Far Acres Farm and Solar Energy


History of Far Acres Farm

The farmstead was built between 1799 and 1813 by Isaiah and Jemmy Palmer. When my grandparents arrived in 1919, the oldest inhabitants told them that Jemmy had been reluctant to marry Isaiah, because his land was on a quiet side road. She'd grown up on the highway (now NH Rt. 107A), busy with wagons, ox-carts and droves of animals coming down to tidewater at Amesbury and Newbury's Port. Isaiah promised Jemmy the best house in South Hampton if she'd marry him, and I guess she was satisfied, although the house didn't appear on the tax rolls until 1800, five years after the wedding.

My grandparents operated the place as a small dairy farm for a number of years before my grandmother's health and worsening economic conditions for small farms led them to different pursuits. After their deaths, my family rented it out until I moved from Cambridge in 1988. Since then my wife and I have done quite a bit of clearing, rehabilitation and construction.

Considering Solar

I had had solar energy on my mind for a number of years, but there were obstacles. The most serious was that Isaiah had built the house facing East by Northeast. This presented the best aspect to visitors coming down from the center of town, and gave the Palmers a view out the front windows clear to the top of the hill (re-forestation and new houses have put an end to that). 192 years later, I was left with no easy way to mount solar energy collectors facing the sun. Another obstacle was the partial cellar, on the North side of the house. Putting it on a slope probably saved the builders a lot of digging, but it meant I didn't have much room for the batteries I'd need to store electricity for after sunset, or cloudy days.

Two events finally started me moving. The first was the hurricane of September 1991, when Exeter & Hampton Electric was out for three days, and my freezer had a crisis. The second was my wife's wish to keep her horse here, instead of boarding elsewhere. The existing cow barn had low ceilings everywhere the floors were strong enough for horses. A new barn could have an East-West ridgepole, with the roof sloped to face the sun in Winter (when there's the least sun and our PhotoVoltaic panels must collect as much as possible), as well as space for the batteries.

In 1983, I'd have had trouble getting the power from the barn to the house, since most DC appliances use 12 volts, and I would have needed 150 feet of VERY heavy wire. However, solid-state inverters that convert DC to AC quite reliably seem to get less expensive every year. Using AC for most loads also meant that I could keep the old grid (power company) connection and switch back if necessary.

In 1988, most available inverters generated what's called "Modified Square Wave" power. It's efficient to produce, but the waveform is enough different from grid power that it can cause some problems with noise on telephone lines and won't run some appliances or computer accessories. Recently, inverters that produce "Sine Wave" power have gotten big enough and cheap enough to be a reasonable alternative, so that's what we chose.

Design and Installation

When we sat down with Chip Mauck (Sunweaver Energy Enterprises, Northwood, NH, 603-942-5863) to design the system, we wound up with a big one: 48 Solarex MSX-60 PV panels (totalling 2.6 kiloWatts) to generate electricity, 48 Trojan L-16 6 volt deep-cycle lead-acid batteries to store it, and an AES 5kW sine-wave inverter to convert DC from the PV/battery system to 120VAC for the house. We chose 48 volts DC as the system voltage in order to make wiring easier (doubling the voltage halves the current).

PV power is too costly to waste, so conservation measures were in order: Incandescent light bulbs were replaced with compact flourescents, and the existing refrigerator and freezer were replaced with SunFrost high-efficiency 120VAC units. We also located all our phantom loads (things like VCRs and wall-socket power cubes that draw current all the time, whether you're using them or not) and re-connnected them via power strips. The PV power system was a big project already, so three major power consumers got left till later: The oil-fired hot water heater, the oil-fired forced hot air furnace and the 3/4HP 120VAC well pump. Because of this we bought quite a bit of grid power just after the system went on-line in February of 1993.

The next step in implementing conservation was replacing the oil-fired hot water with solar. In September '93, Chip installed a Thermomax evacuated-tube collector and a Vaughn/Sepco 120 gal. tank with the solar heat exchanger option. I chose Thermomax collectors because they're a lot more efficient in cold weather and weak sun. I probably wouldn't have used a drain-back system in any case, but the "thermal diode" provided by the Thermomax's heat-pipe and manifold collects enough energy on below-freezing days to justify using a separate propylene glycol loop between the roof and the tank in the cellar.

The Thermomax collectors provide almost all of our hot water in the summer, even while we were washing cloth diapers for our daughter, but during the dead of winter they only manage to keep the tank around 70F. This gives the backup Aquastar tankless LP gas heater more of a workout, but that's what we get for living at 42 degrees North latitude.

