This project focused on the technical methods to convert an existing Air Handling Unit (AHU) from using a chiller system to a Direct Expansion (DX) system in Universiti Teknologi Brunei (UTB) Academic Building. The design and calculations were based on the guidelines and standards from building regulations in Brunei and ASHRAE. The current status of UTB air-conditioning system was compared with these standards. It was observed that UTB air-conditioning system did not comply with the health and safety standards, particularly in providing fresh air into the system. A DX cooling system which used Refrigerant 410A was chosen as the alternative to replace the existing cooling coil. Cooling Load Temperature Difference (CLTD) Method was primarily applied to calculate the cooling load required for the tutorial rooms and hallways, assisted by a Design Engineer from Jurutera OMC. Design parameters with common engineering practice were applied for sizing the cooling coil. A 3D model design of the cooling coil was then constructed using SolidWorks 2019. ANSYS Fluent 2019 was used to simulate the temperature at the cooling coil outlet. The supply temperature of the new design was 21°C, which meant it could provide comfort air conditioning to the tutorial rooms and hallways. The project was also initiated to provide the cooling support for the existing wall mounted split DX air conditioning units in each room.

1.
ISSE Lack of Fresh Air
. https://www.isse.org.uk/index.php/about/lack_of_fresh_air. Accessed 20 Nov 2019
2.
(
2018
)
What is the Difference an Inverter and a Fixed Speed Air Conditioner?
https://toshiba-aircon.com.au/difference-between-inverter-fixed-speed-air-conditioner/. Accessed 12 Sep 2019
3.
Heat Calculator | Daikin Malaysia
. https://www.daikin.com.my/heat-calculator/. Accessed 10 Nov 2019
4.
Al Harbi
F
,
Al Romaih
A
,
Al Hudaithi
S
,
Al Husayyani
A
,
Al Qadhi
T
,
Al Sagri
AS
,
Al Ateyah
AR
,
Basha
SS
(
2019
)
Comparison of cooling load calculations by E20 and HAP software
.
Universal Journal Mechanical Engineering
7
:
285
298
5.
ASHRAE
(
2017
)
Non-Residential Cooling and Heating Load Calculations
. In:
2017 ASHRAE Handbook Fundamentals
pp
18.56
-
18.58
6.
Khamis
M
,
Hassab
M
(
2012
)
Thermal Design of Cooling and Dehumidifying Coils
.
Heat Exch - Basics Des Appl.
7.
Orr
B
(
2020
)
Sensible Heat Ratio (SHR) - HVAC School.
https://www.hvacrschool.com/sensible-heat-ratio-shr/. Accessed 18 Apr 2020
8.
Jones
W.P
(
2001
)
The choice of a suitable supply state
. In:
Air Conditioning Engineering
, 5th Edition p
137
9.
(
2020
)
HVAC-Tips, Why is 410A Freon So Expensive, Air Conditioning Repair for Huntsville and Madison AL
. https://www.conditionedairsolutions.com/410a-freon-expensive/. Accessed 2 Mar 2020
10.
Mindset
E
(
2017
)
HVAC Cooling Coils
. https://www.youtube.com/watch?v=0gv2tJf7nwo. Accessed 29 Sep 2019
11.
ASHRAE
(
2017
)
Thermophysical Properties of Refrigerants
. In:
2017 ASHRAE Handbook. Fundamentals.
pp
30.36
-
30.37
12.
Essentials of working with R-410A. https://www.achrnews.com/articles/92875-the-essentials-of-working-with-r-410a. Accessed 20 Feb 2020
13.
ASHRAE
(
2017
)
Pipe Design
. In:
2017 ASHRAE Handbook Fundamentals
p
22.17
14.
Rosli
A
,
Ali
H
(
2020
)
UTB Air Handling Unit Conversion
.
15.
ABCI
(
2017
)
PBD 12: 2017. Piawaian Brunei Darussalam 2017
16.
ASHRAE
(
2017
)
Fenestration. In: 2017 ASHRAE Handbook Fundamentals
pp
15.5
-
15.13
17.
ASHRAE
(
2017
)
Ventilation and Infiltration
. In:
2017 ASHRAE Handbook Fundamentals
pp
16.31
-
16.32
18.
Jones
W
(
2001
)
The choice of a suitable supply state
. In:
Air Conditioning Engineering
, 5th Edition p
136
19.
(
2020
)
Fluid Mechanics
101
. https://www.fluidmechanics101.com/pages/tools.html. Accessed 4 May 2020
20.
Cooling Calculator | Clean Air
. https://cleanair.co.uk/btu-calculator/. Accessed 10 Nov 2019
21.
Street
M
(
2013
)
Coil Dimension Guidelines Coil Dimension Guidelines.
2
:
5900
5901
22.
Berg
BCE
,
Engineer
M
,
Manufacturing CC Back to basics: useful equations when sizing coils with coilpro.
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