Running my genny quiet

Discussion in 'Off Grid Living' started by The_Quietman, May 2, 2011.

  1. The_Quietman

    The_Quietman Monkey+

    Hi everyone!

    I'm a new member, been lurking for several months. After introducing myself in the new members area, it was suggested I come here and ask if anyone has suggestions how to quiet my 50KVA diesel generator during a SHTF scenario. I've inet pics below:

    Generator is seen behind the garden bed (left) with my barn in the background:


    Here are the details:


    It has a 100 gallon tank, good for about 4 days of continous operation. It runs 20 minutes a week to keep everything running.

    Any ideas or suggestions on how to quiet it (it is very loud!)

    Many thanks,

    hank2222 likes this.
  2. gunbunny

    gunbunny Never Trust A Bunny

    Have you tried the old trick of burying a metal 55 gallon drum and piping the exhaust throught it?
    goinpostal likes this.
  3. VisuTrac

    VisuTrac Ваша мать носит военные ботинки Site Supporter+++

    that genny is going to produce a lot of volume (exhaust).
    You may have to run the exhaust through multiple drums but what is really going to attract attention is the large flat walls of the garage and house that are going to reflect both the engine noise and the exhaust. Look at erecting some privacy fencing that has looks like below plus overlapping slats will help out too.


    or any shape that does not have smooth flat reflecting surfaces.
    If you know of anyone that does recording they can help you with noise reduction and how harmonics will make the sound of your engine droning in the middle of the night attract unwanted attention.

    just remember to make the enclosure large enough not to cause the engine to over heat.

    and holy crap 50KVA! dude you running a cnc machine shop, entire subdivision or what?

    If it were me and if i only needed it for my own household needs, I'd sell that one and get a low speed lister diesel. way quieter.

    Just my 2 copper clad zincs. YMMV.
    Brokor likes this.
  4. ghrit

    ghrit Bad company Administrator Founding Member

    Full fiberglass lined sound enclosure over the unit, making sure the frame does not contact the enclosure at any point. "Hospital grade" muffler. Baffle the cooling air inlet and discharge thru the enclosure ends.

    The sound fence is a good idea, too.

    A more expensive alternative (probably more effective) is a vault in ground.

    There are a couple other tricks for later discussion, but the gains from them will be less.

    Yep, it's a biggie for a house only ---
  5. VisuTrac

    VisuTrac Ваша мать носит военные ботинки Site Supporter+++

    another holy crap is that engine is going to be flowing like 500 cubic feet per minute at 1800 rpm at load. barrels probably aren't going to cut it.

    turbo whine, and flow rate are going to make it whistle pretty good.

    If it's equipped with a sound dampening enclosure the engine noise should be around 70 db at maybe 21 feet but that exhaust is going to be pretty loud when reflected.

    it will be even louder if you open the enclosure to check on the engine if you do not have remote data readouts.

    Hopefully you are in a remote area where you have distance to deaden the engine drone.

    fuel consumption a maybe 4 gal per hour at full load is beyond what i could justify. as it is more than 5 times as large as i could use in an basic SHTF scenario (we wouldn't be running much more than a laptop,portable dvd, well pump, freezers and maybe the blowers on the fireplace inserts)
  6. BTPost

    BTPost Stumpy Old Fart,Deadman Walking, Snow Monkey Moderator

    There are THREE Noise Components that you have to deal with here.
    1. Mechanical Noise... also includes Turbo Noise. This is mitigated by using multiple layers of Sound Deadening Material, in between the Engine, and the property edge.

    2. Exhaust Noise.... also includes some Turbo Noise. This is Mitigated by use of Medical Grade Silencers. You can construct these yourself by using Buried 55 USG Drums connected in series, by 3" Pipes, and Baffels in the drums.

    3. Cooling Noise.... This is mitigated by moving the Cooling System farther away from the engine, and decreasing the flow of air thru the Radiator, and increasing the Size of the Radiator.

    This will ALL cost Money and Effort, but it can be accomplished with the correct Design and Engineering. The larger the Genset, the harder it is to keep it quiet. There is an Excellent Genset Guru, that lives and works in the State of Texas, that could help with the OPs issues. He hangs out over on in the Onan Forum. Billy is the best. .... YMMV....
    hank2222 likes this.
  7. The_Quietman

    The_Quietman Monkey+

    Thanks for all your suggestions! I may do some experiementing this summer.

    I know the unit is large, but it came with the house (part of the negotiations when I bought it back in '07). The home is five bedrooms, all electric (base board heaters before I put in the geothermal). On average, based on my current load, it uses about 1 gal of fuel/hour.

    I'm located 35 miles east of Cleveland in a very rural area on a 7.5 acre property surrounded by forest. The generator itself is located about 800 feet from the main road.

    Your observations about the house and barn reflecting noise are very astute, it almost magnifies the noise.

    Thanks again everyone!

