Ventilation rate estimates play an important role in evaluating the thermal environment and determining emission rates from livestock and poultry housing. Currently, the standard method to measure in situ ventilation rates is the Fan Assessment Numeration System (FANS). A similar sensing system is needed for extension personnel that eliminates the labor and set-up requirements of FANS. In order to efficiently and cost-effectively estimate ventilation rates, a Segmented Wand for Evaluating Airflow Performance (SWEAP) was developed. The objectives of this research were to: (i) design and construct a hand-held device capable of measuring in situ fan intake flowrate, (ii) evaluate SWEAP against a FANS unit, and (iii) assess the in-field applicability of SWEAP. Eight uniformly spaced Omnidirectional Thermal Anemometers (OTA) were heated above ambient temperature using Constant Temperature Anemometer (CTA) feedback methodology. The flowrate was determined by multiplying the cross sectional area associated with each OTA, with SWEAP placed at the intake of a tested fan. SWEAP was calibrated against a FANS unit (42-0002) for several flowrates and to accommodate typical agricultural-use fans. Several in situ fans ranging in diameters: 36 cm (14 in.), 61 cm (24 in.), 91 cm (36 in.), and 122 cm (48 in.), and capacity were tested with SWEAP to determine the feasibility of field applications. In-lab SWEAP traverse rates of 76 ±13, 127 ±13, 178 ±13, and 229 ±13 mm s-1 (3.0 ±0.5, 5.0 ±0.5, 7.0 ±0.5, and 9.0 ±0.5 in. s-1) were tested with no significant difference found between the 76 ±13 mm s-1, 127 ±13 mm s-1 rates. A nominal SWEAP traverse rate of 127 ±13 mm s-1 was used for subsequent in-field testing. Results showed that there was no significant difference (p>0.05) between SWEAP and FANS airflow means for the 36 cm fan, 61 cm fan, and the 91 cm fan. The average percent difference between SWEAP and FANS for all in-lab and infield fans tested was less than 5.0%. SWEAP can be used by extension personnel to quickly and accurately evaluate airflow for multiple fans.
Available at: http://works.bepress.com/brett-ramirez/2/