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AECOM IES Model
AIRAH Site VisitWestfield Carousel
Chiller System Optimisation
Series Counter Flow Configuration Variable Primary/Secondary CHW
System
Understanding Work/Lift Relationships
Wat
ersi
de L
ift
Com
pres
sor L
ift
Ref
riger
ant D
elta
-P
Saturated Condensing Temp
Saturated Evaporating Temp
Leaving Cond. Water Temp
Leaving Chilled Water Temp
Condenser Approach
Evaporator Approach
Compressor Lift = Refrigerant Delta PWork = Mass Flow Rate x Lift
ENTHALPY
PR
ES
SU
RE
HEAT REJECTED
HEAT ABSORBED
LIFT
SST
SCT
Sub-cooled Liquid
Superheated Vapour
“Traditional” Parallel System Configuration
Parallel Configuration 2 x 3550 kW Chillers
Waterside Lift (32.8 - 6) 26,8K
Building Load 100% (7100kW)2 x 3550 kW Chillers …..VSFChilled Water 15/6 Condenser Water 27.5/32.8
3550 kW
3550 kW
BypassDecoupler
Series Counter Flow Solution
BypassDecoupler
Building Load 100% (7100kW)4 x 1775 kW Chillers …..SCF with VPF/VSFChilled Water 15/6 Condenser Water 27.5/32.8
SCF with VPF/SCF Solution4x 1775 kW Chillers
Waterside Lift (32.8 - 6) 26,8K
Upstream Chiller (22.4 K)Downstream Chiller (24.2 k)
1775 kW 1775 kW
1775 kW 1775 kW
ApplicationsVSD Screw Series Counter flow
Both chillers designed to operate at 15/6˚C – 27.5/32.8˚C. (26.8 K W/Lift)
Upstream chiller 15 – 10.5˚C/ 30.15 – 32.8˚C. (22.35 W/Lift)
Downstream chiller 10.5 – 6˚C /27.5 – 30.15˚C (24.15 W/Lift)
Net Operating Savings of 5-15% with same equipment in Parallel Configuration!
15˚C
10.5˚C
6˚ C
27.5˚C
30.1532.8˚C
SCF Configuration Lift Reduction
Upstream
Downstream
SCF Plant room layout
SCF design utilises single pass vessels to avoid system pumping penalties
– Variable Speed Tri Rotor – Positive Displacement Compressor– Integrated Variable Speed (IEE519)– Refrigerant Cooled Drive– 0 ODP R134a (No Phase Out Date)– In Chiller Refrigerant Storage– ASME Heat Exchangers with Full
Waterbox Options– Variable Orifice– Seismic Compliant Option– Acceptable of CHW Flow Rate
Change of Up to 70% Design/Minute
23XRV Product Features
615 to 1935 kW (3870 kW SCF)
23XRV Reliabilityof Design
Semi hermetic-not required
No Shaft Seal Vanes Actuator Solenoids Slide Valve Purge
Reliability Through Simplicity - Fewer Moving PartsBalanced Tr-rotor design cancels load forces so
effectively, at AHRI conditions, the lowest
L10 life of any bearing in the compressor is over
50 years
Positive Displacement Compressor - No Surge- Speed Control directly load based (Not Ambient + Load)
Capacity Control
32MP Condenser pipingByass piping, isolation
valves not shownCH-1Lead
CH-2Lag
CH-1 Programmed as lead chiller, CH-2 programmed as lag chiller
CH-1 loads up until compressor speed = 80%.
At 80% compressor speed, CH-1 commands CH-2 to turn on. Since chillers are in series, pumpflows are already established.
CH-1 sends a demand limit signal to CH-2, thereby ensuring both chillers are running at thesame % of nameplate kW. CH-1 increases or decreases the demand limit to regulate T3 to set point.
At 35% compressor speed, CH-1 commands CH-2 to turn off.
If CH-1 becomes disabled, the on board controls rotate CH-2 as the lead chiller. CH-2regulates to the leaving temperature T3 via the 32MP sensor.
