This lecture notes shows the types of air conditioning systems

1. AIR CONDITIONING SYSTEMS
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WHAT IS AIR CONDITIONING
The American Society of Heating and Refrigerating and Air-
Conditioning Engineers (ASHRAE) defines air conditioning as:
"The process of heating air so as to control simultaneously its
temperature, humidity, cleanliness, and distribution to meet the
requirements of the conditioned space."

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ACTIONS INVOLVE IN AIR CONDITIONING
The important processes involved in air conditioning
include;
Temperature control
 Humidity control
 Air filtering cleaning, and purification
Air movement and circulation.

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REMOTE COMFORT COOLING SYSTEMS

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REMOTE COMFORT COOLING SYSTEMS
These are units controlled from a distance.
Examples are;
Standard split Air conditioners
Chiller Systems
Multizone Ductless Split systems

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REMOTE COMFORT COOLING SYSTEMS
MULTIZONE DUCTLESS SPLIT UNITS

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SELF CONDITIONING UNITS

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SELF CONDITIONING UNITS
This type of units has all the components in single case.
Some types of self conditioning units are:
Room Air conditioners
Packaged Terminal Air Conditioners
Console Air Conditioner
Portable Air conditioner

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ROOM AIR CONDITIONERS
Self Contained Air Conditioning Units

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ROOM AIR CONDITIONERS
Window or through the-wall air conditioners used for room
cooling consist of three basic parts;
A hermetic compressor.
A Condenser
 An evaporator using a capillary tube refrigerant control.

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ROOM AIR CONDITIONERS

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ROOM AIR CONDITIONERS
An adjustable thermostat, mounted on the control Panel,
Provides the necessary control. The thermostat has an On/
Off switch
The compressor and condenser are in the Part of the unit that
protects outside the building. The compressor compartment fan
draws in outdoor air. The fan circulates air over the condenser
and discharges it outside

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ROOM AIR CONDITIONERS
Air flowing through the evaporator (inside the cooled space)
is cooled and, to some extent, dehumidified. Moisture that
collects on the evaporator drains to a drip pan.
In some machines, it flows into a pan in the compressor
compartment. As the moisture evaporates, it helps to cool the
compressor and condenser.

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ROOM AIR CONDITIONERS
ROOM air conditioners are encased assemblies designed primarily
for mounting in a window or through a wall.
They are designed to deliver cool or warm conditioned air to the
room, either without ducts or with very short ducts (up to a
maximum of about 48 in.).

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DESIGN OF ROOM AIR CONDITIONERS

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DESIGN OF ROOM AIR CONDITIONERS
Room air conditioner design is usually based on one or more of the
following criteria, any one of which automatically constrains the
overall system design:
Lowest initial cost
Lowest operating cost (highest efficiency)
Energy-efficiency ratio (EER) and combined energy efficiency ratio
(CEER), or coefficient of performance (COP) and combined
coefficient of performance (CCOP), as legislated by government
Low sound level
Chassis size
Unusual chassis shape (e.g., minimal depth or height)
Amperage limitation (e.g., 7.5 A, 12 A)
Weight

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DESIGN OF ROOM AIR CONDITIONERS
EVAPORATOR AND CONDENSING COILS USED:
These coils are generally tube-and-plate-fin, tube-and-louvered-fin,
tube-and-spine-fin, microchannel-tube-and-flat-folded-fins, or
microchannel-tube-and-louvered-folded-fin.
Design parameters to consider when selecting coils are;
Cooling rate per unit area of coil surface (Btu/h · ft2)
Dry-bulb temperature and moisture content of entering air
Air-side friction loss
Internal refrigerant pressure drop
Coil surface temperature
Airflow
Air velocity
Sensible-to-latent heat factor of coil

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DESIGN OF ROOM AIR CONDITIONERS
REFRIGERANT CONTROL USED
The capillary is the most popular device for room air conditioner
applications because of its low cost and high reliability, even though
its refrigerant control over a wide range of ambient temperatures is
not optimal
Microprocessors monitor and control numerous functions for room
air conditioners.
ELECTRONIC
The two types of motors generally used on room air conditioners are
the low-efficiency, shaded-pole type, and more efficient, permanent
split-capacitor type, which requires using a run capacitor.
FAN MOTOR AND AIR IMPELLER

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DESIGN OF ROOM AIR CONDITIONERS
INSTALLATION OF ROOM AIR CONDITIONERS
Common mounting methods include the following:
Indoor flush mounting. Interior face of conditioner is
approximately flush with inside wall.
Balance mounting. Unit is approximately half inside and half
outside window.
Outdoor flush mounting. Outer face of unit is flush with or
slightly beyond outside wall.
Special mounting. Examples include casement windows,
horizontal sliding windows, and office windows with swinging
units (or swinging windows) to allow window washing, and
transoms over doorways.

