Home » Public Forums » GMCnet » Re: [GMCnet] yamaha inverter generator: how to run inside?
| Re: [GMCnet] yamaha inverter generator: how to run inside? [message #113181] |
Wed, 26 January 2011 13:07  |
mlincoln
Messages: 107
Registered: August 2006
Location: Salt Lake City
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Lunch break time….
There was a question of oxygen starvation raised. As a pulmonary physician, I couldn't let that go without trying to figure out if it was likely to be true or not.
1. Combustion calculation:
1. Gasoline is a mixture of hydrocarbons, nominally about C8 H18 (isooctane), specific gravity 114.23 gm/mole
2. Stoichiometric complete combustion of hydrocarbons:
CxHy + (x + y/4)O2 --> xCO2 + (y/2)H2O
4. Substituting into the equation: C8H18 +(8 + 4.5) O2 à8CO2 +9H2O
5. Thus every molecule of isooctane completely combusted will yield 8 CO2 and 9 water molecules and consume 12.5 oxygen molecules
2. Determine how much isooctane is in a gallon of gas
1. Isooctane specific gravity 688 kg/m^3 liquid state
2. 1 m^3 = 1,000 liters = 264.172 gallons, so one gallon contains 2.60 kg of isooctane
3. 2,600 gms of gasoline / 114.23 gm/mole = 22.76 moles of isooctane.
3. Determine the waste products resulting from burning a gallon of gas completely (assuming no CO, NO2, etc here…complete combustion into water and CO2) All this goes out the exhaust pipe (Shan hopes!)
1. 22.76 moles burned x 9 = 204.84 moles water produced …at 18 gms/mole that’s 18 * 204.84 = 3684.12 grams of water (almost a gallon)
2. 22.76 moles burned x 8 = 182.08 moles of CO2 produced…at 44.01 gm/mole that’s 8013.34 grams of CO2 produced. CO2 weighs (at standard temp and pressure dry) 1.977 gm/liter, so that’s ca. 4000 liters of CO2 produced (Global warming!)
4. Determine the oxygen consumed from burning a gallon of gas completely
1. 22.76 moles burned x 12.5 moles oxygen consumed/mole of gas burned = 284.5 moles of oxygen consumed.
2. With oxygen at 16 gm/mole, that’s 4552 gms of oxygen consumed when a gallon of gas is burned. Oxygen’s density (100% oxygen) is 1.429 gm/liter at zero centigrade (ok, you’re living in a cold coach). In room atmosphere at sea level, with 21% oxygen, that’s ca. 0.30 gms oxygen/liter of room air.
3. If 4552 grams of oxygen are consumed, ca, 4552 / 0.30 = 15,173 liters of room atmosphere are going to be pumped through the engine. That’s ca. 536 cubic feet of atmosphere. If the coach is 7.5 x 6 x 26 feet inside, the total volume of the coach is ca. 1200 cubic feet.
Conclusion: A catalytic heater (which exhausts inside) doesn’t create a negative pressure in the coach by dint of producing 8 CO2 and 9 H2O molecules that take the place of every 12.5 molecules of oxygen consumed. I'd say that a catalytic heater can surely deplete oxygen concentrations if you burn enough fuel. If you could really use up 536 cubic feet of atmosphere by running through a gallon of gas (or equivalent molar weight of propane), using a catalytic heater, that'd be serious, and not just from oxygen starvation but from CO2 acidosis. I suggest that nobody run a catalytic heater without several windows open! On the other hand, an internal combustion engine is a volume air pump and it exhausts all the air it takes in. It thus creates a negative pressure that will be supplied by leaks inward to the coach from the surrounding air. So I don’t think Shan’s arrangement would necessarily cause oxygen starvation because as 21% oxygen room air is consumed and pumped out more 21% oxygen atmosphere will leak into the coach. I think one can practically guarantee that a 35 year old coach _won't_ develop a subatmospheric pressure, even with the windows closed: a multitude of small leaks will suffice to let in all the air pumped out :-).