We put up with the inefficient 3/4 HP centrifugal well pump until it let us down during the Summer of '93. Drought lowered our well's level to the point where the pump couldn't pressurize the tank. After a good deal of research, we settled on a 120VAC high-efficiency vane pump (Slow-Pump, from Dankoff Solar Products, Santa Fe, NM, 505-820-6611). It uses a 1/4HP motor, and after it was installed in November '93, we found that it fills the tank in one quarter the time while drawing one third the power.

The last major conservation measure was replacing my grandfather's coal furnace. He had converted it to oil in the '50s, but the blower and burner used lots of power, running more than 25% of the time in the coldest weather. New hot air furnaces used even more electricity than the old one, probably because they're designed to push air through smaller ducts. We found that forced hot water delivers heat most efficiently. We wanted to avoid the ugliness and wasted space of baseboard units and the possibility of freeze-ups, so we installed radiant panels and filled the system with a mix of water and propylene-glycol antifreeze.

The boiler we installed was an H.S. Tarm combination oil and wood gasifier with a Canadian-made Riello burner, which draws 1/3 the current of the old Beckett. As a bonus, we're no longer completely dependent on fossil fuel for heat. As installed, the control system was using 1.5 kW-hour per day just keeping transformers and contactors warm. During the summer of '96, one high-efficiency toroidal 24 VAC transformer from Plitron replaced three inefficient ones. Later I found a way of re-wiring the Tarm control box to save the 0.27 amp drawn by the two 110VAC contactors.

Afterthoughts

Between 1994 to 2004, we installed insulation in the attic ceilings and all the walls of heated spaces, to reduce both the electric load of the furnace, and the waste of non-renewable fossil fuel generating the heat. Insulating a house this old is never easy, but we had to avoid use blown-in or foamed-in-place products because of the fancy inside sliding shutters that Isaiah gave Jemmy. Nevertheless, we slowly got it into the walls the hard way, from the outside. Simultaneouslym we replaced the aluminum combination storm windows with old-style wood storms, using double-pane glass in the smaller ones.

During the winter of 1993-4 the first battery box was revealed to be inadequate: it let the batteries get too cold in winter. Cold batteries hold less power, which is really bad beause there's less sun in winter (due to short days and bad weather), and demand is up because the heat is on. Other goals included fireproofing, better cable routing, easier access if I needed to lift a battery out, and room for air to circulate around the batteries.

We were on-grid for two weeks in July '94 replacing the box. The new one, besides being better insulated, no longer has a concrete slab carrying cold in underneath it, and is heated in Winter by a removeable 18 square foot solar hot air collector. That winter the new box stayed at or above 45F, about 10F better than the old one. I subsequently improved the weatherstripping, which has held the battery bank at or above 50F through the past winter. At some point in the future I will supplement the simple hydrogen vent pipe with a voltage-controlled fan, possibly integrated with a thermostatic control for the heat collector.

In December 1995 we bought a Staber System 2000 top loading horizontal axis clothes washer. It saves both electricity and water compared to the Kenmore top-loader it replaced. It uses less soap, leaves less residue in the clothes, and extracts more water with its high-speed spin cycle. It has not needed any repairs to date, though I have had to open up the front a couple of times to extract things that accidentally fell down around the clothes bin.

Adding a Wind Generator

Originally, I had hoped to avoid buying any power except in special circumstances (system shutdown for repairs or maintenance). To my annoyance, this didn't pan out even after various energy conservation refits. After living with the system through a couple of winters, it became clear that neither adding more PV capacity nor trimming small amounts of demand would help: In this climate the sun can disappear behind storm clouds for a week or more. The record so far is 10 days without direct sun. Our battery bank is already quite large, but it still stores at best 4 days' power without severe conservation measures like shutting off the freezer and the furnace.

Luckily, in the record-holding January 1998 storm we were south of the icing line. We didn't have an auxiliary generator on hand, and the cloud cover was thick and uninterrupted for the whole 10 day period. North of the icing line, many places in Maine and Quebec were without grid power for weeks afterward. Still, with the battery/inverter combination alone we would have been a lot better off than most people - running a generator for 10 or 12 hours would re-charge our batteries enough for another two or three days.

