Air-conditioner Types
WINDOW AC is sometimes referred to as room air conditioner or small space air-conditioner. It is the simplest form of air conditioning system generally mounted on windows. It is a single unit that is assembled in a casing where all the components are located.
SPLIT AC The most common residential air-conditioning system is Split type conditioner. It is air conditioning unit made up of two units —
Outside unit- compressor, Condenser.
Inside unit- Evaporator, Expansion Valve.
Inside unit is usually referred to as the “wall hung head unit”. The two units are connected by coil (thin diameter pipes) that carry refrigerant for cooling purpose.
The conditioned air is transferred to the space to be conditioned through ducting which is usually hidden in the ceiling and wall of the building. The unit is placed outside the house, a special room in a building or even on top of a roof. This unit is factory assembled and skilled technicians are needed to install this type of unit.
Protection devices such as High/Low pressure switch, overload relays for all motors, water flow and air flow switches are included in the units. The compressor has winding protection thermostat built into the winding to disconnect the circuit in the event of overheating.
There is an interlocking circuit with the evaporator fan motor starter to ensure that the compressor can only start if the fan motor is running.
Components- This self-contained unit is assembled in a casing where all the air conditioning components are housed. They include:
SPLIT AC The most common residential air-conditioning system is Split type conditioner. It is air conditioning unit made up of two units —
Outside unit- compressor, Condenser.
Inside unit- Evaporator, Expansion Valve.
Inside unit is usually referred to as the “wall hung head unit”. The two units are connected by coil (thin diameter pipes) that carry refrigerant for cooling purpose.
- The Daikin VRV system is a multi-split type air conditioner for commercial buildings that uses variable refrigerant flow control developed by Daikin to provide customers with the ability to maintain the both cooling and heating effect simultaneously at same time. We can maintain heating effect while cooling the area by using VRV system is possible by heat absorbed by cooling conditioned space. That’s why split AC is more efficient for both effected by consuming lesser energy.
- Variable refrigerant flow (VRF) is an HVAC technology invented in India by Blue Star Company in 1982. Like ductless mini-split VRVs use refrigerant as the cooling and heating medium. It is a copy paste technology of VRV system invented by Japan.
- A difference between the VRV and VRF is that VRV system is connected in Parallel manner and VRF is connected in Series manner.
The conditioned air is transferred to the space to be conditioned through ducting which is usually hidden in the ceiling and wall of the building. The unit is placed outside the house, a special room in a building or even on top of a roof. This unit is factory assembled and skilled technicians are needed to install this type of unit.
Protection devices such as High/Low pressure switch, overload relays for all motors, water flow and air flow switches are included in the units. The compressor has winding protection thermostat built into the winding to disconnect the circuit in the event of overheating.
There is an interlocking circuit with the evaporator fan motor starter to ensure that the compressor can only start if the fan motor is running.
Components- This self-contained unit is assembled in a casing where all the air conditioning components are housed. They include:
- Compressor usually hermetic or semi-hermetic type for operation on 380/400 Volts 3 Phase is used.
- Water-cooled or Air-cooled condenser.
- Electrical Panel.
- Thermostatic Expansion Valve.
- Air Filter.
- Front Panel & Return Air Grill.
- Evaporator Coil.
- Evaporator Fan and Housing.
- Heating and Humidifying Components may be included in the unit. De-humidification is needed for cooling mode during summer and Humidification for heating mode during winter.
- The condenser used in a package air conditioner can be air-cooled or water-cooled type. Air-cooled type is usually for capacity below 5 tonne and water-cooled for capacity above 5 tonne. The capacity of air-cooled type is lower than that of water-cooled condenser using the same compressor.
- The water-cooled type can be completely factory assembled, tested and charged with refrigerant before being installed in the field. This is advantages because less man power is needed in the field to do the installation hence cost saving.
- The air-cooled type cannot be factory assembled or charged as the laying of refrigerant piping, pressure testing, charging and evacuation have to be carried out in the field.
- In the air distribution, centrifugal fans are usually provided at the evaporator side which can develop higher static pressure. The higher the static pressure, the better the air throw to the room is. Air distribution is done through ducts and grills. The air quantities are usually in the range of 10-11.3 cubic meter/min (350-400 cfm) per tonne.
- In critical application such as computer room which need higher rate of air flow, higher capacity fans with air flow up to 550 cfm are provided. This usually needs to be factored in during the design of the system.
- In some units, two independent refrigeration systems are included in the package. In this case, the cooling coils have a common tube sheets though the two systems are independent. The tubes of the coil are entwined.
- Two separate water-cooled condensers or a condenser with an internal partition that forms two independent condensers are used. The water side is common to both the independent condenser portions.
- It is a common practice to have one compressor running all the time with the other compressor control by a single-stage thermostat. In this case, the capacity can be controlled either to 50% or 100%. However, newer units have two-stage thermostat that can control the capacity from 0%, 50% or 100%.