Here, it's my job to equip my new apartment with the most energy and cost effective lighting. I will be performing a life cycle analysis for incandescent and CFL lighting schemes in this section and will eventually recommend the most cost effective lighting scheme.
Given Information:
The number of footcandles required for each room in the house and their dimensions were given on the course website and they are listed below.
The areas were calculated by doing the following: Area = length x width
Example: Area of Living Room = 18' x 17' = 306 ft^2
Living Room 18' x 17' 306 ft^2 10 - 20 footcandles
Kitchen 9' x 10' 90 ft^2 30 - 40 footcandles
Stove 2.5' x 3' 7.5 ft^2 70 - 80 footcandles
Dining Room 9' x 10' 90 ft^2 30 - 40 footcandles
Bedroom 13' x 19' 247 ft^2 10 - 20 footcandles
Bedroom 14' x 19' 266 ft^2 10 - 20 footcandles
Hallway 18' x 4' 72 ft^2 5 - 10 footcandles
Sink 4' x 3' 12 ft^2 70 - 80 footcandles
Bathroom 9' x 7' 63 ft^2 70 - 80 footcandles
Lumens = Area x Footcandles
Example: Lumes required for Living Room = 306 ft^2 x 15 footcandles = 4590 lumens
*NOTE: Since the footcandles required for the living room is between 10 and 20 footcandles, I chose to use 15 footcandles in the calculation since it was a convenient number in the middle of this range. I did this for the rest of the rooms, too.
Living Room 306 ft^2 10 - 20 footcandles 4590 lumens
Kitchen 90 ft^2 30 - 40 footcandles 3150 lumens
Stove 7.5 ft^2 70 - 80 footcandles 562.5 lumens
Dining Room 90 ft^2 30 - 40 footcandles 3150 lumens
Bedroom 247 ft^2 10 - 20 footcandles 3705 lumens
Bedroom 266 ft^2 10 - 20 footcandles 3990 lumens
Hallway 72 ft^2 5 - 10 footcandles 360 lumens
Sink 12 ft^2 70 - 80 footcandles 900 lumens
Bathroom 63 ft^2 70 - 80 footcandles 4725 lumens
This value will be used later for other calculations.
Light Output: 615 lumens
Watts: 60 Watts
Price: $1.38 /bulb
Lifetime: 800 hours
Incandescent "B"
Light Output: 1221 lumens
Watts: 100 Watts
Price: $4.98 /bulb
Lifetime: 800 hours
Light Output: 900 lumens
Watts: 13 Watts
Price: $6.95 /bulb
Lifetime: 15,000 hours
CFL "B"
Light Output: 1600 lumens
Watts: 23 Watts
Price: $9.95 /bulb
Lifetime: 15,000 hours
1) To find out how many incandescent or CFL bulbs we'll need for the 60 watt bulb type (for example), we must divide the total lumens needed for all of the rooms divided by the numbers of lumens that each 60 watt bulb gives off.
Equation: Bulbs needed = Lumens needed for all of the rooms / Lumens given off by 60 watt bulb
2) To find the cost of bulbs, multiply the number of 60 watt bulbs needed by the price of 60 watt bulbs to find out the total cost.
Equation: Cost of bulbs = Number of 60 watt bulbs x Price of each 60 watt bulb
Total lumens needed for all of the rooms (found above): 25,132.50 lumens
~*~*~*~We use these same equations for Incandescent and CFL bulbs.~*~*~*~
1) Bulbs needed = Lumens needed for all of the rooms / Lumens given off by 60 watt bulb
Bulbs needed = 25,132.50 lumens / 615 lumens = 40.87 = 41 bulbs
2) Cost of bulbs = Number of 60 watt bulbs x Price of each 60 watt bulb
Cost of bulbs = 41 bulbs x $1.38 = $56.58
1) Bulbs needed = Lumens needed for all of the rooms / Lumens given off by 100 watt bulb
Bulbs needed = 25,132.50 lumens / 1221 lumens = 20.59 = 21 bulbs
2) Cost of bulbs = Number of 100 watt bulbs x Price of each 100 watt bulb
Cost of bulbs = 21 bulbs x $4.98 = $104.58
1) Bulbs needed = Lumens needed for all of the rooms / Lumens given off by 13 watt bulb
Bulbs needed = 25,132.50 lumens / 900 lumens = 27.93 = 28 bulbs
2) Cost of bulbs = Number of 13 watt bulbs x Price of each 13 watt bulb
Cost of bulbs = 28 bulbs x $6.95 = $194.60
1) Bulbs needed = Lumens needed for all of the rooms / Lumens given off by 23 watt bulb
Bulbs needed = 25,132.50 lumens / 1600 lumens = 15.71 = 16 bulbs
2) Cost of bulbs = Number of 23 watt bulbs x Price of each 23 watt bulb
Cost of bulbs = 16 bulbs x $9.95 = $159.20
3) To find out the energy consumed by the 60 watt bulbs, multiply the number of 60 watt bulbs we'll need for the whole apartment (which means all of the rooms) by the number of watts each bulb consumes (60 W).
