Posted by Paul on June 18, 2005, 10:43 pm
I've got an estimate here from a PV installer for a grid-tied system
which should zero my annual bill. I'm concerned because there is an
inverter listed which I've never heard of before. I'd like to run this
by the group for your comments.
Inverter: Fronius IG2000
Panels: Sharp 167 watt (14)
He states this is a 1.9 KW system and should zero my meter based on
consumption of 3,326 kwh over the last 12 months. I live 10 miles north
of San Francisco.
I'm also curious about your thoughts regarding heating the house. I
have baseboard heaters which I haven't used since shortly after the
first few electric bills 20 years ago. I put in an efficient woodstove
with catalytic converter and used that for several years until I
finally had a forced air furnace installed. I burn about 45 therms per
month during the cold (or what passes for cold hereabouts) season. The
"cold" season lasts about 6 months. That's a very rough estimate and
includes the NG used by the water heater.
I stopped using the baseboards because I know just enough to know that
electricity is not a very efficient source of heat. But now I'm
thinking that if I produce my own with PV, it might not be such an
insult to the environment. Your thoughts? Any formula to determine how
much extra electricity I'd have to produce?
Finally, the installer's estimate was given via fax without a site
visit. On the one hand that seems cavalier. On the other, he's local
and has been doing this for a long time so he probably knows his
territory. He also discounted the notion that the panels needed to be
oriented for best efficiency. The roof has little slant (tar and
gravel) and there is no surface which faces due south. He seemed to
think aesthetics (flush mounts) outweighed ultimate efficiency and that
it made little difference anyway. Again, your thoughts?
Posted by George Ghio on June 19, 2005, 12:14 am
Never heard much wrong with the Fronius.
Can email you a spreadsheet to work out what you want to know. Cost $.
You can also down load several others from the net. The big advantage is
that you can check on your suppliers numbers.
George L Ghio
Solar Power Consultant
Posted by Bill Kaszeta / Photovoltaic Re on June 19, 2005, 4:12 am
The estimate of 3,326 kwh per year for 14 Sharp 167 watt modules
is correct for installation at a 30 to 35-degree tilt using San Francisco
solar and temperature data. You would have a 2338-watt system
(rated at 25 DegC, lower at operating temperature). Likely you will
loose a little winter performance due to the 2000-watt rating of the
inverter. I believe that the Fronius IG2000 has been tested by
the California Energy Office and is on the list of approved inverters.
Photovoltaic Resources Int'l
Tempe Arizona USA
Posted by Solar Guppy on June 19, 2005, 1:39 pm
For all the CEC listed inverters and there verified performance visit
The IG2000 is on the bottom of the heap in efficiency ,
The best price/performance is the Xantrex GT3.0 , street price of 1900.00
for 3kw , also includes RS232/software built-in disconnects which with most
other inverters are add-on options
14 sharps in a single string would work well with this inverter
Posted by Paul on June 20, 2005, 8:51 am
Thanks for the replies. I'll look at the Xantrex, a name I've run
Any thoughts on heating the house with electricity?