Air Quality. [RE-wrenches]

Wed Apr 18 20:05:06 PDT 2001

Bill,
I found two Small Air-C (8,000 to 11,000 BTUs) window units at Lowe's (a
local home-depot competitor) that are rated at 800-watts with a LRA of 28
the other 42. on the larger unit I saw 580w when running on low, 68w for
just the fan and 1w just sitting there doing nothing, I took a watt meter
with me when I went to the store .  If the place is small one of them will
work. (note they were not suppose to be used for a house only a mid-size
room or kitchen) The SW can possibly run other loads like Refrigeration and
ac well pump at the same time.  Do you have an idea where to set the
hysteresis so the dump load does not turn off when the load comes on and
puts a serge on the batteries? Looks like the Air-C will cut into the total
power produced of the system by 580-wh while in use.  I'd use at least 1.289
SR-100s on a fixed mount per hour of running time (with the summer smog
???).  I should say I don't care now that we have 30 degrees out there and
snow got great power no dirt and no need for the Air-C.  Is this weird
weather or what?  Now lets see I got 1.289x lets say 6 hours = 7.734 SR-100s
"AM  I  CRAZY or what?"  Oh it stays at 90 degrees or so after dark in the
summe here.
Lyn at solarvillage.com
Solar Village Institute inc.
PO Box 14
Saxapahaw, NC  27340
Tel. 336-376-9530
Fax. 336-376-1809
www.solarvillage.com

----- Original Message -----
From: Bill Brooks <billbrooks7 at earthlink.net>
To: <RE-wrenches at topica.com>
Sent: Monday, April 16, 2001 5:59 PM
Subject: RE: Air Quality. [RE-wrenches]