Equation: Number of 60 watt bulbs used x 60 Watts
4) To find out how much energy these bulbs will use over their lifetime, multiply the energy consumed by the lifetime of the bulbs, which is 800 hours for both incandescent "A" and "B".
Equation: Energy Consumed over Lifetime = Energy Consumed x Lifetime of Bulbs
5) To find the cost of energy consumed of all bulbs, multiply the cost of energy (which we are assuming is 0.10 $/kWh by the energy consumed over the lifetime (value calculated in step 2).
Equation: Cost of energy consumed of all bulbs = Cost of energy x Energy consumed over lifetime
6) To find out how much the total cost of the incadescent or CFL bulb over the lifetimes are the cost of all the bulbs plus the cost of the energy they'll consume over the lifetime.
Equation: Total cost of incandescent or CFL bulbs over lifetime = Cost of all bulbs + Cost of energy they'll consume over lifetime
REMINDER: To figure out the cost of the energy bulbs will consume over lifetime, we will assume that energy costs 0.10 $/kWh.
~*~*~*~We use these same equations for Incandescent and CFL bulbs.~*~*~*~
3) Energy Consumed = Number of 60 Watt bulbs used x 60 Watts
Energy Consumed = 41 bulbs x 60 W = 2460 Watts
4) Energy Consumed over Lifetime = Energy Consumed x Lifetime of Bulbs
Energy Consumed over Lifetime = 2460 W x 800 hours = 1968 kWh
5) Cost of energy consumed of all bulbs = Cost of energy x Energy consumed over lifetime
Cost of energy consumed of all bulbs = 0.10 $/kWh x 1968 kWh = $196.80
6) Total cost of incandescent bulbs over lifetime = Cost of all bulbs + Cost of energy they'll consume over lifetime
Total cost of "A" bulbs over lifeitme = $56.58 + $196.80 = $253.38
3) Energy Consumed = Number of 100 Watt bulbs x 100 Watts
Energy Consumed = 21 bulbs x 100 W = 2100 Watts
4) Energy Consumed over Lifetime = Energy Consumed x Lifetime of Bulbs
Energy Consumed over Lifetime = 2100 W x 800 hours = 1680 kWh
5) Cost of energy consumed of all bulbs = Cost of energy x Energy consumed over lifetime
Cost of energy consumed of all bulbs = 0.10 $/kWh x 1680 kWh = $168.00
6) Total cost of incandescent bulbs over lifetime = Cost of all bulbs + Cost of energy they'll consume over lifetime
Total cost of "B" bulbs over lifetime = $104.58 + $160.00 = $272.58
3) Energy Consumed = Number of 13 Watt bulbs used x 13 Watts
Energy Consumed = 28 bulbs x 13 W = 364 Watts
4) Energy Consumed over Lifetime = Energy Consumed x Lifetime of Bulbs
Energy Consumed over Lifetime = 364 W x 15,000 hours = 5460 kWh
5) Cost of energy consumed of all bulbs = Cost of energy x Energy consumed over lifetime
Cost of energy consumed of all bulbs = 0.10 $/kWh x 5460 kWh = $546.00
6) Total cost of CFL bulbs over lifetime = Cost of all bulbs + Cost of energy they'll consume over lifetime
Total cost of "A" bulbs over lifeitme = $194.60 + $546.00 = $740.00
3) Energy Consumed = Number of 23 Watt bulbs x 23 Watts
Energy Consumed = 16 bulbs x 13 W = 368 Watts
4) Energy Consumed over Lifetime = Energy Consumed x Lifetime of Bulbs
Energy Consumed over Lifetime = 368 W x 15,000 hours = 5520 kWh
5) Cost of energy consumed of all bulbs = Cost of energy x Energy consumed over lifetime
Cost of energy consumed of all bulbs = 0.10 $/kWh x 5520 kWh = $552.00
6) Total cost of CFL bulbs over lifetime = Cost of all bulbs + Cost of energy they'll consume over lifetime
Total cost of "B" bulbs over lifetime = $159.20 + $552.00 = $711.20
To account for the differences in lifetimes, we have to divide the number of hours that the CFL bulbs last divided by the number of hours that the incandescent bulbs last.
15,000 hours / 800 hours = 18.75
7) We can now determine how many more incandescent bulbs we'll need that will last 15,000 hours, like the CFL bulbs do by multiplying the cost of the incandescent bulbs by 18.75
Equation: Readjustment of Cost of bulbs = Cost of bulbs (from #2) x 18.75
8) To determine the energy cost of energy that these bulbs will consume, we must multiply the wattage (from #3) by the new amount of hours, 15,000, and then by the cost of electricity to find the which we are assuming is 0.10 $/kWh.
