Air-conditioning systems
Air Conditioning Installations
Air conditioning installation is dependent on many elements including use of space, size of facility and climate. In a new construction there is suffic-ient flexibility in selecting which system to be used. However, this is not the case in a renova-tion project where architectural limitations (aesth-etics, space issue, etc.) can turn the selection of the air conditioning system into a challenging process. The main air conditioning systems are:
1. Split DX Installation
A Split DX (Direct Expansion) installation normally is for a single room. The system consists of two separate units: air handler and evaporator coil located inside and the compressor and condenser outside. They basically move heat from inside the space to outside (cooling mode) or from outside to inside (heating mode) by reversing their refrigerant cycle. The inside and outside unit can not be far apart.

2. Packaged Rooftop Installation - The evaporator, condenser, and compressor are all located in one cabinet, which usually is placed on a roof or on a concrete slab next to the building's foundation. This type of air conditioner is used in small commercial buildings. Air supply and return ducts come from indoors through the building's exterior wall or roof to connect with the packaged air conditioner.
3. VRV "Variable Refrigerant Volume" - The system consists of a number of air handling units connected to a modular external condensing unit. The refrigerant flow is varied using either an inverter controlled variable speed compressor, or multiple compressors of varying capacity in response to changes in the cooling or heating requirement within the air conditioned space.The volume or flow rate of refrigerant is accurately matched to the required heating or cooling loads thereby saving energy and providing more accurate control. Mainly are used in mid to large applications.
4. Central Chilled Water Air Conditioning - An air cooled (outside stored) or water cooled (inside stored) chiller cools water down to between 4 °C and 7 °C which is then piped throughout the building and connected to air handlers, fan coils, CAV (Constant Air Volume) and VAV (Variable Air Volume) boxes. No particular limit in the length of pipes if they are well insulated.
5. VAV (Variable Air Volume) - The space conditions are met by varying the volume of the air introduced in the space, rather than the temperature. After the air is cooled in the air handlers it passes with the use of ductwork through the VAV reheating coil for final adjustment. The system allows multiple zones where one zone can be heated and the adjusted to be cooled. Suitable for large applications.
6. Closed Control - used mainly in computer rooms, telecom rooms where precision in the temperature and the relative humidity are required. The air is introduced through a pseudofloor (upward) or a pseudoceiling (downward) after is being cooled by the inside unit.