Air-side data interpretation and performance analysis for heat exchangers with simultaneous heat and mass transfer: Wet and frosted surfaces

Data reduction methods for wet- and frosted-surface heat exchangers are reviewed, and logarithmic-mean temperature difference (LMTD) and logarithmic-mean enthalpy difference (LMED) methods for data interpretation are formulated, including fin efficiency expressions for flat-tube heat exchangers with constant-area fins. With these improved formulations for data interpretation in place, the two methods are compared using a numerical simulation of a flat-plate heat exchanger. For all conditions considered—spanning wet and frosted surfaces—the new UA-LMTD method provides the air-side convective heat transfer coefficient to within 3% and is more accurate than the HA-LMED method, which results in large errors under some conditions.