A 7kW fuel cell is proposed for use to deliver combined heat

A 7-kW fuel cell is proposed for use to deliver combined heat and power (CHP) to a dormitory. The fuel cell converts natural gas into electricity with 35% efficiency, and another 40% of the input fuel ends up as useful heat for the dormitory\'s hot water, space heating, and space cooling demand. Natural gas costs 90 c/therm (1 therm = 100.000 Btu). The fuel cell costs $25,000 to install, and is to be paid for with a 6%. 20-year loan. It operates with a capacity factor of 90%. The useable waste heat from the fuel cell would displace the need for heat from an 85%-efficient natural gas fired-boiler. a. What is the energy chargeable to power (ECP), in Btu/kWh? b. What is the fuel cost chargeable to power (CCP), in c/kWh? c. What is the cost of electricity from the fuel cell, in c/kWh?

Solution

75 KW is proposed to use combined heat and electricity.

Fuel cell efficiency = 35% (Electrical)

= 40% (Heat energy)

Fuel cell cost $25,000

Loan with 6% and time 20 years.

Operating capacity is 90%

Now considering the efficiency, Total efficiency is 35 + 40 = 75%

Therefore the total power required to run the unit = 75KW/0.75 = 100KW

/Please mention the unit of natural gas clearly

You may divide it to the natural gas price, to know the chargable amount.