Generator Enclosures

New_Mexico_WillNew_Mexico_Will Registered Users Posts: 105 ✭✭
I think I've finally picked a generator that will work with my system, and I'd like to put it in an enclosure to (1) keep it out of the sun/weather, and (2) to cut down on the noise.  It allegedly only produces 56 decibels, so the weather is the main concern.

I have an extra job site steel toolbox that would be just the right size, but I'm thinking that maybe putting it in a steel box would actually amplify the sound.  At the same time, steel being fireproof seems like a good idea.

I'll be running it exclusively on propane, and it will sit outside my power house, with a total distance of about 6 feet between the generator and the inverter charger.

Does anyone have any tips on building the enclosure?  Is wood a better choice for the sound deadening properties?  Have any pictures to share?

Comments

  • Dave AngeliniDave Angelini Solar Expert Posts: 5,799 ✭✭✭✭✭
    In New Mexico? Buy more solar ;)   Seriously!
    Short of that metal is a bad idea. If I needed a genset I would just buy one of the rain tents for a $100 and make this easy. Your gen will last longer if it goes inside at night. The level of sound you sight is low enough to not bother anyone. Even me, I do not like to hear them running in places that have plenty of solar and storage. 
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • New_Mexico_WillNew_Mexico_Will Registered Users Posts: 105 ✭✭
    Good points, but we sometimes get a few cloudy days in a row, and a generator is much cheaper than a battery upgrade.  I don't want to have to move it around.  Sound isn't a concern, as I don't really have neighbors and it won't run much.  A tent will last one day in our spring wind.  Why is metal a bad idea other than sound amplification?
  • New_Mexico_WillNew_Mexico_Will Registered Users Posts: 105 ✭✭
    I also am a fan of redundancy since I am completely off grid, and a generator fixes anything that could go wrong.
  • EstragonEstragon Registered Users Posts: 4,494 ✭✭✭✭✭
    I built a shed (for a 4kw diesel) out of 6x6 timbers with type 'X' drywall lining.  Higher frequencies can be attenuated pretty easily, but low frequencies need mass.  The mass also smooths out ambient temperature fluctuations.  A jobsite box sound kind of small (heat buildup?).  Different materials and thicknesses attenuate different frequencies, so a mix works well.  For propane, I'd build it a bit off the ground, with a drain to daylight.  The fuel is heavier than air, and can accumulate in the bottom of an enclosed space.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • Dave AngeliniDave Angelini Solar Expert Posts: 5,799 ✭✭✭✭✭
    Wow completely offgrid ! I am impressed.  ;)
    Actually,  you can get redundancy without a genset. You may be on a budget so I get it. There are plenty of people I work with who can afford a second power system and go for alot more than 3 cloudy days.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • New_Mexico_WillNew_Mexico_Will Registered Users Posts: 105 ✭✭
    Estragon said:
    I built a shed (for a 4kw diesel) out of 6x6 timbers with type 'X' drywall lining.  Higher frequencies can be attenuated pretty easily, but low frequencies need mass.  The mass also smooths out ambient temperature fluctuations.  A jobsite box sound kind of small (heat buildup?).  Different materials and thicknesses attenuate different frequencies, so a mix works well.  For propane, I'd build it a bit off the ground, with a drain to daylight.  The fuel is heavier than air, and can accumulate in the bottom of an enclosed space.
    Good point about the drain.  I forgot about propane being heavier than air.  The internal volume of the job box is 2.5 times the "volume" of the generator.  Perhaps too small.  I think fire is much less of a concern with propane as compared to gasoline, so perhaps wood is the way to go.  Thanks for the input!
  • New_Mexico_WillNew_Mexico_Will Registered Users Posts: 105 ✭✭
    Wow completely offgrid ! I am impressed.  ;)
    Actually,  you can get redundancy without a genset. You may be on a budget so I get it. There are plenty of people I work with who can afford a second power system and go for alot more than 3 cloudy days.
    No need for the snarkyness, really.  I was specifically asking about generator enclosures.  I could afford a second power system, but what a waste of money if I only used it once a year.  That doesn't make sense.  I just survived the bulk of the winter without either.
  • mike95490mike95490 Solar Expert Posts: 9,244 ✭✭✭✭✭
    Generator enclosures need to allow for airflow, since most are air cooled engines & alternators.   A small prefab garden shed would do it, and be sure the exhaust port is not pointed at anything flammable.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • Dave AngeliniDave Angelini Solar Expert Posts: 5,799 ✭✭✭✭✭
    Glad you survived the first year!
    You can also just go and buy a genset in most of North America 7 days a week so redundancy is there.
    After some years, the redundancy of a second power source safe from lighting can be an issue for many. The other way to get onsite redundancy is with alot of solar and spares.

