An industrial building has 196 mercury vapor light fixtures (1 lamp/fixture). Each fixture draws 285 W, including ballast. The lamp life is 20,000 hours, and the lamp cost is $44.00/lamp. These fixtures are replaced by 140 high-pressure sodium fixtures (1 lamp/fixture). Each fixture draws 185 W, including ballast. The lamp life is 24,000 hours and the lamp cost is $54.00/lamp. The facility operates 8760 h/year. (a) Calculate the annual lighting cost savings if energy charge is $0.1/kwh and demand charge is $5/kW. (b) Calculate the increase in heating cost due to the savings in part (a) if the heating system efficiency is 80%, fuel costs is $5.00/MMBtu, and there are 200 heating days per year.