A good deal has been written about the way PV and wind power can complement each other - in many climates, when there's no sun, there's usually wind, and vice versa. Here in New England, the match isn't perfect (the January 1998 ice storm had long periods of calm), but the idea still interested me. I started digging into wind technology in 1995, but the two old Enertech wind generators I salvaged required grid-intertie; We needed a stand-alone unit to take advantage of our existing battery bank. It appeared that our existing PV didn't need a whole lot of help, and some research into average wind speeds in the area convinced me that around 1 or 2 KiloWatts capacity would do.

Taking factors like required maintenance, availability and manufacturer's reputation for quality into account, I decided on a 1500 watt unit from Bergey Windpower Company, Inc. . This is a self-furling 3-bladed upwind-rotor machine, with a permanent magnet 3-phase direct drive alternator. Its tower-top weight is about 170 lb., with a 10 foot rotor diameter. In my application, a solid-state control box installed near my batteries converts the AC to regulated DC for battery charging.

Because our house is in a partially forested valley, our wind generator wanted a tall tower. Surveying from the roofs of my barn and a neighbor's house with a level convinced me we needed about 100 feet worth. Tilt-up towers are the cheapest way to get height, but in 1995, I had had a couple of unpleasant experiences with one while conducting wind speed measurements. What tipped the balance was salvaging the second Enertech genny; UNH wanted it dismantled, and threw in a never-used 60 foot Rohn free-standing tower as an incentive. That job also confirmed that I wasn't any more bothered by heights than I had been while climbing trees as a kid. So, rather than worry about when (not if) a farm animal or vehicle would clip a guy wire, I decided to extend the free-standing tower to 100 feet by buying two new sections.

I had expected that buying everything off the shelf would mean that the installation would go quickly. Boy, was I wrong. I wrote the first check in September 1997, hoping to be on-line by winter. However, the foundation couldn't be poured until the day before Christmas, because Chip wanted to assemble the tower first to ensure it fit the bolt pattern. The Bergey and its special tower stub for use with a free-standing tower didn't arrive until February. But, everything finally came together, and I scheduled the crane for March 24, 1998.

The crane arrived on time, the weather was fine, and not too windy. The only glitch was that Chip had assembled the tower too close to a tree, so we had to lift it once, horizontally and move it a bit before we could put it upright. I was taking pictures as the crane began the lift. It handled the load (less than 3000 lb.) easily, bringing it almost upright in about a minute. Then it lifted the whole tower and swung it over to the foundation. After we got it onto the mounting bolts and tightened down, Chip's employee Ian climbed the tower to unhook the sling . It took another couple of days to finish the wiring and tower grounding.

Things started out well. As expected, when the wind blows, the Bergey adds quite a bit to our capacity. So far, we've only seen two consecutive days with neither clear skies nor wind, which the batteries handled easily. The generator is a bit noisier than I had expected - the most noticeable noise is the swish of the blades as a gust dies down and the rotor decelerates. The only early problem was a fuse blown in the Bergey control/rectifier unit. I was confused to find a 1 amp fuse where the manual specified a 2 amp fuse, but a couple of calls to Bergey set that straight.

After a year or two in service, the wind generator was a bit of a disappointment - despite the 105-foot height, it wasn't making a great deal of power. A hilltop or waterfront site might do better, but in my case I would have gotten much more power from spending the same money on PV panels.

Lightning Strike

In July of 2001 we got hit by lightning. Five ground rods on the tower were nowhere near enough. It came down the tower and jumped through the electronics in the barn on the way to the drilled well's casing. The cost to get back off-grid was about $5000.

As part of the repair, I greatly improved the grounding. We ran a 1" copper pipe around the barn from where the tower wires enter to the well casing, with ground rods bonded to it every 10 feet. In retrospect, I should have run the power feeds from the tower to the barn's power room in a metal pipe with similar grounding.

But that wasn't all: In spring 2002, the Bergey started to make noise. By the time the ground was dry enough to get a crane in, the bearings were completely shot and the blades had a dangerous amount of play in them. We got a new bearing from Bergey and installed it, going back on-line in spring 2003. However, it now has way too much rotating friction - maybe the preload was wrong. At any rate, the Bergey only makes power in winds of 18 MPH and up. And since then I've been procrastinating getting the crane in, trying to fix it, and putting it back up (another $1600 for the crane alone). But so far (knock on wood), we haven't had another lightning strike, and it earned some points by performing well during the ice storm.

Meanwhile, the original Trojan L-16 batteries were showing their age (9 years as of replacement). We had found them tiresome to water: we found the 144 screw-off caps took a full day of bending over the side of the box, even with garage-style automatic water dispensers. So in Nov. 2001, we replaced them with 48 Surrette KS-21 2-volt 1100 Amp/hour cells: 48 flip-open caps only took a couple of hours to water and they proved long-lived.