HOWEVER, I still have a dire concern that Shan will kill himself, German engineering genes and all, from incompletely exhausted carbon monoxide. Shan, think of how your obit might look: do you really want even a small chance of that? Then there'd be the humiliating post-mortem endowment, in your name, to the local firefighters. For the next 50 years they'll to go to the elementary and high schools to warn kids about the dangers of carbon monoxide poisoning, all in your name (imagine a flower-wreathed picture on an easel in the gymnasium, standing to the firefighter's podium, and the bored kids texting each other about what a turkey you must have been to have engendered a perpetually endowed safety assembly in your name). I know that such an ignoble end would be too embarrassing for me by far.
Run the generator outside!
Now it is time to return to work!
Mike Lincoln
On Jan 26, 2011, at 12:59 PM, Shan Rose wrote:
>
>
> My Onan runs like a top, the reason for the smaller gen is 4 fold, one is the fact that it uses about .1 gal an hour at 1/4 load the onan with almost no load burns about .4 gallons an hour. Second is noise, unless running the roof AC, water heater, or some other electrical appliance which demands heavy current, the onan is overkill. Third is portability, I can take the smaller gen with me anywhere without having to drive the coach there. 4th is to reduce wear and tear on the onan, since mantainance costs are significantly more ofor the onan (last oil change for the onan was about $40, compared to just $6 for the yahmaha) the onan is a great genset, once I worked out the bugs, mine has provided me with several hundred hours or reliable service, and by splitting the load with another APU I can make the onan last even longer before a major overhaul will be required, so now I will only need onan under severe usage conditions and not just to nuke something or watch a little TV whe
> n im in my rig...
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| Re: [GMCnet] yamaha inverter generator: how to run inside? [message #113182 is a reply to message #113181] |
Wed, 26 January 2011 13:36  |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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For me running the Onan outside in stock location produces more fumes than I care for. On a still day it lingers all around the coach and some seeps in. I only run when necessary. Inside, no thanks as even a slight leak would be bad. Also is the crank case breather vented back to the intake..... I would hope in 2011 that it is. On old small engines that would vent blowby into the coach if it just came out the old stink vent tube.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] yamaha inverter generator: how to run inside? [message #113183 is a reply to message #113181] |
Wed, 26 January 2011 13:36 |
Gary Worobec
Messages: 867
Registered: May 2005
Karma: -1
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Senior Member |
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Dr. Mike,
Excellent explanation. I really like the last paragraph. I think we should
all write our own Obit to avoid embarrassing ourselves when the time comes.
Thanks
Gary and Joanne Worobec
1973 GMC Glacier
Anza, CA
----- Original Message -----
From: "Michael Lincoln" <mlincoln1@gmail.com>
To: <gmclist@temp.gmcnet.org>
Sent: Wednesday, January 26, 2011 11:07 AM
Subject: Re: [GMCnet] yamaha inverter generator: how to run inside?
Lunch break time….
There was a question of oxygen starvation raised. As a pulmonary
physician, I couldn't let that go without trying to figure out if it was
likely to be true or not.
1. Combustion calculation:
1. Gasoline is a mixture of hydrocarbons, nominally about C8 H18
(isooctane), specific gravity 114.23 gm/mole
2. Stoichiometric complete combustion of hydrocarbons:
CxHy + (x + y/4)O2 --> xCO2 + (y/2)H2O
4. Substituting into the equation: C8H18 +(8 + 4.5) O2 à8CO2 +9H2O
5. Thus every molecule of isooctane completely combusted will yield 8
CO2 and 9 water molecules and consume 12.5 oxygen molecules
2. Determine how much isooctane is in a gallon of gas
1. Isooctane specific gravity 688 kg/m^3 liquid state
2. 1 m^3 = 1,000 liters = 264.172 gallons, so one gallon contains 2.60
kg of isooctane
3. 2,600 gms of gasoline / 114.23 gm/mole = 22.76 moles of isooctane.
