I’m planning to get a whole-house backup generator. In trying to weigh the pros and cons of the different fuel sources I want to get other’s perspectives.
Understanding that it’s difficult to anticipate every reason the power might go out, I want to cover as many bases as possible.
The options I’ve looked at include Natural Gas, Propane, and Diesel, but I’m not set on just these if other options are suggested.
What fuel source would you choose and why?
Replies
natural gas
Any idea what the smallest propane generator available is. I really only need it to run the circ pump for the radiat floor heat, and the electronics that control the boiler. The only other thing I would want to power is the fridge.
This is for a second home and cost is an issue and most of the backup gens are far larger than I really need. Really just want it for freeze protection.
Fairly small. You might look and see what Northern Tools has.But there are conversion kits that you can use on most any small gas engine.But my guess is that you want an automatic unit.That is probably the limiting factor. .
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Yes automatic is the issue as I live 1000 miles away.
I'm fine with building one from parts if I can come up with a plan for a reliable unit. The alarm system I have could be set up control starting and periodic tests faily easily.
Edited 1/29/2008 7:10 pm ET by TomW
That is a tiny draw. You should plan to have a battery set up and then charge off solar or a genset that only runs an hour or so a week.I have an Onan 6000 that could have been set up for natgas/propane. The tech is simple. Any gas engine almost can be made to run on fumes
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Can you give me any guidance for battery options. I know the load is pretty low and I would really like to have something in place for freeze protection.
What is the heat source for this radiant heat loop anyways?How to set up a battery system is beyond my knowledge. I'm the global thinker on this - then I get somebody good to do it.But sounds interesting. Somebody will get you going here.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Heat source is a propane fired wall hung boiler. I beleive the only electric consumption of this unit is for ignition and control. Probably very light load and there is 1 circ pump in the system. I don't have the specifics of any of it here but the total load can't be much.
Since you already have a propane boiler i would use propane as the fuel.
Up here in the far frozen north and prime earthquake country I run a 7K Honda I series. The inverter delivers as clean or cleaner power than the utility (this is the primary reason I bought this because I run several computers and my furnace control electronics are important to me). It is light enough two people can put it in the back of a pickup and with the econo switch it will run around 12 hours on a tank and it is fairly quiet.
Granted the longevity of aircooled engines is of some importance but lets face it, if it gets ran 10-12 hours a year and keep the oil changed every 6 mo or so I think it will last a very long time. Up here I run gasoline because if we have another big quake we will not have NG available for some time.
I am going to install a outside transfer switch next summer and will be able to feed the entire house. It also has a built in load meter, electric start and a hobbs meter function, battery status etc.
Jim
Yes propane would be my choice, the OP was looking for fuel. I asked aout a small unit or battery backup (thansk Piffin) instead of a genset. Probably should be in another thread to avoid confusion.
My bad....I was reading through to see if he ever mentioned what type of heat he had and lost track of the id of the OP while seeing your propane set up......
Any gas engine almost can be made to run on fumes
In a perfect world a gas engine runs a 14.7 parts air to 1 part gas----- that's almost fumes ;-)
In search of a new tagline, don't worry I'm sure I'll find one that will bother somebody. ;-รพ
The fumes I meant was natural gas
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
plumbbill,
Peak power is at 13.7 parts whereas optimum clean burn is at 14.7 again that varies slightly depending on factors such as combustion chamber shape and flame front propagation..
A lot of research needs to be done on alcohol based fuels because the rules appear to be slightly different there due to the slower burn rates.. It appears that the old short stroke long bore approach needs revision. Recent trends seem to indicate that a true hemispherical combustion chamber with a minimum squish area is best for maximum clean burn when used with alcohol..
Then too if we alter the traditional bore/stroke ratios to favor longer strokes with smaller bores, while friction goes up due to higher ring drag numbers, because of the slower burn rates of alcohol based fuels there is a net gain in power at even leaner fuel air ratios..
