Yes, I didn't do a very good job of coping my scratch paper..... Jeff On 09/28/2014 05:19 PM, Art Krenzel wrote: > I believe there was a math/typing error on the initial email > > 140,000 TPY X 2000 lbs/ton X 8,000 BTU/# = 2.24 X 10^12 BTU > (not 10^24) > > Therefore 1.56/2.24 should equal about 69.6% conversion efficiency. > > Art