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Thread: Generator Exhaust Through a Steel Wall

  1. #11
    Join Date
    Nov 2005
    Location
    Tasmania
    Posts
    491

    Re: Generator Exhaust Through a Steel Wall

    My generator is housed in a metal room beside my workshop, the exhaust goes through the wall near the roof and down into a water filled drum out the back. When first set up, it created a huge amount of noise and vibration, didn't notice it to much until was wondering what the weird rumbling noise was when out in a paddock on a tractor, close to 1klm away.

    Tried carpet on the walls and insulated the exhaust more, but it still made lots of noise. So bought some of that expanding foam in a can, put some ply lining on the interior walls and roof and pumped in the foam. Then wrapped insulation round the exhaust where it goes through the wall and buffered it by cutting a tyre up and put that round the exhaust pipe where it goes through the wall, also put a wood block so the exhaust wouldn't vibrate out. Did end up installing one of those flexible bits on the pipe which reduced the vibration to almost zero and the noise that comes from the shed now, is a very low hum. You have to get close to the shed before you hear it. Until you open the door, also hung a light carpet across the door on the inside, this reduced the noise coming through the door edges considerably. Have 2 fans on the shed, one pumps hot air from the shed into the workshop and the other is used in summer to disperse the hot air to the outside. It heats the workshop from cold to bearable and there is no smell from the old lister, have the engine breather plumbed to the outside.

  2. #12
    Join Date
    Dec 2007
    Location
    South Australia
    Posts
    1,127

    Re: Generator Exhaust Through a Steel Wall

    You could dispense with the fan pushing hot air out of the container if you connect the generator radiator outlet to the vent of the container with a rubber gasket of some sort. Yes heavy carpet will work, not as well as auto sound shield but if free the value is much better. Don't use foam under felt it is too light, weak and burns too. Maybe wool carpet. Fit in such a way that rodents can't make it home. Yes the roof will also act as an amplifier but on flat land the only people affected will be those in light aircraft as the sound goes up. You say the neighbor is 70m away up hill, hoping the hill is not too steep as noise travels uphill much better than on the flat. The corrugated roof may vibrate if the exhaust outlet is too close, take it up a metre or so and you should be right.
    Johnnojack
    4WD Isuzu Jackaroo 3.1 170,000km on WVO,(2017) 2 tank home built system 6 solenoids. Mk. 9 version. Improvements under investigation

  3. #13
    Join Date
    Sep 2009
    Location
    Brisbane (North Side)
    Posts
    680

    Re: Generator Exhaust Through a Steel Wall

    I still think there is value in pulling the radiator off the gen set and investing in some hoses and an electric fan and put the radiator outside. I would definitely do that. you are actively carting heat out of the container with the fluid not the air. The less holes you have in the walls / roof the better if you are worried about noise. the smallest of holes that isnt treated right will let out a heap of noise. small holes for the hoses are super simple to seal with a dektite (spelled correctly this time!)

    If you really wanted to knock the noise down, you would build a plasterboard wall on studs inside the container, and fill the cavity with insulation. USG boral publish data that certifies (tested in a lab) that a single 10mm normal plasterboard sheet on one side of a timber stud wall with no insulation will knock 27 decibels off the transmission. upgrade that to 2 layers of 10mm pbd and you get a reduction of 33 decibels. insulation properly packed will go further again. of course you can do all of that later if it is too noisy, as that represents dollars.
    Regards,

    Cade.

    2002 100 series Landcruiser
    240,000 Km and counting on B100, 330,000km total on car.
    Naturally aspirated, Walbro Pusher pump just upstream of tank switch valves, Cav filter with reversed fuel flow direction.
    At 160,000 km Rebuilt pump, Reconditioned head and manifolds, glow plugs. Injectors all good after 160,000 km on B100.

  4. #14
    Join Date
    Sep 2005
    Location
    WA
    Posts
    4,063

    Re: Generator Exhaust Through a Steel Wall

    Quote Originally Posted by Captaincademan View Post
    I still think there is value in pulling the radiator off the gen set and investing in some hoses and an electric fan and put the radiator outside. I would definitely do that. you are actively carting heat out of the container with the fluid not the air. The less holes you have in the walls / roof the better if you are worried about noise. the smallest of holes that isnt treated right will let out a heap of noise. small holes for the hoses are super simple to seal with a dektite (spelled correctly this time!)

    SNIP.
    Cade, I suggest that using the radiator fan to blow the air thru the radiator and outside the container will work better than moving the radiator outside.
    My justification is that the engine heat is also moved outside by the fan pushing air from inside the generator enclosure to outside the container.

