Building Service Chapter 5

PSMZA Course Note (Chapter 5)
Ver. 1 (MSH-Jun2013): CC608 Building Services 1
5.1 AIR CINDITIONING (A/C) SYSTEM
5.1 The Basic Principle of Air Conditioning
Air conditioning is the process whereby the condition of air, as defined by its temperature
and moisture content, is changed. Note that in practice other factors must also be taken into
account especially cleanliness; odour; velocity & distribution pattern.
5.1.1 Human Comfort
Inevitably 'comfort' is a very subjective
matter. The Engineer aims to ensure 'comfort'
for most people found from statistical surveys.
Most people (90%) are comfortable when the air
temperature is between 18-22°C and the %sat
is between 40-65%. This zone can be shown
on the psychometric chart and is known as the
“comfort zone”.
Outside air is quite likely to be at a different
condition from the required comfort zone
condition. In order to bring its condition to within
the comfort zone we may need to do one or
more of the following:- heat it; cool it;
dehumidify it; humidify it; or mix it.
When people or animals are present in
buildings, ventilation air is necessary to dilute
odours and limit the concentration of carbon
dioxide and airborne pollutants such as dust,
smoke and volatile organic compounds (VOCs).
Ventilation air is often delivered to spaces by mechanical systems which may also heat,
cool, humidify and dehumidify the space. Air movement into buildings can occur due to
uncontrolled infiltration of outside air through the building fabric (see stack effect) or the use of
deliberate natural ventilation strategies. Advanced air filtration and treatment processes such
as scrubbing, can provide ventilation air by cleaning and recirculating a proportion of the air
inside a building.
5.1.2 Types of Ventilation
i. Mechanical or forced ventilation: through an air handling unit or direct injection to a
space by a fan. A local exhaust fan can enhance infiltration or natural ventilation, thus
increasing the ventilation air flow rate.
ii. Natural ventilation occurs: when the air in a space is changed with outdoor air without
the use of mechanical systems, such as a fan. Most often natural ventilation is
assured through operable windows but it can also be achieved through temperature
and pressure differences between spaces. Open windows or vents are not a good
choice for ventilating a basement or other below ground structure. Allowing outside
air into a cooler below ground space will cause problems with humidity and
condensation.
iii. Mixed mode ventilation or hybrid ventilation: utilises both mechanical and natural
ventilation processes. The mechanical and natural components may be used in
conjunction with each other or separately at different times of day. The natural
component, sometimes subject to unpredictable external weather conditions may not
always be adequate to ventilate the desired space.
The mechanical component is then used to increase the overall ventilation rate so
that the desired internal conditions are met. Alternatively the mechanical component
may be used as a control measure to regulate the natural ventilation process, for
example, to restrict the air change rate during periods of high wind speeds.
Figure 5.1: Thermal comfortable zone

iv. Infiltration: is separate from ventilation, but is often used to provide ventilation air.
5.2 The Basic Principle of Air Conditioning System
The principle of this system must be referring to the heat transfer at the two medium. Heat
is a form of energy. Every object on earth has some heat energy. The less heat an object has,
the colder we say it is.
Cooling is the process of transferring heat from one object to another. When an air-
conditioning system cools, it is actually removing heat and transferring it somewhere else.
This can be demonstrated by turning on a spot cooler and placing one hand in front of the
cold air nozzle and the other over the warm air exhaust. You will feel the action of the transfer
of heat. Air conditioning system is a one of mechanical ventilation part. The system by which
air conditioners provide cooling is called the refrigerant cycle.
5.2.1 How Does Air Conditioning Work
As with all air conditioning systems the principle remains the same whereby the heat is
removed from one area and replaced with chilled dry air and the hot air is expelled, normally
to the outside atmosphere. As you can see from this typical example of a air conditioning
system, the ambient air is drawn over the condenser that can best described as a ‘radiator’ as
seen on motor vehicles but instead of water running through the system it contains a
refrigerant gas.
On its journey around the system it has three main stages; the evaporator contains the
sub-cooled refrigerant and air blows through its veins to release the chilled dry air into the
room, the condenser contains the high temperature gas that once again air is blown through
the veins collecting the heat as it passes through and this is then expelled outside.
5.2.2 Basic Operations
An air conditioner is able to cool a building because it removes heat from the indoor air
and transfers it outdoors. A chemical refrigerant in the system absorbs the unwanted heat and
pumps it through a system of piping to the outside coil. The fan, located in the outside unit,
blows outside air over the hot coil, transferring heat from the refrigerant to the outdoor air.
Figure 5.2: Ventilation by ducting

Most air conditioning systems have five mechanical components:
i. A compressor
ii. A condenser
iii. An evaporator coil
iv. Blower
v. A chemical refrigerant
Most central air conditioning units operate by means of a split system. That is, they
consist of a ‘hot’ side, or the condensing unit - including the condensing coil, the compressor
and the fan-which is situated outside your home, and a ‘cold’ side that is located inside your
home. The cold side consists of an expansion valve and a cold coil, and it is usually part of
your furnace or some type of air handler. The furnace blows air through an evaporator coil,
which cools the air. Then this cool air is routed throughout your home by means of a series of
air ducts. A window unit operates on the same principal, the only difference being that both
the hot side and the cold side are located within the same housing unit.
The compressor (which is controlled by the thermostat) is the ‘heart’ of the system. The
compressor acts as the pump, causing the refrigerant to flow through the system. Its job is to
draw in a low-pressure, low-temperature, refrigerant in a gaseous state and by compressing
this gas, raise the pressure and temperature of the refrigerant. This high-pressure, high-
temperature gas then flows to the condenser coil.
The condenser coil is a series of piping with a fan that draws outside air across the coil.
As the refrigerant passes through the condenser coil and the cooler outside air passes across
the coil, the air absorbs heat from the refrigerant which causes the refrigerant to condense
from a gas to a liquid state. The high-pressure, high-temperature liquid then reaches the
expansion valve.
The evaporator coil is a series of piping connected to a furnace or air handler that blows
indoor air across it, causing the coil to absorb heat from the air. The cooled air is then
delivered to the house through ducting. The refrigerant then flows back to the compressor
where the cycle starts over again.
5.2.3 Air Conditioner Filters
The most important maintenance task that will ensure the efficiency of your air conditioner
is to routinely replace or clean its filters. Clogged, dirty filters block normal airflow and reduce
a system’s efficiency significantly. With normal airflow obstructed, air that bypasses the filter
may carry dirt directly into the evaporator coil and impair the coil’s heat-absorbing capacity.
Filters are located somewhere along the return duct’s length. Common filter locations are in
walls, ceilings, furnaces, or in the air conditioner itself.
Some types of filters are reusable; others must be replaced. They are available in a
variety of types and efficiencies. Clean or replace your air conditioning system’s filter or filters
every month or two during the cooling season. Filters may need more frequent attention if the
air conditioner is in constant use, is subjected to dusty conditions, or you have fur-bearing
pets in the house. If you use a disposable type filter, it’s always wise to keep several spares
inside the house.
Below are some commonly used terms in the heating, ventilation and air conditioning
industry. These may be useful when dealing with contractors or assessing a solution to your
problem.
5.2.4 Air Conditioning Cycle
Mechanical refrigeration is accomplished by continuously circulating, evaporating, and
condensing a fixed supply of refrigerant in a closed system. Evaporation occurs at a low
temperature and low pressure while condensation occurs at a high temperature and high
pressure. Thus, it is possible to transfer heat from an area of low temperature (i.e.,
refrigerator cabinet) to an area of high temperature (i.e., kitchen).

