- #1
boyblair
- 8
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Hi everyone!
I am having a bit of a problem solving the following question, and would be very grateful for any advice given.
1. Homework Statement
A car is run for 400 hours per year, with a total mileage of 10,000 a year. The car uses diesel and consumes 2,000 litres per year. A litre of diesel cost £1.10 and holds 38.7MJ of primary energy.
a) Calculate the mean engine power?
b) If the engine is 20% efficient overall, how much energy would need to be stored in 95% efficient batteries to give a range of 300 miles on full battery charge?
3. The Attempt at a Solution
a) energy in 2000litres of diesel 38.7MJ * 2000litres = 77400000000MJ
number of seconds in 400hours 3600*400 = 1440000secs
power = energy/time = 77400000000/1440000 = 53750Watts or 53.75kW
b) Really stuck with this part
I am having a bit of a problem solving the following question, and would be very grateful for any advice given.
1. Homework Statement
A car is run for 400 hours per year, with a total mileage of 10,000 a year. The car uses diesel and consumes 2,000 litres per year. A litre of diesel cost £1.10 and holds 38.7MJ of primary energy.
a) Calculate the mean engine power?
b) If the engine is 20% efficient overall, how much energy would need to be stored in 95% efficient batteries to give a range of 300 miles on full battery charge?
3. The Attempt at a Solution
a) energy in 2000litres of diesel 38.7MJ * 2000litres = 77400000000MJ
number of seconds in 400hours 3600*400 = 1440000secs
power = energy/time = 77400000000/1440000 = 53750Watts or 53.75kW
b) Really stuck with this part