Air Conditioning Systems for Different Types of Buildings

AIR CONDITIONING SYSTEMS FOR DIFFERENT TYPES OF BUILDINGS

The choice of which air conditioner system to use depends upon a number of factors including how large the area is to be cooled, the total heat generated inside the enclosed area, etc.

An HVAC designer would consider all the related parameters and suggest the system most suitable for your space.

 

Types of Air Conditioners

There are various types of air conditioners like window air conditioner, split air conditioner, packaged air conditioner and central air conditioning system.

1. Window Air Conditioning System

2. Split Air Conditioner System

3. Central Air Conditioning Plants

4. Packaged Air Conditioners

 

1. Window Air Conditioner

These air conditioners are also known as unitary air conditioning systems. Window air conditioner is the most commonly used air conditioner for single rooms.

In this air conditioner all the components, namely the compressor, condenser, expansion valve or coil, evaporator and cooling coil are enclosed in a single box. This unit is fitted in a slot made in the wall of the room, or more commonly a window sill.

One end of the unit transports heat from indoors to the outside, while the other blows cool air inside the house. The device is very easy to install and can be used in almost any room that has a window. (Fig. 2.18)

Room air conditioners are generally available in capacities varying from about 0.5 Ton to 3 Ton.

 

2. Split Air Conditioner

This is one of the most popular air conditioning systems in the world. It is also known as Ductless Air Conditioning Units

The split air conditioner comprises of two parts:a wall-mounted indoor unit and an exterior component.

The outdoor unit which includes components like the compressor, condenser and expansion valve fitted outside the room.

The indoor unit comprises the evaporator or cooling coil and the cooling fan.

The indoor unit sucks in hot air from the room and cools it before blowing cool air back into the room.

On the other hand, the outdoor unit cools the refrigerant first, before transporting it to the secondary units (air handlers) indoors.

The two units are connected by electrical cables and metal tubes carrying the refrigerant.

There is no need to make any hole in the wall of the room. Further, present day split units have aesthetic appeal and do not take up as much space as a window unit.

A split air conditioner can be used to cool one or two rooms.

Advantages of Split Air conditioner

• Noiseless operation.

• Less vibration.

• No necessity of wall opening.

• Occupies less space in the room.

• Better circulation of air.

• More accessible for maintenance, as condenser, compressor and fan can be located at convenient place.

• Aesthetic quality of unit is high.

Disadvantages of Split Air Conditioner

• High cost of unit.

• Longer refrigerant lines and thus more leakage.

• COP of unit is poor.

• Control over operation is difficult. 

Applications of Split Air Conditioner

These are preferred for offices, schools, auditoriums, etc.

 

3. Packaged Air Conditioner

The window and split air conditioners are usually used for the small air conditioning capacities up to 5 tons. The central air conditioning systems are used for where the cooling loads extend beyond 20 tons.

The packaged air conditioners are used for the cooling capacities in between these two extremes. The packaged air conditioners are available in the fixed rated capacities of 3, 5, 7, 10 and 15 tons. These units are used commonly in places like restaurants, telephone exchanges, homes, small halls, etc.

There are two possible arrangements with the package unit.

In the first one, all the components, namely the compressor, condenser (which can be air cooled or water cooled), expansion valve and evaporator are housed in a single box.

The cooled air is thrown by the high capacity blower, and it flows through the ducts laid through various rooms.

In the second arrangement, the compressor and condenser are housed in one casing.

The compressed gas passes through individual units, comprised of the expansion valve and cooling coil, located in various rooms.

 

4. Central Air Conditioning System

Central air conditioning is used for cooling big buildings, houses, offices, entire hotels, gyms, movie theaters, factories etc.

If the whole building is to be air conditioned, HVAC engineers find that putting individual units in each of the rooms is very expensive making this a better option.

This is a fully ducted system that can either be high velocity or low velocity.

It works by extracting warm air from different parts of the house, cools it at a central location before distributing the cooled air through a series of ducts and vents.

A central air conditioning system is c is comprised of a huge compressor that has the capacity to produce hundreds of tons of air conditioning.

Cooling big halls, malls, huge spaces, galleries etc is usually only feasible with central conditioning units.

 

5. Portable Air Conditioner (localized cooling T requirement)

Portable air conditioners are considered as the next generation of window units. This type of air conditioning unit takes in air from the room and cools it, then directs it back into the room. The e unit then vents any warm air outside by means exhaust hose that is installed in a window. (Fig. 2.24)

Like window air conditioning units, portable conditioners are designed to cool only one room. They are easy to install, versatile and an affordable option.

 

6. Hybrid Air Conditioning System A New Development for Energy Conservation

For the hot and dry climate the evaporative cooling serves the purpose along with energy conservation. On the other hand, the conventional air conditioner renders human comfort in the hot and humid environment. Thus an air conditioning system should provide comfort air conditioning operating as:

(i) evaporative cooling mode during hot-dry climate.

(ii) conventional air conditioning mode during hot-humid climate, in order to conserve energy.

The new system developed for the above purpose has been named as a hybrid air conditioner. A 1.5 ton such unit takes about 1650 W in the air conditioning mode of operation while 300 W in the evaporative cooling mode of operation. The system is shown schematically in fig. 2.25, being self explanatory.

Like hybrid cars, hybrid heat pump systems alternate between burning fossil fuels and using electricity to run.