Field Measurements of Air Conditioners with and without TXVs

摘要

This paper summarizes field measurements of 4,168 air conditioners with and withoutTXVs. Approximately 72 percent of the air conditioners had improper refrigerant charge and 44percent had improper airflow. Average energy savings for correcting RCA are 12.6 ± 2.3percent. The paper provides detailed EER measurements and the relative efficiency improvementfor sixteen TXV and forty-nine non-TXV air conditioners. EER measurements of airconditioners with improper RCA indicate a relative efficiency gain of 21 ± 7 percent for TXVand a gain of 17.1 ± 2.8 percent for non-TXV air conditioners. The difference in efficiency gainbetween TXV and non-TXV air conditioners is 3.9 ± 0.3 percent at the 90 percent confidencelevel. The uncertainty associated with field measurements of capacity and EER was evaluatedusing the propagation of error technique and the overall uncertainty error is ± 4.4 percent. Thepaper indicates proper RCA is much more effective than a TXV in terms of delivering ratedefficiency performance, especially if TXV sensing bulbs are improperly attached to the vaporline or are not insulated. The paper describes an easy-to-use method to verify RCA using PDAsoftware or automated voice telephony. The paper should be of value to anyone interested inreducing peak air conditioning demand.