3. Determine the waste products resulting from burning a gallon of gas
completely (assuming no CO, NO2, etc here…complete combustion into water and
CO2) All this goes out the exhaust pipe (Shan hopes!)
1. 22.76 moles burned x 9 = 204.84 moles water produced …at 18 gms/mole
that’s 18 * 204.84 = 3684.12 grams of water (almost a gallon)
2. 22.76 moles burned x 8 = 182.08 moles of CO2 produced…at 44.01
gm/mole that’s 8013.34 grams of CO2 produced. CO2 weighs (at standard temp
and pressure dry) 1.977 gm/liter, so that’s ca. 4000 liters of CO2 produced
(Global warming!)
4. Determine the oxygen consumed from burning a gallon of gas completely
1. 22.76 moles burned x 12.5 moles oxygen consumed/mole of gas burned =
284.5 moles of oxygen consumed.
2. With oxygen at 16 gm/mole, that’s 4552 gms of oxygen consumed when a
gallon of gas is burned. Oxygen’s density (100% oxygen) is 1.429 gm/liter
at zero centigrade (ok, you’re living in a cold coach). In room atmosphere
at sea level, with 21% oxygen, that’s ca. 0.30 gms oxygen/liter of room air.
3. If 4552 grams of oxygen are consumed, ca, 4552 / 0.30 = 15,173
liters of room atmosphere are going to be pumped through the engine. That’s
ca. 536 cubic feet of atmosphere. If the coach is 7.5 x 6 x 26 feet inside,
the total volume of the coach is ca. 1200 cubic feet.
Conclusion: A catalytic heater (which exhausts inside) doesn’t create
a negative pressure in the coach by dint of producing 8 CO2 and 9 H2O
molecules that take the place of every 12.5 molecules of oxygen consumed.
I'd say that a catalytic heater can surely deplete oxygen concentrations if
you burn enough fuel. If you could really use up 536 cubic feet of
atmosphere by running through a gallon of gas (or equivalent molar weight of
propane), using a catalytic heater, that'd be serious, and not just from
oxygen starvation but from CO2 acidosis. I suggest that nobody run a
catalytic heater without several windows open! On the other hand, an
internal combustion engine is a volume air pump and it exhausts all the air
it takes in. It thus creates a negative pressure that will be supplied by
leaks inward to the coach from the surrounding air. So I don’t think Shan’s
arrangement would necessarily cause oxygen starvation because as 21% oxygen
room air is consumed and pumped out more 21% oxygen atmosphere will leak
into the coach. I think one can practically guarantee that a 35 year old
coach _won't_ develop a subatmospheric pressure, even with the windows
closed: a multitude of small leaks will suffice to let in all the air
pumped out :-).
HOWEVER, I still have a dire concern that Shan will kill himself,
German engineering genes and all, from incompletely exhausted carbon
monoxide. Shan, think of how your obit might look: do you really want even
a small chance of that? Then there'd be the humiliating post-mortem
endowment, in your name, to the local firefighters. For the next 50 years
they'll to go to the elementary and high schools to warn kids about the
dangers of carbon monoxide poisoning, all in your name (imagine a
flower-wreathed picture on an easel in the gymnasium, standing to the
firefighter's podium, and the bored kids texting each other about what a
turkey you must have been to have engendered a perpetually endowed safety
assembly in your name). I know that such an ignoble end would be too
embarrassing for me by far.
Run the generator outside!
Now it is time to return to work!
