NIST Technical Note 1651 Particle Image Velocimetry Measurements and CFD-Based Predictions of Air Distribution at Evaporator Inlet and Outlet

We examined the air flow distribution through a residential indoor air conditioning heat exchanger. The test heat exchanger was a finned tube, A-shaped coil outfitted with a condensation collection pan required for a horizontal installation configuration. We examined the air flow distribution approaching and exiting the coil at two different air flow rates and two humidity levels. Our dry coil PIV measurements indicate that the presence of the condensation collection pan impedes air flow through the lower slab of the coil causing approximately 20 % more air flow through the upper slab than the lower slab.