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AIRAH 2014
Chiller Plants for Tropical ClimatesToday’s Agenda Chiller developmentsVSD advantagesYMC2 Technology Chiller plant optimizationSeries counter-flow configurationOpportunities from ‘de-coupling’Opportunities from de-couplingMulti CHW loop applicationsEfficiency possibilities Example project
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
Despite using more environmentally benign, yet less efficient refrigerants, chiller efficiency has improved significantly
In recent decades, significant gains in chiller efficiency at full & part load through advances in HX, compressor, motor, driveline, and economizers.
The biggest single efficiency gain has been at reduced ‘lift’ condition
MotorRectifier InverterDC
with the adoption of the variable speed drive.
L1
L2
L3Control electronics
C t l it d i ti
M3
U1
V1
W
L
C UV1 V3 V5
V4 V6 V2
YK YMC2Control, monitor, and communication
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
VSD technology benefits
Reduces inrush current to < than FL amps (soft start)
Corrects power factor close to unity
Reduces utility demand
Regulates compressor speed to provide the most efficient chiller operation, reducing energy consumption
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
Most recent technology introductionVariable speed magnetic bearing oil free centrifugal chillers
High efficiency permanent magnet motorg y p g
Latest Generation VSD
Frictionless magnetic bearings
Direct drive compressor
Oil free design
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
York magnetic bearing chillers were originally developed for mission critical nuclear submarinesdeveloped for mission critical nuclear submarines
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
Magnetic bearing driveline technology
Permanent Magnet Permanent Magnet MotorMotor
Impeller Impeller SectionSection
Low noise and vibrationLow inrush current – variable speedLow maintenance - no oil related componentsRapid start and re-startCompatible with the wide range of condenser water temperatures
6Johnson Controls ‐ Proprietary & Confidential
Compatible with the wide range of condenser water temperatures
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
Comparing fixed speed to variable speed technology
At AHRI “relief “ conditionsAt constant conditions
YK VSD
YKCSD
YMC2
VSDYK
CSDYMC2
VS YMC2
VS
Load% LWT EWT COP EWT COP COP COP % %100 6.7 29.4 6.46 29.4 6.46 6.28 6.60 2.1 5.0
VSDCSD VSDCSD YK CSD YK VSD
90 6.7 29.4 6.54 27.2 7.05 7.05 7.43 5.6 5.680 6.7 29.4 6.52 25.0 7.55 7.99 8.41 11.5 5.570 6.7 29.4 6.44 22.8 7.83 9.09 9.66 22.8 6.260 6.7 29.4 6.25 20.5 8.12 10.34 11.23 38.6 9.050 6.7 29.4 6.14 18.3 8.18 11.72 13.12 61.1 13.040 6.7 29.4 5.75 18.3 7.55 11.31 12.79 89.5 13.030 6.7 29.4 5.28 18.3 6.77 10.34 11.96 76.1 15.720 6.7 29.4 4.46 18.3 5.55 9.30 10.31 85.9 10.915 6 7 29 4 3 96 18 3 4 88 8 25 8 60 75 7 4 015 6.7 29.4 3.96 18.3 4.88 8.25 8.60 75.7 4.0
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
VSD chillers perform best with condenser water “relief”
13 0
14.0YK CSD Constant CEFT YK CSD AHRI Relief YK VSD AHRI Relief YMC2 AHRI Relief
Chillers operate
11.0
12.0
13.0 Chillers operate for 85% of the time within this capacity range
8.0
9.0
10.0
CO
P
5 0
6.0
7.0
4.0
5.0
10 20 30 40 50 60 70 80 90 100% Capacityp y
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
How to effectively apply high efficiency VSD chillers to HVAC systemsVSD chillers to HVAC systems
in tropical climates?Chiller
58%
Tower5%
Fans24%
P
Design Performance
5%Pumps13%
One of the most ‘constant’ tropical climates is SingaporeOne of the most constant tropical climates is Singapore.What levels of plant efficiency can be achieved where operating conditions have limited variance ?
