|Adams, W -|
|Montross, M -|
|Davis, J -|
Submitted to: International Symposium on Air Quality and Waste Management for Agriculture
Publication Type: Proceedings
Publication Acceptance Date: July 1, 2011
Publication Date: August 7, 2011
Citation: Purswell, J.L., Adams, W.C., Montross, M.D., Davis, J.D. 2011. Evaluation of automotive mass airflow sensors for animal environment research and control. International Symposium on Air Quality and Waste Management for Agriculture. ASABE #1110839. Interpretive Summary: Mass air flow is a necessary measurement when determining heat and moisture production of animals. However, measurement in high flow rate systems such as environmental chambers is costly. Automotive fuel management systems have employed low-cost mass air flow sensors for many years, but their accuracy has not been characterized under flow conditions found in animal research applications. Two types of automotive mass air flow sensors were evaluated at three different temperatures in an environmental chamber with flows ranging up to 250 scfm and compared against a reference instrument. Regression analysis indicated error rates for the automotive sensors were in the range of 1% at full scale flow of the reference instrument. Automotive mass air flow sensors may provide a more cost effective means of measuring mass air flow in animal research applications.
Technical Abstract: Mass air flow is an important parameter to consider in animal research applications, especially for the generation of heat and moisture production data. The high flow rates and low operating pressures in animal research facilities present a unique and costly challenge for measurement of mass air flow rates. Mass air flow sensors for automotive applications are designed for mass production and are inexpensive. In addition, automotive sensors are designed for minimum restriction of intake air supplied to internal combustion engines. Two commonly available mass air flow sensors for passenger vehicle engines were compared against a NIST-traceable mass air flow sensor to assess accuracy over a range of temperatures and flow rates. Air was supplied from an environmental chamber at 10, 20, and 30 °C using a variable speed blower. Concurrent measurements of mass air flow were recorded from the automotive sensors and the reference sensor over a range of 60 to 425 m3•h-1. Regression analysis showed that a quadratic relationship exists between output frequency and mass air flow through the sensors; coefficients of determination (R2) exceeded 0.99 for all cases tested. Full scale flow error for the hot-wire and hot-film sensor were 1.0% and 1.3%, respectively. Automotive mass air flow sensors could provide a more cost effect means of measuring mass air flow in animal research applications.