Then too effects of forced induction enter into the equation and provide further confusion. Squish is required to create the needed turbulence required for complete combustion, however under forced induction (either by super charging or turbocharging) turbulence can be achieved in the inlet tract and carried into the combustion chamber without the need for any squish area. Given the lack of requirements for squish and the slower burn rates of alcohol max power is coming at even leaner fuel to air ratios without excessive combustion chamber temps.
These rules were first established in the mid to late 20's with the work of Miller and the Dusenburg brothers.. However due to their limited resources at the time they weren't fully explored..
Cheap High octance fuels developed shortly thereafter obsoleted any real interest in alcohol based fuels and the information is only rarely if ever reviewed for possible applications today.
Did I mention that I'm a really serious gear head?
Thanks to all for your insight and comments. I think diesel is out of the running. It also seems like there are pros and cons to natural gas and propane I'll have to weigh.Natural gas could have an interruption if there was a large enough earth quake. At least I could use the propane I had on hand if I go that route. Then again, depending on the disaster, I might not be able to get a propane truck out to come refill my tank and the natural gas could still be running. I guess I could go with natural gas and have the parts on hand to convert to propane if needed. I have several propane tanks on hand that could run it for a few hours at a time if needed. Thoughts on that option?(I think I’m over thinking this.)
FWIW in spite of what has been said about reliability of N.G. the recent storm that passed through the Great Lakes region caused a natural gas outage in several neighborhoods in either Toledo or Port Clinton, Ohio Outages lasted for up to 12 hours IIRC and there was no reason listed other then high wind combined with well below freezing temps. Caught the news of it when I was looking a local to that area news site about a train derailment over Sandusky Bay caused by the same storm.
They can't get your Goat if you don't tell them where it is hidden.
Don't worry you weren't confusing me.
I'm one of those goofy grads of a technical institute that was for auto/diesel mechanics.
A reciprocating motion to obtain a spinning shaft is a Rube Goldberg all the way. Turbine is what everyone should be driving towards.
In search of a new tagline, don't worry I'm sure I'll find one that will bother somebody. ;-รพ
Plumbbill,
The trouble with turbines is they are more efficient at altitude than at sea level. I have yet to see a really small turbine that is fuel efficient. In theory the losses at operating rpm would be too great. Thus the requirement for transmissions designed to operate at lower RPM which further increase your losses.
If you look into the earliest jet engines there is a glimmer of possibility but size becomes massive Efficiency comes from size but that very size is what will destroy the possibility of turbines ever achieving anything realistic..
2 cycle diesels driving generators is the likely interim solution. Diesel because of the low operating RPM which reduces friction losses. Two cycle because of power to weight ratio's.
Tiny 2 cycle diesel units as Hybreds to extend the range beyond the capability of storage batteries.. BioDiesel is renewable and relatively clean, potential gains still exist. I envision a unit of about 1000cc. capable of producing 25 horsepower. 25 Hp is more than enough to keep the batteries charged on extended trips while daily commute driving needs would most efficently be met by small solar/ wind units mounted on your residence.
As units that size become available the price of standby power will plummet..
Turbines can be built for any elevation it's the fuel that they burn that depends on altitude.
Turbine is still a 4 stroke motor.
I can't remember the guys name, but a former NASA guy brother of Compaq CEO at one time used a small turbine (about 6" x 24") to power a generator inturn powering electric motors. Was placed in a Saturn & running about 1400 miles on pump gas standard size tank.
It had some resin core flywheel type thing in the trunk that spun around 65,000 rpm that provided the boost for HP gains----- it was really cool. He had some beef with GM & ended up dealing with Mercedes.
I think a Moller rotary can provide a better power to weight ratio than a 2 stroke can, & they can run on pretty much anything liquid that can burn.
Ofcourse this will all be moot once the hydrogen fuel cells ramp up production.