Mike Lincoln
On Jan 26, 2011, at 12:59 PM, Shan Rose wrote:
>
>
> My Onan runs like a top, the reason for the smaller gen is 4 fold, one is
> the fact that it uses about .1 gal an hour at 1/4 load the onan with
> almost no load burns about .4 gallons an hour. Second is noise, unless
> running the roof AC, water heater, or some other electrical appliance
> which demands heavy current, the onan is overkill. Third is portability, I
> can take the smaller gen with me anywhere without having to drive the
> coach there. 4th is to reduce wear and tear on the onan, since mantainance
> costs are significantly more ofor the onan (last oil change for the onan
> was about $40, compared to just $6 for the yahmaha) the onan is a great
> genset, once I worked out the bugs, mine has provided me with several
> hundred hours or reliable service, and by splitting the load with another
> APU I can make the onan last even longer before a major overhaul will be
> required, so now I will only need onan under severe usage conditions and
> not just to nuke something or watch a little TV whe
> n im in my rig...
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: [GMCnet] yamaha inverter generator: how to run inside? [message #113186 is a reply to message #113181] |
Wed, 26 January 2011 13:37 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Gee, did someone ask for the time??? :-)
(I agree with you,. Dr. Mike.)
Ken H.
On Wed, Jan 26, 2011 at 2:07 PM, Michael Lincoln wrote:
> Lunch break time….
>
> There was a question of oxygen starvation raised. As a pulmonary
> physician, I couldn't let that go without trying to figure out if it was
> likely to be true or not.
>
> 1. Combustion calculation:
>
> 1. Gasoline is a mixture of hydrocarbons, nominally about C8 H18
> (isooctane), specific gravity 114.23 gm/mole
>
> 2. Stoichiometric complete combustion of hydrocarbons:
>
> CxHy + (x + y/4)O2 --> xCO2 + (y/2)H2O
> 4. Substituting into the equation: C8H18 +(8 + 4.5) O2 à8CO2 +9H2O
>
> 5. Thus every molecule of isooctane completely combusted will yield 8
> CO2 and 9 water molecules and consume 12.5 oxygen molecules
> ...
>
...
...
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List Information and Subscription Options:
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] yamaha inverter generator: how to run inside? [message #113230 is a reply to message #113181] |
Wed, 26 January 2011 21:38 |
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 I must say that's probably the most complete breakdown on the combustion cycle of gasoline I've read in a long time if ever! One of the reasons I love this place is because of the wealth of information which exists with the members here, which is why I posted this question here to begin with. I actually plan to move the battery tray and install the micro gen there, which will solve any ventilation issues related to combustion. yes it is the easy way out, but I posed the question just the same.
However I want to take just a little issue with the consumed oxygen level if indoor air were used, this is assuming a completely sealed fuselage in which no new air would be drawn in to replace the exhausted air, and thus depleting the amount of breathable O2. However this is hardly the situation with a GMC which in my case has open vents above the fridge and stove as well as 2 poorly sealing roof vents, and main door seal. (yes I still have some items to fix on my rig) so even if the relatively small 76cc engine were run inside, assuming a completely sealed exhaust path outdoors, the negative pressure differential created inside the coach would invite a current of air to flow in from the afire mentioned sources of ventilation. something probably not really wanted on a cold evening.
I simply wanted to pose the question could it be safely done, I believe if a sealed compartment were constructed with powered ventilation and ducting for both drawing in outside air, and drawing out exhaust with bilge fans, it would be a moot point, since neither indoor air would be used nor would exhaust be an issue with a constant flow of air moving through the sealed chamber with no chance for any exhaust to enter the living space.I have arrived at the conclusion that putting the gen in the engine compartment and moving the battery would simply be easier and it would be protected from the elements just as well with much less hassle or hazard.
To Dr Lincoln, I want to thank you for taking your lunch time to write that up, as a Doctor I know your time is very valuable, and when one is busy, getting time to eat even more so. Just for the record its not the first time I've been told "if you do that you're gonna kill yourself!" I like to push the envelope a bit, so if I do wind up in the obit section someday, I can assure you it won be for something as embarrassing as that. I take pride in being a little bit out there and non conventional, but not stupid. 
| mlincoln wrote on Wed, 26 January 2011 13:07 |
Lunch break time….
There was a question of oxygen starvation raised. As a pulmonary physician, I couldn't let that go without trying to figure out if it was likely to be true or not.
