Bridges System

Orin Bridges

Unlike most alternative energy homes, our residence is not a remote
homesite.  It is located just 5 1/2 miles from Sandpoint, Idaho on
4.2 acres of land and electrical power is just 1/2 mile away.  Our
main objective was to sever the umbilical cord of utility companies
and become more self sufficient.  The fact that the original outlay
of cash and the absence of monthly bills represents a monetary savings
is an additional bonus.

Location
5.5 miles west of Sandpoint , Idaho.  Although not remote by most
standards, the property is at the end of a 1/2 mile road and has
a remote feeling.  In addition to the "feel", the lay of the land
makes it highly unlikely that others can build within the immediate
area.  The land is from flat to gently rolling hills, mostly wooded,
with about 1 acre open for residence, outbuildings, garden and meadow.

Power Requirements
This system was designed to maximize the use of DC.  The ac requirements
are appliances that are used infrequently or for short periods of
time.  DC power is utilized for all lighting (mostly fluorescent),
water pumping, hot water circulation, solar hot water pump, refrigeration,
color TV, answering machine, grain grinder and ceiling fan.

The ac requirements are washing machine, vacuum, computer and peripherals,
electric broom, circular saw, drill, juicer, food processor, blender,
VCR, electronic typewriter and hair dryer.  The inverter is a Power
Pal, which has been modified to include remote switches operated
from the kitchen, one for general use and one on the electric ignition
propane stove.  The vacuum takes the most power - 13 amps ac, but
is used at most once every 10 days.  In the interim, a very efficient,
small Bissel carpet sweeper is used.  The next largest consumer is
the washing machine - 11 amps ac, but this high energy consumption
is used only during the agitation and spinning cycles, not during
the filling cycles.  The washer is used, at most, every week.

During the "gray sky period", which lasts a long time in Northern
Idaho, the vacuum, washing machine and all other possible ac appliances
are put to use when the generator is simultaneously charging the
batteries.  When the generator is running, one extension cord goes
from the generator to the battery charger and another from the generator
directly into the ac circuits in the house, by-passing the Power
Pal inverter.

Power Sources
A Briggs and Stratton Industrial gasoline engine drives a 4,000 watt
ac generator.  28 PV panels are mounted on the roof, 26 of which
are Sovonics and 2 "left over" small panels that were installed on
the original cabin.  The Sovonics panels in this installation are
individual cells, so the Sovonics array consists of 13 cells connected
in series in each array.  On a sunny day, the 2 "left over" panels
are producing 1.5 Amps and the Sovonics arrays are collectively producing
an additional 28 - 31 Amps.  This has not changed since they were
installed almost 2 years ago.

A special note:  the Sovonics panels, not having been field tested
in this area, had no track record, but two unsuspected benefits came
to light after installation.  First, there is no tempered glass over
the panels, making them much lighter than other brands.  This means
that with five panels attached to each roof mounting bracket, the
tilt adjustment for seasonal solar changes can be done by one person
with little effort and in about 15 minutes.  Secondly, during a very
heavy storm last winter, which blew down many trees in the area,
a loose bolt came out of the aluminum foot which attaches the brackets
to the roof, allowing the 5 panels to thrash about on the roof for
2 or 3 hours during the night, before it was rebolted.  I believe
that if the panels had been covered with tempered glass, they might
have broken.

There is no charge controller used in the system, since the C/60
charge rate will not be able to overcharge the 2,016 Ampere-hour
battery.

Batteries
12 Volt DC is stored by 6 @ 2 Volt lead-acid batteries.  We purchased
9 year old telephone cells which were in good shape, hooked them
in series using 3/4" copper tubing with the ends flattened in a vise.
We installed them in the garage on the common wall of our "sun space".
(Note:  I wish I could take credit for the 3/4" copper tubing idea,
but in my many trips to the salvage yard looking for copper bus bars,
the young man working there finally said "Why don't you use copper
pipe?")

