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Mechanical Engineering Seminar 2017_3
1. Knowledge Sharing
for ACMV Design & Installation in New
and Existing Building.
AUNG ZAW MYINT
M&E Manager
Lendlease Singapore Pte Ltd.
B.E (MECHANICAL)
GMM
SCEM (IES, Singapore)
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2. CONTENTS
New Building
Secondary Chilled water distribution system in SOLARIS
Building.
Existing Building
Replacement of Kitchen Exhaust system in Raffle City
shopping mall.
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5. SOLARIS POJECT
• The SOLARIS development project consist of 2 office tower, 16 storey (Tower-A), 10
storey (Tower-B) and 3 Basement car park.
• Original preliminary design was developed by CPG consultant.
• Our company was engaged to carry out the ACMV system to supply and install
accordingly but not limited to CPG original design for following system.
ACMV system with VAV Variable Air Volume terminals
Secondary Chilled water distribution system
BMS system.
Car park ventilation & smoke purging system.
Toilet exhaust & plant room Mechanical Ventilation system.
Staircase & lift lobby pressurization system.
Fresh air purging system @ offices.
• I was assigned as ACMV project manager to complete the project & achieved
Green Mark Platinum award from BCA
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9. Chilled Water Distribution
• ACMV system of SOLARIS building is using the DCS (District Cooling System) heat
exchangers instead of using chillers in the building.
• Primary circuit of DCS system up to the heat exchanger plant room is by DCS
contractor. Our scope is from Heat Exchanger room to the whole building.
3nos heat exchangers @ 1,100 RT. (2 duty 1 stand-by)
3nos of Chilled water pump set with 152 l/s @ 30m,H. (Duty circle in sequence)
2nos of Chilled water pump set with 15 l/s @ 30m,H. (night mode)
4nos of Pre-cooled AHUs @ Roof level
43nos of AHUs @ each office floor
546 nos of VAV terminal units in offices area
30 nos of FCUs for common area and retail shops @ level-1.
196 nos of MV fans
95 nos of jet fan @ basement car park
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11. PIPE HEADER & RISER
• 450mm diameter suction header pipe from heat exchanger before each suction line
of 3 pumps.
• And another 450mm diameter discharge header pipe connecting with the each
discharge line of the pumps and distributed to office tower A and B by using 4nos
of separate riser pipes, each two risers at each block.
• riser-1 and 2 for the Tower-A and riser 3 and 4 for Tower-B. Each riser pipes are
300mm in diameter.
• One By-pass pipe c/w motorized control valve and isolation valves, inside the main
plant room, between suction and discharge headers.
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12. CONTROL VALVES & BTU METERS
• 2 way motorized valves are installed at AHUs and FCUs to control and modulate in
accordance with the occupancy and / or cooling load demand.
• On each riser, pressure transducers are installed at the location, approximately two
third the distance of entire length.
• Btu meters and flow meter are installed at pipe headers and main plant room.
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13. PROBLEM TO SOLVE
• Problem come to notice in the way that our chilled water system pumps are
consuming a lot of energy although there was not many demand, cooling load in
the building.
• There was one By-pass pipe c/w motorized control valve and isolation valves, inside
the main plant room, between suction and discharge headers.
• In accordance with the start-up procedure, system started running with all FCUs
and AHUs level by level.
• Then follow by the pumps running in the main plant room and request to turn on
DCS heat exchanger one by one according to the load demand from the FCUs and
AHUs inside the building.
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14. PROBLEM TO SOLVE
• After system started, each and every FCU and AHU 2 way motorized valves are
open almost fully to achieve the designed room temperature in the office to cool
down the heat absorbed by the building.
• After running continuously for 30 to 45 minutes, 2 way motorized valves are start
to modulate and tends to close back due to very little occupancy in the office area.
• Once the differential pressure at one of the riser exceed the pre-set point for more
than 10 minutes, BMS system start giving the commend signal to open the by-pass
motorized valve at plant room header to relief the pressure in the system.
• Then system is keep running without reducing frequency of any pumps although
the demand on the building is not that much. Pumps are keep circulating thru the
by-pass line just to maintain the constant running and wasting energy
unnecessarily.
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16. SOLUTION
• Finally, we realized that pumps are running without optimizing with the cooling
load requirement.
• In fact, pumps can be modulate to reduce the speed instead of opening the by-pass
valve. By-pass valve opening shall be the last resolve.
• The only thing we need to be carefully considered is to maintain the minimum
chilled water flow rate required by Heat Exchanger manufacturer. That means, we
cannot reduce the pump frequency and flow rate lower than minimum
requirement.
• More importantly, we also need to consider the furthest / longest AHU is achieving
the required chilled water when the pumps are ramping down. Because, once we
reduce the pump motor frequency, it was not only reducing the water flow rate,
but also the system pressure.
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31. • Design & Build ANA Job for Kitchen Exhaust System
• Add new centrifugal Kitchen Exhaust Fans c/w new starter panel.
• Implement new vibration monitoring system.
• Study existing system for improvement.
• Change and replace duct work & accessories wherever possible.
• Survey and recalculate design static pressure and air flow to meet optimum design
condition.
RAFFLES CITY PROJECT
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