Lisa asks…
which are the top 10 solar companies in the world?
those who manufacture pv systems
Michael answers:
1) Solar World 91
2) Trina Solar 89
3) First Solar 87
4) REC 87
5) Sun Power 85
6) Yingli Solar 72
7) Sharp 0 
Suntech 0
9) Canadian Solar 0
10) Hanwa SolarOne 0
Laura asks…
why pv street lighting system is not recommended for urban area?
Michael answers:
Ask in Science, it’s not a Wordplay question.
Mary asks…
Why does the term PV appears in the open system energy equation and not in that for a closed system?
Thermodynamics
Michael answers:
Open/closed to what? You have to consider the constraints on the system. Usually the PV term refers to the WORK energy aspect of a process (as opposed to the heat energy aspect TS).
But your question is way too vague for any meaningful discussion. There are a lot of ways of manipulating the equations and controlling the system in order to replace or ignore various state parameters.
Donna asks…
How to calculate PV of this problem?
A boiler permit cost $1800 with a escalation rate of 0% and a interest rate of 8%..the life of the system is 20 yrs ..however the permit is renew every 3 yrs..now the answer is Present Value (PV) = $1996.06 ..but i do not know how to get there
Michael answers:
Maybe there’s a typo. I get $6996.34. Could the leading 1 really be a 6?
I threw the problem into Excel, rather than use formulas:
Year-PMT-Int-PV
1-1800-1.000000-$1,800.00
2-0.00-0.925926-$0.00
3-0.00-0.857339-$0.00
4-1800-0.793832-$1,428.90
5-0.00-0.735030-$0.00
6-0.00-0.680583-$0.00
7-1800-0.630170-$1,134.31
8-0.00-0.583490-$0.00
9-0.00-0.540269-$0.00
10-1800-0.500249-$900.45
11-0.00-0.463193-$0.00
12-0.00-0.428883-$0.00
13-1800-0.397114-$714.80
14-0.00-0.367698-$0.00
15-0.00-0.340461-$0.00
16-1800-0.315242-$567.44
17-0.00-0.291890-$0.00
18-0.00-0.270269-$0.00
19-1800-0.250249-$450.45
20-0.00-0.231712-$0.00
ANSWER(SUM) ===>$6,996.34
Jenny asks…
What sort of PV Inverter should i get?
Hi Guys,
I’m sort of a newbie in solar technology and student researching on the topic on PV inverter. Was wondering could anyone recommend me good grid-tied and off-grid inverter for each of the mention types of inverter possible to implement into PV systems for me to start off my research?
I’ve tried searching online but there’s so many variant of inverters that i’m quite lost what to pick because i’m sort of new in this area.. So please pardon me for asking such question in the open..
1. I’m required to identify the inverter’s mechanical, electrical and general/environment specific parameters.
2. Reasons for the chosen types of inverter?
3. A pure output sinewave inverter is preferred rather than a modified sinewave.
Michael answers:
An inverter selection is done for 4 parameters
1. What is your peak power load on the inverter?
2. Do you want a cheap (square wave) or a better psuedo-sine wave one
3. Do you want a grid tie inverter?
4. 120 VAC 60Hz or 230 VAC 50 Hz output? (easy to pick this one)
#3 is selected if you want to sell excess power back the the power company. This one has to be approved by the power company.
#1,4 is obvious
#2, you should get the psuedo-sine wave version if you are driving any electronics.
You are required to list those parameters? By who? Mechanical is just the size and weight. Electrical are listed above. Environmental ??
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