    Obviously, replacement air needs to come into the container, so a suitably sized filtered vent will be necessary. By using wood to make an "n" shaped inlet duct, the engine noise would be significantly attenuated outside the container. Suitable weather protection for the wood will ensure a long life for the duct. The duct should have a cross sectional area similar to the radiator opening.

    Relocating the radiator outside will still leave a large, hot lump of metal to heat up the engine room. It would still need to have an air inlet to replace the air used by the engine. (eg, a 1 litre 4st engine will use 750 Litres of air per minute at 1500 RPM. The advert does not give the engine cubic capacity, so used 1 litre for this example)
    Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

    Current Vehicles in stable:
    '85 Mercedes Benz W123 300CD Turbodiesel single tank using 95% used cooking oil and 5% to 10% misfuel (where someone had filled diesel vehicle with petrol).
    '06 Musso Sports Crew Cab. Running on used cooking oil with 5% to 10% misfuel.
    Toyota Camry Hybrid - (Wife's Car)

    Previous Vehicles:
    '90 Mazda Capella. (2000 - 2003) My first Fatmobile. Converted to fun on veggie oil with a 2 tank setup. Died when supercharger stuck at max boost for weeks. Stretched head bolts.
    '80 Mercedes 300D. 2 tank conversion [Sold]
    '84 Mercedes 300D. 1 tank, no conversion. Replaced engine with rebuilt OM617A turbodiesel engine. Finally had good power. Donor for current Fatmobile coupe. (body parted out and carcass sold for scrap.)
    '99 Mercedes W202 C250 Turbodiesel (my darling Wife's car)[sold]
    '98 Mercedes W202 C250 Turbodiesel (my car)[sold]



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  5. #15
    Join Date
    Sep 2009
    Location
    Brisbane (North Side)
    Posts
    680

    Re: Generator Exhaust Through a Steel Wall

    Valid point about the heat from the engine block. end result is big holes in the walls. sound is going to be difficult to cut down, especially at night when you just want to run a few things (telly, lights etc), but maybe you could hook up a battery system for that occasion.

    good luck with it Jens, you have an interesting project on your hands. keen to see your end result.
    Regards,

    Cade.

    2002 100 series Landcruiser
    240,000 Km and counting on B100, 330,000km total on car.
    Naturally aspirated, Walbro Pusher pump just upstream of tank switch valves, Cav filter with reversed fuel flow direction.
    At 160,000 km Rebuilt pump, Reconditioned head and manifolds, glow plugs. Injectors all good after 160,000 km on B100.

  6. #16
    Join Date
    Apr 2011
    Location
    Lismore NSW
    Posts
    312

    Re: Generator Exhaust Through a Steel Wall

    Thanks guys,

    The generator is only as a backup for our off grid solar system, to run dryer and hot water system during long rainy periods and to cook my bio of course. My main concern is that I am cooking bio usually on a Sunday. Last thing I want is being the new kid and by far the youngest in our street and to upset the neighbors by having the geny thumping all day on Sunday.
    Given we are on large residential lots, there is always someone moving the lawn with a ride on or harassing a tree with a chainsaw, so total silence is not just impossible but also not needed. As I stated previously, reducing it to 25 db at 10 m and I am happy.
    I will move the genie in its new home next week and will report back results.

    Thanks again for the feedback and thoughts!
    1990 Toyota Hilux LN106 with ATG 2 tank system (sold after running 150.000 ks on mainly WVO)
    1993 Toyota 75 Series with 1 HZ engine both 75l factory tanks and a custom 170l under tray tank.
    200.000km 80% on bio 10% on WVO 10% on dino,

    "him who never made a mistake, made no discovery either"


  7. #17
    Join Date
    Sep 2005
    Location
    WA
    Posts
    4,063

    Re: Generator Exhaust Through a Steel Wall

    Quote Originally Posted by Captaincademan View Post
    Valid point about the heat from the engine block. end result is big holes in the walls. sound is going to be difficult to cut down, especially at night when you just want to run a few things (telly, lights etc), but maybe you could hook up a battery system for that occasion.

    good luck with it Jens, you have an interesting project on your hands. keen to see your end result.
    Case, You can attenuate sound from the engine by using sound absorbent materials, about 500mm from opposite the opening, parallel to the wall. eg a flat panel of ply, covered in carpet, will significantly attenuate the sound from the opening. You can 'tune' the sound intensity by moving the panel in / out and angling it to minimise the sound in particular directions.
    Beuff,
    Do you have access to a sound pressure meter? This would be useful in positioning any sound absorbent material and checking how well it works.
    We look forward to your next message.
    Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

