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sabianq
2010-Feb-08, 07:46 PM
hi all,
well the power went out Again!

ugg..
this is getting old..
it happens at least 3~4 times per year with an average of 25 hours of no power per outage.

the outage usually affects about 100 homes..
i want to hook up our generator to the whole house.

but first i want to convert the gas generator to natural gas.
i have been researching on line and that conversion seems pretty straight forward, all you need is a vacuum regulated pressure regulator that feeds the natural gas to the slightly modified carburetor..

my generator is rated at 5500 watts @120vac peak.

my wifes dad suggests that a typical house uses 10K watts..

so far not a problem as with extension cords run through out the house i can run everything i need, the oven stove is natural gas, so electricity is only needed for the ignition in the oven.
the whole house heater is natural gas only needing electricity for the fan and ignition.

put i discovered, the whole house heater is sensitive to sin wave fluctuations due to safety.
any thought on how i might give the heater a nice clean sin wave? the generator is quite erratic and the heater is quirky when hooked up to it.
i was thinking about a 12 volt battery to DC/AC inverter setup as a buffer...

but the biggest problem is noise, the sound of a generator is stupid loud and annoying.

besides placing it in an acoustic isolated space, i was actually looking for another solution.

does anyone here know if thermoelectric generator can be built to be run off of the natural gas?
i imagine a natural gas fireplace with thermoelectric strips in the flame.. (looks nice, heats the house and generates electricity)

i also am secretly wanting a fuel cell that would work on natural gas.

any thoughts on any aspect of this post would be greatly appreciated.. thanks

schmidtj
2010-Feb-08, 09:21 PM
Do your homework on your gas pressure requirements.
I came very close to installing a whole house generator.
I had to upgrade my meter to handle the increased volume.
Also depending on how long the run is from the meter to the generator you might need a additional regulator to feed the generator at a higher PSI than the rest of the house.
The gas company hit me $200 to upgrade the meter and my contractor was going to charge me $1000 to update to larger diameter black pipe and additional regulator.
Since my outages are much less frequent than yours my risk assessment resulted in me backing out of the whole idea.

swampyankee
2010-Feb-08, 09:23 PM
Well, you could try micro-turbines (http://www.capstoneturbine.com/) ;-) For the more budget-conscious, a well-muffled gas engine in an acoustic enclosure shouldn't be too obtrusive. Get an electrician to install the appropriate transfer switch.

To size the generator, you should probably determine what you need: lights, well-pump, tv, computer, and your whole-house heater. Find the specs for the heater, then pick the generator.

Thermoelectric power generation is likely to be a trifle inefficient.

Atraveller
2010-Feb-08, 11:39 PM
hi all,
well the power went out Again!


put i discovered, the whole house heater is sensitive to sin wave fluctuations due to safety.
any thought on how i might give the heater a nice clean sin wave? the generator is quite erratic and the heater is quirky when hooked up to it.
i was thinking about a 12 volt battery to DC/AC inverter setup as a buffer...
thanks

Hi Sabang, this is actually what I am doing for a living right now. It is a typical problem, most gensets put out a very messy wave - and will also have lots of noise on the line.

We usually solve that by puting a "Double on line" UPS between the genset and any sensitive equipment. The UPS takes messy power - passes it through a DC stage, then puts it through a high quality inverter. The result is you get a "pure" sine wave output.

To solve the genset noise we use acoustic enclosures. We can reduce most gensets to about 40db at 5 meters.

Links:

primers on power protection (http://www.youpowerthrough.com/education/education.html)

genset enclosures (http://www.fgwilson.com/cda/layout?m=75344&x=7&mode)

sabianq
2010-Feb-09, 01:32 AM
i love the turbine idea,
i am actually thinking about a design for a whole house turbine that is quiet, and may even allow me to completely disconnect from the electric company..
i already talked to the gas company, and they seem all for the idea!...
i worked out the numbers and it will actually be cheaper for me if i can get better than 60% efficiency out of the gas...

it would be sooo cool to be able to pull the plug from the electric company..

i have always imagined a small "chest freezer sized box sitting next to the heater that generates all of the power for the house.

it would be able to run off of natural gas or propane and would vent to the same place as the hot water heater and furnace.

it has to be quiet and reliable and inexpensive,, then everyone can disconnect...

i have to wonder if it would be greener..

if it were fuel cell technology then the efficiency could be raised by a substantial amount.

Atraveller
2010-Feb-09, 02:31 AM
i love the turbine idea,


it would be able to run off of natural gas or propane and would vent to the same place as the hot water heater and furnace.

it has to be quiet and reliable and inexpensive,, then everyone can disconnect...

i have to wonder if it would be greener..

if it were fuel cell technology then the efficiency could be raised by a substantial amount.

