Prepared for: Pacific Gas & Electric Company
Research and Development Department
3400 Crow Canyon Road,
San Ramon, CA 94583
Project Manager:
Lance Eberling, P.E.
Report, June 27, 1996
Prepared by:
Proctor Engineering Group
with
Energy Systems Laboratory, Texas A&M University
Contributors:
John Proctor, P.E.,
Tom Downey,
Curtis Boecker, P.E.,
Zinoviy Katsnelson, Ph.D., P.E.,
George Peterson, P.E.,
Dennis O'Neal, Ph.D., P.E.
These include: increased condenser/evaporator areas and efficiencies, increased condenser/evaporator fan efficiencies, and increased indoor/outdoor fan motor efficiencies.
In that study PEG simulated multiple air conditioner designs with various parameters. Four designs were found capable of reducing peak draw by at least 500 Watts. In this study, one of the reduced peak units was assembled from "off the shelf" components. The prototype unit was tested in the laboratory under hot dry and hot moist peak conditions. The prototype unit met the goal, showing a reduced peak watt draw equivalent to the simulation. Diversified local peak reduction was estimated at 550 watts.
The prototype unit had a higher efficiency than the typical units at SEER test conditions (82¡F outside) and the difference in efficiency increased at higher outdoor temperatures. All high SEER air conditioners tested in a 1995 EPRI laboratory test of ten units (Bain et. Al., 1995) had efficiencies that deteriorated faster than the prototype unit at high temperatures.
This improvement in efficiency would not only benefit the utility at peak, but also benefit the customer since the equipment sees greater use at higher temperatures. The annual customer energy savings are estimated to be between 11% and 20%. This study also determined the effect of incorrect charge and low air flow across the inside coil at hot dry conditions. These common problems can increase peak load by over 500 watts on typical units. The Prototype is less affected (but not unaffected) by incorrect charge. Additional peak reduction items are also discussed. Notably the indoor fan motor drew over 450 watts while producing only 44 watts of effective work.
The efficiency of the indoor fan and motor assembly was 9% at standard flow conditions. An increase to 15% efficiency was accomplished merely by reducing the cabinet restriction at the blower inlet. Significant efficiency improvement is possible through optimization of fan/motor/cabinet configurations.
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