Figure 5.3: Air conditioning cycle

Referring to the illustration at figure 5.3.
i. Beginning the cycle at the evaporator inlet (1), the low-pressure liquid expands,
absorbs heat, and evaporates, changing to a low-pressure gas at the evaporator
outlet (2).
ii. The compressor (4) pumps this gas from the evaporator through the accumulator (3),
increases its pressure, and discharges the high-pressure gas to the condenser (5).
iii. The accumulator is designed to protect the compressor by preventing slugs of liquid
refrigerant from passing directly into the compressor. An accumulator should be
included on all systems subjected to varying load conditions or frequent compressor
cycling. In the condenser, heat is removed from the gas, which then condenses and
becomes a high-pressure liquid.
iv. In some systems, this high-pressure liquid drains from the condenser into a liquid
storage or receiver tank (6). On other systems, both the receiver and the liquid line
valve (7) are omitted.
v. A heat exchanger (8) between the liquid line and the suction line is also an optional
item, which may or may not be included in a given system design.
vi. Between the condenser and the evaporator an expansion device (10) is located.
Immediately preceding this device is a liquid line strainer/drier (9), which prevents
plugging of the valve or tube by retaining scale, dirt, and moisture.
vii. The flow of refrigerant into the evaporator is controlled by the pressure differential
across the expansion device or, in the case of a thermal expansion valve, by the
degree of superheat of the suction gas. Thus, the thermal expansion valve shown
requires a sensor bulb located at the evaporator outlet. In any case, the flow of
refrigerant into the evaporator normally increases as the evaporator load increases.
viii. As the high-pressure liquid refrigerant enters the evaporator, it is subjected to a much
lower pressure due to the suction of the compressor and the pressure drop across
the expansion device. Thus, the refrigerant tends to expand and evaporate. In order
to evaporate, the liquid must absorb heat from the air passing over the evaporator.
ix. Eventually, the desired air temperature is reached and the thermostat or cold control
(11) will break the electrical circuit to the compressor motor and stop the compressor.
x. As the temperature of the air through the evaporator rises, the thermostat or cold
control remakes the electrical circuit. The compressor starts, and the cycle continues.
xi. In addition to the accumulator, a compressor crankcase heater (12) is included on
many systems. This heater prevents accumulation of refrigerant in the compressor
crankcase during the non-operating periods and prevents liquid slugging or oil pump
out on start-up.
xii. Additional protection to the compressor and system is afforded by a high- and low-
pressure cut-out (13). This control is set to stop the compressor in the event that the
system pressures rise above or fall below the design operating range.
Other controls not indicated on the basic cycle which may be part of a system include:
evaporator pressure regulators, hot gas bypass regulators, electric solenoid valves, suction
pressure regulators, condenser pressure regulators, low-side or high-side float refrigerant
controllers, oil separators, etc.
It is extremely important to analyze completely every system and understand the intended
function of each component before attempting to determine the cause of a malfunction or
failure.

5.3 Types of Air Conditioning System
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. Commonly home and office were used windows unit,
split unit, cassette unit, tower unit and cube air conditioner.
Figure 5.4: Standard home air condition part

5.3.1 Window Air Conditioner
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.
These types of AC are designed to be fitted in window sills. A single unit of Window Air
Conditioner houses all the necessary components, namely the compressor, condenser,
expansion valve or coil, evaporator and cooling coil enclosed in a single box. Since a window
AC is a single unit, it takes less effort to install as well as for maintenance. The advantages:
i. Single unit air conditioner
ii. Less effort needed for installation
iii. Costs lesser in comparison to other varieties
5.3.2 Split Air Conditioner
The split air conditioner comprises of two parts: the outdoor unit and the indoor unit. The
outdoor unit, fitted outside the room, houses components like the compressor, condenser and
expansion valve.
The indoor unit comprises the evaporator or cooling coil and the cooling fan. For this unit
you don’t have to make any slot 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. The advantages:
i. Internal unit takes up less space for installation
ii. Usually more silent than window ACs
iii. Minimally affect your home décor
iv. Can be installed in room with no windows
Split air conditioners are used for small rooms and halls, usually in places where window
air conditioners cannot be installed. However, these days many people prefer split air
conditioner units even for places where window air conditioners can be fitted.
The split air conditioner takes up a very small space of your room, looks aesthetically cool
and makes very little noise, ensuring sound sleep for you when you return from your day’s
hard work.
Figure 5.5: Window unit type

There are two main parts of the split air conditioner. These are:
i. Outdoor unit
This unit houses important components of the air conditioner like the compressor,
condenser coil and also the expansion coil or capillary tubing. This unit is installed
outside the room or office space which is to be cooled. The compressor is the
maximum noise making part of the air conditioner, and since in the split air
conditioner, it is located outside the room, the major source of noise is eliminated. In
the outdoor unit there is a fan that blows air over the condenser thus cooling the
compressed Freon gas in it. This gas passes through the expansion coil and gets
converted into low pressure, low temperature partial gas and partial liquid Freon fluid.
ii. Indoor unit
It is the indoor unit that produces the cooling effect inside the room or the office. This
is a beautiful looking tall unit usually white in color, though these days a number of
stylish models of the indoor unit are being launched. The indoor unit houses the
evaporator coil or the cooling coil, a long blower and the filter. After passing from the
expansion coil, the chilled freon fluid enters the cooling coil. The blower sucks the
hot, humid and filtered air from the room and it blows it over the cooling coil. As the
air passes over cooling coil its temperature reduces drastically and also loses the
excess moisture. The cool and dry air enters the room and maintains comfortable
conditions of around 25-27 degree celsius as per the requirements.
The temperature inside the space can be maintained by thermostat setting. The
setting should be such that comfortable conditions are maintained inside the room,
and there is also chance for the compressor to trip at regular intervals. If the
compressor keeps running continuously without break, its life will reduce.
These days multi-split air conditioners are also being used commonly. In units for one
outdoor unit there are two indoor units which can be placed in two different rooms or
at two different locations inside a large room.
Since there is long distance between the indoor and the outdoor unit, there is always
loss of some cooling effect; hence for the same tonnage, split air conditioners
produce somewhat less cooling effect than window air conditioners. However, with
modern insulation material this gap has been reducing between the two. In any case,
there are number of instances where there is just no alternative to the split air
conditioners.

