mini microcogen multifunction unit

[admin]

i really don't have time, however i do have all the parts  so i might make time to build this unit.

it is a neat and useful little multifunction emergency cogenerator, based on a minimal basic requirement for power, domestic
hot water, air and charging capability,  the unit would be very portable, and take up little space in a garage.

many folks in a emergency situation can get by with under a kwatt of generator capacity, but they need surge capacity
to start more difficult loads such as pumps, microwaves, larger refrigerators etc.

this unit could provide that sort of backup power provided the loads are intermittently above ~3kwatts or short duration or
~2kwatts , or continuous of no more than ~800 watts

the unit could provide sufficient air to fill a car/motorcycle or bicycle tire if necessary, could also charge a dead car battery as well.

the unit incorporates a heat exchanger/water tank with the ability to deliver about one shower per hour of operation, or wash dishes.

i think it might be a very useful project

probably not the most efficient unit, but should rank fairly high on the useful scale.

bob g

[rl71459]

Looks handy to me Bob, Probably get you out of a pinch now and then.

Rob

[Ronmar]

Is that little HF generator water cooled, or were you thinking of just recovering exhaust heat?

[mobile_bob]

it is aircooled, and i was considering only recovery of exhaust heat

i measured the exhaust heat no load, and it is about 350 degree's F
it probably gets upwards of 500 plus degree's under load, i guess i will see when i get some time.

the little bugger has proven to be a pain in the ass to start, until i changed the plug for one i had on hand
however it failed to restart after a heavy run, and found the new plug failed

finally used another i had on hand, and it works exceptionally well now, starting cold, restarting hot, and then
after a full cool down a good restart, no more than 3 to 4 pulls which i feel is adequate.

i checked the emission certs on it, it is epa and carb certified, and is listed as a 3 on a scale of 0 to 10, ten being the worst
of those tested,  so i guess it is fairly clean if the fuel is mixed appropriately.

its just hard not to marvel at just how well it seems to work for the price

checked it under load,  with the following results

no load 60.4 hz at 117volts
half load 60.3 hz at 115volts
near full load 60.3 hz at 114volts

when the load is applied the hz first droops to around 58hz, then as the governor picks it up
it peaks at about 64hz before settling down to between 60.3 and 60.4hz and between 114 and 117volts
it takes about 2 seconds to stabilize and settle in.

in my opinion it has a pretty good governing system that is adequately responsive,

next i want to get a look at the output on a scope, i expect it will be somewhat nasty at full load, with the
harmonic excitation affecting the peaks of the sine curve.

if this thing can run for a thousand hours, it would be an incredible accomplishment by  the chinese engineers and manufactures.

i wish i still had my little century portable mig welder, it was power by two internal sealed lead acid batteries, and was rechargeable with a little wallwart unit, it was very handy for short welds on up to about a quarter inch.  one of these little generators reworked to provide for 24vdc charging would extend the range of a mig welder like that and one would have a really cool compact portamig
that could get some real work done.

don't have it anymore though some thief liked it better than me

bob g

[Henry W]

Bob I like it. It should run a small refrigerator, some lights, and a gas furnace.

Henry

[Ronmar]

I would guess the full load exhaust temps will be considerably hotter than 500F at full load. 

[BioHazard]

LOL, I've been thinking up something almost exactly the same, except I forgot the fancy cart. For surge capability, I plan on using a 3kw inverter and a 45A battery charger plugged into the HF generator. I may end up with two generator/charger units, so I can use them in parallel if needed, or just as a backup.

My three person household only averages about 2kw/hour during normal use, with mostly gas appliances. I can definately live on 800w continuous, but must have the surge power for a few minutes.

I've also got a pair of chinese copies of Viair compressors, 'bout half a HP each at 12v. $15 on ebay! Air tank is going to be a former propane tank.

It is quite amazing what the chinese can put together for the price...they only cost $49 in china! I can barely change the oil on a bigger generator for that much. Goes to show you how much Honda has been ripping people off with their $2000 generators...

What are your thoughts for capturing the exhaust heat, bob?

[mobile_bob]

i am thinking a double pass simple tube in shell, because the little engine likely wouldn't like any back pressure.

the goal of course would be to make some hot water, not peak efficiency
if it would eek out one quick shower worth of hot water an hour that might be quite welcome in a power outage.

especially after a few days without hotwater

also have an idea of another unique design, that if the back pressure worked out low enough would be more efficient
but that will have to wait a while.

bob g

[BioHazard]

You might want to add a place to your fancy cart for a long, heavy gauge extension cord...you don't want that thing very close to the house! I've got all kinds of portable power distribution stuff and heavy cords, that way in the event of a (rare) power outage I don't need a transfer switch, and it's completely portable.

I start with a 10ga from the generator to the house, then it spits off into a few 12ga cords from the spider box with 6 breakers. From there individual items get 14ga cords as needed. Easy to juggle stuff off and on that way when you have limited power.

Also thinking about a 6 gallon RV water heater for the storage tank, that way you could use your compressed air source to push the water out of the tank for a shower. Also could have propane/electric backup heat, maybe find an 800w element for the WH.

[rl71459]

stumbled on this on ebay... Looks like they have plenty of them.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270678149183&ssPageName=STRK:MEWAX:IT

Rob

[BioHazard]

stumbled on this on ebay... Looks like they have plenty of them.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270678149183&ssPageName=STRK:MEWAX:IT

Rob

You're already taking about a 50/50 risk that the generator isn't going to work when buying it from harbor freight. You can be almost certain that one which has already been returned, is not likely to work. This part of the description is especially troubling...
"This item appears to be in good shape. It looks used. It started with ether and powered a testing tool."

[vdubnut62]

Yep ran it with NO lubrication long enough to see if it would power "something". Even worse, ether is a really good oil and grease solvent.
Ask Mobile Bob how to get 5th wheel grease out of a cloth truck seat.
Ron

[WGB]

Did you check out the testers comments on the unit, did not run it on gasoline!
What the heck does that mean?

[wrightkiller]

LOOK AT THIS  AND FREE SHIPPING ........WOW WE........

http://cgi.ebay.com/DuroMax-MX1500-1500-Watt-Pull-Start-Gas-Power-Generator_W0QQitemZ120657212804QQcategoryZ46412QQcmdZViewItemQQ_trksidZp4340.m8QQ_trkparmsZalgo%3DMW%26its%3DC%26itu%3DUCC%26otn%3D5%26ps%3D63%26clkid%3D5737035033313650383

http://cgi.ebay.com/DuroStar-6000-W-Enclosed-Diesel-Electric-Generator-/200509130891?pt=LH_DefaultDomain_0&hash=item2eaf46888b

[rl71459]

I realize this unit is "JUNK" I was thinking it may be a way to aquire the small gen head that is on it for use on my little Subaru engine.

I have no illusion's that these returned units are a prize of some sort. That said... it could be a source of parts for someone who already has one of these or wants parts for a project.

Rob