The only thing that didn't work according to plan was the "sun space".
It has insulation below the slab, and a concrete wall filled with
sand and painted black.  The full windows faced true south and the
batteries were placed on the opposite side of this concrete block
wall.  The theory was that the solar heat storage would discharge
into the well insulated battery area during the winter months.  Since
there was little sun for the first half of the winter, we heated
the sun space with natural convection from the woodstove in the living
area.  After that, we deserted our hopes for sun in the sun space.
We finally put a sliding door & insulated drape between the sun space
and the living area to save heat.  It did the job, but the batteries
were deprived of the heat.

Late last winter, I moved the batteries.  The sheetrock on the lower
part of the garage side of the living room was removed along with
the insulation.  We built a box around the batteries.  It was double
insulated with R-19 insulation, thereby trapping the heat that was
escaping from the dining area.  This will reduce our reliance on
the generator considerably, since the capacity of the batteries will
not be as greatly diminished due to the cold.  Last January, they
remained about 48iF. to 50iF. when it was between zero and 20iF.
above outside.

We heated the sun space most of the winter the year before last and
as a result we only used the generator 34 1/2 hours that year, after
the initial charging.  Last year, due to the colder sun space and
more gray skies, we used the generator 69 hours.  The sun space is
now used to propagate seedlings during warm spring days and cold
nights.

DC and ac Connections
In order to differentiate between the DC and ac outlets in the house,
the receptacles that are DC supplied are ivory (99 44/99% pure power)
and the ac are brown (like air pollution from petroleum products).
As an extra precaution, to prevent any damage to DC appliances that
were plugged into a brown (ac) outlet, I wired the DC receptacles
with the negative connected to the round (grounding) point and the
positive to one of the slot connectors.  This turned out to be over
kill.  There are three reasons I would not do this again.  1) Since
the inverter must be switched on manually, the odds against the accidental
plugging in a DC appliance are high.  2) The only DC appliance that
we own is the answering machine, which remains plugged into the same
outlet.  3) All of the lamps had to be converted to 3 wire, bulky,
expensive, and unattractive plugs.

Water
Water cannot be separated from energy.  It takes energy to bring
it up from the ground, to distribute it and to heat it.  The well
on the property is 325 feet deep, with a static water level of 124
feet.  The former owner of the cabin had put in the well and pumped
the water by hand, with a long pump handle.  He had installed a 500
gallon cistern which is lower than the well house, so the water was
- and is - delivered to the cistern by gravity.  From the cistern,
the water is pumped by a Flojet pump to a pressure tank to supply
the house.

When we added on our house to the cabin, I bought a used jack pump,
a 12 Volt DC motor which had been used to power a motorized wheelchair.
I picked up a scrapped garage door spring, cut it into the proper
lengths and used the springs as a counter balance for the jack pump.
I ran #00 gauge aluminum wire in PVC pipe underground to the mechanical
room.  There, a toggle switch, ammeter and electronic water level
sensor provide all the information needed to assure the proper supply
of water.

This is an example of what is very important to an alternative energy
home; work with sun/wind/water, whatever is available.  Limit the
use of automatic devices.  When the sun shines and the batteries
are up, we pump water.  If it is cloudy, we wait.  I set a mechanical
timer for 1/2 hour, check the ammeter to make sure the pumping is
smooth, reset the timer, etc.  After the pump makes a few strokes
to warm up, the ammeter rides between 18-20 Amps in warm weather
and 22-25 Amps in the winter.  The movement of the meter tells me
if the well pump is running smoothly or if one of the counter balance
springs is broken.  (There are extra springs on hand.) The Flojet
pump caused our copper plumping to vibrate noisily, so at Steve Willey's
suggestion, I installed some garden hose between the pump and the
pressure tank.  This dampened the noise.  My first try was about
6-8 feet of hose.  This has been recently replaced by an entire 50'
length.  We can now barely hear the pump when it is on.

Hot Water
Hot water is supplied by two different systems.  In the winter, all
the hot water we can use is provided by 3/4" copper pipe passing
through the woodstove.  Since the storage tanks are in the attic,
the heated water is moved by thermosiphon to the tanks, eliminating
the need for pumps, controls and energy consumption.

