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Better Unitary Equipment Air-Handlers for Efficiency and Humidity Control
Regulatory requirements drive unitary equipment design. For residential equipment, SEER reflects performance at moderate temperatures, and is largely independent of high temperature efficiency and high latent heat removal capability. The test procedure gives too little credit for advanced air handlers that reduce air conditioning load and facilitate adaptive humidity control through automatic fan speed adjustment. DC permanent magnet variable speed motors have much lower market share than less efficient permanent split capacitor designs: changing saves 15% - 25% at high fan speed, and at least 50% at lower speeds (high latent cooling). Humidistats allow dynamic humidity control by reducing air flow, cooling the evaporator. Following market transformation to increase market share, federal equipment stanards should be augmented to include specific air handler air flow efficiency levels, such as 0.2 watts/cfm at size-dependent static pressures. We estimate that customer payback will be less than three years in a mature market.
Sachs, H. M. (2002). Better Unitary Equipment Air-Handlers for Efficiency and Humidity Control. Energy Systems Laboratory (http://esl.tamu.edu); Texas A&M University (http://www.tamu.edu). Available electronically from