E-PORTFOLIO LENGKESHINY

JABATAN TENAG

KEMENTERIAN SUM

THANK

GA MANUSIA

MBER MANUSIA

K YOU

www.jtm.gov.my

JABATAN TENAG

KEMENTERIAN SUM

GA MANUSIA

MBER MANUSIA

Diploma Teknologi
Penyejukbekuan dan Penyamanan

Udara (L05)

L05-34-31
HVACR Architecture Drawing

and Cooling Load

INSTRUCTOR : SHARIFFAH SYAHIDAH BINTI S AMIR

www.jtm.gov.my

JABATAN TENAGA MANUSIA

Latihan m
data men

Psychro
Ch

memplot
nggunakan
ometric
hart

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JABATAN TENAGA MANUSIA Contoh 1

Tentukan data berikut pada ke
kering 22°C dan suhu bebuli b

Relative humidity 17.5
0.852
81
13.2

PSYCHOMETRIC CHAR

eadaan udara bersuhu bebuli
basah 19°C

54

2
%
g

RT

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JABATAN TENAGA MANUSIA Contoh 1

Tentukan data berikut pada ke
kering 22°C dan suhu bebuli b

Relative humidity

PSYCHOMETRIC CHAR

eadaan udara bersuhu bebuli
basah 19°C

%

RT

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JABATAN TENAGA MANUSIA Latihan 1

Tentukan data berikut pada ke
bebuli kering 20°C dan relative

eadaan udara bersuhu
e humidity 50%

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JABATAN TENAGA MANUSIA Latihan 2

Tentukan data berikut pada ke
dew point 25°C dan relative hu

Dry bulb temperature

eadaan udara bersuhu
umidity 70%

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JABATAN TENAGA MANUSIA Contoh 2

Berapakah perbezaan entalpi
dipanaskan dari suhu bebuli k
nisbah kelembapan bagi kedu

PSYCHOMETRIC CHART

yang terhasil bagi udara yang
kering 19°C ke 30°C . Jumlah
ua-dua keadaan adalah 10 g/kg

T

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JABATAN TENAGA MANUSIA Contoh 1

Tentukan data berikut pada ke
kering 22°C dan suhu bebuli b

Relative humidity

PSYCHOMETRIC CHAR

eadaan udara bersuhu bebuli
basah 19°C

% H1 = 56 kJ/kg
H2 = 44 kJ/kg
RT
H1 – H2
= 56 – 44
= 12 kJ/kg

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JABATAN TENAGA MANUSIA Latihan 3

Berapakah perbezaan entalpi
dipanaskan dari suhu bebuli k
nisbah kelembapan bagi kedu

yang terhasil bagi udara yang
kering 14°C ke 25°C . Jumlah
ua-dua keadaan adalah 5 g/kg

Be Inspired, Be Extraordinary, Be World Class with TVET

JABATAN TENAGA MANUSIA Latihan 4

Berapakah perbezaan entalpi
disejukkan dari suhu bebuli ke
nisbah kelembapan bagi kedu

yang terhasil bagi udara yang
ering 34°C ke 20°C . Jumlah
ua-dua keadaan adalah 12 g/kg

Be Inspired, Be Extraordinary, Be World Class with TVET

JABATAN TENAG

KEMENTERIAN SUM

THANK

GA MANUSIA

MBER MANUSIA

K YOU

www.jtm.gov.my



• TEPU (SATURATED)
• MASS
• HUMIDITY
• WATER VAPOUR



APAKAH PE
ANTA

HUMIDITY R
RELATIVE H

ERBEZAAN
TARA
RATIO DAN

HUMIDITY?

























UNIVERSITY OF HONG KONG
Faculty of Engineering

M.Sc.(Eng) in Building Services Engineering
MEBS 6013 Testing & Commissioning

CHILLER START UP PROCEDURES

A) Inspection prior to start up

1) Check for general cleanliness. Check that all pipings are free of visible signs of leakage.
Inspect all metal components for corrosion and if needed wire brush to clean and paint
with anti-corrosion paint.

2) Check that pressure and temperature gauges (and flow meter if any) are properly
installed.

3) Check that inlet strainers to evaporator (and water cooled condenser) are fitted by the
installation contractor and are of the right mesh size. This is particularly important if
plate heat exchangers are used as evaporator.

