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Post by jlafrenz on Sept 14, 2013 17:37:14 GMT -5
We have a portable generator that we use during hunting season and need to build a small cover for it to keep it out of the rain. I figured it might be worth a shot to try and make it quieter at the same time. I have been looking online and there are lots of ideas, but all have downfalls. The main one is that the generator needs air flow in order not to overheat or possibly catch on fire. I have looked into fans etc, I don't know how weather proof that it. I have also thought about cinder blocks, but that would not allow it to be portable if necessary. I do not want to go the muffler route as that does not seem to be the best overall and can cause additional issues. I see a lot of people say, "just get a Honda". Well we already have the generator and even if I had a Honda, I would still have to keep it out of the way of mother nature. Has anyone here built something they felt was successful or found and plans that are actually decent?
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hemster
Global Moderator 
Particle Manufacturer
...still listening... still watching
Posts: 51,950
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Post by hemster on Sept 14, 2013 18:01:36 GMT -5
How about one of those outdoor utility cabinet/shed? You can either buy something like the one below and drill holes on the sides for airflow and leave the doors open/ajar when in use. Or build one as I'm sure that'll be much cheaper. Click pic for details..  |
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Post by jlafrenz on Sept 14, 2013 18:29:05 GMT -5
I have seen a few plans on the net where people are using those. I could build a box out of 2x4's and plywood for less most likely. The issue with opening the doors is that the sound reduction is then negated.
I have an idea in mind that would modify a plan I saw online. It is a box with a slanted roof. The top section is hinged so it opens up and the front section is also hinged so it pulls down (like an oven). This would give a lot of access to the generator when needed. I would then put at least 2 larger PC fans on the highest part of the box to pull out hot air. On each of the sides near the front door I would have a fan so that it would bring in fresh air.
I still don't have a real good idea as to what to use for sound deadening that could handle the potential heat.
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Post by sheetmetalworker on Sept 14, 2013 18:31:39 GMT -5
Build a 4 wheel cart for it. Place a dog house over it, not litteraly a dog house. Now its mobile and protected. Also will muffle the sound a bit.
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Post by jlafrenz on Sept 14, 2013 18:36:53 GMT -5
That is the basic idea I have. I was just hoping to find a way that I could also quiet the generator down and keep it cool. It seems difficult to do.
My PC fan idea above has me curious if the fans would move enough air to keep the generator cool enough.
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Post by sheetmetalworker on Sept 14, 2013 18:41:20 GMT -5
I think a fan is a good idea, you have the power right there. Make sure the fan motor is a sealed non combustible motor though. exploision proof
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Post by sheetmetalworker on Sept 14, 2013 18:51:50 GMT -5
You could line the box with fat mat sound deadening material. Install a fan that moves approximately 120 cfm. Install a grill for the intake air.
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Post by jlafrenz on Sept 14, 2013 18:53:48 GMT -5
Some further reading points out that the box will need to be a great deal larger than the generator to reduce heat build up.
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Post by jlafrenz on Sept 14, 2013 18:55:14 GMT -5
You could line the box with fat mat sound deadening material. Install a fan that moves approximately 120 cfm. Install a grill for the intake air. I was thinking about 3 140mm or larger exhaust fans and probably 2 of the same for intake. |
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Post by sheetmetalworker on Sept 14, 2013 19:02:06 GMT -5
mm is this metric. Is this the diameter of fans. Are you saying 3 140mm fans? And similar for the intake.
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Post by jlafrenz on Sept 14, 2013 19:04:48 GMT -5
3 fans that are 140mm in size
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Post by sheetmetalworker on Sept 14, 2013 19:09:55 GMT -5
OK so 5.5" fans. How many cfm does each fan move. I think you would not need fans for the intake air. Just a grill large enough to supply those fans with the air they need. I can tell you the size of the grill you would need, if you can tell me the cfm rating of the fan.
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Post by jlafrenz on Sept 14, 2013 19:12:20 GMT -5
OK so 5.5" fans. How many cfm does each fan move. I think you would not need fans for the intake air. Just a grill large enough to supply those fans with the air they need. I can tell you the size of the grill you would need, if you can tell me the cfm rating of the fan. I haven't picked out any specific fans yet. I was probably just going to get something from Newegg that wasn't too pricey. |
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Post by sheetmetalworker on Sept 14, 2013 19:22:53 GMT -5
Well if you need any help let me know. Good luck on your project. Whatever the cfm rating is of the fans you pick out. Add them up and divide by 2 this will give you the the square inches of free air you'll need for the grill. You can then install one at that size or instal 2 at half that size.
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Post by jlafrenz on Sept 14, 2013 19:28:41 GMT -5
Well if you need any help let me know. Good luck on your project. Whatever the cfm rating is of the fans you pick out. Add them up and divide by 2 this will give you the the square inches of free air you'll need for the grill. You can then install one at that size or instal 2 at half that size. So the idea is to make the intake at half the value of the outtake, correct? Would I be able to use a smaller intake if I used fans to pull the air in? I ask because I want to avoid making to many open spaces to keep the noise down. Is there a way that I can figure out how much airflow I would need to keep the generator cool? |
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Post by sheetmetalworker on Sept 14, 2013 19:37:21 GMT -5
Well either way if the fans are pulling air in or exhausting air out you will need the correct size grill or opening to allow the fans to work to there full potential. The question of how much air is a lot harder. There are variables as outdoor air temp. HP of engine and amount of BTU/h the engine is dissapating. No easy answer.
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Post by jlafrenz on Sept 14, 2013 19:41:07 GMT -5
That is what I was afraid of. Even if I get the fans intake/outtake to the right ratio, it doesn't mean that it will be enough to do the job of keeping the generator cool.
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Post by sheetmetalworker on Sept 14, 2013 19:43:54 GMT -5
Maybe do a mock up and run a trial run with temperature guage. also remember its easier for a fan to move hot air than it is to move cool air. cooler air being heavier.
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Post by Mountainbiking Fool on Sept 14, 2013 20:14:30 GMT -5
They also make attic roof exhaust fans that have a solar panel on them that runs the fan motor or you could hard wire it in. They are pretty quiet.
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Post by jlafrenz on Sept 14, 2013 21:08:59 GMT -5
I'm not to worried about any noise the fans might make as it is likely less than the generator. I am more concerned that they will provide the necessary air flow to keep it cool.
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