5.3.3 Packaged Air Conditioner
An HVAC designer will suggest this type of air conditioner if you want to cool more than
two rooms or a larger space at your home or office. 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.
Figure 5.6: Split unit type

Figure 5.8: Package unit type without cooled condenser
Figure 5.7: Package unit with water cooled condenser

5.3.4 Central Air Conditioner
Central air conditioning is used for cooling big buildings, houses, offices, entire hotels,
gyms, movie theatres, 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. A central air conditioning system is comprised of a huge compressor that has
the capacity to produce hundreds of tons of air conditioning. Cooling big halls, malls, huge
spaces, and galleries is usually only feasible with central conditioning units. See also clause
5.4.
5.4 Principle of the Cooling Substance - Central Air Conditioning Plants
Central air conditioning plants are used for applications like big hotels, large buildings
having multiple floors, hospitals, where very high cooling loads are required. The article
describes various possible arrangements of central air conditioning plants.
The central air conditioning plants or the systems are used when large buildings, hotels,
theatres, airports, shopping malls, are to be air conditioned completely. The window and split
air conditioners are used for single rooms or small office spaces. If the whole building is to be
cooled it is not economically viable to put window or split air conditioner in each and every
room. Further, these small units cannot satisfactorily cool the large halls, auditoriums,
receptions areas etc.
In the central air conditioning systems there is a plant room where large compressor,
condenser, thermostatic expansion valve and the evaporator are kept in the large plant room.
They perform all the functions as usual similar to a typical refrigeration system. However, all
these parts are larger in size and have higher capacities. The compressor is of open
reciprocating type with multiple cylinders and is cooled by the water just like the automobile
engine. The compressor and the condenser are of shell and tube type. While in the small air
conditioning system capillary is used as the expansion valve, in the central air conditioning
systems thermostatic expansion valve is used.
The chilled is passed via the ducts to all the rooms, halls and other spaces that are to be
air conditioned. Thus in all the rooms there is only the duct passing the chilled air and there
are no individual cooling coils, and other parts of the refrigeration system in the rooms. What
is we get in each room is the completely silent and highly effective air conditions system in the
room. Further, the amount of chilled air that is needed in the room can be controlled by the
openings depending on the total heat load inside the room.
The central air conditioning systems are highly sophisticated applications of the air
conditioning systems and many a times they tend to be complicated. It is due to this reason
that there are very few companies in the world that specialize in these systems. In the modern
era of computerization a number of additional electronic utilities have been added to the
central. There are two types of central air conditioning plants or systems:
i. Direct expansion or DX central air conditioning plant
ii. Chilled water central air conditioning plant

5.4.1 Direct Expansion or DX Central Air Conditioning Plant
In this system the huge compressor and the condenser are housed in the plant room,
while the expansion valve and the evaporator or the cooling coil and the air handling unit are
housed in separate room. The cooling coil is fixed in the air handling unit, which also has
large blower housed in it. The blower sucks the hot return air from the room via ducts and
blows it over the cooling coil. The cooled air is then supplied through various ducts and into
the spaces which are to be cooled. This type of system is useful for small buildings.
i. The Plant Room
The plant room comprises of the important parts of the refrigeration system, the
compressor and the condenser. The compressor can be either semi-hermetically
sealed or open type. The semi-hermetically sealed compressors are cooled by the
air, which is blown by the fan, while open type compressor is water cooled. The open
compressor can be driven directly by motor shaft by coupling or by the belt via pulley
arrangement.
The condenser is of shell and tube type and is cooled by the water. The
refrigerant flows along the tube side of the condenser and water along the shell side,
which enables faster cooling of the refrigerant. The water used for cooling the
compressor and the condenser is cooled in the cooling tower kept at the top of the
plant room, though it can be kept at other convenient location also.
ii. The Air Handling Unit (AHU) Room
The refrigerant leaving the condenser in the plant room enters the thermostatic
expansion valve and then the air handling unit, which is kept in the separate room.
The air handling unit is a large box type of unit that comprises of the evaporator or the
cooling coil, air filter and the large blower. After leaving the thermostatic expansion
valve the refrigerant enters the cooling coil where it cools the air that enters the room
to be air conditioned. The evaporator in the air handling unit of the DX central air
conditioning system is of coil type covered with the fins to increasing the heat transfer
efficiency from the refrigerant to the air.
There are two types of ducts connected to the air handling unit: for absorbing the
hot return air from the rooms and for sending the chilled air to the rooms to be air
conditioned. The blower of the air handling unit enables absorbing the hot return air
that has absorbed the heat from the room via the ducts. This air is then passed
through the filters and then over the cooling coil. The blower then passes the chilled
air through ducts to the rooms that are to be air conditioned.
The DX expansion system runs more efficiently at higher loads. Even in case of
the breakdown of the plants, the other plants can be used for the cooling purpose.
The DX types of central air conditioner plants are less popular than the chilled water
type of central conditioning plants.
iii. Air Conditioned Room
This is the space that is to be actually cooled. It can be residential room, room of
the hotel, part of the office or any other suitable application. The ducts from the air
handling room are passed to all the rooms that are to be cooled. The ducts are
connected to the grills or diffusers that supply the chilled air to the room. The air
absorbs the heat and gets heated and it passes through another set of the grill and
into the return air duct that ends into the air handling unit room. This air is then re-
circulated by the air handling unit.
Though the efficiency of the DX plants is higher, the air handling units and the
refrigerant piping cannot be kept at very long distance since there will be lots of drop
in pressure of the refrigerant along the way and there will also be cooling losses.
Further, for the long piping, large amounts of refrigerant will be needed which makes
the system very expensive and also prone to the ma instance problems like the
leakage of the refrigerant.