4) Water circuit properly flushed and purged.
5) Check that external water pumps are operational and flow switches function properly.
6) Make sure that differential pressure bypass supplied by the control supplier is

operational.
7) For air-cooled condenser, inspect for cleanliness, brush clean as needed. Make sure

there is no short circuiting. Whenever there is distribution ductwork associated with air
cooled condensers, inspect regulating devices and visual check for air tightness.
8) Lubricate motor bearings as needed.
9) Check tightness of bearing locking collars, if any. This is very important for fan motors
of the air cooled condensers – experience has shown that these motors can easily burnt
out due to water seepage through the bearing collars.

10) Check for loose wiring termination.
11) Ensure that unit is properly supported on anti-vibration mounting.

K.F. Chan (Mr.) Page 1 of 9
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UNIVERSITY OF HONG KONG
Faculty of Engineering

M.Sc.(Eng) in Building Services Engineering
MEBS 6013 Testing & Commissioning

B) Electrical check
1). Verify continuity of all conductors
2). Inspect the windings of all motors. Input 10 to 20V AC low voltage power supply to the

motor windings or suspend a heater near the motor casing to drive out moisture inside, if
needed.
3). Rotate the motor shaft, whenever possible, to make sure that the motor runs smoothly.
Grease if necessary.
4). Tightly fix those junctions that can be loosened easily, e.g. socket of the junction box etc.
5). Make sure that the power is disconnected. Then measure the voltage of the power supply.
Make sure that it is equal to the normal rating before closing the main switch.
6). Before connecting the power to the equipment and control circuit, measure the resistance
across ay one of the phase conductors and the earth by a meggar tester and make sure that
there is no short circuit. Minimum resistance between any phase and phase to earth should

not be less than 1M . Then switch on the power supply.
7). Check that the oil heater is working properly. The heater should be operated for at least 4

hours to 1 day before starting up corresponding compressor.
8). Check that all protection devices are able to function.

C) Strength and leakage test

Carry out pressure test as follows:
1). Major components must have been strength tested. Strength tests are typically done in the

factory prior to delivery rather than on site. Every part of the system must then be leak
tested on site according to the following diagram.

For air-cooled R22 systems, values are typically:-

high pressure side: 1.1 x 18.5 = 20.3 Bar

low pressure side: 1.1 x 10.9 = 12 Bar

water side: 1.1 x 10 = 11 Bar

For air-cooled R134a systems, the values will typically be:-

high pressure side: 1.1 x 12.2 = 13.4 Bar

low pressure side: 1.1 x 7.9 = 8.7 Bar

K.F. Chan (Mr.) Page 2 of 9
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UNIVERSITY OF HONG KONG
Faculty of Engineering

M.Sc.(Eng) in Building Services Engineering
MEBS 6013 Testing & Commissioning

(Adopted from “Safety Code for Refrigerating Systems utilizing chlorofluorocarbons Part II – Commissioning,
Inspection and Maintenance”, The Institute of Refrigeration.

For minimum reference temperatures to establish design pressure and minimum design and test pressures, please

refer to Table B1 and B2 respectively of the this InstR Code)

K.F. Chan (Mr.) Page 3 of 9
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UNIVERSITY OF HONG KONG
Faculty of Engineering

M.Sc.(Eng) in Building Services Engineering
MEBS 6013 Testing & Commissioning

2). Where test pressures exceed the allowable pressures on items such as pressure relief
valves or pressure controls, remove or isolate these components.

3). Check that all valves and components are properly opened or closed as required to
ensure that no section of the system is inadvertently isolated. All manual valves except
those open to atmosphere must be opened and all control valves, such as solenoids,
should be jacked open or electrically energized (if normally closed) In certain cases,
compressors should be isolated during the pressure test (e.g. open compressor)

4). Connect a cylinder of dry nitrogen to the refrigeration system.
5). With the cylinder in upright position, admit dry nitrogen slowly (to avoid shock) until

the desired test pressure is obtained.
6). Isolate and disconnect charging apparatus leaving system at test pressure.
7). Check the entire system for leakage using soap solution bubble test especially at valves

and piping connections. In the event of a leak being detected, pressure must be relieved
before any repair is attempted.
8). When the system is rendered leak-free, allow it to stand for 24 hours. The system
pressure shall not have appreciable drop. Record the gauge pressures and ambient air
temperatures at the beginning and end of this period.
9). If there is a significant change in ambient temperature which cause a drop in system
pressure, the actual loss in pressure shall be compensated by the formula:

where
P1, P2 are initial and final system pressure, gauge
t1 and t2 are initial and final ambient temperatures, oC
Pa is the barometric pressure

10). On satisfactory completion of pressure test, relieve the system pressure. Purge gas
through the circuit.

11). If necessary, charge the circuit to 7 Bar and purge to remove any free contaminants
again.

