Propane & Natural Gas: Interchangable?

[(PeteCresswell)]

If an engine will run on propane, will it run on natural gas
without modification?

"Natural Gas" = the stuff they pipe into people's houses
underground from a central distribution point.

Pressure considerations?

 

[Vaughn Simon]

If an engine will run on propane, will it run on natural gas
without modification?

My Onan generator happily runs off of either fuel. I only need to make a
slight mixture adjustment for most efficient operation. It requires the same
fuel pressure for either fuel, though it naturally takes different regulators to
supply that pressure. By the way, the pressures involved are very low. If I
remember correctly, it only takes 11" water column (less than 1 PSI).

Vaughn

 

[(PeteCresswell)]

Per Vaughn Simon:

My Onan generator happily runs off of either fuel. I only need to make a
slight mixture adjustment for most efficient operation. It requires the same
fuel pressure for either fuel, though it naturally takes different regulators to
supply that pressure. By the way, the pressures involved are very low. If I
remember correctly, it only takes 11" water column (less than 1 PSI).

I've got my little EU2000 and about 200 feet of heavy-duty
extension cords.... and that certainly fills the bill of what I
wanted a generator to accomplish.


But the more I read, the more I think that for anything larger
the only sensible route for somebody who has natural gas piped
into their property and doesn't need to run the gennie at other
locations... and doesn't anticipate earthquakes... is a natural
gas installation.

Bolt the gennie to a poured concrete pad somewhere in the yard
far enough from the house to avoid exhaust fume issues, put a
little dog house over the gennie (or maybe build a garden shed
around it), run the gas to the gennie, run an electrical cable
from the gennie to a cutover panel in the house.


To wit:
--------------------------------------------------------------
- No worries about "feeding the beast" when gas stations may
be shut down due to the same power outage you're using
the generator for.

- No fuel storage issues.

- Cheaper per-hour running given no road-fuel taxes on nat gas

- No issues with going outside in the dark in freezing rain
to refuel.

- Greatly-reduced theft issues if the thing is bolted to the
pad thoroughly enough.

 

[Balanced View]

regulators to

If I

You need to get enough fresh air to it or it will suffocate. Maybe a
small fan forcing air in will help. I've seen some "mighty-fine" shed
designs around generators that ended up with a bunch of vent holes cut
into them and eventually the genny ended up outside.

my buddy built one with fatmat auto sound insulation and he cut a hole
with a small electric fan that ran off the gen. Its super quiet

You mentioned earthquakes so better make sure you don't have one of
those gadgets that shuts off the gas when it shakes.

Why wouldn't a simple inlet for the carb intake and one for the exhaust
suffice?

 

[Daniel Who Wants to Know]

Why wouldn't a simple inlet for the carb intake and one for the exhaust
suffice?

The gen head and engine both produce heat that must be dissipated. Even if
the engine is liquid cooled and the cooling loop extends outside the shed
the block, exhaust manifold, and gen head will still heat up the air inside
the shed so it still must have some ventilation.

 

[[email protected]]

The gen head and engine both produce heat that must be dissipated.

An EU2000 generator head that's 90% efficient would produce 160 watts,
ie 546 Btu/h, which would only raise the temperature of an 8' R1 cube
by 546xR1/(6x8'x8') = 1.4 degrees F.

Even if the engine is liquid cooled and the cooling loop extends outside
the shed the block, exhaust manifold, and gen head will still heat up
the air inside the shed so it still must have some ventilation.

If it burns 1.08 gallons of gas with a high heating value of 135K Btu
in 4 hours at the 1600 W rated load and makes 6.4 kWh (21.8K Btu) of
electricity and 113.2K Btu of heat (another 33.2 kWh, ie 39.6 kWh total),
it's only 16% efficient, ie the heat output is 6 times the electrical
output, ie 28.3K Btu/h. Why waste it?

An EU2000 might depressurize a plastic film room in a basement with
the exhaust bubbling through some water, then leaving the house. If
a 1000 Btu/h-F auto radiator and its 20 watt series-connected fans
remove 15K Btu/h, the room will be 15 F warmer than the basement.

Can we plug the EU2000 into an active wall socket and make the meter
go backwards? This doesn't seem economical compared to grid power,
with $4/gallon gasoline. If the EU2000 lasts 10,000 hours, it costs
about $0.09/hour to run, with a combined energy output costing about
16 cents/kWh, or 11 cents, with natural gas at $1.50/therm.

Nick

 

[You]

snipped for brevity

Why wouldn't a simple inlet for the carb intake and one for the exhaust
suffice?

How would you exchange the COOLING Air inside the enclosure??????

 

[Balanced View]

snipped for brevity


How would you exchange the COOLING Air inside the enclosure??????

How small an enclosure are you going to make it? Anything big enough to
walk in to service the beast
should be fine.