Due to these reasons the DX type central air conditioning systems are used for
small air conditioning systems of about 5 to 15 tons in small buildings or the number
of rooms on a single floor. If there are large air conditioning loads, then multiple direct
expansion systems can be installed. In such cases, when there is lesser heat load
one of the plants can be shut down and the other can run at full load.
The DX expansion system runs more efficiently at higher loads. Even in case of
the breakdown of the plants, the other plants can be used for the cooling purpose.
The DX types of central air conditioning plants are less popular than the chilled water
type of central conditioning plants.
Figure 5.9: Central air conditioning plant

5.4.2 Chilled Water Central Air Conditioning Plant
This type of system is more useful for large buildings comprising of a number of floors. It
has the plant room where all the important units like the compressor, condenser, throttling
valve and the evaporator are housed. The evaporator is a shell and tube. On the tube side the
Freon fluid passes at extremely low temperature, while on the shell side the brine solution is
passed. After passing through the evaporator, the brine solution gets chilled and is pumped to
the various air handling units installed at different floors of the building.
The air handling units comprise the cooling coil through which the chilled brine flows, and
the blower. The blower sucks hot return air from the room via ducts and blows it over the
cooling coil. The cool air is then supplied to the space to be cooled through the ducts. The
brine solution which has absorbed the room heat comes back to the evaporator, gets chilled
and is again pumped back to the air handling unit.
To operate and maintain central air conditioning systems you need to have good
operators, technicians and engineers. Proper preventative and breakdown maintenance of
these plants is vital.
The chilled water types of central air conditioning plants are installed in the place where
whole large buildings, shopping mall, airport, hotel, comprising of several floors are to be air
conditioned. While in the direct expansion type of central air conditioning plants, refrigerant is
directly used to cool the room air; in the chilled water plants the refrigerant first chills the
water, which in turn chills the room air.
Cooling Tower
Figure 5.10: Chilled Water Central Air Conditioning Plant

In chilled water plants, the ordinary water or brine solution is chilled to very low
temperatures of about 6 to 8 degree Celsius by the refrigeration plant. This chilled water is
pumped to various floors of the building and its different parts. In each of these parts the air
handling units are installed, which comprise of the cooling coil, blower and the ducts. The
chilled water flows through the cooling coil. The blower absorbs return air from the air
conditioned rooms that are to be cooled via the ducts. This air passes over the cooling coil
and gets cooled and is then passed to the air conditioned space.
All the important parts of the chilled water air conditioning plant are shown in the above
figure and described in detail below:
i. Central Air Conditioning Plant Room
The plant room comprises of all the important components of the chilled water air
conditioning plant. These include the compressor, condenser, thermostatic expansion
valve and the evaporator or the chiller. The compressor is of open type and can be
driven by the motor directly or by the belt via pulley arrangement connected to the
motor. It is cooled by the water just like the automotive engine.
The condenser and the evaporator are of shell and tube type. The condenser is
cooled by the water, with water flowing along the shell side and refrigerant along the
tube side.The thermostatic expansion valve is operated automatically by the solenoid
valve.
The evaporator is also called as the chiller, because it chills the water. If the
water flows along the shell side and refrigerant on the tube side, it is called as the dry
expansion type of chiller. If the water flows along tube side and the refrigerant along
the shell side, it is called as the flooded chiller. The water chilled in the chiller is
pumped to various parts of the building that are to be air conditioned. It enters the air
handling unit, cools the air in cooling coil, absorbs the heat and returns back to the
plant room to get chilled again. The amount of water passing into the chiller is
controlled by the flow switch.
In the central air conditioning plant room all the components, the compressor,
condenser, thermostatic expansion valve, and the chiller are assembled in the
structural steel framework making a complete compact refrigeration plant, known as
the chiller package. Piping required to connect these parts is also enclosed in this unit
making a highly compact central air conditioning plant.
The air handling units are installed in the various parts of the building that are to
be air conditioned, in the place called air handling unit rooms. The air handling units
comprise of the cooling coil, air filter, the blower and the supply and return air ducts.
The chilled water flows through the cooling coil. The blower absorbs the return hot air
from the air conditioned space and blows it over the cooling coil thus cooling the air.
This cooled air passes over the air filter and is passed by the supply air ducts into the
space which is to be air conditioned. The air handling unit and the ducts passing
through it are insulated to reduce the loss of the cooling effect.
ii. Air Handling Unit (AHU) Rooms
The air handling units are installed in the various parts of the building that are to
be air conditioned, in the place called air handling unit rooms. The air handling units
comprise of the cooling coil, air filter, the blower and the supply and return air ducts.
The chilled water flows through the cooling coil.
The blower absorbs the return hot air from the air conditioned space and blows it
over the cooling coil thus cooling the air. This cooled air passes over the air filter and
is passed by the supply air ducts into the space which is to be air conditioned. The air
handling unit and the ducts passing through it are insulated to reduce the loss of the
cooling effect.

iii. Air Conditioned Rooms
These are the rooms or spaces that are to be air conditioned. These can be
residential or hotel rooms, halls, shops, offices, complete theater, various parts of the
airport etc. At the top of these rooms the supply and the return air ducts are laid. The
supply air ducts supply the cool air to the room via one set of the diffusers, while the
return air ducts absorbs the hot return air from the room by another set of the
diffusers. The hot return air enters the air handling unit, gets cooled and again enters
the room via supply duct to produce air conditioning effect.
iv. Cooling Tower
The cooling tower is used to cool the water that absorbs heat from the
compressor and the condenser. When water flows through these components some
water gets evaporated, to make up this loss some water is also added in the cooling
tower. The cooling tower is of evaporative type. Here the water is cooled by the
atmospheric air and is re-circulated through the compressor and the condenser.
5.4.3 Comparison of DX and Chilled Water Central Air Conditioning Plants
The Direct Expansion (DX) and Chilled Water central air conditioning plants are both used
at different places depending on the applications and size of the place to be air conditioned.
Both of them have their own advantages and disadvantages.
i. DX Central Air Conditioning Plants Are More Efficient
In the DX type of central air conditioning plants the air used for cooling the room
is directly chilled by the refrigerant in the cooling coil of the air handling unit. Due to
this heat transfer process is more efficient, since there is no middle agency involved
for the heat transfer resulting in higher cooling efficiency.
In case of the chilled water system, the cooling effect from the refrigerant is first
transferred to the chilled water, which is then used to chill the air used for cooling the
room. There is some loss of the cooling effect when it is being transferred from the
refrigerant to the chilled water and from there to the air due to which the chilled water
systems have lesser cooling efficiency. The chilled water acts as the secondary
medium for cooling the room air in air handling unit.
Further, the chilled water has to flow long distance along the whole building. On
its way it tends to get heated due to friction of flow and also due to surrounding heat
absorption. The chilled water also has to be pumped by the pump, which adds more
heat to it. Thus as the chilled water flows from the chiller to the air handling unit and
again back to the chiller, apart from the heat from air, it also absorbs lots of additional
heat, which leads to high increase in its temperature.
The chiller has to remove this additional heat from the water due to which its
efficiency decreases or rather additional power is required to remove this additional
heat. In the DX type of central air conditioning plants the refrigerant travels only
through the small distances and there is no pump involved so the additional heat
absorption is less, which makes the DX plants even more efficient.

