Answer:
a) Cost_incandescent = $ 375
, Cost _CFL = $ 75
, Cost_LED = $ 45
b) total = 20833 days
, total_day = 3472 days
, Total_days = 1736 d
c) LED
Explanation:
This problem is interesting to solve it, we must have a very important factor, such as the equivalence of the light emitted by the three systems, let's perform the calculation for a light intensity of 1000 lumen in the three bulbs.
consumed potence
incandescent 100W = fluorescent (CFL) 20W = Led 12 W
Now if we can solve your exercise
a) Let's find the power consumed by each type of bulb in the 25000 h
E = P t
incandescent
E_incandescent = 100 25000
E_incandescent = 2.5 105 Wh
E_incandescent = 2.5 103 kWh
Fluorescent (Low Power) CFL
E_CFL = 20 25000
E _DFL = 5 102 kWh
LED
E_LED = 12 25000
E_LED = 3 102 kwh
Let's use a direct rule of proportions (rule of three) for the cost of energy, if 1 kWh costs $ 0.15, the energy calculates how much it costs
incandescent
Cost_Incandescent = 2.5 103 kW / h ($ 0.15 / 1kWh)
Cost_incandescent = $ 3.75 102 = $ 375
CFL
Cost_CFL = 5 102 0.15
Cost _CFL = $ 75
LED
Cost_LED = 3 102 0.15
Cost_LED = $ 45
Here we do not take into account the possibility of burning incandescent bulbs and there is an extra replacement cost
b) for this part we use direct proportion rules
If the day has 24 hours and the light is on for 5%, how many days are 25000 hours?
for 5% = 0.05
hours on in a day
#_hoursdays = 24 hrs 0.05 = 1.2 hrs
total days
total = 25000 / 1.2
total = 20833 days
for 30% = 0.30
# _hoursday = 24 0.30 = 7.2 h
Total_days = 25000 h (1 day / 7.2 h)
total_day = 3472 days
for 60% = 0.602
#_hours = 24 0.60 = 14.4 h
Total _days = 25000h (1day / 14.4 h)
Total_days = 1736 d
c) you should decide between the CFL and the Led are much lower.
Between these two should take into account the cost of the bulbs, if we only take into account the cost of the energy consumed, the selection should be LED