Equation: Readjusted Cost of Energy Consumed = Energy Consumed x 15,000 hours x 0.10 $/kWh
9) To find the total cost we add up the cost of the bulbs plus the cost of the electricity, which is the sum of the values from #7 and #8.
Equation: Total Cost = Readjustment of Cost of bulbs + Readjusted Cost of Energy Consumed
7) Readjustment of Cost of bulbs = Cost of bulbs (from #2) x 18.75
Readjustment of Cost of bulbs = $56.58 x 18.75 = $1060.88
8) Readjusted Cost of Energy Consumed = Energy Consumed x 15,000 hours x 0.10 $/kWh
Readjusted Cost of Energy Consumed = 2460 kWh x 15,000 hours = 36900 kWh x 0.10 $/kWh = $3,690
9) Total Cost = Readjustment of Cost of bulbs + Readjusted Cost of Energy Consumed
Total Cost = $1060.88 + $3,690 = $4,750.88
7) Readjustment of Cost of bulbs = Cost of bulbs (from #2) x 18.75
Readjustment of Cost of bulbs = $104.58 x 18.75 = $1960.88
8) Readjusted Cost of Energy Consumed = Energy Consumed x 15,000 hours x 0.10 $/kWh
Readjusted Cost of Energy Consumed = 2100 kWh x 15,000 hours = 31500 kWh x 0.10 $/kWh = $3,150
9) Total Cost = Readjustment of Cost of bulbs + Readjusted Cost of Energy Consumed
Total Cost = $1960.88 + $3,150 = $5,110.88
Total Energy Consumption = 36,900 kWh
Total Cost = $4,750.88
Incandescent "B" - 100 Watt bulbs
Total Energy Consumption = 31,500 kWh
Total Cost = $5,110.88
Total Energy Consumption = 5,460 kWh
Total Cost = $740.60
CFL "B" - 23 Watt bulbs
Total Energy Consumption = 5520 kWh
Total Cost = $711.20
The CFL lighting scheme is a lot more economical. It costs a significant amount less to use CFL bulbs over incandescent bulbs over a 15,000 hour span, as you can see from the numbers above. We will be consuming much less energy and will be saving a lot of money (because we'll also have to buy less light bulbs) by going with the CFL lighting scheme.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2. What is the total energy saved by the more economical scheme compared to the other scheme over the lifetime of the fluorescent light?
The most energy efficient incandescent bulb is "B".
The most energy efficient CFL bulb is "A".
Energy Consumed by Incandescent "B" = 31,500 kWh
Energy Consumed by CFL "A" = 5,460 kWh
Total Energy Saved = 31,500 kWh - 5,460 kWh = 26,040 kWh saved by the CFL bulb over the 15,000 hours.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3. How much money will be saved by using the more economical lighting scheme over the lifetime of the fluorescent light?
The least energy efficient but cheapest incandescent bulb is "A", so since it is the cheapest, we will use it in this calculation.
The most energy efficient but cheapest CFL bulb is "B", so since it is the cheapest, we will use it in this calculation.
Total Cost of Using Incandescent "A" = $4,750.88
Total Cost of Using CFL "B" = $711.20
Total Money Saved = $4750.88 - $711.20 = $4039.68 saved over 15,000 hours by using the CFL bulb.
This life cycle analysis first determined how much lighting I'd need for each room in my apartment, figured out how much I'd be spending on two different kinds of incandescent bulbs and two different kinds of CFL bulbs, figured out how much energy I'd be using, and lastly figured out where I'd be getting my biggest bang for buck when I equated the lifetimes of all of the bulbs.
Again, I would choose the CFL "B" option because it is has the best economice value (it is the cheapest) and also uses a reasonable amount of energy.
However, if someone in my situation really wanted to conserve the most energy as possible, then they could go with CFL "A" and would just have to pay ~$30 more.
With CFL "B" choice, I estimate that I would need lighting for about 8 hours a day. This accumulates to about 3,000 hours a year. So, I estimated that I'd save 26,040 kWh over 15,000 hours. This means that in about a year, I'd save 26,040 kWh / 5 = 5,208 kWh in a year. According to the link given at the bottom of the lighting assignment, I'd save $506 over a year. There would be a 10536 lb/yr reduction of greenhouse gases (carbon dioxide), a reduction of 23 lb/yr of nitrogen oxides, a reduction of 1 lb/yr carbon monoxide, a reduction of 82 lb/yr of sulfur dioxide, a reduction of 1 lb/yr of PM10, and a reduction of 193 mg/yr of mercury.
So, there are so many positive benefits, besides just saving money, to using the CFL "B" bulb. I would be reducing the amount of pollutants in the air, too!