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
Efficient chillers are a great foundation, but optimization is a process
Maintain
p p
Measure & Verify
Optimize SystemOperating Decisions
p y
Automate System
Apply components effectively, optimally
Select components effectively, optimally
Design Decisions
Select components effectively, optimally
Design system infrastructure to maximize efficiency potential
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
The key functional components of chiller plant optimization are the same irrespective of jobsite location
Apply variable speed drivesChillersPPumpsTower Fans
Reduce “lift”Reduce “lift”lower CW temperatureshigher CHW temperatures
Reduce pump energywide delta Tvariable flow
Efficient chiller stagingenergy based vs load based
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
All chillers benefit from reduced “lift”…..especially VSD chillers.How to achieve reduced ‘lift’ in tropical climates ?
Lower tower water tempsLimited opportunity at design condition.Some opportunity when at off-design.
AND
Higher chilled water temps
AND
Higher chilled water temps
Significant opportunity with HT CHW, chiller arrangement,and airside design
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
One has to ‘create’ the optimum operating environment
Every 1 deg C of ‘lift’ reduction improves VSD hill ffi i b 3 6%VSD chiller efficiency by 3-6% depending on the technology
MotorRectifier InverterDC
Supply
L1
L2
L3M3
U1
V1
W
L
C UV1 V3 V5
V4 V6 V2
Control electronics
Control, monitor, and communication
Every 1 deg C counts !
Johnson Controls - Proprietary & ConfidentialYMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
Every 1 deg C counts !
Conventional design @ “ASIA” conditions
Pressure
Lift
32 ° C95° F 35°C
37° C
Lift
12° C12 C6° C
Enthalpy
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
Can we lower tower water temps ?
The cooling tower is the most effective heat transfer device in the system
Design ConditionEnergy efficiency ratio
250 ton tower super low noise tower
32 - 37 deg C
OR
= 7.5 kW / 875 kWr
= 117
30 - 35 deg CConventional design = approach 5-7 deg C
Optimized design = approach 3 4 deg C
Tower water does not have to be held constant
Optimized design = approach 3-4 deg C
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
Singapore Building Operation Profiles cantake some advantage of ambient wet bulb relief ASHRAE 32.8db / 27.3wb
Source: ASHRAE IWEC Weather Bin Data
Singapore tower water will achieve 3 deg C of relief based on ‘office’ hours with 5 deg C of relief available for 24/7 systemsg y
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
Can we raise CHW temps ?
Chiller HX approachtemperatures <= >1 deg C
Conventional coil design = 2.5 m/s Face velocity & approach 6-7 deg C
p g
Optimized coil design = < 2.0 m/s Face velocity & approach 3-4 deg C
13 deg C air off coil = 9 deg C CHW @ 4 deg C approach
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
12 5 / 7 0 deg C
Can we widen the CHW temperature range to 8-10 deg C?12.5 / 7.0 deg C
13.5 / 6.0 deg C
14.5 / 5.0 deg C
Design delta T 5.5C 7.5C 9.5C% Flow reduction 0 2/7.5 =27% 4/9.5 = 42%
Wide delta T chilled water systems save significant pump energy,but to use ‘similar’ CHW coils, the chillers must work harder.