12). Install filter dryers and carry out evacuation and dehydration.

Note :
Use of compressed air for pressure testing is not recommended unless the compressed air is
dehydrated to –20°C dew pint or below.

K.F. Chan (Mr.) Page 4 of 9
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UNIVERSITY OF HONG KONG
Faculty of Engineering

M.Sc.(Eng) in Building Services Engineering
MEBS 6013 Testing & Commissioning

D) Vacuum test / evacuation and dehydration

Strength and leak test must have been satisfactorily completed before commencing
vacuum test.

Carry out the vacuum test as follows:-
1). Pressure switches may be valved off or disconnected since some switches may not have

vacuum protection. All manual valves except those open to atmosphere must be opened
and all control valves, such as solenoids, should be jacked open or electrically energized
(if normally closed)
2). All seals and other components requiring an oil charge for sealing should be charged with
specified oil and any rotating devices should be rotated by hand to assure distribution of
this seal oil to sealing surfaces. Never start the compressor under vacuum.
3). Connect suitably sized vacuum pumps and vacuum gauges to appropriately located valves
in the refrigeration system.
4). Start the vacuum pump and evacuate until the vacuum reaches 1000 microns. Initial
evacuation should be rather rapid but if free water is present the process will become slow
as evaporation of water takes place. Occasionally open the valve to the vacuum gauge to
check system pressure during evacuation.

(Adopted from CIBSE Commissioning Code R: 1991)

1000 microns corresponds to the vapour pressure of water at -17oC. It is recommended
that evacuation is done when ambient temperature is not lower than 19oC. For lower
ambient temperature, the vacuum pressure must be lowered accordingly.

K.F. Chan (Mr.) Page 5 of 9
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UNIVERSITY OF HONG KONG
Faculty of Engineering

M.Sc.(Eng) in Building Services Engineering
MEBS 6013 Testing & Commissioning

5). Record the vacuum reading. Isolate the vacuum pump and the vacuum gauge from the
system. Stop the vacuum pump but do not disconnect.

6). After 1 hour, open the valve to vacuum gauge. There shall be no significant rise in
vacuum pressure, typical value – shall not rise to more than 2000 microns in 1 hour.

7). Re-open valves connecting the vacuum pump to the system and start the pump. Allow
it to operate for about 5 more minutes. Open the valve to the vacuum gauge while the
pump is still operating. When there is no noticeable loss of vacuum, the system is
satisfactorily evacuated and dehydrated.

8). Close valves connecting the pump to the system and close the valve to the vacuum
gauge. Stop the pump and disconnect. Also disconnect the gauge.

9). Upon completion of evacuation and final leakage check, return all automatic and
electrically controlled valves to their normal operating positions. Any other controls or
valves which were jacked open for the evacuation procedure shall be returned to their
normal operating state.

E) Lubrication Oil
After electrical check, the oil heater shall be switched on for at least 4 hours to 1 day to allow
the lubrication oil to reach operating temperature as designed by manufacturer.

If oil cooler is employed in the refrigeration unit, make sure that the cooling medium (usually
water but may be air, sometimes liquid refrigerant too) is ready and the associated controls are
able to work properly.

Polyester oil for HFC refrigerants is highly hygroscopic. Special care is therefore required
when dehydrating system and when handling open containers of oil – all cans must be finished
daily and no cans should be allowed to remain open overnight.

F) Charging
Charging of refrigerant can be carried out after lubrication oil is properly heated (and oil cooler
is proved to be working properly, if any)

During charging up, make sure that condensing water is circulating through the condenser
(and/or oil cooler) or make sure that the air cooled condenser can be operated.

Refrigerant must be added in gaseous form until its pressure corresponds to the saturation
pressure at 0oC, [i.e. about 4 and 1.9 Bar(g) for R22 and R134a respectively]. Thereafter, add
refrigerant liquid at the receiver inlet point (or evaporator inlet)

Charge the refrigerant circuit as follows:
1). Shut off the liquid line inlet valve of receiver (or stop valve upstream of low pressure

solenoid if there is no receiver)
2). Connect a cylinder of refrigerant to the charging valve at inlet of receiver (or

evaporator)
3). Purge the charging line of air
4). Start the condensing water pumps or fans. Ensure that the heat rejection medium is

circulating

K.F. Chan (Mr.) Page 6 of 9
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UNIVERSITY OF HONG KONG
Faculty of Engineering

