Hello!
So it seems that I will in fact be able to move forward with my 24VDC
system in the very near future after all! Of course as things would
be I have to make some changes to how I will proceed but the fact
is... I will very soon be building my new system!!! And yes, I will
post with images the new system as it goes up and comes on line.
This
particular post I will be focusing on a new spreadsheet I have set up
that I would love to share with you that are reading. The idea was to
create a way to track costs and really compare components by cost,
feature and need. The spreadsheet (which I will link to at the bottom
of this post) is essentially a live one that I am using to build my
upcoming 24VDC system. I have a limited budget (yeah... really who
doesn't today!) so I need to put a lot of thought into the items I
purchase and where my money goes.
In
an earlier blog post I mentioned converting my AC refrigerator and
freezer to DC, and this is still going to happen, just not for a
while. The conversion cost is pretty high and while the payback is
reasonable I just don't have the money at the moment to do it. So I
will be using an inverter to run the refrigerator for now. Now
currently I expect the refrigerator to consume about 90AMPS of power
per day. BUT I have a plan to reduce that!
See
the idea is to improve the efficiency with as little cost / effort as
possible. And the only real way I can do this is to improve the
insulation of the current equipment. And since I will have to do this
anyhow for the DC conversion, well I will be just one step ahead! So
the wife and I will add hard foam insulation to the exterior of the
fridge (See
here) then she will put a nice finish exterior over that. I will
admit right here and now my wife is better than I am with finish
carpentry so I do the rough stuff and she does the finish. By adding
the extra insulation and installing it in such a way that is seals
around the gasket area, we will increase the efficiency of the chill
box and reduce the run times of the compressor. This should net us an
estimated 30-40% decrease in power consumption.
And
if it works as I think it will (it's all theory right now) then I can
do the same thing for my deep freezer that I have. And that would be
the bomb diggity right there! So that is really the major change I
have in my current plans.
Now
the planning spreadsheet that I have put together is pretty simple to
use really. And all you have to do is download it and tweak it for
your needs. I was going to use Google docs again but it's a pain in
the ass to take the spreadsheet and recreate it there so I am using a
free file sharing site for now. Anyhow to use it is simple, the areas
that are light gray and have a border around it are where you make
your manual entries. The top portion is called the component pricing
list. Here you enter the component(s), their unit cost (how much each
item costs) the tax rate if applicable and the shipping rate. Keep in
mind this is not accurate and is essentially and estimation form. The
whole idea is to allow you to see how much your components will cost
and plan accordingly.
It
also again will touch on your load requirements and will you meet
them with the items you are selecting. Anyhow the next area in the
components list is the source and URL, where are you planning on
getting this stuff. As you enter items the F, G and H fields will
auto-calculate for you. Then in column|row H12 a total sum will be
auto-calculated. In column|row H13 you enter the amount you have
budgeted and below that the estimated remainder will be
auto-calculated for you.
Now
you will notice that in column|row I14 there is an area that is gray
and had borders, this is where you put the actual remaining amount.
What I mean by that is I will often times start the purchase process
so I can see exactly how much shipping and tax will be and get a
total value. I will then take that total and put it somewhere and add
other actual totals to it. I don't commit the purchase (not until
I am finished shopping and I have the $$ in place!) I simply
close the web page and move to the next item. This is one way to
validate my buying estimations. It's also a way for me to test the
web site if I have never purchased from them before, see if there is
anything that strikes me as odd. Also as an added method of
protection I use a pre-purchased Visa with only $5.00 on it, that way
if it turns out to be a funky site I lose $5.00 and nothing else. By
doing this I can also use a bogus address during the test phase,
again as a way to protect myself and test the site.
Anyhow
the next section is the battery breakdown. By this time you should
have already narrowed you battery choices down to a brand, voltage
and AH rating as well as the configuration you need. This section is
for you to validate your load / run times as well as ensure that when
you start selecting solar panels (and wind turbines as well, hell
even pelton wheels!) you are selecting enough to replenish your
batteries. So you enter the following information, manufacture and
model, voltage, AH Rate, quantity, how many in series (this will give
you your system voltage) and how many sets in parallel to get total
system AH. Once this is done you move to the next section which is
the load!
