality before being sent to the air-conditioned area.