Accurate field measurement of air flow through air handlers in residential forced air distribution systems has multiple important applications. Current techniques for measuring air handler flows are subject to substantial uncertainty. This project will develop, refine, and test a simple, easy-to-use, practical air flow measurement device which replaces the filter on the return side of the air handler. In addition to accuracy, the device must be durable for field use. In Phase I, a prototype device was fabricated from perforated metal and tested in a laboratory setting. Testing was done over a range of flow rates and with several return duct configurations. Calibration runs showed excellent performance of the prototype, with a standard deviation of the calibration coefficient of only 1.7% of the mean. In Phase II, the device will be refined with a focus on durability and application to a wide variety of filter sizes and air handler configurations. The resulting device or devices will be tested extensively in the field, and results will be compared to flow rate estimates based on other current techniques.

Commercial Applications and Other Benefits as described by the awardee: This device will enable the flow rate over the coils of air conditioners and heat pumps to be accurately measured so that adjustments can be made before low flow rates become a problem. The device will also allow for improved estimates of duct losses and subsequent savings due to retrofits.