Question

4. A heater has an efficiency of utilization of 90%. If gas is available at $1.25 per therm. What is the net cost of heating energy in dollars per million Btu? How could 90% efficiency be achieved?

Answer 1

so Comen efficiency one million BTU of etization = 90%. will requme 1,000,ooo - therme 10.90 x 100, 000) 11111 thermu per frem Areme Cost for million and = $11111881125 = $13.89 heating energy = $13.89 | per million BTU Cuven for $1,25 $11.111 so ovet cost of - - Furnace with efficiencies of about qox. are known as high efficiency or condensing furnace * The use of spark ignition in the combustion chamber call keep exhaust gave at 120 F instead of 400° F or more the proceu allows almost all the useful heat to be removed and the gaver are cool enough to be cuhausted Anrough a plaute pire using this type of system allows reasonal and steady-state efficiencies to reach 90%