The Design and Development of a Capture Efficiency Test Facility By Using Tracer Gas Monitoring For Performance Testing of Kitchen Ventilation Systems

Effective kitchen ventilation systems are critical for removing hazardous pollutants generated during cooking to maintain acceptable levels of indoor air quality. Current indoor air quality standards specify air flow and sound ratings as the only metrics to analyze the performance of kitchen ventilation. Lawrence Berkeley National Laboratory has been working alongside ASTM to develop a test standard for analyzing the fraction of cooking pollutants removed by kitchen range hoods. RELLIS Energy Efficiency Laboratory (REEL) was given the opportunity to design, develop, and construct a capture efficiency test facility using tracer gas monitoring to analyze the performance of kitchen ventilation systems. REEL established seven sub-components of the testing facility based on the requirements outlined in the test standard developed by LBNL. The 4.34 m x 3.93 m x 3.05 m testing chamber was sized to best represent a residential kitchen, which can accommodate range hood flow rates up to 200 L/s. All components and necessary equipment and instrumentation were designed and selected to conform to the dimensional, measurement, and accuracy requirements outlined in the test standard. Testing procedures were developed and preliminary data for 5 kitchen range hoods were taken to qualify the room and to analyze the effects of range hood air flow, mounting height, and cooking surface temperature on capture efficiency. Air flow rates 150 cfm yielded capture efficiencies between 86-92%. Average capture efficiencies were 67.7% and 77.8% for mounting heights of 30” and 21” for flow rates < 150 cfm, respectively, while at air flow rates > 190 cfm, capture efficiencies were measured to be 88.2% (30”) and 90.3% (21”). At air flow rates < 130 cfm capture efficiencies were 66.4% and 55.6% for surface temperatures of 150 0C and 200 0C, respectively. At air flow rates > 160 cfm, capture efficiencies were measured to be 79.9% and 74.3%. It was found that capture efficiency increased with increasing air flow rates, and decreasing mounting heights (closer to cooking surface) and surface temperatures. Large differences in measured capture efficiencies at flow rates < 150 cfm suggests that cooking and ventilation parameters are more impactful at lower operating speeds