ii. The Chilled Water Plants Used For The Large Multi Storey Buildings
In the direct expansion types of the central air conditioning plant, the refrigerant
like R22 flows through the whole air conditioning system including the air handling
unit. When the refrigerant flows in the refrigeration piping there is lots of drop in its
pressure. Due to this the length of the refrigeration tubing and the distance between
the condenser and the air handling unit should be kept minimum possible.
If the air handling unit is kept at the height more than the condenser, the loss in
pressure is pronounced since refrigerant travelling from the condenser to the air
handling unit is in liquid state. As the distance between the air handling unit and the
condenser increases the loss in pressure also increases. At certain point the losses
may be so high that the refrigerant may not be able to reach the air handling unit,
leading to complete failure of the system. At the larger height difference there is also
oil return problem from the refrigerant to the compressor.
Due to these reasons, in direct expansion type of the central air conditioning plant
there is limitation on the distance between the condenser and the air handling unit.
The distance between the two cannot be too high. This limits the application of the
direct expansion type of central air conditioning systems to the small buildings or a
number of rooms on the single floor. In such cases the plant room and air handling
room and the rooms to be cooled are located on the same floor. The height difference
between the condenser and the air handling units has to be quite reasonable so that
they can function well.
One of the solutions to increase the capacity of the DX systems can be to
increase the number of air handling units on upper floors. But with this will be
additional number of joints in the refrigerant tubing from which there will be higher
chances of leakage of highly expensive refrigerant. This leads to too many
operational and maintenance problems.
One may think that we can employ compressor of very high capacity to increase
the refrigerant pressure, but this will lead to highly excessive capital and running
costs of the plant. This is because we will have to install the compressor of capacity
much higher than needed. Thus the direct expansion types of the air conditioning
plants can be used only for smaller buildings or various rooms on the same floor.
There are no pressure loss problems in the chilled water system. In this system
chilled water is pumped by the pump at very high pressure, which is good enough to
carry it to various floors of the multi storey building. The losses in the pressure of
water are accommodated by the sufficient capacity of the pump, which has low
capital and running cost. Further, the water doesn’t carry any oil so there are no oil
return problems.
In case of the chilled water system the compressor, condenser, expansion valve
and the chiller are all kept at the same level in the single plant room. There is no
problem as such of the height difference between the condenser and the air handling
unit since the refrigerant does not travels to the air handling unit. The flow of the
refrigerant is limited to the chiller plant. The water chilled in the chilled flows to the
various air handling units kept on different floors of the building.
The whole arrangement and the structure of the chilled water type of central air
conditioning plant makes it more suitable for cooling the large multi storey buildings
and even for very long distances along the same floor level. This makes the chilled
water central air conditioners more popular than the direct expansion type ones.

5.5 Factors for Choosing Air Conditioning Units
The basic things for a man is food, cloth and house but now the summer seasons are too
long so mostly people require cooling and this requirement is fulfilled by air conditioning units
which are available in market according to need and requirement of people.
To choose best air conditioning unit there are some factors to consider:
i. Energy effectiveness: It means how much energy it takes while in working and this
is the most important thing to consider for consumers they don't afford too much
billing. So take that conditioner which has Energy saving star ratings.
ii. Funds: This is the important thing while purchasing conditioner. That conditioner
which not breaks budget and gives comfortable feel when at home or in office.
iii. Atmosphere: Always want that conditioner that is according to environment. Mostly
portable air conditioning unit use CFC refrigerant but use chooses that one which
filters all the air before entering into room.
iv. Vacant dish: Many people working for a long hours so they always want that
appliance never have to empty. Don't want that appliance which fills your entire home
with water when come back to home after working.
v. Automatic resume: Always buy that conditioner which have automatic restart option
if room is too hot in summer and automatically adjust temperature according need.
vi. Portable unit: If living in a house i.e. on rent than portable conditioning is a great
choice.
If portable air conditioning units were chosen, research needed on the features that are
present in that, it is better to decide which type of air conditioner want because it is the basic
necessity to relief in summer season. The portable air conditioning units are easy to maintain,
clean, portable and can be taken wherever want. Before committing to a solution here are five
important factors to consider when planning air conditioning design:
i. Budget
For those looking to invest in an installation, it's important to get it right first time.
There are plenty of options out there to suit budget, but do research on what to need
first. Running costs should be considered as well as maintenance. And if don't
choose the right one, a replacement can be costly to the business.
ii. Noise
Whatever workplace, it's imperative that staff don't suffer from the unwanted
distraction of a noisy air-con system. While all of them some sort of sound, it needn't
be a problem if have an appropriately sized air conditioner and its location is well
thought-out.
iii. Energy Consumption
By ensuring have a supplier that designs project using CIBSE (Chartered Institution
of Building Services Engineers) recommendations, its equipment capacity will be
correctly calculated to provide with the most energy efficient air conditioning solution.
iv. Practicality
Make sure choose a system that is easy to understand and that you feel comfortable
using. Too many systems aren't used to their full capability because staff too nervous
to press certain buttons due to not knowing what they do.
v. Future expansion
It's vital to consider both current and future company needs when making decision.
They will help design an effective long-term solution that can be added when
business evolves. Commercial air conditioning can be of huge benefit to businesses,
but before embarking on an air conditioning installation should seek the advice of a
reputable supplier who can help make the right decisions about air conditioning
design for organisation.