Using 9 deg C CHW & 10 deg C delta T will need different AHU CHW coils
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
Using 9 deg C CHW & 10 deg C delta T will need different AHU CHW coils
air ON db 25air ON wb 18.5air OFF db 13Air Qty l/s 5 000
What is the impact to the AHU CHW coil with 9 deg C CHW temp and 10 deg C delta T ?Air Qty l/s 5,000 g p g
Increasing face area and reducing coil velocity is key to equivalent energy performanceIncreasing face area and reducing coil velocity is key to equivalent energy performance
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
1st cost economics of a 9 /19 deg C CHW system
Smaller CHW pipes
Savings Costs Larger AHU coil HX areas and p p
Smaller CHW valves and fittings
Reduced thermal insulation area
rows to achieve equivalentenergy performance
If the additional coil area cannot be d t d i AHU h i ht th Smaller CHW pumps, motor kW, and VSD’s
Smaller CHW pump electrical requirements
Smaller chiller electrical requirements
accommodated in AHU height, the AHU footprint will increase
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
Wide CHW delta T best suits Series Counter-flow chillers
VPF = variable primary CHW flow & fixed delta T
9 d C
VPF
CHW flow & fixed delta T
9 deg C 14.0 deg C 19 deg C
30 deg C 32.5 deg C 35 deg C
Lift is reduced 2.5 degrees C Lift is reduced 5.0 degrees C
Series Counter-Flow chillers further reduce lift
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
9 14 19
Series counter flow YMC2 performance at Singapore conditions (office hours)
1645 kWr1520kWr9 14 19
30 32.5 35
1645 kWr1520kWr
Load% CHW in CHWint CHWout CWin CWint CWoutUP
COPDN
COPSYS COP
100 19 13.8 9 30 32.4 35 8.75 7.83 8.29
90 19 13.8 9 29.4 31.6 33.9 9.33 8.14 8.70
80 19 13.8 9 28.8 30.7 32.8 9.96 8.49 9.20
70 19 13.8 9 28.2 29.9 31.7 10.56 8.79 9.6370 19 13.8 9 28.2 29.9 31.7 10.56 8.79 9.63
60 19 13.8 9 27.6 29.1 30.7 10.95 8.92 9.88
50 19 13.8 9 27 28.2 29.5 11.42 8.92 10.07
40 19 13.8 9 27 28 29.1 10.95 8.43 9.58
30 18.5 13.6 9 27 27.7 28.5 10.02 7.46 8.60
20 15.4 12.1 9 27 27.5 28.1 6.83 5.38 6.04
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
How does optimized series counter flow YMC2 efficiency compare to conventional Singapore design with YK CSD ?
Load% YK YMC2 S/C
YK CSDat AHRI
constant CWYMC2 S/C at 9 deg C & 30 deg C
with 3 deg C CW reliefLoad% YK YMC S/C
100 6.46 8.29 28%90 6.54 8.70 33%80 6.52 9.20 41%70 6.44 9.63 50%60 6.25 9.88 58%
The bulk ofoperating hours
50 6.14 10.07 65%40 5.75 9.58 66%30 5 28 8 60 48%30 5.28 8.60 48%20 4.46 6.04 35%
Chiller energy reduced on weighted average by 55% !
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
gy g g y
How has performance improved over conventional design ?
11 0
12.0YK CSD Constant CEFT YMC2 SCF Office
Si ifi t b fit f VSD
9 0
10.0
11.0 Significant benefit from VSD
7 0
8.0
9.0
CO
P
5.0
6.0
7.0
4.0
5.0
10 20 30 40 50 60 70 80 90 100% Capacityp y
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
Energy economics of a 9 /19 deg C S/C CHW system
Compared to constant speed chillers
Savings Costs Marginally higher design flow Compared to constant speed chillers
at AHRI constant condenser water
conditions
g y g gpump pressures with series HX
Note : pressures are reduced at . . part load with variable flow
CHW pump energy savings 35 % Marginally greater tower fan energy
to leverage the 3 deg C reduction in CW temperature
YMC2 S/C chillers 28-66 % more efficient Note: tower efficiency is an order of
magnitude greater than chillers
2YMC2 S/C chillers 28% more efficient at designYMC2 S/C chillers up to 66% more efficient at reduced load & lift
YMC2 S/C chillers 55% more efficient on weighted average
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
Typical system = CHW VAV AHU’s
HT CHW loop
9 C 14 C
19 CVPF
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
Are there more efficiency gains to be found ?
Can we go higher than 9 deg C CHW ?
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
The most efficient HVAC systems treat the latent loads separately “De-coupling”
Cooling Load Component Latent Sensible
C d ti th ll f tConduction thru walls, roof etc
Solar radiation
Lights
People
Equipment (some…most is sensible)
Infiltration
Ventilation
System heat gains
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
A typical application that de-couples loads is a chilled beam system
DOAS
+Chilled Beam
+One HVAC system performs
all dehumidification One HVAC system performs
only sensible cooling De-coupled
Typically @ 14 degrees C CHW
De coupled
Typically @ 6 degrees C CHW
The management of high humidity infiltration loads in tropical climatesmakes the application of chilled beam systems challenging.
The question becomes…. can we utilize 14 degree HT chilled water in some way ?
