Reverse Cycle Air-Conditioning

Definition/Functional Detail

Air-conditioners (also termed as “heat pumps”) condition the air of the area to a comfortable temperature level.

An air-conditioning system which can provides heat in winters and cooling in summers is termed as “Reverse Cycle Air-conditioning System”. A reverse cycle heating system has a built-in valve, which reverses the direction of flow of refrigerant where the compressor would change its function to a condenser (evaporator) while the condenser turning into a compressor.

Efficiency in comparison with “Element-Heater” System

An air-conditioner with a Reverse Cycle Air-conditioning capability is far more efficient as compared to a direct element heating system (Resistive Electric type) which would provide about one unit of heat for a unit of electricity, whereas, a Reverse Cycle Air-conditioning system can provide more than two units of heat for a unit of power, resulting in savings in power bills.

Types of Air-Conditioners

There are various types of air-conditioners. Depending on the size or area of the room or building, a suitable type of system should be selected.

Window Type

This type is cheaper in cost. However, it is used only on the external walls of a room. It has the compressor, condenser and fans located into a single unit. Due to the compressor being located in the same unit, the Window type air-conditioners are noisier than the other types.

Split Type

This type is termed as “split type” because it comprises of two separate units, compressor (located normally on the roof or outer wall of the room or building), and the condenser installed inside the room which has to be heated or cooled. The two units are connected together by copper pipes carrying the refrigerant. The connecting pipes have to be properly insulated to avoid loss of heat and cooling. Split type air-conditioners are suitable for a room which is located inside a building, having no access to external atmosphere. This type is more expensive than the Window type systems. Split type air-conditioners are quieter than the Window type as the compressor is located away from the area to be air-conditioned.

Central Type

Central air-conditioning systems are used where many rooms, a part of a big building or the whole of a building has to be air-conditioned. This system is comprised of a Reverse Cycle Air-conditioning plant which is installed in a specified space in the building (sometimes on the roof of the building). Conditioned air (hot or cool) is supplied to the rooms through a system of ducts installed in each room. The ducts between the air-conditioning plant and the area to be served must be properly insulated to avoid losses of heat (and cooling). Due to the larger size, the central type of air-conditioning systems are more expensive in original cost as well as in running, as they need more electrical power.

Portable Type

This type of air-conditioner is used where different rooms in a building are to heated or cooled at different times of the day and the night hence allowing economy in cost of equipment. A Portable air-conditioner has an air pipe attached to it to allow exhaust of “used” air out of the room. They are normally more expensive than the Window type of a comparative capacity.

Capacity/Size of Air-conditioning Systems

Capacity of an air-conditioner is measured normally in Tons (B.T.U.’s) or KWH’s (which represents the power consumption of the compressor motor, starting from one-half ton to many tons (depending on the area under service).

Inverter Technology

This is a new technology introduced for air-conditioning systems where the compressor has the capability of running at variable speeds depending on the requirement of the environment to be conditioned. This results in sizable savings in power bills and reduction in running cost.

Power Requirement

The air-conditioner should be provided electric power from a proper source. A domestic single-phase wall socket can provide electric power to a small unit, while a larger unit would require a dedicated power line having more capacity (Amperes) and a Central Air-conditioning system may run on a three-phase high capacity power line.