T1T2T3
Series Counter Flow
Hydronic Considerations VPF
Variable Primary Flow has synergistic effect with series evaporators.
VPFDS Lvg
100% 75% 50% 25%6.7 6.7 6.7 6.7
11.115.5
11.115.5
US LvgReturn
11.115.5
OffOff
With constant speed pumping delta T falls with load
Const. FlowDS LvgUS LvgReturn
100% 75% 50% 25%6.711.115.5
6.71013.3
6.78.911.1
6.7OffOff
Utilising VPF Series Configuration the leaving chilled water temperature of the upstream chiller stays warmer longer, increasing system efficiency compared to
constant primary flow
Carrier Chiller System Manager (CSM)• Chiller Set staging • Variable Primary CHW Flow Control • Cooling Tower Optimisation• Variable CW Pump Control
Site BMS• Chiller Cooling Call• Variable Secondary Pump Control• Chilled Water Reset (Valve Position)
Internet
Firewalli-Vū Pro Server PC
Web Browser
Chiller System Optimisation
Westfield CarouselHVAC UPGRADE
Presentation by:Ryan Hipps
Contents
• Existing installation• Original proposal• Burke Air proposal• Construction• Summary
Existing installation
Existing installation
Plantroom # 6
Existing installationPlantroom # 2
Existing installation
• Plantroom # 10
Existing Installation• Cooling Capacities:
– Chillers 1 & 2: 1440 kW• Feeding AHUs 1,2,3,4,5• Total AHUs cooling capacity: 1508 kW
– Chillers 3,4 & 5: 4623 kW• Feeding AHUs 7 to 14, 16 to 26 & FCUs 3 to 6 • Total AHUs cooling capacity: 4491 kW
– Chiller 6: 700 kW• Feeding AHU 15• Total AHU cooling capacity: 700 kW
– Total Chillers: 6723 kW• Total AHU cooling capacity: 6699 kW
• Issues:– Chillers 3,4,5 Condenser coils corroded, compressors
failures and end of life cycle.– Pipes corrosion– Pipes insulation: 25 mm– Chillers 1,2,3,4,5,6 refrigerant: R22– No balancing valves on AHUs– Pumps undersized– Recirculation
Existing Installation
Original Proposal
• Central plant room:– 4 water cooled chillers in series counter
flow– 3 cooling Towers in parallel– 2 CCW pumps– 2 PCWHP– 5 SCWHP – 5 separate loops– Total cooling capacity: 4x1775 kW=7100
kW
Original Proposal
Original Proposal
• Risks– Electrical mains to new plant room– Structural: existing roof and concrete slab– Vibration (Cinema)– Building works (DA approval, extra cost, less car bays, restriction
for future development)– Running of large pipework across car ramp
Original Proposal
BURKE AIR ProposalRoof Pipework layout
BURKE AIR Proposal
Central Plantroom # 6
• 4 Water cooled chillers in series counter flow
• 3 cooling towers in parallel• 2 CWP• 2 PCHWP• 4 SCHWP (Loop 1 to 4)• Cooling Capacity: 4x1775 kW
= 7100 kW
ConstructionTender / Design / Procurement
• December 2012 : Original Tender documents released• January 2013: Original bid based on original proposal• February to June 2013: BA design proposal with Westfield
Engineering and AECOM, 3D Concept design• June 2013: New tender documents• July 2013: 3D final design, Final Tender offer• August 2013: Signed contract / Procurement / Engineering /
Drafting
Construction
• September 2013: Start on site• October 2013: Roof pipework completed• October 2013: Installation of 4 chillers and 2 Cooling towers
associated pumps• October 2013: AHU plantrooms 70% completed• November 2013: Commissioning of Chillers 1.1 & 1.2 + CT 1
& 2• November 2013: AHU plantrooms 90% completed, chilled
water to loop 2 to 4.• December 2013: Commissioning of remaining chillers and
CT• January 2014: Commissioning of Loop #1 and associated
AHUs• January 2014: PC
Summary