Renewables, homework help
Q1. (85%) Based on the discussion in the last lectures on
Renewable Energy Systems, and from your point of view, what would be the
optimum renewable energy system to proceed with in the next two decades?
Support your argument by statistical analysis, potential advances for the
system considering the sustainable criteria of:
- Environmental impact ( i.e. less emissions to air
, water, land; less depletion of resources,…etc) - Economical Impact (i.e. cost, economy of
resources, viability,…etc) - Human well-being, acceptance
Please remember that for the
system to be sustainable there is compensation between the 3 previous
attributes, so do not hesitate to choose any system you see has potential
applications, fast wide-spreading, environmentally
sound,…etc. Support your argument with examples, initiatives, more governmental
support than the others. You can choose from Biomass, Wind, Hydrogen, Solar PV,
Geothermal, Tidal, Hydro power, or a new promising system you see (must provide
strong evidence for brand-new systems). You will have a brief presentation (15
slides) on your chosen system (please see class schedule) for 10 minutes.
Q2. (15%) You have a client in Norfolk, VA (36.9 o N
Latitude). She asked you to design a small scale house with basic appliances
(refrigerator, washer, microwave, stereo, fan, and TV) and the lighting
fixtures will be energy efficient (fluorescent bulbs, high efficient
incandescent, no sodium or halogen lamps). One of the ideas was to power the
house with a grid-connected PV system since the weather is good and sunny she
will use fans and cross ventilation in cooling the house (no ACs) to minimize
energy consumption.
Make a rough estimate of the
PV array area required for the house and the annual energy production giving
the following equations (please refer to resources on D2L, Chap 17: system
sizing, p.163 – p.172 for more information, equations and other illustrations:
1. Area (PV) [m2] = Power PV [kW] / η PV
2. Power PPV [kW] = Daily load [kWh/day] / Lowest insolation on
PV array [(kW/m2) / day] / wiring loss factor
3. Annual Energy E = η whole
system x K x PPV [kW] x Annual insolation (S) [kWh/m2]
Assumptions:
1. The system will operate
all year long since the weather is good
2. η PV :
efficiency for Polycrystalline silicon module =
20% (0.2)
3. η whole system : losses in wires and inverter =
85% (0.85)
4. K : safety factor = 0.9
5. Tilt angle =
30o (i.e. slope of the roof)
6. Azimuth angle =
0 (true south)
7. Shading factor =
0
8. Wiring loss factor =
0.9
9. Daily Load =
3 kWh/day
10. Safety factor = 0.9
(You use the most advanced module available)
11. Solar Insolation and
energy is given according to the following table:
|
Month |
Horz’l |
Array plane |
||||||
|
Horizontal Insolation |
x |
Tilt angle (30), azimuth,shade factor for 36.9o |
= |
Insolation at 30o |
x |
Days per month |
kWh/m2.month |
|
|
kWh/m2.day |
kWh/m2.day |
|||||||
|
Jan |
2.1 |
x |
1.5 |
= |
3.36 |
x |
31 |
104.16 |
|
Feb |
2.9 |
x |
1.4 |
= |
4.06 |
x |
28 |
113.68 |
|
Mar |
4.0 |
x |
1.2 |
= |
4.8 |
x |
31 |
148.8 |
|
Apr |
5.3 |
x |
1.0 |
= |
5.3 |
x |
30 |
159 |
|
May |
6.0 |
x |
0.9 |
= |
5.4 |
x |
31 |
167.4 |
|
Jun |
6.3 |
x |
0.9 |
= |
5.67 |
x |
30 |
170.1 |
|
Jul |
5.8 |
x |
0.9 |
= |
5.22 |
x |
31 |
161.8 |
|
Aug |
5.3 |
x |
0.9 |
= |
4.77 |
x |
31 |
147.8 |
|
Sep |
4.4 |
x |
1.1 |
= |
4.84 |
x |
30 |
145.2 |
|
Oct |
3.4 |
x |
1.3 |
= |
4.42 |
x |
31 |
137 |
|
Nov |
2.6 |
x |
1.5 |
= |
3.9 |
x |
30 |
117 |
|
Dec |
2.0 |
x |
1.5 |
= |
3.0 |
x |
31 |
93 |
|
S: Annual insolation on PV array [kWh/m2] |
1665 |