> Lynne,
>
> In North Carolina and other hot, humid climates, it is best to put a small
> (5,000 Btu or 10,000 Btu) window air conditioner on a high voltage relay
> sensor. This way you can use the A/C unit as a useful diversion load and
get
> the dehumidification you desparately need.
>
> The restaurant you may be referring to is Applebee's in Salisbury, North
> Carolina. For information, contact Shawn Fitzpatrick at the NC Solar
Center
> (919)515-7147. It was one of the first applications in the country for a
> Trace SW connected to a utility and used for load reduction and backup
power
> for cash registers.
>
> My house in California is grid-connected and my PV system provides all the
> electricity I need on an annual basis. I am a net producer, spring,
summer,
> and fall, and a net user in the winter. We annualize our net metering here
> which makes it much easier to obtain an annual minimum bill.
>
> Bill.
>
> > -----Original Message-----
> > From: Lynne A Carter [mailto:solarvil at netpath.net]
> > Sent: Monday, April 16, 2001 8:30 PM
> > To: RE-wrenches at topica.com
> > Subject: Re: Air Quality. [RE-wrenches]
> >
> >
> > Bill,
> > Yes  your correct the losses from equipment is something to look
> > at.  But I
> > want to know if sizing a system for the winter will also make the power
> > needed for the summer.  We over size systems a little most of our system
> > don't have grid back up nor a (willingness for) gas back up.  Giles B.
For
> > example has no grid connection, no generator and makes plenty of
> > power, the
> > rub comes with the question of air-conditioning.  So if there is a
Smoggy
> > day the power for that air-conditioned becomes a issue.  it is
> > not a winter
> > load.  I wonder if you have any information on that "Arbys"
> > project you did
> > back a few years ago?  Is it still going and are there any
> > results from the
> > voltage set up you did?  do you know if can it be determined is the
summer
> > smog effecting it?  I can't remember if it was grid connected or
> > not.  Thank
> > you for trying so hard to answer this question.  You are in the perfect
> > place to see effects of the Air Quality issue.  Do your systems
> > now generate
> > 100% of the power for the homes that they are installed on?  Is
> > it a yearly
> > average or is it a daily reed out?  Home power is dynamic in the
> > sense that
> > we use power to meet the needs of living; laundry, vacuuming, cooling
and
> > entertaining our friends. It may be that the air Quality has nothing to
do
> > with the out put of PV power.  It may be that the Combo of heat
> > and smog may
> > be the same as heat.  Therefor sizing with a temperature
> > compensation i.e.:
> > the number of 90 degree days is the most important guide for this issue.
> > Thank you again (my partner agrees with you, that it may not be
> > measurable )
> > Lyn at solarvillage.com
> > Solar Village Institute inc.
> > PO Box 14
> > Saxapahaw, NC  27340
> > Tel. 336-376-9530
> > Fax. 336-376-1809
> > www.solarvillage.com
> >
> > ----- Original Message -----
> > From: Bill Brooks <billbrooks7 at earthlink.net>
> > To: <RE-wrenches at topica.com>
> > Sent: Monday, April 16, 2001 10:29 AM
> > Subject: RE: Air Quality. [RE-wrenches]
> >
> >
> > > Lynne,
> > >
> > > A few of the losses that I listed you dismissed too quickly. Most PV
> > systems
> > > I have worked on have wire losses above 5%. Our goal should be to keep
> > them
> > > below that but it is often difficult in the field. Living with
inverter
> > > losses is a necessity, but not necessarily something we should accept.
> > There
> > > is a huge difference between 85% and 95% and if we don't plan for it
we
> > are
> > > in trouble. Battery losses are much higher in flooded, Lead-Antimony
> > (L-16)
> > > batteries than in Lead-Calcium batteries. We can live with
> > these but do we
> > > know what they are? Charge controllers are a notorious source of loss.
I
> > am
> > > familiar with RV products and they show in their MPPT controller
product
> > > manual that the unit little or no benefit for a grid-connected
> > systems in
> > > hot weather. Max power tracking with battery systems is not free by
any
>
> > > means.
> > >
> > > The numbers I use are real and off-grid systems have even
> > greater losses.
> > > These may be numbers we don't like, but that is partly because we have
> > false
> > > concepts on how our equipment works and then we don't express
> > our concern
> > to
> > > manufacturers to clean up their acts.
> > >
> > > Without third-party information about equipment performance, everyone
is
> > in
> > > the dark until they test it for themselves. Not a very
> > reassuring position
> > > to be in.
> > >
> > > Bill.
> > >
> > > > -----Original Message-----
> > > > From: Lynne A Carter [mailto:solarvil at netpath.net]
> > > > Sent: Friday, April 13, 2001 4:04 PM
> > > > To: RE-wrenches at topica.com
> > > > Subject: Air Quality. [RE-wrenches]
> > > >
> > > >
> > > > Hi I did not get an ok on sending an (Jpeg) attachment if you want
to
> > see
> > > > the pollen and Grey sky send me personal email I will send copy for
> > those
> > > > interested.
> > > > Bill,
> > > > You made a good list I agree theses things can effect the power
> > production
> > > > of the PV array and/or the whole system.  We have a customer that
> > > > is willing
> > > > to test the Uni-solar Laminates. The pollen count is high the
> > > > past few days
> > > > everything here is that yellowey-green dust from the loblollies.
> > > > So yes I do
> > > > have dirty PVs to day.  NO rain so far but the temperature is
> > going down
> > a
> > > > little. I have attached some Jpeg photos as examples
> > > > Your list in relation to our systems here in the east.
> > > > Shading. Not much of an issue for us good solar access on systems.
The
> > air
> > > > is the question. Dirt. Maybe so, dirt in the air could stick to the
> > array
> > > > looks as if that is
> > > > what is happing today.  Wire Losses. not more than 2% - 5% Module
> > > > Mismatch.
> > > > not here Inverter Losses (much higher than most people predict)..
> > > > I can deal
> > > > with that.  Battery Losses. I can deal with that.
> > > > Charge controller losses.  Have you check out the RV power products
> > > > recently?
> > > > NC recent reports have us in the orange zone and the red zone for
most
> > of
> > > > the summer. We are 6th in the nation for smog depending the report
> > > > www.epa.gov.
> > > > You said >Our diffuse (scattered) radiation can be 30% of the
> > > > energy we get
> > > > from the sun. This also makes tracking systems a little less
> > effective.
> > <
> > > > I disagree on the tracker issue. However, I am off-grid and when the
> > array
> > > > follows the sun every day, I have made more power. I simply get a
> > > > more power
> > > > form tracking arrays with a smaller footprint.  Besides, they are
sexy
> > as
> > > > hell.  In the morning, I am making power sooner.  During cloudy
> > > > days, it is
> > > > great to be at a maximum power (optimal tilt) when the sun appears
for
> > an
> > > > hour of the day.  Maybe it just feels good. What do you mean by
> > effective?
> > > >
> > > > So could do an example of this? Take the STC rating and multiply
> > > > by 0.7 and
> > > > that is a fair number for system with a STC > 1
> > > > max AC power (spring and fall). Take STC rating (in kW) x 0.6 x
solar
> > > > resource (5.0 kWh/m2/day--Raleigh, NC) x 365 days/year = Annual
Energy
> > > > I am not getting numbers I like.
> > > >
> > > > Lyn
> > > > PS I did find out that Most air quality databases are about two
years
> > > > behind.
> > > >
> > > >
> > > > Lyn at solarvillage.com
> > > > Solar Village Institute inc.
> > > > PO Box 14
> > > > Saxapahaw, NC  27340
> > > > Tel. 336-376-9530
> > > > Fax. 336-376-1809
> > > > www.solarvillage.com
> > > >
> > > >
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