A friend offers to sell you an experimental Stirling engine to power your house. The engine isguaranteed to last 15 years and is fueled by burning natural gas with a combined combustionand heat transfer efficiency of 0.90 and a generation efficiency of 0.98. Your friend tells you thatthe Stirling engine has an efficiency of 0.50. Operations and maintenance costs total $0.01/kWh. Assume natural gas costs will be $6/MBtu for the next 15 years and an interest rate of6% and financing for 15 years. Assume your house requires 25 kWh per day and you currentlypay $0.20/kWh and you anticipate this will remain constant for the next 15 years.
a. What is the overall efficiency of the Stirling engine system?
b. What is the cost of fuel per kWh?
c. If you are willing to spend 80% of your current electrical costs on this system, what is themaximum should you pay for the Stirling engine system?