“The world is a dangerous place, not because of those who do evil, but because of those who look on and do nothing.” —Albert Einstein
Fumes, what fumes.We don't need any stinking funes.Mine runs on water vapor. Special carburter. Gets 200 miles to a gallon of water.I sold the rights to the oil companes. So I can't tell you how it works..
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Hey, they bought my special carburetor fan as well. Did you get paid for your device yet? ;-)
They can't get your Goat if you don't tell them where it is hidden.
RSmout,
Here's my take on back up generators..
They are fine at first, but they need to be maintained.. Oil changed, anitfreeze replaced and etc.. Even if you don't use them you must do the maintinance.. failure to do it means that when they are needed they will fail.. period!
Diesel fuel has the disadvantage of aging if not used. It will slowly turn to jell and evaporate.. or evaporate and turn to jell <grin> Please note slowly!
Propane needs to be replenished periodically.
Natural gas if it's available is an excellant standby power source..
Both propane and natural gas are slightly less demanding on frequency of oil changes.
Whatever you choose you should start and run the unit for at least an hour or so every month.. failure to do so will result in ring shadows and loss of spring tension on the valve in the open position..
Ring shadows will eventually cause the rings to fail requiring a rebuild.. and spring weakness will cause valves to hang open bring about back fires.
So what's your back up to the back up plans? Or do you plan on doing or having done the periodic mainitinance required?
PS I have known some who sign maintinace agreements only to find out if they aren't monitiered, sometimes the maintinance is skipped by the service tech because it's only a "standby generator".. He pencil whips it and doesn't do anything.. who's to know?
If you have natgas available, there is no more discussion.
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
Diesel is a huge pain. You'll only be able to run for so long on the fuel you store in the tank and it will empty at the most inconvenient time. You also have the likely problems of gelling, evaporation, condensation, etc. like any other liquid fuel tank that sits unused most of the time. Fuel stabilizer will help somewhat until the generator goes into an automatic test mode and uses some of the fuel. A lot of AHJs will also limit the amount of diesel you can store on site which takes you back to the first problem. Another thing to think about is that insurance companies don't really like unattended fuel tanks at second homes. You'll also possibly have problems with theft of the fuel itself.
Propane would be OK except you'll be working with a limited of supply again like with diesel.
If natural gas is available, it's your best option.
As far as routine maintenance, a lot of generator controls have a test feature that will make them cycle once or twice a month to make sure the system is working properly and to make sure the battery is fully charged (if it has one). You'll still have to do oil changes, coolant flushes, etc.
Natural gas!!
As the others have noted the fuel choices are narrowed due to availability.
If situations are that you need to run the generator, you want to do this without interruptions. If power is out in an area you might not be able to get some of the fuels like Gasoline or diesel. Pumps won't work.
Natural gas is a continuous feed of fuel. Mine is on natural gas. 15KW standby generator. No regrets other than we haven't had a hurricane lately! :-)
“Some people wonder all their lives if they've made a difference. The Marines don't have that problem.”
Reagan....
Failure is the condiment that gives success its flavor.
-Truman Capote
Bryant, Guardian and others make automatic standby generators starting at 7kw, which would be more than enough for your needs.
Since you already have a propane fuel source for the heat, it would make the most sense to use a propane generator. Here in VT, all emergency back-up generators at fire departments and other critical locations are propane (of course, we don't have natural gas).
In a disastrous storm, it's even possible that natural gas supply could be disrupted, but the propane in your tank is under your control.
You can get air-cooled units to reduce maintenance. Changing oil often doesn't need to occur more than once in two years.
You might also want to hook it up to your water pump to keep the taps running should you be at the house during an outage - nice to be able to flush the toilet.
Solar & Super-Insulated Healthy Homes
Riversong.
If you did a little research you will quickly find that the few air cooled engine options are extremely short lived . Air cooled also has real high demands on oil changes and maintenance.. Oil is the cooling medium and the acids which build up with inactively really damage air cooled motors a lot.. Since oil is the cooling medium in air cooled engines but because of temp rises the oil has more demands on it and must be replaced more frequently.