    Current Vehicles in stable:
    '85 Mercedes Benz W123 300CD Turbodiesel single tank using 95% used cooking oil and 5% to 10% misfuel (where someone had filled diesel vehicle with petrol).
    '06 Musso Sports Crew Cab. Running on used cooking oil with 5% to 10% misfuel.
    Toyota Camry Hybrid - (Wife's Car)

    Previous Vehicles:
    '90 Mazda Capella. (2000 - 2003) My first Fatmobile. Converted to fun on veggie oil with a 2 tank setup. Died when supercharger stuck at max boost for weeks. Stretched head bolts.
    '80 Mercedes 300D. 2 tank conversion [Sold]
    '84 Mercedes 300D. 1 tank, no conversion. Replaced engine with rebuilt OM617A turbodiesel engine. Finally had good power. Donor for current Fatmobile coupe. (body parted out and carcass sold for scrap.)
    '99 Mercedes W202 C250 Turbodiesel (my darling Wife's car)[sold]
    '98 Mercedes W202 C250 Turbodiesel (my car)[sold]



    Searching the Biofuels Forum using Google
    Adding images and/or documents to your posts


  8. #18
    Join Date
    Apr 2011
    Location
    Lismore NSW
    Posts
    312

    Re: Generator Exhaust Through a Steel Wall

    Quote Originally Posted by Tony From West Oz View Post
    Beuff,
    Do you have access to a sound pressure meter? This would be useful in positioning any sound absorbent material and checking how well it works.
    We look forward to your next message.
    I only have an app on my phone which currently tells me that the generator is at 70 db, which is the rough equivalent to a loud conversation. I'll report back results once its in the container. Will make the decision on wall or roof opening for the exhaust there and then. I guess if I weld a 100mm pipe through the wall, the 51mm exhaust should be okay with exhaust wrap on it to seal it off and prevent noise transfer.

    Again many thanks for the input everyone! there is just nothing to replace shared knowledge!
    1990 Toyota Hilux LN106 with ATG 2 tank system (sold after running 150.000 ks on mainly WVO)
    1993 Toyota 75 Series with 1 HZ engine both 75l factory tanks and a custom 170l under tray tank.
    200.000km 80% on bio 10% on WVO 10% on dino,

    "him who never made a mistake, made no discovery either"


  9. #19
    Join Date
    Apr 2011
    Location
    Lismore NSW
    Posts
    312

    Re: Generator Exhaust Through a Steel Wall

    Well, I have manged to get the generator in the container, the exhaust is going through the wall and a fan is connected to the air outlet. After the first test run it was a rather disappointing result, the generator was still noticeable at 40 m distance. It's more the vibration than the actual engine noise. I then put the rubber mounts under it and it improved the situation dramatically. Now one can barely hear the generator running at 40 m and the exhaust and extractor fan are the only way to tell that its running.
    The first big run is planned in a few to cook the next batch of bio. I will report back how that is going.
    Have a good week everyone and thanks again!
    1990 Toyota Hilux LN106 with ATG 2 tank system (sold after running 150.000 ks on mainly WVO)
    1993 Toyota 75 Series with 1 HZ engine both 75l factory tanks and a custom 170l under tray tank.
    200.000km 80% on bio 10% on WVO 10% on dino,

    "him who never made a mistake, made no discovery either"


  10. #20
    Join Date
    Sep 2005
    Location
    WA
    Posts
    4,063

    Re: Generator Exhaust Through a Steel Wall

    You need to check the temperature in the container when you have the big run, so you know whether you need more ventilation. You do not want the battery room heating up as it will impact on the electronics and battery performance. It may be beneficial for Lead - Acid cells to be kept above 0C though.

    What battery technology do you have?
    Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

    Current Vehicles in stable:
    '85 Mercedes Benz W123 300CD Turbodiesel single tank using 95% used cooking oil and 5% to 10% misfuel (where someone had filled diesel vehicle with petrol).
    '06 Musso Sports Crew Cab. Running on used cooking oil with 5% to 10% misfuel.
    Toyota Camry Hybrid - (Wife's Car)

    Previous Vehicles:
    '90 Mazda Capella. (2000 - 2003) My first Fatmobile. Converted to fun on veggie oil with a 2 tank setup. Died when supercharger stuck at max boost for weeks. Stretched head bolts.
    '80 Mercedes 300D. 2 tank conversion [Sold]
    '84 Mercedes 300D. 1 tank, no conversion. Replaced engine with rebuilt OM617A turbodiesel engine. Finally had good power. Donor for current Fatmobile coupe. (body parted out and carcass sold for scrap.)
    '99 Mercedes W202 C250 Turbodiesel (my darling Wife's car)[sold]
    '98 Mercedes W202 C250 Turbodiesel (my car)[sold]



    Searching the Biofuels Forum using Google
    Adding images and/or documents to your posts


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