Hey folks,
OK, following the hurricane(s) and being without power for 6 days last time and going on 4 this time, I’ve decided to upgrade my generator to power the whole house. The 6k one I have now for a few items just doesn’t cut it. So with the new 22k generator and switching panel on its way, I need to build a building for it.
I’m planning on around 6′ x 6′, 8″ CMU walls, poured solid to slab on grade maybe around 5-6′ tall. Exhaust fan built in for air circulation and possibly I’ll weld up the doors from steel for fire resistance.
Any other thoughts on how to make this a good design obvioulsy wind-proof but also fire resistant and sound muffling to control the noise?
It’ll be my fall project so I’ve got some time to plan…
Thanks for any and all input.
Mike
Replies
last I heard, those things need fuel
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What kind of fuel does it take?
The larger ones that I have seen are self-contained and hook up to natural gas or propane.
They are just installed on a slab, just like an AC unit.
I'd build it a little larger than the 6' X 6' so you can get around it for service OR build it as you describe with a roof that can be removed as a unit so the generator unit can be hoisted out.
Otherwise, you'll enjoy the convenience of uninterrupted power (just a brief lag time after you lose your grid power and the unit powers up).
As someone mentioned, get the propane set up. These units, when properly installed, do an automatic start-up self-check every week (or whatever you program it for) and it's good to not have to worry about having adequate fuel at crunch time.
A 100 gal. or better propane tank with keep-full service is nice insurance.
> Any other thoughts on how to make this a good design obvioulsy wind-proof but also fire resistant and sound muffling to control the noise?
Would it be possible to put it all below grade, in its own little storm cellar? That would get it out of the way of wind and the debris it throws at things. It would also direct noise upward rather than sideways. It might also look better hidden underground. The big problem would be flooding.
-- J.S.
is the engine air cooled, need some air flow for the engine.
Talk to the manufacturer of the generator set and see what their recommendations are. You need to allow enough room to get around the thing for maintenance purposes, but more importantly you have to have enough air coming in and going out to cool the engine (as well as combustion air for the engine to run on.) The manufacturer will have data on how much heat the genset generates when running, and you'll need to provide enough airflow to match that. I assume you're in Florida, so the requirements for running in hot weather are even more important. Even small generators can produce a LOT of heat and you have to get it out of the building.
As a rule of thumb, the dimensions of the building should be such that there's at least as much space between the genset and the surrounding walls as the generator is tall. You can get a concrete block designed for sound absorption, it looks like a regular CMU but the inside of the block that faces the generator have slots in them. I think they're kinda expensive, though.
The manufacturer may be able to provide the generator with two or three different kinds of mufflers - there's the standard muffler, a better one generally referred to as residential grade, and one even better called critical grade (like what would be used at a hospital, for instance.)
Is it going to be diesel, propane or natural gas? At this size, a gas generator will probably be less expensive. If you will have reliable natural gas supply even during a hurricane, it would be the most convenient choice since you don't have to worry about refilling tanks.
The generator should be equipped with a battery charger and a block heater, to keep the battery topped off and the oil in the engine warm and ready to go. This may not be as important during summer in Florida, but you may need it during cooler weather and it's awful hard on the engine to start it up cold. I assume the control panel will have an exercise mode to run the generator every couple weeks or so, to keep it exercised.
Are you going to have a manual or automatic transfer switch? Either way, since you're going to run the whole house with it you'll most likely have to coordinate installation with the local electric utility. If it's an automatic transfer switch, the utility may have a 'peak shaving' program you could look into -- this is a program where they hang a little box on your generator controls that will switch you off the grid and onto the generator during high demand periods, for a substantial reduction in your monthly bill.
Sorry if this is kind of wordy, but I'm an electrical engineer who designs generator installations all the time, although I generally work with much larger generators (250kw-1000kw) that go into municipal water treatment plants and wellhouses, that sort of thing. Again, the most important design point here is to make sure you're getting enough air in and out of the building, and you'll need to talk to the manufacturer to get the information you need about that.
edited to add: If you're going with a natural gas generator, make sure you have an adequate supply to the house to handle it. The manufacturer can tell you how much it will consume, and the local utility can then tell you if your gas service will work out OK. I would imagine with a unit of this size it probably isn't a problem. Also, sometimes the gas pressure from the service doesn't match the generator requirements and it will need a regulator, again the manufacturer can tell you the pressure required and the utility can tell you what you have.
Edited 9/28/2004 9:48 pm ET by Stuart
As you said you need to vent the building, but one ive seen installed at one of my customers homes removed the small muffler added a lg muffler ( about 20in lond and 7in round ) probibly a car muffler, then som black pipe and elbows out the side of wall. solved 2 problems-1. fumes and 2 reduced noise quite a lot. it was also run propane off a lg 200 pound tank.. I dont know the power it is but its large and runs enough power for the main house for owners family and a sm apt for a couple.
dogboy
Mikie: DON"T put it below grade. Fla gets a lot of rain - especially during hurricanes. You don't want it swimming in water. Second - gasoline & Propane are heavier than air. A below grade enclosure is a bomb waiting to go off due to fumes collecting around the genny. Also - you'll have a devil of a time keeping it ventilated & dry to keep it from corroding. Maintenance will be a nightmare on a below grade unit - you will need to build in lots of butt room around it. How you gonna lower it into the hole - have access to a lifting device all the time?
Build above grade, make it tall enough that you don't conk your conk while working on it. Also - suggest making four sturdy corner columns w/ Hinged along the top sides out of steel. Also louver the sides for easy air flow. Make the pad bigger than the enclosure so you can stand on dry - well, at least not puddled water - surface while tending it. Make one apron large enough to slide the unit out on for access For maintenance / replacement.
Trust me this thing, in FLA will be a maintenance hog.
Good luck!
Don
Guys,
Thanks for the excellent responses! That input is really helpful.
Mike