Ice Storm

Unlike 1998, we were north of the ice line in the storm of December 12, 2008. Most of Rockingham County and neighboring towns in Massachusetts lost power that night, and damage was so extensive and widespread that it stayed off longer than we've ever seen before: Half of South Hampton got it back on the 16th, but our side wasn't restored till the next day. Friends in central New Hampsire weren't expecting grid power till after Christmas.

Through it all, we had light, heat and water. We hosted relatives, pumped water for neighbors and animals elsewhere, and went about our business pretty much as usual. There were a couple of days of sun, but otherwise the period was cloudy. We took conservation measures, switching off non-essential loads (the cable internet was down anyway) and heating with wood stoves instead of our furnace (luckily, that week was mostly mild weather). I was pleased with the wind generator, because this time the correlation between bad weather and wind worked out, and it kept our battery well above the minimum through several days of bad solar charging.

Does it Pay?

I often get asked "Does it pay"? Solar hot water with LP gas backup costs a lot less than electric. I don't know how it compares with oil; I never knew exactly how much oil went to the water heater and how much to the furnace. PV electricity is fairly costly; the PV panels and other hardware will last a long time, but even with the best treatment the lead-acid battery bank deteriorates in 10 years. We've had to replace the bank once so far, and I figure that what I saved on electric bills over 10 years just about paid for the new one.

However, there are less tangible values: One of my major concerns was power outages. Back in 1994, our daughter was born here at home, with a midwife attending. While her mother was in labor, thunderstorms knocked out grid power throughout the town. We never even noticed. As far as I'm concerned, the whole PV system paid for itself that evening. And if that isn't enough, our power was not interrupted by the 6-day grid outage in December 2008.

There's also power quality: When we bought all the compact flourescents for the house, we gave quite a few to friends. None of the 1993-vintage gift lamps lasted even two years on commercial power. But only six or seven have failed on our inverter power in 15 years. And we aren't included in those myserious events I hear about where several people on our street have appliances fail at more or less the same time.

Future Plans

We've considered an electric car for all the short trips and errands to town. The existing PV system isn't big enough to handle a large daily charging load, and moving power from one battery to another doubles your inefficiency. Had we gone that route, we would have had to change over to grid-intertie (where we sell power to the grid when we have extra, we buy it when we aren't generating as much as we need). The original AES inverter wouldn't do that, but the Trace that replaced it after the lightning strike will. However, its software insists on topping off the battery every night, so I'm not really satisfied.

As things turned out, we couldn't get an EV with a Nickel-Cadmium battery pack without waiting until the manufacturer had four orders, so we bought a Honda Insight hybrid in May 2000. It's given good service over 120,000 miles (Dec 2008), and 68.1 MPG lifetime average. My best trip was Amesbury to Cincinatti OH and back at 81 MPG. We liked it enough that I bought a Honda Civic hybrid (manual transmission) in May 2005, which continues to get a 55.6 lifetime average MPG.

We've also taken a few steps to reduce the overall refrigeration load. We moved the freezer to the barn cellar, where it only needs to work against an unheated environment in winter, when power is hardest to come by. There are also some people with interesting ideas about dumping waste heat from refrigerators into the hot water tank, which might make the compressors run more efficiently as well.

PV Power System Components

As installed:

Upgrades and maintenance:

Electrical Loads (in rough order of power used)

Total consumption is about 6.7 kWh/day in summer (refrigerators working hard). The Winter of 1995 was about the same, partly because the the heating system wasted a remarkable amount of power. The electrical changes I made in the Summer of 1996 reduced the idle current draw quite a bit, and with the house mostly insulated, the heat ran less as well. Still, I bought power to charge up the batteries at least once in every month from November to March in the succeeding winters.

PV system cost

Roughly $47,000, including 110VAC distribution wiring to house. The battery bank would cost about $9,000 to replace after a 10 year lifespan (by 2003). The only other maintenance cost is distilled water for batteries, about $12/year. A newer, better-insulated house wouldn't need as large a system, and eliminating one of the refrigerators or switching to wood stoves for heat would also save quite a bit.

Solar Hot Water System cost

Roughly $6,000. LP gas use (including gas stove) is about 12 gallons per month in Winter. The only maintenance is periodic refresh of the propylene glycol antifreeze.

James B. VanBokkelen