1. A small business would like to install a wind turbine to produce electricity. A wind study has been completed and produced the wind distribution in the table below_ A wind turbine with a rated capacity of 250 kW and a 350 m2 swept area has been identified for installation. The cost of the turbine with installation is $750,000_ Over the planned 25 years of user the operating and maintenance costs have been annualized to $15000/year.
At the end of 25 years, the salvage value is estimated to be $ 60001 Assume the average wind speed for bin 17 is 18 m/s, the air density is 1.15 kg/m3, and a MARR of 6%.
a. What is the capacity. factor for this wind turbine?
b. What is the levelized cost of electricity from this wind turbine?
c. Recalculate the capacity factor using an appropriate average wind velocity
|
Bin
|
Min (m/s)
|
Max (m/s)
|
hours/year
|
|
1
|
0
|
0
|
256
|
|
2
|
0
|
1
|
130
|
|
3
|
1
|
2
|
618
|
|
4
|
2
|
3
|
1405
|
|
5
|
3
|
4
|
1249
|
|
6
|
4
|
5
|
1311
|
|
7
|
5
|
6
|
1086
|
|
8
|
6
|
7
|
802
|
|
9
|
7
|
8
|
663
|
|
10
|
8
|
9
|
527
|
|
11
|
9
|
10
|
341
|
|
12
|
10
|
11
|
180
|
|
13
|
11
|
12
|
67
|
|
14
|
12
|
13
|
75
|
|
15
|
13
|
14
|
26
|
|
16
|
14
|
15
|
10
|
|
17
|
15
|
none
|
14
|
2. Biodiesel fuel is commonly produced from soy. The energy requirement per acre to grow nor beans is the following:
|
Input
|
Energy (1000 BTU)
|
|
Fue Is
|
1025
|
|
Fertilizer
|
615
|
|
Machinery (embodied energy)
|
205
|
|
All other
|
205
|
Each acre yields 452 pounds of soy, and each gallon of soy b i °diesel requires 73 pounds of soy as input. A gallon of bicodiesel contains 117,000 BTU of net energy content Production energy requirements per 1000 pounds of soy beans processed are in the table below.
|
Input
|
Energy (1000 BTU)
|
|
Process heat and electricity
|
1784
|
|
Machinery (embodied energy)
|
595
|
|
Transportation
|
297
|
|
All other
|
297
|
What is the net energy balance ratio for the production of biodiesel from soy?
3. You are replacing a 75 W light bulb in your home that operates, on average, 6 hours per day. You can select from the three light bulbs shown in the table below. Note that each light bulb produces the same amount of visible light (lumens) and the cost of electricity is constant at $0.11/1cW-hr. Which light bulb would you purchase, based on levelized cost analysis, and why?
| Type |
Cost/bulb
|
Bulb power consumption
|
Buld lifetime
|
MARR
|
|
Incandescent
|
$1
|
75 W
|
1 year
|
7%
|
|
CFL
|
$9
|
40 W
|
10 year
|
7%
|
|
LED
|
$26
|
14 W
|
25 year
|
7%
|
4. The solar power plant shown below operates on a Rankine cycle with Refrigerant
134a as the wo rking fl uid. The turbine and pump operate adiabatically but not necessarily isentropically. The rate of energy input to the collectors from solar radiation is 0.3 kW per m2 of collector surface area, with 60% of the solar input to the collectors absorbed by the refrigerant as it passes through the collectors. Determine the solar collector surface area per kW of power developed by the turbine.
|
State
|
P (bar)
|
h (kj/kg)
|
x
|
|
1
|
18
|
276..83
|
1
|
|
2
|
7
|
261.01
|
0..9952
|
|
3
|
7
|
86.78
|
0
|
|
4
|
18
|
87.93
|
-
|