5.5.1 Air Treatment by Air Conditioner System
The purpose of air retreatment is to adjust the supply air to the comfort needs of individual
rooms or room zones in a building. The overall goal is to optimize energy consumption. This
goal is primarily achieved by providing only as much comfort as necessary, when and where it
is used or requested. For example, there is no point maintaining comfort levels in office or
hotel rooms when they are unoccupied.
The different heat gains in individual rooms or zones require individual adjustment of
heating or cooling output by varying either the temperature or flow volume of the supply air.
How these adjustments are made by control means in common system types is explained in
this chapter. These treatment were:
i. Humidity Control
Refrigeration air-conditioning equipment usually reduces the absolute humidity of the air
processed by the system. The relatively cold (below the dew point) evaporator coil
condenses water vapour from the processed air (much like an ice-cold drink will
condense water on the outside of a glass), sending the water to a drain and removing
water vapour from the cooled space and lowering the relative humidity in the room. Since
humans perspire to provide natural cooling by the evaporation of perspiration from the
skin, drier air (up to a point) improves the comfort provided.
The comfort air conditioner is designed to create a 40% to 60% relative humidity in the
occupied space. A specific type of air conditioner that is used only for dehumidifying is
called a dehumidifier. Uncontrolled moisture indoors can cause major damage to the
building structure, as well as to furnishings and to finish materials like floors, walls, and
ceilings, otherwise can lead to health and performance problems for students and staff.
ii. Temperature Control
Heating, ventilation and air conditioning (HVAC) systems control the temperature,
humidity and quality of air in buildings to a set of chosen conditions. To achieve this, the
systems need to transfer heat and moisture into and out of the air as well as control the
level of air pollutants, either by directly removing them or by diluting them to acceptable
levels. Heating systems increase the temperature in a space to compensate for heat
losses between the internal space and outside. Otherwise an air temperature generally
was controlled by heating and cooling process (as technically means the removal of heat,
in contrast to heating, the addition of heat) the air.
iii. Clean Air
Air-conditioning systems can promote the growth and spread of microorganisms,
however, this is only prevalent in poorly-maintained water cooling towers. As long as the
cooling tower is kept clean (usually by means of a chlorine treatment), these health
hazards can be avoided.
Conversely, air conditioning (including filtration, humidification, cooling and disinfection)
can be used to provide a clean, safe, hypoallergenic atmosphere in hospital operating
rooms and other environments where an appropriate atmosphere is critical to patient
safety and well-being. Air conditioning can have a negative effect on skin, drying it out,
and can also cause dehydration. Air conditioning may have a positive effect on sufferers
of allergies and asthma.
iv. Provide Air Ventilation and Air Movement
Although a typical HVAC system has many controls, the control of outdoor air quantity
that enters the building can have a significant impact on Indoor Air Quality (IAQ), yet
typically is not part of standard practice. Demand controlled ventilation is addressed as a
method of humidity control, but is not otherwise discussed here because its primary use is
to reduce the supply of outdoor air below the recommended minimum for the purposes of
saving energy, not for improving IAQ. Otherwise air motion refers to air velocity and to
where the air distributed. It is controlled by appropriate air distribution equipment.

5.5.2 Differences With In Central and Split Unit Air Conditioning System
No. Item Central Unit Split Unit
1 Layout
2 Component
3 The system
4
Outside
unit
More than 2 package unit: compressor,
condenser, fan
Outdoor unit : compressor, condenser, fan
5 Inside Unit
Cooling coil, Indoor blower, ceiling
diffuser and ducting system used
Indoor unit: evaporator, blower, air filter
6 Space Large area to locates outside unit
Small area need as well as suitable located
outdoor unit
7 Location
Outside unit located on the ground and
inside unit in the roof/ceiling
Outdoor unit located at outside wall or floor
and indoor unit place at a wall or ceiling in the
house
8
Cooling
area
Suitable for large area and more room
to cool at the one time
Suitable for single room and not loo large
area
9
Cost of
placement
More expensive than a split unit type More cheaper than a central unit type
10
Electrical
power
supply
Three phase power supply (415V)
Can be choose one phase (240V) or three
phase (415V) depending a suitable
Table 5.1: Central and split unit comparison

5.6 Effects of Air Conditioning System to the Environment
When examining the environmental impact of air conditioning and heat pump systems. It
has been shown repeatedly that the greatest contribution to global warming comes from the
power it takes to run the system over its useful life.
Compares the contribution of the direct impact of the refrigerant due to leakage to the
impact due to the power the device consumes. The average contribution to the total global
warming due to refrigerant leakage averages 3 to 4%. It also shows the benefit of increasing
the efficiency of the system. A 20% increase in efficiency translates to a 12% decrease in
total warming or more than three times the total direct effect of the refrigerant. In order to
reduce the global warming influence of future air conditioning and heat pump systems
increasing the energy efficiency of these systems will provide the greatest impact.
It was shown that using R-410A would allow for a more cost-effective approach when
designing high efficiency air conditioners and heat pumps. It would reduce the size increase
of heat exchangers needed for high efficiency equipment. Optimized design will also reduce
the required refrigerant charge by 25 to 30% thereby reducing the direct effect as well. Other
leading choices such as hydrocarbons and CO2 make designing higher efficiency equipment
more difficult.
Figure 5.11: No and used air conditioning heating
Figure 5.12: Heating situation

In the case of hydrocarbons, the need for a secondary loop or ether changes in the
system necessary to reduce the risk of a highly flammable refrigerant use materials and there
by cost that could be used to improve the efficiency of non-flammable refrigerant systems.
Improvements are also needed in CO2 systems to make-up for the considerably lower
thermodynamic efficiency of the cycle.
5.6.1 Environmental Impact
i. Energy Use
The electricity generated to power air conditioning carries both global and personal health
consequences. In burning fossil fuels such as coal to supply electricity to homes and
workplaces, power plants discharge clouds of soot and other pollutants into the
atmosphere. Among these are mercury and carbon dioxide (CO2). Air conditioner use in
the U.S. results in an average of about 100 million tons of CO2 emissions from power
plants every year.
ii. Pumping Out HCFCs
Formerly used as cooling agents, ozone-depleting chlorofluorocarbons (CFCs) have been
replaced by hydro-chloro-fluoro-carbons (HCFCs), which deplete 95% less ozone.
However, booming demand for air conditioners in hot climates such as India and China
has upped the chemical's output in developing countries 20 to 35% each year, causing
damage at an alarming rate and possibly setting back ozone recovery by 25 years.
In industrial countries, HCFCs are being replaced with ozone-safe cooling agents and will
be banned in the U.S. by 2010. But HCFCs will be allowed in developing countries
through 2040, and because they're still cheaper to use than ozone-safe chemicals,
production in developing countries is expected to increase fivefold by 2010.
iii. Disposal
Federal law requires that HCFCs be recovered from air conditioners and other appliances
before they are dismantled for recycling or tossed in landfills, and the EPA is authorized
to impose fines of up to $25,000 for failure to comply with regulations. Before discarding
your old unit, search for a company that is EPA-certified to recover HCFCs. Share the Air
has certified companies listed by region.
iv. Raising the Local Temperature
However, turning your air conditioning up also heats up the atmosphere outside in a
much more literal way. The heat doesn’t just magically disappear – instead, that hot air
didn’t want in our home or car is pumped outside, creating a mini heat zone. Add lots of
these together, such as in a city centre, it’s have a full-blown urban heat island on our
hands. This hot air rises quickly and forms small pockets, leading to abnormal weather
patterns directly above the area.
Figure 5.13: Energy illustration