Ignoring the added pollution of air cooled engines over more common water cooled engines..
Finally you will find that repair parts of air cooled engines are dramatically more expensive and rare than common water cooled engines..
In the end a few gallons of antifreeze every couple of years is trivial and depending on the engine may be replaced every 5 years.
If you change the oil every two years plan on replacing the engine every 10 years.. the ring shadow I spoke about would become significant enough to require reringing soon.
Acid build up would also destroy bearing surfaces.. acid build up increases dramatically with time in engine following running..
While the oil filter will hold a lot of contaminants moisture and acid won't be contained in the filter..
As for your idea of keeping the water pump operating most water pumps are electric.. The disastrous stormthat interupts Natural gas you are referring to would need to disturb the ground, around here at least 4 feet down!
Must be a real earth shaker!
We'll have to agree to disagree on the reliability of air-cooled engines.
My first career was as one of the first fully-certified auto mechanics in the US. The VW air-cooled engine, produced for 70 years, was a reliable machine that didn't require much maintenance - and it had to operate under much more demanding and variable conditions than a fixed, RPM-governed generator engine. It was so reliable, in fact, that it was used in a number of airplanes and for commercial usage around the world including running chair lifts at ski resorts.
Engines run on natural or LP gas run much cleaner with less oil contamination (particulary the sulfur that causes acidification) than gasoline or diesel engines. Even running an hour a month for testing, and during the occassional power outage, any quality standby generator will last for many years.
Of course water pumps are electric, which is why I suggested powering it with the generator in addition to the heating system and fridge.
And when I refered to interruption in natural gas supply, that's because gas requires compressors to move it through the pipeline and they can be knocked out in a storm or other calamity (terrorism?).
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 1/30/2008 12:13 am ET by Riversong
Riversong,
If you notice there are no more air cooled cars anymore. Porsche has gone to water cooled and VW stopped decades ago.. Your ideas of durability are woefully out of date. Normal is near twice or three times what VW's would do with absolutely the finest maintinance available..
The reason is the expansion needed to accomidate air cooled engines leads to far too much pollution.. It also has extremely tight manufacturing tolerances and the costs of those make it not cost effective to produce.. There had been a few air cooled engines used in construction equipment but their unreliability, high costs for parts, plus their high intial costs eventually cost them the market..
Small air cooled generators designed for temporary or construction use don't have to meet the pollution rules automobles do. They will remain a fixture on construction sites and in campgrounds as long as we don't regulate the pollution they create..
Over the decades I've sold construction equipment I've sold plenty of gen sets.. air cooled isn't as durable as water cooled and by far the most durable are in line six clyinder diesels.. As standby units their life is measured in decades.. We replaced a diesel unit providing power for a major hospital that was 4 decades old with 30,000 hours on it.. It had never once been repaired.It went to power a farm and has done so for more than a decade now still without a rebuild..
Finally I have never ever seen a natural gas failure.. Even when the local gas company had a major fire with their electric compressor. There are standby natural gas powered compressors for exactly that use.. (Grimmer Schmidt makes them and I sold Grimmer Schimidt) <grin>
Frenchy,
Most standby home gensets are air cooled----- how much more would the HO have to dish out to purchase a liquid cooled unit of the same KW ?
Your ideas of durability are woefully out of date.
If you notice there are no more air cooled cars anymore. Porsche has gone to water cooled and VW stopped decades ago...
