A Clean Solar Life George B. Chase c.1992 George B. Chase Caption: Our solar powered wood frame home stands on 10 foot stilts. Photo by George B. Chase Our trip to energy independence started with a canoe camping trip on the Peace River in southwest Florida. We had such a good time in the wilderness with the alligators, turtles, herons, and hawks that we decided to look for a weekend "get- away" from the fast paced life we lead in the big city. Small Beginnings What we found was a small cabin (about 500 square feet) on the river with seven acres of land. The cabin is about 1 1/2 miles from the power line and the previous owner had a car battery to run a few 12 Volt lights and a small fan. We continued to use the battery and added a gas refrigerator from an old RV. After about a year of switching the battery in the house and car back and forth, we invested in our first photovoltaic module, an ARCO M65 self-regulating module. Along with a 100 Amp-hour deep cycle battery, we began producing our own power. Now when we arrived for the weekend the battery was fully charged and ready to go. This one module, one battery system was used for over 6 years as our only power source and is still producing power today, 10 years later! Building a Home When we decided to build a home big enough to live in and leave the city for good, our first step was to check with the local electric company. They told us it would cost about $15,000 to bring power to our site! Our budget forced us to find more cost effective power. Over the last 6 years we had been doing research on solar power. We were familiar with many products, and had a fairly good idea of what was necessary to go stand-alone solar. I did my own architectural and electrical plans and had them okayed by the building inspector prior to building. I had great luck with the local building inspectors by going to them early. I told them what I planned to do and asked for help. They knew I was not trying to cut corners on safety and actually asked my opinion on many items. I had to show them areas of the National Electric Code for solar. Since it gets hot and humid in Florida, and since air- conditioning is not cost effective in a PV home, the basic design of the house had to take advantage of each breath. We got information from the Florida Solar Energy Center on any subject we thought might give us a hint on overall planning. The FSEC has a large library of solar publications and the time spent researching saved us money. In a warm climate radiant barriers are probably the most overlooked yet most easily installed item. They can reduce heat gain tremendously in both roofs and walls. The foil- backed barrier came in three foot rolls. We installed the radiant barrier foil-side down under the rafters in the attic. Heat is reflected from the house and escapes through the ridgevents. Soffit vents under the eaves aid circulation of the attic. Large doors and windows carefully located can take advantage of prevailing breezes to keep a house much cooler. Three foot wide overhangs, and shade trees strategically planted help, too. Planning is the key. It can make the difference between a successful project or one you will be redoing for years to come (see house drawing). INSERT HOUSE DRAWING Assessing power needs Our next step was to establish our power needs. We knew we wanted to have a normal electrical lifestyle. We first decided what we must have, and what we could do without but still live comfortably. We chose a standard 30 inch gas range and a Sun Frost RF-16 (16 cubic foot) refrigerator/freezer. Since the Sun Frosts are not shaped like a standard 110 volt refrigerator you must preplan space for it. A regular automatic washer is used for clothes and is powered by our inverter. A 10 gallon RV gas water heater provides our hot water needs. Once we estimated our total electrical needs we could then start to design our power system. INSERT LOAD TABLE We have fourteen ARCO M75 photovoltaic modules that produce 47 Watts each. The panels are located on the roof on standard ARCO ground racks. I change the angle of the racks twice a yearÄa flat angle for summer and steeper angle for the winter sun. Efficient Design Building your home yourself allows you to take advantage of efficiency options most contractors disregard. The floor plan should be given special consideration to allow for a centrally located battery room or box. This will cut costs and increase efficiency by keeping wire lengths to a minimum. Our battery bank is located in a vented box just outside the wall from the control room. We have eight 6 Volt 260 Amp- hour Exide golf batteries, wired in series and parallel for 1040 Amp-hours at 12 Volts. The batteries sit on a strong wooden tray of 2 by 4's and plywood with two sets of refrigerator roller wheels on the bottom. You can easily open the box and roll the batteries out for maintenance and specific gravity checks. The control room is about 3 x 2 feet with bifold doors. It holds the voltage regulator, quick disconnects for array, both ac and DC breaker boxes, and a Heart inverter. Control gauges show charge current, both ac and DC draw, battery voltage, and temperature. It also houses an alarm system with auto-dialer for police and fire assistance. INSERT SCHEMATIC Wiring Don't try to save money on wire for your DC system. Regular #12 or #14 Romex wire used in conventional home wiring will not do. Larger wire is needed for low voltage DC. Be sure to use a wire chart to arrive at the proper size (see Home Power #18, p. 31). We divided the house into zones and used large Romex 2-strand wire (#6) under the house to carry the current from the breaker box to each zone. We then stepped down to smaller Romex wire (#12) for short runs from junction boxes to outlet receptacles. The number of outlets per run were kept at a minimum to keep resistance low. We soldered all connections. A soldered connection will have less electrical resistance than a wire nut and seals the wires from corrosion. We installed two different receptacles for 12 Volt and 120 volt appliances. Maintenance and Backup Since there are no moving parts to squeak, grind, or suck gas and oil in a PV system, maintenance is minimal. A properly designed system works so well you could easily forget to check it out every now and then. About the only part of your system that will need any regular attention is the battery bank. Specific gravity and water levels should be checked regularly to prolong battery life. The Complete Battery Book by R. Perez is a great source of information on all types of batteries. Since Florida weather includes cloudy days, we decided a back-up battery charger would come in handy. We got a used alternator (60 Amp) from a friend and mounted it to a slab of wood. Then we put a large pulley on the power take-off (PTO) of our tractor and back onto the wood slab to hold the alternator down solidly. Simply run a belt from the PTO to the alternator and bingo! 60 Amp output to the battery bank. The diesel tractor will run for about 15 cents per hour and this system will equalize the battery bank. We've installed an ammeter next to the alternator and merely adjust to idle speed to change the output as needed. Designing a System If you are thinking of making the move to solar power, talk to as many people as possible. The solar industry is no different than any other in that there are some people selling equipment who have never used it, and they will tell you what they think you want to hear just to make a sale. Time spent on the phone will save you money and aggravation. Each time you talk to a different company you will get a different opinion of how your system should be equipped. Research is the only way to ensure your system will be right for your needs. A great system doesn't need to be purchased all from the same dealer. Components in solar systems are compatible and expandable. You can easily start with a small system and add to it later. If you choose this route, make sure you buy components that will allow you to expand. If you plan to add more modules at a later date, make sure you buy a regulator that has the capacity to handle the added power. INSERT COST TABLE Standard and Solar! If you visit our 2,000 square feet stand alone solar home, you would not think it was any different from a standard utility connected house. Most people we've spoken to think that PV- powered homes are just "cabins" without any creature comforts. All our fixtures and appliances are standard, although some have been modified to run more efficiently. Our home has beautiful tongue & groove pine flooring, a cedar lined walk-in closet, and standard bath fixtures. The kitchen has solid wood hickory cabinets and Corian countertops. Lots of windows and french doors let in the air and light. Our home is proof that you can live a clean solar life and not sacrifice modern convenience or beauty. Our fragile environment needs protection and we feel our home is a small contribution to saving the planet. Access Author: George B. Chase, 1183 Girl Scout Rd., Arcadia, FL 33821 ù 813-993-0391