  8. -06

    -06 Monkey+++

    Slip another pipe over the exhaust enroute to the muffler system. That will help with the noise also. You may want to go to a multi bladed clutch driven fan. It slows at high speed to reduce the roar. Flex blade fans are a bit quieter also. Look at the sound deadening panels on comercial air compressors. They work nicely. Plant some Cedars close together for visual and sound reduction. Two deep will do wonders.
  9. Gafarmboy

    Gafarmboy Monkey+++

    Move it...

    The first thing I would do is to move that thing to another location that is NOT between two buildings. That would reduce the amplification affect of the buildings. Then I would do what BTPost said. But moving it away from the house would be the 1st thing I would do.

    On a side note, Dang I would love that have that monster on my farm..[drooling]


    If you can not protect what you own, you won't own it long.
  10. Monty

    Monty Monkey+++

    I run a 5kw military generator, it's loud also. I'm doing the 55 gal muffler/heat exchanger. I'm coiling copper tube in a loose spiral inside the drum then hooking it to the exhaust to use the heat from the engine to warm waste oil. Once it's to temp I want to try and run it cut with diesel through the engine.

    Bt hit it on the head with the issues you'll have maybe enclose it in it's own building?
    The option to move it would be a little pricey.

    In the military we just dug holes and dropped them in, hole was about double the depth and 1 1/2 times the diameter. You had a hard time hearing them unless you were right on top of them.

    GAfarmboy I just sold a 125KVA 6cylinder Koheler generator to a guy who sells the to hog farms in Iowa. Guess I should have posted it on here for sale??

  11. Gafarmboy

    Gafarmboy Monkey+++

    It would be nice...

    It would be nice to have such a large Genset on the farm. With that said, it is way down the list of things to do. Maybe in two or three years when all is built/re-built and bought for the farm I can actually afford it. Being continually broke due to projects is starting to get really old..

    If you can not protect what you own, you won't own it long.
    VisuTrac likes this.
  12. Cephus

    Cephus Monkey+++ Founding Member

    Some of the old oil rig pumpers around here that would run the old hit or miss engines would bury a 6" pipe about 3 feet deep 10'long that had holes in it cover it with 2" rock and dirt ,made them pretty QT . But if ya stood near them ya could fell the ground move !! LOL
    Might work might not don't know !!
  13. thebastidge

    thebastidge Monkey+

    I think I would just pile a berm around it. The slope of a dirt berm is good for not echoing, as the soft surface will absorb a lot. It also provides protection from stray bullets, prying eyes, and could be a firebreak. It requires no technical knowledge or special equipment (a tractor makes it much easier, but you could shovel a few pikup loads around it over time) and no maintenance.
  14. spud

    spud Monkey++

    gensets are noisy
  15. gejoat

    gejoat Monkey+

    If you put up a building what about thick acoustic tile all over, in addition to what the others have said. I don't have anything else to add about quieting; but some thoughts on use get some batteries maybe put lights on 12 volt system? and an alternative heat source, then only run your unit 1 or 2 hours a day, heat the house up for an hour in the morning and then in the evening. 4 days in the middle of January isn't going to do you much good.. If you watch how much you are in the freezers, refrigerators they will stay cold just fine even in the summer. By the way do you have a well or spring on your property what happens when the city water drys up?
  16. BTPost

    BTPost Stumpy Old Fart,Deadman Walking, Snow Monkey Moderator

    There are three sources of noise eminating from an engine driven genset.
    1. Mechanical Noise from the Engine.
    2. Cooling System Noise from the Radiator.
    3. Exhaust Noise from the Exhaust Pipe.

    Mechanical Noise is mitigated by enclosing the genset in a noise abated enclosure of some kind. Double, or Triple Walls, with noise dampening material in between, seems to work best.

    Cooling System Noise can be mitigate in various ways. I like to use a Co-Generation system to move the Cooling system BTUs into a Secondary Cooling Loop thru a Heat Exchanger, and only thru a Radiator if you absolutely can'y use the BTUs elsewhere. I mean you paid for those BTUs when you bought the fuel. It just seems such a waste, to use them to heat the whole out of doors, and make all that noise, when they could be used to heat buildings and Domestic Hot Water.

    Exhaust Noise is by far the easiest to deal with. A GOOD Medical Grade Muffler/Silencer will take care of 90% of noise from this source. One can mitigate the rest, by running the exhaust thru a series of Noise Traps. Usually buried 55 USG Drums, loosely filled with fiberglass batting, connected by 3-4 inch pipes, and then vented to atmosphere.
  17. goinpostal

    goinpostal Monkey+++

    1)Stucco the interior,and exterior of the genset enclosure with pumicecrete.Pumicecrete is just pumice/lava rock mixed with portland cement,and water to make it stick.Airports are now using this in their buildings for deadening the sound from the planes.This can be done under the roof as well.
    2)Deadening the exaust noise with the buried drums is great,but remember as well that the more twists,and turns you put in the pipe the quieter it will be.
    3)The heat exchanger for the cooling system is a great idea that could be used to heat your house.This could also be done with the exaust heat.
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