Actually, the air-cooled VW was produced in Germany until 2003 and in Brazil until 2006. Its demise was not due to durability, but to stricter emission standards that were impossible to achieve in an air-cooled engine.Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Riversong
I'm pretty sure that's what I said, also it's demise was also due to higher costs and poorer gas mileage than could be obtained by water cooled engines with their tighter operating clearances.
i think you are a bit out of date on your thinking... most onan RV gen sets are air cooled... and have a service life of many thousands of hours... the "ring shadow" thing and the valve spring issue... is a non issue because just about every back up gen set has a monthly start up and run cycle where it brings the genset up to temps... burns off moisture that may have gathered and keeps everything lubed... most of these units will require less than 2hrs a year in maint time... and should last as long you own your home...... i doubt many if any would ever get the hours on them that would require a rebuild...
oh yeah... and nat gas... is the only answer if it's an option....
p
ponytl,
Onan gen sets last many thousands of hours.. (if you are lucky and properly maintain them)... If you attempt to rebuild one you will quickly find out that it rapidly approaches the price of a new unit.. Thus they tend to be use and toss units.. Simple water cooled units cost less to produce and pollute far less. Plus since they are common repair/replacement parts are cheap and readily available..
You are correct in that maintinace on standby units is really brief but it must be done.. True the oil never wears out, it becomes contaiminated with the by products of disimilar metals and acid plus water which is the result of running..
On an engine that would be exteme to run 250 hours a year (10 days working and 10 hours monthly testing) how much extra to you want to pay for any engine that will last 100,000 hours vs one tht only last 5,000..
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
I'm guessing that would depend on whether it was for life support in hospitals and nursing homes, or just a convenience like watching TV and running the AC.Saving a thousand bucks worth of meat in the freezer and taking a daily shower probably falls someplace in between, depending on how bad the BO gets.;)
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
BillHartmann,
Very solid reasoning, however a small aircooled generator will not be worth much on the used market while a durable diesel generator with tens of thousands of hours of life left in it not only has great value, it can provide power to run pumps needed to control sewage back up should you live at the low spot on on the waste line..
There are so many varables that no one answer will suit all.. It's not just the power to keep your refrigerator and TV operating. It may be the power required to deal with waste water (sewage) for a whole neighborhood.. Maybe you need to water your cattle or have some other major power user..
Frankly I tend to think locally and somehow my solutions should be everybodies answers.. that's not the case.. I hope everybody understands that.
I have a Kohler stand by unit in service at my second home to prevent freeze ups and allow basic use of the house if we are there and the power goes out. I bought an air cooled propane powered unit. It is very quite while running and there was no reason to place it away from the house like I did in hind sight. ANYONE who knows anything about LP or LNG powered equipment knows that service life is long and maintenance is very low. Diesel powered units are bigger bucks and require more maintenance. They are also louder than other units and they stink when they are running.
LP was my only choice due to the fact it's my heat source and it is my cooktop choice as well. If I was burning oil I might think about diesel but we hate electric cooktops, ovens are fine.
A 500 gallon vessel lasts a good long time providing the filling company fills it. (Don't ask :-() I could also upgrade the size at anytime if I feel the need. If your NG supply is compromised by street work or major flooding away from your local your not going to have a fuel to burn. Diesel does degrade and also can get contaminated. When this happens you have major problems in your engine and major expense removing it from the tank.
You will need to provide an electric outlet for all units for cold starting (block or carb heater) as well as a battery maintainer.
A proper system will run the system weekly on no load or load, it's your choice. I do shut off the weekly test in the warmer months to save needless wear and tear. I think that by the time your done buying and mousing parts together, the 6 K for an off the shelf unit with parts available over the counter or very soon if needed is money well spent. My unit has dry contacts that signal zones on my alarm panel. It tells me when it's running or if there is a fault. I know that if I don't get a call at the programmed time I have an issue with communications. If I get a call outside the testing time I know the power is out and pay attention. If the unit fails to start I can plan a trip ASAP or call a repairman who knows the unit as it was off the shelf and not a bunch of parts tied with duct tape and tie wraps.
Good luck. I'm only 270 miles away, I can't imagine 1000.
The local jail here in central NC has a diesel and the jailer told me that the diesel jells when it gets really cold, which is when they need the generator. They switched over to natural gas. If you go with propane you may have to pay for the tank if it is for the generator only. I use a gas generator at home and exercize it several times a year and use fuel stabilizer. If no use for a year or two I switch out the fuel for fresh anyway. It has always started.