    Unless you have spare time to build something for an application that is hardly used, kind of a time drain. To each their own!

    BTW, the Gen tent is speced for 70 MPH. At that speed you probably should not be running a genset from all the junk that is in the air.
    My clients use them just fine for years. Just roll it out. Marine grade fiberglass.


    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • New_Mexico_WillNew_Mexico_Will Registered Users Posts: 105 ✭✭
    edited February 9 #11
    I don't do things that way.  Your clients drop thousands extra on batteries but want to roll out a generator with a beanie hat on it?  I guess they have more dollars than sense.  Over 70mph gusts are not rare in the spring here.  I will install an air filter intake on the enclosure.  Thanks for your input though.  
  • wellbuiltwellbuilt Solar Expert Posts: 569 ✭✭✭✭
    Here you go a little less ghetto , my genarator shed built with left over  materials . 
       My solar panels have been covered in snow since New Years and I mite not see them till April. 
    Out back  flex power one  with out back 3648 inverter fm80 charge controler  flex net  mate 16 gc215 battery’s 4425 Watts solar .
  • mike95490mike95490 Solar Expert Posts: 9,244 ✭✭✭✭✭
    wellbuilt said:
    Here you go a little less ghetto , my genarator shed built with left over  materials . 
       My solar panels have been covered in snow since New Years and I mite not see them till April.
    Nice to see a rolling door that you don't have to shovel clear !
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • Dave AngeliniDave Angelini Solar Expert Posts: 5,799 ✭✭✭✭✭
    Definitely nice! And an application that warrants the structure. Not sure many that I know need that in the southwest living offgrid full time, but you can always store firewood in there also.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • Graham ParkinsonGraham Parkinson Registered Users Posts: 69 ✭✭
    I've got a fair bit of experience with living with and trying to tame generator noise having lived with camp generators throughout a mining exploration career.  Some observations:

    • Distance is your friend, as are liquid cooled, slow speed generators (air cooled gensets radiate huge amounts of noise from vibrating cylinder fins, liquid cooling jackets effectively dampen noise) - Invertor generators are pretty low noise, but not entirely quiet and still benefit from an enclosure.  Their ducted internal fans are easy to adapt to route exhaust and heat out of the enclosure, meaning that you don't need a separate outlet vent but you do need an inlet vent.
    • Sound is a wave phenomenon, you need to baffle all air inlets and outlets with absorbent baffles, unless baffled with absorbers on the baffle surfaces, a tiny opening can radiate surprising amounts of sound power. Air inlet vents need to be designed like mufflers in reverse with baffles to make indirect air paths.
    • Absorption of sound energy is multi-faceted: Energy is reflected and absorbed at every transition in density/stiffness (acoustic impedance contrast). In order to absorb sound you first need to get it into the medium and not reflect it - so ideally you want a gradual, or layered and increasing density or at least gentle transitions in density/stiffness - think holes in acoustic tiles or lots of void space in insulation batts to let sound get in without reflecting.  My initial experiments with cement block wall generator enclosures basically created perfect echo chambers and the annoying noise of a 24/7 high speed Chinese diesel escaped through the unbaffled vent holes....with almost no reduction in the din.
    • Multiple layers (dense to block, openwork to absorb, dense, open etc.) with compliant isolation between layers are best to avoid transmission - multiple layers of drywall / acoustic tile with compliant standoffs or spacers between layers works well.
    • Previous comments about mass to block/damp low frequency and air tightness for keeping high frequency in are spot on.
    • Marine installations use lead loaded foam or alternating lead sheet foam layers to both trap and absorb a wide range of frequencies (pretty pricey stuff though)
    • Isolating the generator from the floor helps a great deal.  Ours is placed on a rectangle of heavy 1" particle board sitting on a layer of 2.5" rockwool board - avoids making the plywood floor act like a drum.

    As an example for our cabin we recently built a 3' x 3' x 3' enclosure for a Honda 2200 which works really well: It was built within a corner of a half open, 8' tall outer plywood roofed shed structure. The sound enclosure has a 2x4 frame and consists of an outer layer of 3/4" Home Depot solid rubber matting (3' by 4' sheets of stall liner like material were on sale for about $25 ea), and an inner layer on it's walls of 2.5" Roxul ComfortBoard (compressed rockwool rigid board) with rubber sheeting on floor and all around.  Exhaust and cooling air are ducted out through a hole in the wall via a homemade aluminum adaptor bolted and sealed to the gen set's exhaust/cooling grille, 6" flex aluminum ducting into a 1/2" fiberglass matting (salvaged from fiberglas ceiling tiles, wrapped around some wire mesh to hold against walls) lining an 8" galv stove pipe "supplementary muffler" with stovepipe cap that was also fibreglass lined as an exit baffle.  The Genset enclosure has a hinged multi layer rubber sheet door for starting, and a removable top made of two sheets of 1.5" neoprene foam lying on top of the walls.  Two hole sawed 4" holes in floor lead to a baffled space under floor and act as the air inlet.   