During the sunnier 3 seasons, the 3 solar collectors are used to
provide plenty of hot water.  There is a solar circulating pump in
this circuit, since the water storage tanks are level with or below
the collectors on the roof.  If it had not been for the design of
the house with the living areas on the south side or if we had a
hillside sloping away from the south side, I would have used thermosiphon
for the summer hot water too.  A manual switch turns on the solar
circulating pump as it is needed.  My first inclination was to dedicate
one PV panel to this pump, but since we don't need the water heated
every single day during the sunny period, this is another example
of working with the weather and balancing the needs with availability.

Reusing Water
The washing machine is located in the attic.  The gray water from
the washer goes into the septic tank during the winter, but is routed
to a couple of 55 gallon barrels during the summer.  The combination
of gray water and rain water form a low tech method of using water
twice.  These sources of water flush the toilet in the cabin and
furnish water for the garden.  In order to prevent clogging the pump
between the barrels and the toilet, I removed some of the filtering
material from a water filter so it would not take all the dirt out
of the water, but would take out the large particles, such as dead
bugs, twigs, etc.  Additional 55 gallon barrels - a total of 18 of
them - plus a 250 gallon storage tank, reduce pumping water for the
garden.  The large roof area provides a large shed, routing the rainwater
to the rain barrels below the downspouts.  The water is then siphoned
from the downspout barrels to the storage barrels in the garden.
The garden is hand-watered from these storage barrels.  These barrels
are covered to avoid mosquito propagation.

Hot Water Circulation
It takes about 20 Amps to pump water from the well and only 3 Amps
to circulate hot water.  I designed a loop in the hot water system.
The long runs from the storage tanks to the kitchen and bath could
be the cause of much water loss - and subsequent additional pumping
- while waiting for the cool water in the hot water lines to move
out.  Rather than waste that water, a pump moves the cooler water
in the hot water lines back into the storage tanks.  One switch,
controlling the hot water circulation pump is located by the kitchen
sink and another in the bathroom.  A switch is turned on before hot
water is drawn.  Within one minute, hot water is at the tap.  No
wasted water or energy.

Refrigeration/Cold Box
On the North side of the house is a small room we call the cold box.
This room provides all the cooling needed for food from about November
to May.  The other months, when the sun is shining at its best, a
small Nova-Kool refrigerator located in the cold box is used.  The
cold box has three outside vents and by opening and closing - and
in the coldest weather insulating these vents, the temperature is
kept within tolerance.

System Cost
In as much as all the design, plumping, wiring and installation -
except for the PV mount - was done by myself, the costs were kept
to a minimum.  The costs shown here do not include items that would
have been necessary whether or not the home was powered by alternative
energy.  Such items as the solar hot water collectors ($525), refrigerator
($600), the DC pump and pump jack ($235) and the additional copper
pipe used for the solar hot water would still be a part of the design
if there was a grid-connected utility.


With a little help from our friends+
The batteries, as well as the solar panels, inverter and 99% of the
solar electric items were purchased from Backwoods Solar Electric
(208-263-4290), owned by Steve and Elizabeth Willey.  They have never
- in 2 1/2 years - failed to return a phone call, their prices are
competitive, their philosophy relating to the cooperation with the
earth and all its inhabitants is greatly in tune with our beliefs.
Their personal service and willingness to share information is invaluable.

Afterthoughts
Had it occurred to me at the time, I might have designed and included,
in the main bath, the flushing system now used for the cabin toilet
- rainwater and washwater, with a "Y" connector for use when neither
are available.

If I were to do it again, I would give more thought to the battery
location and installed them in a warmer area to maximize their capacity,
maybe about 10i to 20iF warmer than they are now during the winter.
Outside of that, there is nothing I can think of that I would change,
except perhaps our gray winters.

Access:
Orin Bridges, 6307 Hwy 2, Sandpoint, ID 83864.  Please include SASE.

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