UNT is trying to replace 200 two hundred bulbs 100 Watts am

UNT is trying to replace 200 (two hundred bulbs!) 100 Watts am incandescent light bulbs by 200 (two hundred bulbs!) 15- Watts-LED bulbs. Assume that the incandescent bulbs Operate 6 hours per day and need to be replaced every year at a cost of $1.50 each. The LED bulbs will last 8 years with initial cost of $15 each. The cost of electricity over this 8 year period is $0.10/kwh. Assume a discount rate of 9%. calculate The payback period in years TLCC of 200 incandescent light bulbs in 8 years TLCC of 200 LED light bulbs in 8 years Level zed cost of Energy saving (LCOE), in the unit of $/kwh/year show (or copy from EXCEL) detailed steps even if you used EXCEL for calculation.

Solution

1) Let payback year be x

therefore cost for 1 bulb = 1.5*(x-1) + 100*6*0.1*x*365/1000

cost of 1 led = 15 - 9*15/100 + 15*8*0.1*x*365/1000

equating both, we have , x= 0.7965

therefore payback year is 1 year

2) TLCC of 1bulb for 1 year = 1.5 + 100*6*0.1*365/1000 = $ 23.4

TLCC of 200 bulbs for 1 year = $200*23.4 = $ 4680

TLCC of 200 bulbs for 8 years = $ 4680*8 = $ 37440

3) TLCC of 1 LED for 8 years = 13.65 + 15*8*0.1*8*365/1000 =$ 48.69

TLCC for 200 LED for 8 years = 200*48.69 = $ 9738

4) Total energy consumed by bulb in 1 year = 100*6*0.1*365/1000= 21.9 $/kwh/year

Toatl energy consumed by led in 1 year = 15*8*0.1*365/1000 = 4.38 $/kwh/year

therefore total energy saved in 1 year = (21.9 - 4.38) = 17.52 $/kwh/year