    The Honda's built in cooling fan does a great job of drawing air through and due to the sealed exhaust/cooling air adaptor no heat gets into the enclosure and everything runs nice and cool.   One caveat, rock wool should really be covered and not exposed inside a genset enclosure (I used some spare 1/8" EDPM pond liner sheets) as rockwool eventually sheds abrasive rock dust into the air which can contribute to genset wear.

    Almost completely inaudible outside!

    Offgrid in cloudy PNW

    MacGyver'ed museum collection of panels, castoff batteries and generators - ready for state of art system install ....

  • New_Mexico_WillNew_Mexico_Will Registered Users Posts: 105 ✭✭
    edited February 5 #16
    Some very useful information here!  Thanks to those addressed my question.  I like your style wellbuilt.
  • Dave AngeliniDave Angelini Solar Expert Posts: 5,799 ✭✭✭✭✭
    edited February 6 #17
    Yes this was a good thread! Thanks Will for starting it! I know what I was thinking about when I commented on totally offgrid. It was about some people I met who really were what I call offgrid or off the map. They cooked on a cooking woodstove and used candlelight and were afraid of RF in the home.

    The Marine apps are expensive also because the foam is fire resistant.

    Below was my gen shed. It became firewood storage after 2005 when solar panels started goin down in price. They were 10$ a watt in the early days and even more back in 1992 when we cut the grid. The Redtail on the shed use to live here up in a Ponderosa.




    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • wellbuiltwellbuilt Solar Expert Posts: 569 ✭✭✭✭
    I do have some smoker wood in the shed, plus a bait tank and log splitter 
     but I burn 8/10 cord of wood a year 
      I can stop burning around June 15 and I start again August 15 
     I’ve had snow july4 weekend 
     the good news is the place stays 67o all summer so no A/C needed 🤗
    Out back  flex power one  with out back 3648 inverter fm80 charge controler  flex net  mate 16 gc215 battery’s 4425 Watts solar .
  • Dave AngeliniDave Angelini Solar Expert Posts: 5,799 ✭✭✭✭✭
    edited February 6 #19
    The mini split for heating, cut our firewood use in 1/2 or more. Just a fire at happy hour and the split goes on at 7am.
    The split sips power at around 300 or 400 watts and takes the chill off for breakfast. By 9 am it is bringing the room up to 77F.

    Sounds nice to not need cooling. The last 5 years we have had wildfire smoke for a month or 2. It would be like Hell to live here without cooling as we can't open windows. If you open them, you have a fire drill at 2 am because of windshifts in the mountains. The up slope and down slope mountain air has it's own microclimates.

    Do the sliding doors keep rodents out? Or, what do you do? I use the alley cat traps and have tried mint-oil in the shed. Still a pain!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • 706jim706jim Solar Expert Posts: 410 ✭✭✭✭
    My place is built on short posts (about 3') and I've had no problem with mice even though they were abundant this year. So the patio door should keep them at bay as long as it is always kept closed. Owning a cat helps too.
    Island cottage solar system with 2400 watts of panels, 1kw facing southeast 1kw facing southwest 400watt ancient Arco's facing south.Trace DR1524 MSW inverter, Outback Flexmax 80 MPPT charge controller 8 Trojan L16's. Insignia 11.5 cubic foot electric fridge. My 27th year.
  • Dave AngeliniDave Angelini Solar Expert Posts: 5,799 ✭✭✭✭✭
    My cats won't go out in the snow and I do not want them out of the yard where the shed is. We have Cayotes and our Bears that do not hibernate like they are suppose to. :# Thanks though!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • 706jim706jim Solar Expert Posts: 410 ✭✭✭✭
    Our place (with the solar system) is located on a 100 acre island in Lake Superior. Our cat would go out from about 3am until 6am and would usually show up with a mouse. The last year we had her, there were two foxes on the island. When we had to put her down (inoperable tumor) the next week we heard the foxes howling outside our bedroom window. It's almost as if they and the cat had made friends and they missed her. Sounds strange and we'll never know for sure, but it's a nice story.
    Island cottage solar system with 2400 watts of panels, 1kw facing southeast 1kw facing southwest 400watt ancient Arco's facing south.Trace DR1524 MSW inverter, Outback Flexmax 80 MPPT charge controller 8 Trojan L16's. Insignia 11.5 cubic foot electric fridge. My 27th year.
  • wellbuiltwellbuilt Solar Expert Posts: 569 ✭✭✭✭
    Dave , I’ve never had heat ? My family comes from a area in Norway that is not Accessible 8 months out of the year .
     My uncle would start the lister at 400 pm and it was lights out at 800 . 
      I don’t even have heat at home on grid 👍 . 
     At home   I keep the house 62o but it’s warmer buy the stove . 
     A77o I would be wearing a toga and splashing ice water on my self .
     Off grid I burn one good fire in the morning then add 2 logs at a time every  4/5 hours , when it’s below 0 I need a fire going most of the day .
     In the summer I have guests asking me to turn down the AC  ,  I stay 67o or so all summer even when it’s 95 for a few days .
     The shed doors are hinged , but it hard to be mouse proof ?
     Mice are not a problem up there they stay out side in the summer and once it gets cold they are gone ?
    so I trap a few with peanut butter in the fall . 
     All you need for mice is a couple of these guys , he is a  Maine coon cat He may look lazy but he is up mousing all night long .
     Zeus is about 21 lbs but his brothers where 24 and 27 lbs I have a runt 7lbs allso but she is Vicious
     He can handle him self out side and go’s out every day. 
      Coyotes not not a problem . 
      The only thing in the shed that the mice could harm is my Honda but it sits on a shelf with a box over it so the mice can’t get in there.
     You could try to trap the mice , my mom would get a 5 gallon bucket and place it next to the wood pile fill the bucket with water 2” from the top and float dry corn and sunflower seed on top . The mice can’t resist a feast like that and they drop in and drowned. 


