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Show Stability Characteristics and Emission Levels of a Laboratory Hot Water Heater Utilizing a Weak-Swirl Burner ABSTRACT Derek T. Yegian, Robert K. Cheng Lawrence Berkeley National Laboratory Combustion Group Energy and Environment Division Berkeley, CA 94720 This paper reports the test results of a collaboration between Lawrence Berkeley National Laboratory and Teledyne Laars to assess the viability of incorporating the Weak-Swirl Burner (WSB) into a 15 kW (50,000 Btu/hour) Telstar spa heater. By stabilizing premixed lean combustion down to equivalence ratios $ ~ 0.6, the WSB greatly reduces NOx levels by minimizing thermally generated NOx through the Zeldovich mechanism. The first set of experiments focus on establishing the WSB' s minimum and maximum swirl requirement (corresponding to blowoff and flashback) for varying $, power levels, burner size, and enclosure. The second set of experiments evaluates the performance of a laboratory water heater where the WSB is incorporated into a Telstar heat exchanger. It was found that the laboratory test station achieves "low" « 50 ppm) and "ultra-low" « 25 ppm) NOx emissions without compromising the thermal efficiency. The optimum operating condition is for $ = 0.8 at 18 kW (60,000 Btu/hr) where NOx < 25 ppm and CO < 50 ppm (both corrected to 30/0 02). The results will be used as design guideline for using the low emission WSB in a prototype. The stable operation we found for enclosed WSB demonstrates the potential for its use in other combustion applications as well. 1 |