A particular location has consistent daily wind patterns Fro

A particular location has consistent daily wind patterns. From 10 pm to 6 am the winds are 20 m/s from the NW. Then they die out completely from 6am to 4pm. The winds build up again in the evening from 4pm, consistent at 10 m/s from the east. Calculate the EPF at this location.

EPF= (Actual Energy production/Energy Using Average)

Solution

>> As, Energy is directly proportional to the square of velocity

Actual Energy Production

As, energy actually comes between 10 pm to 6 am and from 4 pm to 10 pm

From 10 pm to 6 am, no of hours = 8 hrs

and velocity = 20 m/s

So, Specific Energy produced per sec = V²/2 = 20*20/2 = 200 J/s = 72000 J/hr

So, between 8 hrs, actual energy produced = 200*8*3600 = 5760000 J = E1

>>

From 4 pm to 10 pm, no of hours = 6 hrs

and velocity = 10 m/s

So, Specific Energy produced per sec = V²/2 = 10*10/2 = 50 J/s = 18000J/hr

So, between 8 hrs, actual energy produced = 50*6*3600 = 1080000 J = E2

So, Actual Energy Produced = E1 + E2 = 6840000 J

and, Average Energy Produced = Total hours*Average Energy per hour

As, Average Energy produced per hour = (72000 + 18000)/2 = 45000 J/hr

SO, Average Energy Produced = 24*45000 = 10800000 J

>> So, EPF = (Actual Energy production/Energy Using Average) = 6840000/10800000 = 0.633