Modification to Generator Enclosure

ChrisOlsonChrisOlson Banned Posts: 1,807 ✭✭
I don't recall where I posted this project before, but this is the photo gallery of my generator enclosure project for our Honda standby gen, and I think every photo has a caption for it that explains things
https://plus.google.com/photos/110979388690716770927/albums/5785954905109999617

This has worked great all winter and spring. But when warmer weather got here the ventilation exhaust temp was a little higher than I liked - around 140° F. The problem is the heat from the muffler. The Honda EM-SX series generators have an extended air baffle from the cylinder that directs the air from the flywheel fan over the cylinder and head, and then the muffler. The hot air is exhausted out the side of the genset thru a grille that covers the muffler.

In colder weather trapping some of that hot air inside the enclosure works nicely to get the temperature in the enclosure up to 70-80° F so the air-cooled engine operates at the correct temp in extreme cold. In warmer weather it traps it too well and the problem is not the ventilation fan capacity - it's the louvered grills that exhaust the air. Too much restriction on the louvered grilles.

So I removed the bottom grille and put a much larger screened opening in the enclosure to exhaust warm air.

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Then I put a baffle inside the enclosure made of plywood with the duct stat mounted on it, just above where the hot air is exhausted out the side of the genset. I also installed a 6" diameter duct fan in the top louvered grille. Works much better.

100_2936.JPG

The ventilation fan forces cool air in the top on the opposite end. The combination of the forced ventilation air, plus the plywood baffle, keeps the hot air from the genset from rising up the wall of the enclosure and re-mixing with the cool ventilation forced-air. The airflow is such that it now makes the hot air turn the corner to the end of the enclosure and be exhausted out the screened opening.

As it turns out, the 6" duct fan in the top louvered grille was not even needed. That simple plywood baffle, and making the exhaust vent larger, works so well that the air coming out the top louvered vent is only 3-5° F over ambient temp with the generator at full load for one hour at 87° F ambient temp.

The blast of hot air coming out that screened opening is pretty impressive on a hot day - it killed the grass right by the screen from the heat.

Thankfully, the generator only has to run for peak load support in the summer time, so it doesn't get many hours. It's only burned 1.7 gallons of fuel for the whole month of May so far - and that was because of me doing a bunch of welding and using the Plaz and air compressor in the shop. And we've had an all-time record for energy production for the month of May in the seven years since I've been keeping logs on it - most of it from wind power. We've logged 1,015.2 kWh produced for the last 27 days, or 37.6 kWh/day. So the generator has been mostly resting up for next winter :D
--
Chris

Comments

  • Ralph DayRalph Day Solar Expert Posts: 887 ✭✭✭✭
    Re: Modification to Generator Enclosure

    Interesting Chris. My big old diesel unit has an engine fan about 3 inches less in diameter than it's radiator shroud. Air would just be forced back into the room instead of out the louvered vent resulting in overheat and shutdown. Solved by putting a small barn fan and barn thermostat (closes circuit on rising temp) which gets power only when the genset is running. In the winter it cycles on and off, in the summer too, but mostly on when running. That fix was easier than trying to find an oddball sized fan or shroud for the 40 year old Nissan run generator. The "oil change" note in your picture reminds me it's about time to change the oil on the genset and tractor, thanks.:p

    ralph
  • Ralph DayRalph Day Solar Expert Posts: 887 ✭✭✭✭
    Re: Modification to Generator Enclosure

    Ok, I re-learned something after 5 minutes of CPR on my diesel genset...fill the fuel filter before you snug it up! The filter screws up into it's base. I put it on and pumped a few times, started and was satisfied, until it ran out of the fuel in the lines and pump. Next start I pumped as it was running, and pumped and pumped. It took 5 minutes before the beast would run on it's own.

    Scratched the date and hours on the filter, and the word FILL. It is so easy to screw the filter on, pump some fuel until it spills onto a rag below the filter, then start. Maybe I'll remember next time. Only 8 hours on engine and fuel filter in 2 years, so another 2 until next time. Leave note to self to leave notes.

    Ralph
  • ChrisOlsonChrisOlson Banned Posts: 1,807 ✭✭
    Re: Modification to Generator Enclosure
    Ralph Day wrote: »
    Interesting Chris. My big old diesel unit has an engine fan about 3 inches less in diameter than it's radiator shroud. Air would just be forced back into the room instead of out the louvered vent resulting in overheat and shutdown

    Not if you put the fan on backwards to force the air the other way thru the radiator. Liquid cooled engines are much easier to control operating temp than air-cooled in very cold weather.
    --
    Chris
  • Ralph DayRalph Day Solar Expert Posts: 887 ✭✭✭✭
    Re: Modification to Generator Enclosure

    Well, there's an idea Chris. The door of the enclosure has a large screened opening, but the other end had a set of louvres oriented for exhaust through from door to vent. Another thing is the cramped working space in and around the genset. There's about 1.5 feet on either side of the genset before you're up against a wall. Enough to work, but not comfortably. Right now everything works, but for less than 5 running hours per year...meh. Needs a new ECM, only works on manual, only works when the electronics are warm (light bulbs in control housing), I can keep it working, but could anyone else (present company excepted).

    Ralph
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