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
Let’s examine a CHW system for a chilled beam application
ACB HT CHW loopDOAS supplies dry cool conditioned primary O/A to the active chilled beams
LT CHW loop 14 0 C
6 C 11 C
LT CHW loop(S/C chillers)
14.0 C
VPF VPF16 C 18 C
Pl t Pl tPlant room Plant room
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
Efficiency is further improved where a % of O/A load is removed by the HT loop
ACB HT CHW loop DOAS with cascade reduction in primary air temp
LT CHW loop14 0 C
6 C 11 C
C oop(S/C chillers)14.0 C
VPFVPF16 C
Pl t
18 C
Pl t Plant roomPlant room
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
In tropical climates treating the outside air load separately through a DOAS has merit, particularly for applicationsthrough a DOAS has merit, particularly for applications that require higher percentages of fresh air.
DOAS can provide-DOAS can provide
Effective de-humidification
Th bili ffi i l d h d i f id The ability to efficiently cascade the reduction of outside air temperature
The ability to include energy recovery devices
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
With VAV t d i t t l i t iti l
DOAS applied to a traditional VAV system
VAV AHU(s)DOAS diti th O/A
With a VAV system space dew point control is not as critical.
DOAS pre-conditions the O/Asupplied to the zone VAV AHU’s
9 C 14 C
CHW loop14 C
19 C
VPF
VPF19 C
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
What efficiency levels can the HT loop chiller deliver ?
Load% YK YMC2 s/c YMC2
Office profile
YK CSDat AHRI
constant CW
YMC2 S/C at 9 deg C YMC2 at 14 deg C Office profile
Load% YK YMC s/c YMC100 6.46 8.29 28% 9.2090 6.54 8.70 33% 9.77
42%49%
80 6.52 9.20 41% 10.3770 6.44 9.63 50% 10.9560 6.25 9.88 58% 11.38
59%70%82%
50 6.14 10.07 65% 11.6840 5.75 9.58 66% 11.2030 5 28 8 60 48% 10 34
90%95%95%30 5.28 8.60 48% 10.34
20 4.46 6.04 35% 8.45
HT YMC2 delivers weighted average 79% improvement over base design
95%89%
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
With dual loops, plant performance can be further improved
11 0
12.0YK CSD Constant CEFT YMC2 Evap 14/18C YMC2 SCF Office
9.0
10.0
11.0
6 0
7.0
8.0
CO
P
4.0
5.0
6.0
10 20 30 40 50 60 70 80 90 10010 20 30 40 50 60 70 80 90 100% Capacity
The greater the load transferred to the HT loop, the greater the efficiency is further improved
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
Example of Dual CHW loop project
JEM ProjectSingapore
Multi stageMulti stage fresh air
treatment
Dual CHWDual CHW loops
Elevated CHW tempsC te ps
Series counter-flow LT chillers
Wide delta T LT loop
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
Low temp loop = 9/18 deg C with 2 S/C York YK CSD chiller pairs
Hi h t l 15/20 d C ith 2 Y k YK VSD hillHigh temp loop = 15/20 deg C with 2 x York YK VSD chillers
Greenmark ‘Platinum’ rating @ 0.55 kW/Ton = 6.4 plant COP
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
For Consideration
High Efficiency VSD or VSD magnetic bearing chillers High Efficiency VSD or VSD magnetic bearing chillers
Raise CHW supply temperatures
Wide delta T CHW with series counter-flow chiller arrangement Wide delta T CHW with series counter-flow chiller arrangement
Re-evaluate design approach temperatures
cooling towers are efficient and low costcooling towers are efficient and low cost
lower face velocity coils
De-couple and condition outside air loads separately De-couple and condition outside air loads separately
Dual HT & LT CHW loops with cascade coils & ‘low lift’ VSD chillers
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
If these concepts can be successfully li d th b i f Si thapplied on the basis of Singapore weather
data, there is even greater opportunity in less stringent tropical locations.
VSD centrifugal and VSD magnetic bearing centrifugal chillersVSD centrifugal and VSD magnetic bearing centrifugal chillerscan offer significant efficiency opportunities in tropical climates
A wide delta T, variable CHW flow, Series Counter-Flow chiller , ,configuration maximizes these benefits
Revised design temperatures further maximizes these benefits
YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers
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YMC2 – YORK® State of the Art Magnetic Centrifugal Chillers