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Step by Step to an RE Powered Home
(assumes you are using an existing home) |
| 1. Conserve Energy. |
| Most people can not afford to buy the additional PV & solar heating modules to run the average US home. There are many people who figure they are quite well
off just by doing this step alone! |
| 1A. Insulate as much as you can afford. |
| Put in double and triple pane windows. Insulate the roof, walls and maybe floor. Use light colored roofing to reduce your cooling expenses in hot climates. |
| 1B. Get energy efficient appliances, lighting, heating, and cooling. |
| Remember heating and cooling are your major loads. Solar can replace heating (or even cooling) depending on your site (and INSULATION). Please see table below
for various heating/cooling methods. |
| Your refrigerator, unless new within the last 5 years, probably should be replaced with a new one. Check the renewable energy catalogs for the best efficiency
ones. If you can't afford a new one, consider mounting a couple of muffin fans to blow away the heat generated by the motor of the refrigerator. A 4 watt muffin fan, left on all the time to
cool under the refrigerator, will save you electricity because it removes most of the heat that would normally rise up in to the cooling compartments. |
| Washers, the best efficiency ones are the horizontal axis ones. Lighting, choose fluorescent, compact fluorescent, or LED.
To see how much CF bulbs or other more efficient/long lasting bulbs will
save you try the bulb saving form. |
| Cooling/venting your attic reduces the load on your living space cooling system. Most people use 110vAC fans which use a lot of electricity. You can use
solar, but that is very expensive. A turbine vent or ridge vent are less expensive, they don't use electricity, don't have a motor to burn out, and use natural convection currents to cool the
attic. Some say ridge vents work better than turbine vents. However you need to make sure your input/soffit vents are not blocked, and that you have plenty of them. |
| 2. Examine your site |
| How many hours of sun per day does your site average? Is there any objects blocking the sun? The clearer the view of the sun's path, the longer you'll get
usable energy out of your solar modules. Atlas for The Solar Radiation Data Manual
For Flat-Plate and Concentrating Collectors for the United States. Surface meteorology
and Solar Energy Data Set, Global solar energy data. |
| You can use a single or dual axis tracking mount to get more usable energy of you pv modules per day. A tracking mount points your pv's directly towards the
sun. The difference between a single and a dual axis tracking mount is that a single axis one has to be adjusted seasonally. The dual axis tracker automatically adjusts for seasonal
variations. A dual axis tracking mount usually won't increase your power output enough over a single axis tracking mount, for most places, to make the dual axis tracking mount worth it. A
tracking mount is more expensive than a fixed mount, but may be more cost efficient than buying more pv modules. |
| Do you have a stream available? Hydro can give you surplus electricity if there is enough flow and head. How much flow is the stream?
Measuring Irrigation Water in a Ditch, Stream or Reservoir. How high
is the stream (head/vertical fall)? Head times flow is your hydropower output. 500 Gallons per min. over a 3 foot drop, or 3 gallons per min. over a 500 foot drop give you the same power
output. The higher the head, the lower the gallons per minute you need to make the same power. Micro-hydro equipment is what is generally sold in renewable energy businesses. Micro-hydro is
usually high head (over 10ft), low flow (less than 120GPM). Please be considerate of the environment: Ensure that there is plenty of bypass water for the wildlife all year around. Be careful
if there is any fish in the stream about damming the stream. To quickly
estimate whether or not your hydropower site is a good one, please try my hydro power estimator form. |
| What is the average miles per hour of the wind at your site, per year?
Wind Energy Resource Atlas of the United States. The lowest startup wind speed for a wind
generator I've seen is 7mph or 3.0m/s. At that speed not much electricity is generated, however having a hybrid solar/wind system generates electricity when the sun is out with the pv's and
when it is stormy with the wind generator. For best performance, mount the wind generator on a tower about 30 or more feet above any obstacles and for safety's sake, put the tower at least two
times the height away from any building, power line (on poles or towers), and property lines. There is roof mounts for the Air Modules, performance will not be as good as on it's own tower due
to turbulence from nearby obstacles. |
| Do you have the grid available? |
| Check out Home Power Magazine's web site for
great info, US maps of sun and wind data. |
| 3. Add up your electrical load. |
| You need to find the total watt-hours of the load's you want to put on RE battery system or to compensate for the load usage in a battery less grid-tied RE
system. By using the data plate on your appliances will give you a quick, but general idea of that appliance's energy usage. A more accurate, easier, and more expensive way is to use a
watt-hour meter. You can also use your electric bill, which gives you total watts used in kilowatts, or watts times one thousand. |
| Using the data plate, you might have to convert to watts. After you have converted to watts, or starting with watts, watts times the number of hours that
appliance is on per week equals watt-hours per week. Then add up all the watt-hours per week of all the appliances you are going to use on RE. Divide that by seven to get avg. watt hours per
day. |
| Using your electric bills, add up one year's worth, then times one thousand, divided by 364, or 365 depending on the number of days that year to get avg.
watts per day. |
| Take avg. watts/watt hours per day times 1.2 to get DC watts per day that you must generate. |
| Divide this by the avg. hours of sun per year or the avg. hours of sun for the worst month. This gives you how large your PV array must be. Dividing by the
avg. hours of sun per year will undersize the system during the winter, and either needing a generator, or more grid usage. |
| Using different energy sources complicates the calculations a bit. |
| 4. How much money can you spend? |
| Due to a lack of money, people will only put part of their electrical load on an renewable energy system, then spend more later on when they can afford to buy
more. The owner of Real Goods did this a long time ago! Nice thing about PV's is that they have no moving parts and can last a long time (some even have warranties for 25 YEARS!) Note PV's
don't produce as much in HOT climates, as they do in COOL climates. Buy NAME BRAND, DEEP CYCLE batteries for storage (if you decide for any storage at all). A battery bank however has to be
bought all at once. You can't mix old and new batteries because the new batteries will be brought down to the performance level of the old batteries. |
