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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.
Course Evaluations In order to maintain high-quality learning experiences, please access the evaluation for this course by logging into CES Discovery and clicking on the Course Evaluation link on the left side of the page.
Checking Energy Usage - Chiller • We need accurate measurements of the total power of the chiller. • Accurate measurements of the total tons of work the machine is producing. • Allows for a direct measurement method • Fewer monitoring points than standard methods currently used
Standard Method to Determine Refrigeration Tons P1 P3 T1 T3 Amps T2 Volts
Refrigerant Flow to Determine Refrigeration Tons T3 Amps Volts T1 GPM
Can be used in conjunction with a chilled water flow meter with temperature sensors to compare the efficiency of the chiller barrel itself. • Could be used as a preemptive method to schedule chiller maintenance. 2. Could save considerable maintenance costs by only scheduling tube cleaning 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 picosecond accuracy. 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 Example 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
Kw Usage with Mechanical Cooling System Head Pressures set from factory @ 225 PSIG
Kw Usage with Mechanical Cooling System Head Pressures adjusted to 125 PSIG “Floating the Head Pressure”
