In a new high-efficiency furnace, natural gas, assumed to be 90% methane and 10% ethane (by volume) and 110% theoretical air, each enter at 77 F, 15.7 lbf/in.², and the products (assumed to be 100% gaseous) exit the furnace at 100 F, 15.7 lbf/in.². What is the heat transfer for this process? Compare this to an older furnace where the products exit at 450 F, 15.7 lbf/in.².