Solar as You Go Therese Peffer & Amanda Potter c. 1993 Therese Peffer & Amanda Potter Pat and Rick Walker live in a beautiful remote area of northern California with their cockatiels, Sassy and Junior, two cats, and two horses. They didn't leave amenities behind when they left town Ä electricity and hot water are provided by the sun. They communicate with friends and family and run a solar business with their radiotelephone and CB radio. "We're the learn-as-you-go people," Pat says. "We'd never built a house, we'd never done plumbing, we'd never done electrical wiring." "We'd never drilled a well," Rick added. They are still learning as they go, with no end in sight. Sunny Beginnings In 1987, the Walkers bought 40 acres of beautiful tree-covered property four miles outside the small town of Big Bend, California. For the first three years, they set their 23 foot trailer among the pines and oaks. Pat had started reading books and catalogs on solar years before. Three years ago they equipped the trailer with photovoltaic panels and third-hand golf cart lead acid batteries. "All the neighbors went together and bought panels so we could get a good price Ä everybody got two," Pat said. When they started building a log home two years ago, they transferred their solar electric system from the trailer to their new home. The utility lines run about a mile away from their home, but for the Walkers, it wasn't even a consideration. "I like doing solar." Pat says. Rick followed, "It was economical for us to use solar....We like it more than paying a bill. Boy, that gets old!" Solar Business For the Walkers, starting their solar business, Lotsa Watts Solar, was a natural step. "I bought solar equipment for a couple of years for everybody around here," Pat said. "I knew everybody." Pat was used to spending time on the phone getting deals for herself and her neighbors. Working on the phone from her home works well for her. The Walkers didn't want to drive an hour and a half into Redding, the nearest city, to work. They wanted to work where they live. Power System Rick and Pat had done the wiring on their trailer and the solar water pump with the help of a neighbor. They wanted the electrical system for the house "done right" so they called Bob-O Schultze of Electron Connection. Their eight Solarex MSX-60 PV panels sit on a Zomeworks tracker. The panels put out 32 Amperes and 17 Volts on a cold sunny day. The tracker increases the panel's power output on a yearly average by twenty-five percent. The tracker's pole is connected to a ground rod to protect against the build up of static electricity which can attract lightning. Ten 6 Volt, 350 Amp-hour Trojan L-16 deep cycle lead-acid batteries store the sun's energy Ä a total of 1750 Amp-hours of storage. A Heliotrope CC 60C charge controller prevents overcharging by open circuiting the panels when the battery voltage rises too high. The CC 60C also contains a 60 Ampere Schottky diode to prevent current from flowing back from the batteries to the panels at night and being dissipated as heat. In keeping with the National Electric Code, Bob-O installed a Cutler & Hammer 60 Amp double pole fused safety switch. The switch disconnects the charge controller from the solar array and battery. The system sits in the middle of the house Ä a central location is good for keeping tabs on energy usage and in case they need to turn the power off in a hurry. After reading Richard's experience with a battery exploding in the Home Power living space, they decided they are going to build an enclosure for the battery. Hydrocaps replace the standard battery caps. These special caps allow the recombination of hydrogen and oxygen which are normally vented by the battery at the end of its charging cycle. This lessens the potentially combustible mixture of hydrogen and oxygen and minimizes the water lost from the electrolyte. A Trace U2512 inverter converts the DC electricity from the battery to ac electricity for the loads. The 2500 watt inverter is protected by a Class T 400 Ampere DC-rated fuse. The continuous output current rating of the inverter is 20 amperes at 120 volts rms. Its output is connected directly to an ac circuit breaker box. The Walkers did their own ac wiring following the book, Wiring Simplified. The DC loads are protected by a DC rated Square D circuit breaker. A Cruising Equipment Amp-hour+ meter uses a 500 A, 50 mV shunt to keep track of current flowing in and out of the battery. Energy Usage The Walkers don't have a generator. Pat was adamant about not using a gas generator for a backup on the days the sun doesn't shine. They sized their system accordingly and watch their usage when the battery starts to get low. Pat says she doesn't like to use more than 50% of the battery capacity. The primary consumer of power year round is the Sun Frost RF- 12 refrigerator/freezer. This last winter when the batteries started getting low Ä about 500 Amp-hours