Hail Effects on Air-Conditioner Performance

Experiments demonstrated the effects on air-conditioner system performance resulting from dents in fins of their condenser coils and the extent to which conventional fin repair methods restore performance. Two different, commercially available, split-system, residential-type air-conditioners were tested. Flattening substantial areas of the fins caused a reduction in capacity and efficiency of the cooling systems tested. Performance first dropped appreciably when 60% of the fin areas were pressed flat. Incremental increases in total percentages of areas flattened beyond the first reduction in performance resulted in incremental decreases in capacity and efficiency. Specifically, with 60% of the fin area flattened on one condenser, system capacity decreased 4%; system SEER (efficiency), 9%. With 100% of the fin area flattened, system capacity decreased 27%; system SEER, 34%. Combing dents from the fins after the extreme case where all fins were flattened restored capacity to within 1% of the undented condition and SEER to within 6% of the undented efficiency. Similar results were obtained for the second condenser tested.