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PACKAGED TERMINALAIR CONDITIONERS

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PACKAGED TERMINAL AIR CONDITIONERS
AHRI define a packaged terminal air conditioner (PTAC) as a wall
sleeve and a separate unencased combination of heating and cooling
assemblies intended for mounting through the wall.
A PTAC includes refrigeration components, separable outdoor
louvers, forced ventilation, and heating by hot water, steam, or
electric resistance.

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PACKAGED TERMINAL AIR CONDITIONERS
PTACs are designed primarily for commercial installations to
provide the total heating and cooling functions for a room or zone
and are specifically for through-the-wall installation.
The units are mostly used in relatively small zones on the
perimeter of buildings such as hotels and motels, apartments,
hospitals, nursing homes, and office buildings.

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PACKAGED TERMINAL AIR CONDITIONER

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DESIGN OF PACKAGED TERMINALAIR
CONDITIONERS

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PACKAGED TERMINAL AIR CONDITIONERS
COMPRESSOR:
PTAC units are designed with single-speed compressors, either
reciprocating or rotary. They normally operate on a single-phase
power supply and are available in 208, 230, and 265 V versions.
FAN MOTOR: In some PTACs, a single, double-shafted direct-drive
fan motor drives both the indoor and outdoor air-moving devices. This
motor usually has two speeds, which affect the equipment sound
level, throw of conditioned air,
INDOOR AND OUT DOOR AIR MOVER: The air movers may be
centrifugal blower wheels, mixed-flow blowers, or axial-flow fans.

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PACKAGED TERMINAL AIR CONDITIONERS
HEAT EXCHANGERS: PTACs may use conventional plate-fin heat
exchangers, which have either copper or aluminum tubes.
METERING DEVICE: Most PTACs use a simple capillary as an
expansion device.
CONDENSATE DISPOSAL: Condensate forms on the indoor coil
when cooling. Some PTACs require a drain to be installed to convey
condensate to a disposal point. Other units spray condensate on the
outdoor coil, where it is evaporated and dispersed to the outdoor
ambient air.

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PACKAGED TERMINAL AIR CONDITIONERS
CONTROL: PTAC units usually have a built-in manual mode
selector (cool, heat, fan only, and off) and a manual fan-speed
selector.
A thermostat adjustment is provided with set points (usually subjective,
such as high, normal, and low).

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PACKAGED TERMINAL AIR CONDITIONERS
WALL SLEEVE: A wall sleeve is a required part of a PTAC unit. It
must withstand the potential corrosive effects of other building
materials, such as mortar, and must endure long-term exposure to
the outdoor elements.

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CONSOLE AIR CONDITIONERS

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CONSOLE AIR CONDITIONERS

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PORTABLE AIR CONDITIONERS

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PORTABLE AIR CONDITIONERS

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CENTRAL AIR CONDITIONING SYSTEMS

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CENTRAL AIR CONDITIONERS
There are two types of central air conditioning systems;
Unitary Central Systems
Field Erected Central Systems
Central unitary systems are ideal for residential air conditioning.
They are a complete, manufactured, Package ready for assembly.
All internal wiring and piping has been done.
UNITARY SYSTEMS

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APPLICATION REQUIREMENTS FOR UNITARY SYSTEMS
Single Package
Split system
Unitary equipment may be available as
The split system are usually shipped as a single
package and the tubings wrapped around the
evaporator.
It is usually precharged so care must be taken during
installation

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SPLIT AIR CONDITIONING UNIT

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In field – erected air conditioning systems, all components are
assembled and erected at the spot where the system is to be used.
This includes the motor, compressor, receiver, evaporator, piping
and controls.
FIELD-ERECTED SYSTEMS

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FIELD-ERECTED SYSTEMS

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ROOFTOP UNITS

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ROOFTOP UNITS
These are packaged units installed on roofs of a building.
Can be used in commercial structures…supermarkets,
office buildings, etc.
Types of rooftop Units are;
Heating
Cooling
Both Heating and cooling.

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ROOFTOP UNITS

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