DEPARTMENT OF ESTATE MANAGEMENTFACULTY OF ARCHITECTURE, PLANNING AND SURVEYING,

UNIVERSITI TEKNOLOGI MARA, PERAK 

GROUP ASSIGNMENTDIPLOMA IN ESTATE MANAGEMENT

EMT 257 BUILDING SERVICES & EQUIPMENT

TITLE: CENTRAL AIR CONDITIONING SYSTEM

PREPARED FOR: MISS NUR ILYANA BAZLIN BINTI MD NOR

NAME MATRIC NO.NUR HIDAYAH ADILAH BINTI

MALEK2011641458

NURUL ATIQAH BT MAHADI 2011260236NOR AIN BT MOHD MUSTAFA

KAMAL2011297788

FATEN ATHIRAH BT OTHMAN 2011289296MUHAMMAD FAISAL B

NGATIMIN2011296496

DEFINITION OF AIR-CONDITIONING

Process of altering the properties of air mainly of two things which are temperature and humidity to more favorable conditions

Process of altering the properties of air mainly of two things which are temperature and humidity to more favorable conditions

TYPES OF AIR-CONDITIONING SYSTEM

CENTRAL AC SYSTEM

Split-system

An outdoor metal cabinet contains the condenser and compressor, and an

indoor cabinet contains the evaporator

Packaged Unit

The evaporator, condenser, and compressor are all located in one cabinet, which usually is placed

on a roof or on the ground

PORTABLE AC SYSTEM

Consists of a mobile self-contained air conditioning unit that is placed on the floor inside a room and discharges exhaust heat using a hose vent through an exterior wall

A bit noisier

ROOM AC SYSTEM

Also known as window or wall

units. When cooling a single room or small

space

Inexpensive and

easy to install

Noisier, physical

appearance that is

unattractive, lower efficiency and poor constant

temperatures

DUCTLESS AC SYSTEMalso known as a mini split system

perfect where there is no overhead attic or crawl space

Consists of the

following components

such as indoor air handling

unit, outdoor

condensing

unit and remote controller

CASE STUDY

DEFINITION OF CENTRAL AC SYSTEM

The central air – conditioning system is suitable for a large building which is required a very high air cooling such as cinema, hotel, hospital, supermarket and etc. This system is commonly use in a new building.

DEFINITION OF CENTRAL AIR-CONDITIONING SYSTEM

A method of structural cooling in which a

centralized unit cools and dehumidifies air before circulating it throughout

the building

The main unit is located outdoors or in isolated area of a

building

Method of cooling

To cool down the hot and high pressure refrigerant gas that travels from compressor to condenser.

It provides ease during the condensation which occurs in the condenser where refrigerant gas changes into liquid form.

Water Cooling MethodWater from cooling tower

is used to remove heat

Cooling tower functions to cool down the hot water

that flows from the condensed water return

pipe (CWR)

Italso supplies cooled water to condenser through

condensed water supply pipe.

The process of heat extraction in cooling tower

is known as evaporation process whereby the water is cooled by a fan and the

heat will evaporate into air to cool the water

There is a ball float inside the cooling tower to ensure

the water is at specified level

COMPONENTS

COMPRESSOR A pump or other machine that increases the pressure of a

gas. Three basics types of compressor:i. Reciprocatingii. Rotary screwiii. Rotary centrifugal Types of compressor are specified by the number of

compression stage, a cooling method, lubrication and packaged or custom built

AIR HANDLING UNIT ROOM Also known as AHU Shaped like box that content equipment with

a blower, condenser, compressor and expansion valve

A function is to suck air from the rooms and let it pass through air filters then discharging the cooled air back to the rooms.

Located at the top of building and the door of room is always closed

Removable panels are installed with reason a personnel can enter for maintenance

RETURN AIR INLETS This component is to regulate and

extract air from a room and recycle it Use of any ventilating, heating and air

conditioning The air will force air process which blows

through the duct Located either in hallway or in the ceiling

at AHU Rooms

COOL AIR DISPENSER A place that a cooled air passes over the

air filter and is through by the supply air ducts into the space which to be air conditioned

Located at the top of ceiling and it will come in several types

TYPE OF GAS THAT USED AS REFRIGERANT

Chlorodifluoromethane also known hydrochlorofluorocarbon (HCFC)

Usually known as R22 gas Very high quality and competitive price

Condenser Condenser is a component which acts as

a heat exchanger that is being used in air-conditioning system.

The purpose of condenser is to change the hot gas that is released by the compressor to liquid form

Types of condenser;Air-cooled condenser

Water-cooled

condenser

Evaporative

condenser

Case study: Water-cooled condenser

It uses water from the cooling tower to remove the heat from the high temperature gas in the compressor.

The capacity of water-cooled condenser depends on;1. the temperature from the water2. the amount of water circulated 3. temperature of the gas. The capacity increases with the temperature

difference between gas and water. There are two pipes of condenser which are

Condensed Water Return (CWR) and Condensed Water Supply (CWS).

Cross-section of water-cooled condenser

The condenser in Air Handling Unit Room

Cooling method in condenser

Water that flows in the condensed water

supply (CWS) pipe will enter condenser

The water is used to absorb heat from the

hot compressed refrigerant gas that

flows from compressor

Once the heat is absorbed, the cooled water will turn into hot water as it has

absorbed heat

It will flow back through condensed water return (CWR) pipe and enter cooling tower for the

process of cooling

Cooling tower at Dewan Seri Iskandar

PROCESSCooling tower and

AHU controller buttons are switched on.

Water tank supply water to cooling

tower.

Cooling tower cooler and filter the water

before it enters condenser.

In AHU, compressor compress the refrigerant

used; R22 gas causes it to turn into hot and highly

pressured gas.

The gaseous travel into condenser and cold water

used to cool the hot gaseous. Condensation process occur

here.

Refrigerant turns into highly pressured

liquid and enters TXV.

TXV controls the flows of the refrigerant which causes it to

reduce pressure. When pressure reduced, refrigerant expand and

its temperature drops

Refrigerant enters evaporator coil. Lower pressure in

evaporator causes refrigerant to evaporate. It absorbs heat and

turns cold gaseous.

COMMON PROBLEMS

Bad odour

Faulty wiring

Leaky ducts and low airflow

Low refrigerant

MAINTENANCERefrigerant

gas

Clean the filter at the air –

conditioning system

Electric controlBelting

Cleaning

ADVANTAGES

Improves indoor air

quality

Level of indoor noise is almost

negligible

Maintains a constant temperature and

humidity throughout the conditioned space

DISADVANTAGES

The size for the AC unit

The cost of installing the

system

THANK YOU