M.Sc.(Eng) in Building Services Engineering
MEBS 6013 Testing & Commissioning

5). Start the chilled water pump, make sure that the medium to be cooled is in circulation
6). Open all liquid line solenoid valves
7). Slowly open the liquid charging valve allowing system vacuum to draw refrigerant into

the system
8). After the system pressure reaches saturation pressure corresponds to 0°C or above, start

up the compressor so as to complete refrigerant charging. Ensure all the safety device
of the compressor are working properly and allow the compressor to continue to run.
9). Open the liquid line inlet valve of the receiver (evaporator) Continue charging and
observe the liquid line sight glass to ensure that the refrigerant charge reaches the
normal operating level.
10). Record the pressure reading at different measuring points of refrigeration system.
Check that the pressures are equal to the design figures.
11). Leave the refrigerant cylinder readily available but the charge line disconnected until
the system test run has been satisfactorily completed.
12). When finally removing the charging apparatus, close the charging valve and protect the
connection with a seal cap.

In case the refrigeration unit is shipped to site as a complete pre-assembled fully pre-charged
packaged unit, the above pressure test, evacuation and refrigerant charging procedures may
be omitted. However, it is very important to observe pressure gauge readings after unit is
delivered to site and before start up. If these are inconsistent with the manufacturer’s data at
the corresponding ambient temperature, leak testing of the system will need to be repeated.
Where pressures in parts of the system are found to be nominally atmospheric,
evacuation/dehydration and charging must also be carried out again.

It is most common that pre-assembled units are only filled with a holding charge for shipment
though pressure test and evacuation are fully completed. In such case, pressure test and
evacuation will not be necessary but a leak test on all joints using a halide torch is still
recommended prior to applying a complete operational charge on site.

The above processes of strength/leak test, vacuum test/evacuation and dehydration and
refrigerant charging MUST be done in the above described sequence.

G) Revisit Water & Air Systems

H) Setting to work and adjustment
1) Temporarily short-circuit those protective devices and relays which are required to be

connected before test run can commence. Refer to instruction of respective components.
Dry run to ensure that the control circuit works properly.

(a) Check motor rotation direction
(b) Test the operation of each protection device including:

i. Compressor motor high temperature fault
ii. Compressor motor overload
iii. Oil flow fault
iv. High/low pressure cutout
v. Flow switch(es)
vi. High discharge temperature

K.F. Chan (Mr.) Page 7 of 9
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UNIVERSITY OF HONG KONG
Faculty of Engineering

M.Sc.(Eng) in Building Services Engineering
MEBS 6013 Testing & Commissioning

vii. Sequence start fault
viii. Common fault
2) Test run and adjust all protection devices
3) Adjust motor starter sequence to obtain optimal starting current
4) Adjust expansion valve or other metering devices
5) Adjust anti-recycle timer
6) Set temperature / load control in accordance with specification
7) Adjust anti-vibration mounting after both water and refrigerant circuits are fully charged and
purged.

If centrifugal compressor is used with low pressure refrigerant, the purge unit should be
adjusted at this stage.

K.F. Chan (Mr.) Page 8 of 9
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UNIVERSITY OF HONG KONG
Faculty of Engineering

M.Sc.(Eng) in Building Services Engineering
MEBS 6013 Testing & Commissioning

I) Running in

When setting to work and adjustments are finished, the system should be allowed to run for at
least 3 days under normal automatic control. During this period, check carefully for operational
abnormalities:
1). Compressor short-cycles
2). Compressor unable to stop
3). Compressor loses oil/oil pressure too low
4). Compressor is noisy or hammering sounds appear
5). Compressor discharge pressure too high
6). Compressor suction pressure too low
7). Observe for abnormal vibration and noise
8). Check the whole refrigeration system. Make sure that there is no leakage from the

refrigerant pipes. At the same time, tighten the screws of the flanges, the junctions and
the fittings of the pipes etc (Note that screws and nuts may be loosened when the system
starts to operate)
9). Check that there is no loose wiring termination after operation
10). Readjust vibration mounting if necessary
11). Re-tighten bolts and nuts as needed
12). Check seals again
13). Complete the performance data sheets
14). Replace filter dryer and lubrication oil as needed
15). If there is run-in-filter, it should be replaced at this stage.

J) Performance testing and handover
1) Measure flow rate, chilled water in/out temperature, power consumption, ambient

temperature or condensing water in/out temperature, etc as required by contract and
arrange handover to client.
2) Arrange re-visit after roughly 100 hours of operation to change lubrication oil
3) Arrange re-visit in extreme summer/winter to re-adjust settings
4) Carry out capacity measurement under peak summer/winter condition for capacity
verification as required by contract.

K.F. Chan (Mr.) Page 9 of 9
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