down Ä the Walkers turned off the Sun Frost. "We had all these storms. It started looking pretty bad, but we probably could have kept going," Pat said. Rick carved an "ice box" outside in a snow bank, framed it with 2 by 4s, and fashioned a door of plywood. It worked great for three weeks Ä then the sun came out again. The only problem with the outdoor cooler was when foxes got in and stole 6 pounds of butter! To reduce Sun Frost use the rest of the year, they have a small "cellar." A trapdoor in the floor opens up to reveal beer, potatoes, garlic, and other foods kept cool most of the year. Another big consumer of electricity is lighting. Pat likes to read at night, so for efficient lighting, they use compact fluorescent lights. All of their lighting is ac lighting. Ten lights are 7, 11, and 15 watt Osram compact fluorescent lights; three are Lights of America 32 and 22 watt compact fluorescent lights. The 15 watt lights are just right for night reading! In the summer, they have excess electricity Ä a great time to make bread! Pat now has an electric bread machine Ä the kind that you throw all the ingredients in, wait four hours, and then eat! Pat says that the bread machine draws about 2 Amps at 12 Volts for much of the mixing and kneading cycle, and then draws 60 Amps at 12 Volts during the baking cycle (about 50 minutes). Another summertime appliance is the 500 watt microwave oven. Pat really enjoys her Amp-hour meter. When she is curious how much an appliance draws, she can run over to the meter, flip a switch and watch the numbers change. Now she can see first hand whether appliances meet their specified power requirements. One of the reasons she hangs on to her 1965 Sears washing machine is that it draws less power than newer models. Hitting Water Digging a well was one of the first things the Walkers did when they moved to their property. They borrowed a DeepRock Hydra-Drill to drill their well. The Hydra-Drill's two-stroke engine runs the bit at the end of the pipe; water is used to flush out the tailings. With the help of some friends, they drilled a 90 foot deep well, using 5 foot sections of galvanized pipe. "You just keep putting pieces on and go deeper and deeper!" Pat said. The Hydra-Drill is not a heavy duty machine Ä at 73 feet, they hit rock. Fortunately, there was only 4-5 inches of rock, but it took hours to get through those few inches! They cased the well down to about 65 feet. "We got water for that one year," Rick says, "but then things kind of dried up." "We had a lot of water," Pat added, "but the drought happened and we got less and less, and pretty soon we were pumping mud and thought we better quit." Luckily there was a spring about 15 feet from their property. Pat and Rick promptly bought the small piece the spring was on and redeveloped the spring. "We started pumping out of the spring." Rick said. "About 60 years ago somebody framed it in with cedar....we pumped it all out, dug it out." Solar Water They use a solar-powered rotary pump to get water from the spring. Two Solarex MSX-60 panels power a Flowlight SloPump; the panels are mounted on an old angle-iron bed frame on a pole near the spring. The water from the spring has a fair amount of sediment, which the Flowlight pump doesn't like. Currently the water is filtered, but the Walkers plan to build a holding tank down below the spring this summer.The pump moves the cold water up 70 feet elevation to a 1550 gallon storage tank that is about 1000 feet away. Water reaches the house by gravity flow Ä the tank sits about 50 feet above the house. A run-dry switch shuts off the pump when the water gets too low. Pat and Rick have two different pump heads for the Flowlight pump. The smaller pump head pumps about 40 gallons per hour, and only needs one panel to power it. The big pump requires the output of both 60 Watt photovoltaic panels and pumps about 180 gallons per hour. A 7 Amp SunSelector Linear Current Booster (LCB) made by Bobier is used to run the bigger head. Two 60 Watt Solarex panels, wired in parallel, put out 17 Volts and 7 Amperes on a cold, sunny day. On cloudy days, the current out of the two PVs will decrease quite a bit. The bigger pump head requires 7 Amperes of current to run. The LCB converts the power (Volts times Amperes) from the PVs to a lower voltage and higher current and delivers this power to the pump. There is no loss in power (except through the small inefficiency of the LCB) Ä the pump just sees more current but less voltage than what the panel is producing. Hot Water The Walkers heat enough water for all the showers, baths, and dishwashing they need. They use cold water for washing clothes. Water is heated by both their wood stove and a Thermomax solar collector. The hot water is stored in a 120 gallon tank. Bob-O helped them put up their Thermomax system just before last summer. "We'd been getting hot water from the wood stove and I don't want to run it in the summer! The