     
    Out back  flex power one  with out back 3648 inverter fm80 charge controler  flex net  mate 16 gc215 battery’s 4425 Watts solar .
  • Dave AngeliniDave Angelini Solar Expert Posts: 5,799 ✭✭✭✭✭
    edited February 7 #24
    Thanks ! It just shows me once again how different each Offgrid home is. I have a 10 question form I give to new clients. Probably need to add a few more questions.

     I have tried the 5 gallon buckets and it seemed OK. These little guys just somehow get into the shed. The thing I do like about the Alley Cat traps is they do not need to be baited. They also a super easy to toss the dead critter. I think the bait was just attracting more of them. Since I stopped it, I get about 1 a week in winter. I have to go in there for wood so it is not a big deal. It would be if I needed a genset in there ;)


    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • wellbuiltwellbuilt Solar Expert Posts: 569 ✭✭✭✭
    I have 6 traps set at my place and I got 3 as of thanks giving and nothing since . 
     I have some Ravens and a few owls and they pick off a lot of mice on my wrap around porch . 
     There are A couple packs of coyotes and a bunch of red fox allso . 
     Not to mention the place is pretty much frozen from Thanksgiving to April . 
       
    Out back  flex power one  with out back 3648 inverter fm80 charge controler  flex net  mate 16 gc215 battery’s 4425 Watts solar .
  • jtdiesel65jtdiesel65 Solar Expert Posts: 192 ✭✭✭

    I have all my gear in an insulated shed built with 2x6s. Half of the building is walled off, heated, and houses battery, inverter, etc. The other half of the building is open on the end. I have a Kohler 12kw propane (not portable) in that section. You have to walk by the generator through a door to access the section with the inverter. The open end points North and away from the house. All walls are insulated, even the sides of the open end section. It's ~60 ft from the house. You can't hear it inside the house at all. You have to open a window and listen carefully.  I haven't had a problem with heat. But it's a rare event when it would run and heat would be a problem.

    One nice thing about having it in a building is oil changes and maintenance. You don't have scorching sun, rain, or snow to deal with.

    Here's pics from when building it.


  • wellbuiltwellbuilt Solar Expert Posts: 569 ✭✭✭✭
    O nice , I would think the open end would fill up with snow ? 
     I wanted to just make a lean two for the genarator but I got 14” of snow in October when we where building it and I just built the wall across the front . 
     It’s better to be inside 
    Out back  flex power one  with out back 3648 inverter fm80 charge controler  flex net  mate 16 gc215 battery’s 4425 Watts solar .
  • jtdiesel65jtdiesel65 Solar Expert Posts: 192 ✭✭✭
    wellbuilt said:
    O nice , I would think the open end would fill up with snow ? 
     I wanted to just make a lean two for the genarator but I got 14” of snow in October when we where building it and I just built the wall across the front . 
     It’s better to be inside 

    Sometimes some snow will come into the open end, but it's rare due to the direction the open end faces. Most of the time it's just a little bit on the edge of the concrete.  My main generator is meant to be outside so snow is not a problem for it. I also have an outlet on the interior wall which I use to plug an eu2000 into an auxiliary 30amp charger. I mostly just leave the eu2000 there alongside the main generator.
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