A school district is considering heating systems for a high school anticipated to have an annual heating load of 7200 GJ/year. Compute the annual cost of heating the building with these systems:
a. A modern, high-efficiency boiler with a seasonal efficiency of 96% that is fired with natural gas with a heating value of 37 500 kJ/m³ and a cost of $.50/m³.
b. A modern, high-efficiency furnace with a seasonal efficiency of 92% that is fired with fuel oil with a heating value of 140 000 Btu/gal and a cost of $3.50/gal.
c. An electric-resistance furnace with a seasonal efficiency of 100% that is electrically powered with a heating value of 3413 Btu/kWh and a cost of $0.15/kWh.
d. An air source heat pump with a seasonal efficiency* of 150% that is electrically powered with a heating value of 3413 Btu/kWh and a cost of $0.15/kWh.
e. A geothermal heat pump with a seasonal efficiency* of 350% that is electrically powered with a heating value of 3413 Btu/kWh and a cost of $0.15/kWh.