woodstove is great for winter though, we get all the hot water we need," Pat said. The Walkers are very happy with their Thermomax evacuated tube collector. They've found that it heats water very well even on cold, cloudy and windy days. They like the fact that they don't need to worry about a lot of weight on their roof or about freezing pipes. Their system is made up of a manifold and 20 solar collector tubes and only weighs 100 pounds (45 kg). Initially the Walkers had problems with their Thermomax system. They got a good deal on a water storage tank and didn't realize that there was sediment at the bottom of it. The sediment was circulating in the water lines and eventually clogged the heat exchanger. Fortunately, once the dirt was flushed out, the problem was solved. How the Thermomax Works The Thermomax's high efficiency in all types of weather is due to a number of interacting processes (see diagram 1). The absorber plate has a wavelength-selective semiconductor coating which enables high energy absorption and low heat radiation losses. Even infrared rays on cloudy days are absorbed and changed into heat. A heat pipe welded to the absorber plate transfers this heat to alcohol. The absorber and heat pipe are enclosed in a glass tube. The air is evacuated to minimize heat loss by convection and conduction. The vacuum also protects the absorber plate, selective coating and heat pipe from rain, moisture, air and pollution. The heat pipe contains a liquid (alcohol) which undergoes an evaporating-condensing cycle. Heat from the sun evaporates the liquid. The vapor rises up the heat pipe and condenses at the manifold transferring its heat to the glycol via a heat exchanger. The condensed alcohol flows down the heat pipe to the evaporation zone completing the cycle. Heat is thus transferred quickly and in only one direction allowing sustained high temperatures in the collector. The glycol is circulated from the manifold of the Thermomax into the house where it transfers the heat to the water via another heat exchanger. Hybrid Hot Water System If wood is burning in the wood stove, water circulating in the stove heats up and expands. This causes the water to rise up to the water tank Ä the Walkers put their 120 gallon water tank upstairs on the second floor. A thermosiphon is thus created from the bottom of the tank, through the wood stove, to the top of the tank. See diagram 2. Two sensors determine when the Thermomax heats the water. If the glycol at the Thermomax is nine degrees warmer than the water in the bottom of the tank, then two 12 Volt DC, 2.9 Watt Laing pumps turn on. One circulates glycol out of the Thermomax through a heat exchanger and back again. The other circulates water from the bottom of the storage tank through the heat exchanger to the top of the tank. Heat from the glycol is transferred to the water at the heat exchanger. Heat The Walker's home is heated with wood heat, an extra large Consolidated Dutch West wood stove that sits in the center of the house. Rick gathers black oak and other wood from around their area Ä they use about 3 cords of wood per year. At 2600 foot elevation, they see about 6-8 feet of snow every winter. They make good use of their cross-country skis to feed the horses and get around. Pat and Rick like to stay warm Ä the ceiling is insulated to R-30 and the floor is insulated to R-19. Large windows on the south side of the house let in the sun's light and heat. They installed a 12 Volt fan in the high ceiling to circulate the heat in the winter (and help cool things down in the summer.) Still Going... Solar energy is a way of life in the Walker's neighborhood. Although the utility lines keep getting closer, there are plenty of folks nearby using solar power. Last summer a forest fire raged over the area, burning a home they had owned in Round Mountain. Part of the solution for homeless fire refugees was solar. Altogether, 330 homes were lost. The Walkers are doing their part to help (see story on page 37). "We're trying to help people down there buy stuff. We're selling it to them at cost," Rick said. Pat and Rick are still finishing their house and system. As with any new home, they can always find new projects! And as solar equipment dealers, the Walkers keep their eyes on new things to add to their system. They like to get others interested in solar Ä Pat says there is always someone in line to buy her used equipment! The system continues to grow, just as it has from the beginning, a little at a time. "We've scrimped and saved, we've done without much for a long time, we do it pretty easy," Rick says. "I never thought I'd be this fortunate to live up here." And with solar Ä electricity, water, and business Ä they can. Access Pat and Rick Walker, Lotsa Watts Solar, No. 1 Shotgun Road, P. O. Box 167, Big Bend, CA 96011 ù 916-337-6687 Authors: Therese Peffer & Amanda Potter, c/o Home Power, POB 520, Ashland, OR 97520 ù 916-475-3179