v. Personal Health
In the midst of sweltering heat waves, air conditioning can be a lifesaver, protecting
against heat stroke and hyperthermia. But, without proper maintenance, air conditioners
can also be a health hazard. Dirty filters can allow allergens, pesticides and other
particulate matter to enter your home from the outside, posing threats to indoor air quality.
Exposure to those pollutants can trigger a host of health problems, including allergies and
asthma and eye, nose and throat irritation.
vi. Global Warming
Scientists have spent decades figuring out what is causing global warming. They have
looked at the natural cycles and events that are known to influence climate. But the
amount and pattern of warming that's been measured can't be explained by these factors
alone. The only way to explain the pattern is to include the effect of greenhouse gases
(GHGs) emitted by humans.
One of the first things scientists learned is that there are several greenhouse gases
responsible for warming, and humans emit them in a variety of ways. Most come from the
combustion of fossil fuels in cars, factories and electricity production. The gas responsible
for the most warming is carbon dioxide, also called CO2. Other contributors include
methane released from landfills and agriculture (especially from the digestive systems of
grazing animals), nitrous oxide from fertilizers, gases used for refrigeration and industrial
processes, and the loss of forests that would otherwise store CO2.
Some impacts from increasing temperatures are already happening:
a) Ice is melting worldwide, especially at the Earth’s poles. This includes mountain
glaciers, ice sheets covering West Antarctica and Greenland, and Arctic sea ice.
b) Sea level rise became faster over the last century.
c) Some butterflies, foxes, and alpine plants have moved farther north or to higher,
cooler areas.
d) Precipitation (rain and snowfall) has increased across the globe, on average.
Figure 5.15: Effect of global warming
Figure 5.14: Nature effect

Other effects could happen later this century, if warming continues:
a) Sea levels are expected to rise between 7 and 23 inches (18 and 59 centimeters)
by the end of the century, and continued melting at the poles could add between
4 and 8 inches (10 to 20 centimeters).
b) Hurricanes and other storms are likely to become stronger.
c) Species that depend on one another may become out of sync. For example,
plants could bloom earlier than their pollinating insects become active.
d) Floods and droughts will become more common. Rainfall in Ethiopia, where
droughts are already common, could decline by 10 percent over the next 50
years
5.6.2 Product of Environmental Friendly Air Condition
As climate change becomes an increasingly important
concern, particularly for countries with major
population centers to installing environmentally friendly
air conditioners is vital.
i. Check EER
When selecting an air conditioner, it’s important to
consider its EER, or Energy Efficiency Rating (a
scale of 1-6). Air conditioning products with high
EER ratings are more efficient, and consume less
energy, saving cost.
ii. Evaporative or Ducting
The type of air conditioning chosen will also have an environmental impact. If in a dry
heat climate, installing an evaporative air conditioner rather than a refrigerated or ducted
system is a better environmental choice. However this is not an option in humid areas.
iii. Solar Air Conditioning
Solar air conditioning uses solar cells or photovoltaic panels located on the roof to power
your air conditioner. Because the sun is strongest on the days where need cooling, this is
a great concept. Not only will this reduce power bill, but when using less energy than
what system is producing, the surplus energy will be fed back into the main power grid –
for which a credit will be applied to next power bill.
iv. All Refrigerant Are Not Equal
One concern that environmentalists have about air conditioners is that they contain
refrigerants comprised of chemicals that are said to damage the environment. While
impossible to remove all chemicals from air conditioning units, there are eco-friendly
refrigerant options. If a unit that is less polluting you should look for one with R410a
refrigerant or free CFC pollution.
v. Planning
Good planning is key to completing a successful air conditioning project, starting with
taking expert advice to determine the right type and size of unit is best. If pick a unit that’s
too small, it will have to work harder to cool house, running up power bill and having a
larger impact on the environment. By taking the time to adequately consider the
environmentally friendly air conditioning options available, decision will not only impact
the environment, but money as well.
Figure 5.16: Green air conditioning unit

5.7 Active Learning: How Much You Know About Global Warming

5.7.1 Active Learning: Answers

5.8 Glossary
Air Conditioner
Assembly of equipment for the simultaneous control of air temperature, relative humidity,
purity, and motion.
Air Cooled
Uses a fan to discharge heat from the condenser coil to the outdoors.
Air-Source
Air is being used as the heat source or heat sink for a heat pump.
Ambient Temperature
The temperature, usually of the air, that surrounds operating equipment.
BTU (British Thermal Unit)
The standard of measurement used for measuring the amount of heat required to raise the
temperature of one pound of water by one degree (Fahrenheit).
BTUH
The number of BTUs in an hour
Central Air Conditioner System
System in which air is treated at a central location and carried to and from the rooms by one
or more fans and a system of ducts.
Compressor
The pump that moves the refrigerant from the indoor evaporator to the outdoor condenser
and back to the evaporator again. The compressor is often called ‘the heart of the system’
because it circulates the refrigerant through the loop.
Condenser
A device that transfers unwanted heat out of a refrigeration system to a medium (either air,
water, or a combination of air and water) that absorbs the heat and transfers it to a disposal
point. There are three types of condensers: air-cooled condensers, water-cooled condensers,
and evaporative condensers. The evaporative condenser uses a combination of air and water
as its condensing medium. Most residential systems have an air-cooled condenser.
Condenser Coil
A series or network of tubes filled with refrigerant, normally located outside the home, that
removes heat from the hot, gaseous refrigerant so that the refrigerant becomes liquid again.
Cooling Capacity
A measure of the ability of a unit to remove heat from an enclosed space.
COP
Coefficient of Performance of a heat pump means the ratio of the rate of useful heat output
delivered by the complete heat pump unit (exclusive of supplementary heating) to the
corresponding rate of energy input, in consistent units and under operating conditions.
DOE
The Department of Energy. A government agency that sets industry efficiency standards and
monitors the use of various energy sources.
EER
Energy Efficiency Ratio means the ratio of the cooling capacity of the air conditioner in British
Thermal Units per hour, to the total electrical input in watts under ARI-specified test
conditions.

Enthalpy
Heat content or total heat, including both sensible and latent heat. The amount of heat
contained in a refrigerant at any given temperature with reference to -40°F.
Evaporator
Absorbs heat from the surrounding air or liquid and moves it outside the refrigerated area by
means of a refrigerant. It is also known as a cooling coil, blower coil, chilling unit or indoor
coil.
Evaporator Coil
A series or network of tubes filled with refrigerant located inside the home that take heat and
moisture out of indoor air as liquid refrigerant evaporates.
Free Delivery
There are no ducts and the unit may be installed in the field without ducts if needed.
Ground-Source
The ground or soil below the frost line is being used as the heat source or heat sink for a heat
pump.
Ground Water-Source
Water from an underground well is being used as the heat source or heat sink for a heat
pump.
HVAC
Heating, ventilation, and air conditioning.
Heat Pump
An air conditioner capable of heating by refrigeration. It may or may not include a capability
for cooling. Outside air or water is used as a heat source or heat sink, depending upon
whether the system is heating or cooling.
Heating Capacity
A measure of the ability of a unit to add heat to an enclosed space.
HSPF
Heating Seasonal Performance Factor means the total heating output of a heat pump in
British Thermal Units during its normal usage period for heating divided by the total electrical
energy input in watt-hours during the same period.
Insulation
Any material that slows down the transfer of heat.
(K) Factor
The insulating value of any material. Also known as conductivity.
Kilowatt (kW)
Equal to 1,000 watts.
Kilowatt-hour (kWh)
A common unit of electrical consumption measured by the total energy created by one
kilowatt in one hour.
Latent Heat
The heat energy needed to change the state of a substance (i.e.: from a liquid to a gas) but
not it’s temperature.

