Efficiency Vermont is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) earned on completion of this program will be reported to AIA/CES for AIA members. Certificates of Completion for both AIA members and non-AIA members are available upon request.
This program is registered with AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product.
Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.
Learning Objectives
At the end of this program, participants will be able to:
Understand the effectiveness of using a new technology refrigerant flow meter to optimize chiller operation
Understand how flow can be used to identify actual KW/ton energy use rather than relying on energy ratings that use ideal laboratory conditions
Select the proper Kw motor and current sensors for a wide range of system load. Understand how a refrigerant flow meter is used to determine a refrigeration system's total operating tonnage.
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evaluation for this course by logging into CES Discovery and clicking on the Course Evaluation link on the left side of the page.
Chiller Optimization
Utilizing A
Refrigerant Flow Meter
Checking Energy Usage - ChillerChecking Energy Usage - Chiller
• We need accurate measurements of the total We need accurate measurements of the total power of the chiller.power of the chiller.
• Allows for a direct measurement methodAllows for a direct measurement method
• Accurate measurements of the total tons of Accurate measurements of the total tons of work the machine is producing. work the machine is producing.
• Fewer monitoring points than standardFewer monitoring points than standardmethods currently usedmethods currently used
Standard Method to Determine Refrigeration TonsStandard Method to Determine Refrigeration Tons
AmpsAmps
VoltsVolts
TT11
PP11
TT33
PP33
TT22
Refrigerant Flow to Determine Refrigeration TonsRefrigerant Flow to Determine Refrigeration Tons
AmpsAmps
VoltsVolts
TT11
TT33
GPMGPM
CHWS
Evaporator Chiller Barrel
CHWR
N/C
N/O
N/O
N/C
N/O
USFT-CS-04
USFT-R-.75
RTD RTD
Monitoring Points
Chilled Water Supply Temperature
Chilled Water Return Temperature
Chilled Water Flow - GPM
Refrigerant Temperature
Refrigerant Flow - GPM
Chiller Kw
12
54
3
6Kw Meter & Disconnect
Monitoring Points - Kw/Ton
Not to Scale
VaporizationVaporization
VaporizationVaporization
Can be used in conjunction with a chilled water flow meter Can be used in conjunction with a chilled water flow meter with temperature sensors to compare the efficiency of the with temperature sensors to compare the efficiency of the chiller barrel itself.chiller barrel itself.
1.1. Could be used as a preemptive method to Could be used as a preemptive method to schedule chiller maintenance.schedule chiller maintenance.
2. Could save considerable maintenance 2. Could save considerable maintenance costs by only scheduling tube cleaning costs by only scheduling tube cleaning when necessary.when necessary.
Two ultrasonic transducers are positioned and angled as to transmit and receive sound pulses launched at a flat reflection point located on the opposing side of the pipe.
The flight time of the sound pulse from one transducer to the other is shortened if the pulse is launched in the direction of flow and increased if launched opposite to the direction of flow.
By alternating the transmitting and receiving transducers, the difference in these transit times can be used to calculate the velocity of the flow.
ASIC (Application Specific IC ), which provides all the functions required to alternately transmit and receive sonic pulses and measure the transit times to picosecondaccuracy. The ASIC implements the “Sing Around” method to launch and receive pulses, each received pulse initiating the next transmitted pulse. On any one measurement, a number of such cycles are used to accumulate the individual transit times which are then divided by the number of cycles to give an average of these measurements.
Metering Chiller Performance Metering Chiller Performance ExampleExample
BTUH = 500 x GPM x T /12,000
BTUH = 500 x 88.5 GPM x 4.5°F T = 199,125
Tons = 199,125 BTUH / 12,000 BTUH = 16.59 Tons
kW per ton = 1kW / 16.59 Tons = .0602 kW / Ton
Hybrid Free Cooling Chiller
CHWS
Liquid LevelSensor
Receiver
Evaporator Chiller Barrel
CHWR
Muffler
Liquid LevelSensor
N/C
N/O
N/O
N/O
Discharge Pressure
Refrigerant Temp Out
Refrigerant Temp - In
Suction Temp
Condenser Fan # 1
By-Pass Check
N/C
Condenser Fan # 2
LRP
N/O
US Patent Pending No. 11/562,805US Patent Pending No. 11/562,805
Kw Usage with Mechanical CoolingKw Usage with Mechanical Cooling
System Head Pressures set from factory @ 225 PSIGSystem Head Pressures set from factory @ 225 PSIG
Kw Usage with Mechanical CoolingKw Usage with Mechanical Cooling
System Head Pressures adjusted to 125 PSIGSystem Head Pressures adjusted to 125 PSIG
““Floating the Head Pressure”Floating the Head Pressure”
Reduced Pressure Reduced Pressure Readings Readings
Kw Usage with Hybrid Free CoolingKw Usage with Hybrid Free Cooling
Petra chiller- kW Usage
0
1
2
3
4
5
Jan 24 - 30, 2006
kW
Date/Time Velocity (ft/s)Flow (gpm)
Mass flow (lb/m)
1/24/2006 19:00:33 4.29 150 3.786 ID (in)
1/24/2006 19:02:34 4.28 150 0.078179 area (sq.ft)
1/24/2006 19:04:33 4.23 148 7.480519 gal/cu.ft.
1/24/2006 19:06:34 4.21 148
1/24/2006 19:08:33 4.22 148
1/24/2006 19:10:33 4.21 148
1/24/2006 19:12:33 4.22 148
1/24/2006 19:14:34 4.27 150
1/24/2006 19:16:34 4.28 150
1/24/2006 19:18:36 4.28 150
1/24/2006 19:20:33 4.29 150
1/24/2006 19:22:33 4.28 150
1/24/2006 19:24:34 4.26 150
1/24/2006 19:26:33 4.22 148
1/24/2006 19:28:35 4.20 147
1/24/2006 19:30:33 4.20 148
1/24/2006 19:32:34 4.21 148
1/24/2006 19:34:34 4.22 148
1/24/2006 19:36:34 4.20 147
Ultrasonic Water Flow Measurements – Efficiency Vermont Ultrasonic Water Flow Measurements – Efficiency Vermont
FlowRate: Chilled Water Flow
142
144
146
148
150
152
154
Jan 24 - 30, 2006
gp
m
Questions