The turbine idea looks interesting - we put them into a "green" building project here - but unless you also use the heat produced by them, they aren't really very efficient.

As a co-generation system - which you might be able to use - you can get up to 85% efficiency. But you would only get that in winter.

Also, you would still need some sort of load shedding, or energy storage.

Another article on the micro turbines: microturbines (http://www.wbdg.org/resources/microturbines.php)

sabianq
2010-Feb-09, 02:39 AM
i imagine the system would be on demand, and there would be a flywheel storage integrated in the system.

as long as you have a clock radio plugged in the system would be live...

sabianq
2010-Feb-09, 02:40 AM
a turbine with a heavy flywheel could produce a very smooth sin wave.

Atraveller
2010-Feb-09, 04:50 AM
a turbine with a heavy flywheel could produce a very smooth sin wave.

We do have flywheel systems - but they are brutally expensive (starting at $12,000 USD for a 10Kva system.) Typically batteries are a lot cheaper - And you still want to go through a high quality inverter to get the clean power.

With a double on line - and batteries as your storage system, you could run the turbine constantly - or on a fixed schedule, it would just be used to charge the system - and the inverter would be your on demand supply.

sabianq
2010-Feb-09, 05:19 AM
i have been interested in flywheel energy storage ever since i saw a guy in California screaming around in a car with a flywheel energy storage. strictly a proof of concept car, but it sure did prove that flywheels can very easily store more energy than the equivalent weight of a battery.

sabianq
2010-Feb-09, 05:25 AM
you are right,
the frequecny would change in porportion rotational speed.
so all output energy would need to be regulated in the inverter.

as demand will pull down the speed of rotation.
and supply will increase the speed.

and you get more energy storage as you go faster than you do if you get go more massive..

sabianq
2010-Feb-09, 05:28 AM
but the transition would be smoother in a flywheel with a turbine than a gas powered piston driven engine.

am i right that the piston driven generators have a more chaotic output than the turbine driven generators?

sabianq
2010-Feb-09, 05:33 AM
ultimately, i would love to use the Peltier effect to make electricity.
quiet, small, efficient...

Atraveller
2010-Feb-09, 05:59 AM
but the transition would be smoother in a flywheel with a turbine than a gas powered piston driven engine.

am i right that the piston driven generators have a more chaotic output than the turbine driven generators?

There are a few pro's and cons - starting a turbine takes longer, and takes more energy than starting a deisel with the same output. And generally a turbine unit will be about twice the cost of a similar sized diesel, and unless you are using the turbine as a co-generator, the piston unit will be more efficient.

Once the turbine reaches speed they are quite stable - but you can't load them until they reach speed. Then you get the usual +/- 1 Hz variability and +/- 5% voltage (In a quality unit - I know there are some lower quality units which will be all over the place.)

Diesel - takes a few seconds to get to speed, and with some sets, you can start loading them almost right away. But the output, especially on the smaller units like a 10Kva, are very very messy. You can easily have +/- 5 Hz and +/- 20% on Voltage. And the "sine" wave looks more like a saw tooth. So yes, you are right, the piston units are less stable.

sabianq
2010-Feb-09, 06:04 AM
have you been looking at thermoelectric?

Atraveller
2010-Feb-09, 06:35 AM
have you been looking at thermoelectric?

Thermoelectric generators are not yet commercially viable. Their efficiencies and the temperature gradient you need to produce any kind of viable output, usually makes them impractical. (Having said that - thermocouples have been used for years to power gas valves in household appliances. But the power required to hold open a tiny solenoid is a bit different to what you need to power your whole refridgerator.)

There is some work being done, but generally if you have enough energy to drive a peltier engine, you also have the energy to drive something like a steam turbine, which will have a higher efficiency.

tlbs101
2010-Feb-09, 06:42 PM
hi all,
well the power went out Again!

...

my wifes dad suggests that a typical house uses 10K watts..

...

any thoughts on any aspect of this post would be greatly appreciated.. thanks

Hi,
While all of the other BAUT member suggestions and comments, above, have been useful, I question your father-in-law's suggestion about a typical house. My own experience puts a typical 3 bedroom 2 bath house, using both electric and natural gas power at closer to 5 kW and even that is a peak electrical power.

For my own house, since my wife passed away and it's just me, I can run on less than 1 kW with a peak at 5 kW (when the electric dryer is running).

For times when your mains power is out for long periods of time, you could save doing laundry until the mains are back online. With a few necessary motors running (refrigerator, freezer, furnace blower), several luminaries, computer, TV, you could certainly manage with something between 1 and 2 kW. (This is assuming your oven/stove and water heater is natural gas operated.)

.