Sensible Heat
Heat energy that causes a rise or fall in the temperature of a gas, liquid or solid when added
or removed from that material. Sensible heat changes the temperature by changing the speed
at which the molecules move.
Single Package
A central air conditioner which combines both condenser and air handling capabilities in a
single packaged unit.
Split System
A central air conditioner consisting of two or more major components. The system usually
consists of a compressor-containing unit and condenser, installed outside the building and a
non-compressor -containing air handling unit installed within the building. This is the most
common type of system installed in a home.
Super-cooled Liquid
Liquid refrigerant cooled below its saturation point.
Sub-cooling
Creating a drop in temperature by removing sensible heat from a refrigerant liquid.
Superheated vapor
Refrigerant vapor heated beyond its saturation point.
Superheating
Creating a rise in temperature by adding heat energy to a refrigeration vapor.
Ton
The unit of measurement for air conditioning system capacity. One ton of air conditioning
removes 12,000 Btu’s of heat energy per hour from a home. Central air conditioners are sized
in tons. Residential units usually range from 1 to 5 tons.
Water-Source
Water is being used as the heat source or heat sink for a heat pump. Sources of underground
water are wells and sources of surface water are lakes, large ponds, and rivers.
Watt
A unit of power that equals one joule per second. Named after James Watt.

5.9 References
Books
Egan M David (1986). The Building Fire Safety Concept. University Technology Malaysia,
Skudai.
Fullerton R. L. (1979). Building Construction in Warm Climates. Volume 1, 2, 3. Oxford
University Press, United Kingdom.
Hall F. (2000). Building Services & Equipment. Pearson Limited, England.
MS EN 81-1:2012. Malaysian Standard. Safety Rules for the Construction and Installation of
Lift- Part1: electric Lifts (first revision). Department of Standards Malaysia.
Nor Rizman (2010). Risk Assessment for Demolition Works In Malaysia. Faculy of Civil
Engineering and Earth Resources, Universiti Malaysia Pahang. Undergraduate
thesis.
Prashant A/L Tharmarajan (2007(. The Essential Aspects of Fire Safety Management In Hihg-
Rise Buildings. University Teknologi Malaysia. Degree of master science thesis.
Riger W. Haines, Douglas C. Hittle (2006). Control System for Heating, Ventilating and Air
Conditioning. Springer-Verlag, New York.
Stein, Benjamin, Reynolds, John S., Grondzik, Walter T., and Alison G. Kwok, (2006).
Mechanical and Electrical Equipment for Buildings. 10th ed. Hoboken, New Jersey:
John Wiley and Sons, Inc., 2006.
Tan, C. W. and Hiew, B.K., (2004), “Effective Management of Fire Safety in a High-Rise
Building”, Buletin Ingenieur vol. 204, 12-19.
Journals
N.H. Salleh and A.G. Ahmad. (2009). Fire Safety Management In Heritage Buildings: The
Current Scenario In Malaysia. CIPA Symposium Kyoto Japan. UIAM and USM.
Code of Practices
Approved Code Of Practice For Demolition: Health And Safety In Employment Act 1992.
Issued And Approved By The Minister Of Labour September 1994.
Code of Practice for Lift Works and Escalator Works. (2002 ed).
Code Of Practice For Demolition Of Buildings 2004. Published by the Building Department.
Printed by Taiwan Government Logistics Department.
Code Of Practice For Demolition Of Buildings (2009). Malaysia Standard Supersede Ms 282
Part 1: 1975. Technical Committee For Construction Practices Under The
Supervision Of Construction Industry Development Board, Malaysia.
Demolition Work Code Of Practice (July 2012). Australian Government.
Work Health and Safety (Demolition Work Code of Practice) Approval 2012. Australian
Capital Territory. By Dr Chris Bourke, Minister for Industrial Relations.

Others Publishing
Coby Frampton. Benchmarking World-class maintenance. CMC Charles Brooks Associates,
Inc.
Electrical Installation and Systems (2006). Training Package UEE06. Industry Skills Council,
Australia.
Fire Safety Manual (2002). Florida Atlantic University USA.
Garis panduan Pendawaian Elektrik di bangunan Kediaman (2008). Suruhanjaya Tenaga
Malaysia. Jabatan Keselamatan Elektrik.
Laws of Malaysia. Act 341: Fire Services Act 1988. Publish by The Commissioner Of Law
Revision, Malaysia Under The Authority Of The Revision Of Laws Act 1968 In
Collaboration With Percetakan Nasional Malaysia Bhd 2006.
Operations & Maintenance Best Practices: A Guide to Achieving Operational Efficiency.
(August 2010). Release 3.0.
Principles of Home Inspection: Air Conditioning and Heat Pumps. (2010). Educational Course
Note.
Routine Maintenance Modules. Part II.
Uniform Building By Law 1984. (1996). MDC Legal Advisers: MDC Publishers Printers
Guidelines For Applicants For A Demolition Licence Issued Under The Occupational Safety
And Health Regulations 1996. Occupational Safety And Health Act 198. The
Government of Commerce, Western Autralia.
Websites
http://en.wikipedia.org/wiki/Electricity
http://science.howstuffworks.com/electricity.htm
http://en.wikipedia.org/wiki/Electricity_generation
https://en.wikipedia.org/wiki/Fire_safety
http://www.usfa.fema.gov/citizens/home_fire_prev/
https://en.wikipedia.org/wiki/Maintenance,_repair,_and_operations
http://academia.edu/406774/Demolition_Work_in_Malaysia_The_Safety_Provisions
http://www.mbam.org.my/mbam/doc/news/010-05Oct09-COP%20Demolition%20Works-
corrected%20on%20%2030th%20sept%202009-1.doc
http://en.wikipedia.org/wiki/Demolition
http://www.safeworkaustralia.gov.au/sites/SWA/about/Publications/Documents/700/Demolitio
n%20Work.pdf

https://en.wikipedia.org/wiki/Air_conditioning
http://www.nasa.gov/topics/earth/features/heat-island-sprawl.html
http://www.projectnoah.org/education
http://unfccc.int/files/methods_and_science/other_methodological_issues/interactions_with_o
zone_layer/application/pdf/subgene.pdf
http://www.cibse.org/Docs/barney2.doc
http://en.wikibooks.org/wiki/Building_Services/Vertical_Transportation

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