In
the load section you enter the nomenclature of the item that is the
load, the voltage the amps and how long you think it will run. All of
this information should be readily available from earlier research
you should have done by now. Anyhow this will give you your total
watts, kW and amps requirements. In column|row G26 your total daily
power demand will be auto-calculated, below that you need to enter
what you estimate to be system loss due to inefficiency as well as
line loss. 10% is generally a pretty good number to start with. This
will auto-calculate your total load below and this is what you need
to make up every day with your solar, wind or pelton wheel. Now keep
in mind as I said in earlier posts everything you have is theoretical
you may see better performance or worse performance of your system
and that all depends on weather, temperature, quality of equipment,
quality of connections and installation and just luck of the draw.
All the numbers I have listed assume realistic worse case scenarios
and chances are pretty damn good I will see much better performance
than I show on paper.
When
I ran the numbers for the existing system I have now, they showed far
worse performance that I am seeing. Although the exception to that is
on really cold and cloudy days the system is performing almost
exactly as my worst case scenarios predicted. So I suppose in the end
it's a wash. Now the one thing I didn't do was account for the wind
turbine in my scenario that you will see in the planning spreadsheet.
That is because the wind turbine will not come into significant play
until the winter. Sure right now it will produce power but that is
diminishing as we move into spring. Fall and winter is where I will
see the real production capacity of my wind turbine.
Alrighty
I have rambled enough, the next area is the panel capacity cost
analyzer. This is where you search the web for solar panels that meet
YOUR requirements. I need panels that will charge a 24VDC system so
therefore all my panels that I have selected are rated 24V+. you
really need to get accurate data here... otherwise you could very
well under power you system. Generating more than you need is not a
problem, with a load diverter you don't have to worry. Remember
during the summer you will produce far more than you will consume, if
you designed your system correctly. And during the winter you should
hit on the nose or slightly over with your production to use ratio.
Some will argue this is a poor way to design systems... but then
again those people are also grid tied. I am not so therefore I have
to follow a completely different paradigm than grid tied folks. And
if you are looking to be off grid you will have to follow the same
paradigm I am.
So
with the cost capacity analyzer you will need to enter the panel
manufacture name and model (well you don't have to... but that'll
sure fuck things up for you later!) then what type of panel is it.
Remember monocrystaline is the best! But it's also generally the most
expensive! Next enter the individual panel wattage, volts and amps
(the amps are the most important aspect as they determine actual
charge capacity!) next you enter the panel quantity and the unit cost
(individual cost or if sold as such the pallet cost). Now once you
have done that the sheet will auto-calculate sub-total, tax,
shipping, total cost, total amps and total watts. In the time slot
enter the estimated full sunlight of the shortest solar day of the
year. Again you are planning for the worst return on power. Once you
do that then total amp will auto-calculate which tells you how many
amps you will generate. This is important as you need to replace the
amps you consumed. So the spreadsheet will then auto-calculate the
power balance, in other words it will take your estimation of daily
power consumption and subtract your estimation of power production.
The closer to zero you can get the better. If you go negative then
schweet! The next field you will enter data into os the source / URL
from whence the panels may come.
Now
continuing across the sheet you will see a cost per amp and cost per
watt calculation. The lower the cost per watt the better, but you
knew this already! So what I do is I sort by the actual cost
difference then I look at the power balance and the cost per watt.
Sometimes you will pay more overall but it washes out in the cost per
watt AND you are close to or below zero on your recharge capacity.
And
there ya have it! Play with it and see what you come up with and if
you find an error or have a question as always ask and let me know so
I can correct it.
Link
to the planning spreadsheet:
http://www.4shared.com/office/DKs7vhoI/file.html
Peace,
Love and Five Finger Death Punch!!!