1. Combustion calculation:
1. Gasoline is a mixture of hydrocarbons, nominally about C8 H18 (isooctane), specific gravity 114.23 gm/mole
2. Stoichiometric complete combustion of hydrocarbons:
CxHy + (x + y/4)O2 --> xCO2 + (y/2)H2O
4. Substituting into the equation: C8H18 +(8 + 4.5) O2 à8CO2 +9H2O
5. Thus every molecule of isooctane completely combusted will yield 8 CO2 and 9 water molecules and consume 12.5 oxygen molecules
2. Determine how much isooctane is in a gallon of gas
1. Isooctane specific gravity 688 kg/m^3 liquid state
2. 1 m^3 = 1,000 liters = 264.172 gallons, so one gallon contains 2.60 kg of isooctane
3. 2,600 gms of gasoline / 114.23 gm/mole = 22.76 moles of isooctane.
3. Determine the waste products resulting from burning a gallon of gas completely (assuming no CO, NO2, etc here…complete combustion into water and CO2) All this goes out the exhaust pipe (Shan hopes!)
1. 22.76 moles burned x 9 = 204.84 moles water produced …at 18 gms/mole that’s 18 * 204.84 = 3684.12 grams of water (almost a gallon)
2. 22.76 moles burned x 8 = 182.08 moles of CO2 produced…at 44.01 gm/mole that’s 8013.34 grams of CO2 produced. CO2 weighs (at standard temp and pressure dry) 1.977 gm/liter, so that’s ca. 4000 liters of CO2 produced (Global warming!)
4. Determine the oxygen consumed from burning a gallon of gas completely
1. 22.76 moles burned x 12.5 moles oxygen consumed/mole of gas burned = 284.5 moles of oxygen consumed.
2. With oxygen at 16 gm/mole, that’s 4552 gms of oxygen consumed when a gallon of gas is burned. Oxygen’s density (100% oxygen) is 1.429 gm/liter at zero centigrade (ok, you’re living in a cold coach). In room atmosphere at sea level, with 21% oxygen, that’s ca. 0.30 gms oxygen/liter of room air.
3. If 4552 grams of oxygen are consumed, ca, 4552 / 0.30 = 15,173 liters of room atmosphere are going to be pumped through the engine. That’s ca. 536 cubic feet of atmosphere. If the coach is 7.5 x 6 x 26 feet inside, the total volume of the coach is ca. 1200 cubic feet.
Conclusion: A catalytic heater (which exhausts inside) doesn’t create a negative pressure in the coach by dint of producing 8 CO2 and 9 H2O molecules that take the place of every 12.5 molecules of oxygen consumed. I'd say that a catalytic heater can surely deplete oxygen concentrations if you burn enough fuel. If you could really use up 536 cubic feet of atmosphere by running through a gallon of gas (or equivalent molar weight of propane), using a catalytic heater, that'd be serious, and not just from oxygen starvation but from CO2 acidosis. I suggest that nobody run a catalytic heater without several windows open! On the other hand, an internal combustion engine is a volume air pump and it exhausts all the air it takes in. It thus creates a negative pressure that will be supplied by leaks inward to the coach from the surrounding air. So I don’t think Shan’s arrangement would necessarily cause oxygen starvation because as 21% oxygen room air is consumed and pumped out more 21% oxygen atmosphere will leak into the coach. I think one can practically guarantee that a 35 year old coach _won't_ develop a subatmospheric pressure, even with the windows closed: a multitude of small leaks will suffice to let in all the air pumped out .
HOWEVER, I still have a dire concern that Shan will kill himself, German engineering genes and all, from incompletely exhausted carbon monoxide. Shan, think of how your obit might look: do you really want even a small chance of that? Then there'd be the humiliating post-mortem endowment, in your name, to the local firefighters. For the next 50 years they'll to go to the elementary and high schools to warn kids about the dangers of carbon monoxide poisoning, all in your name (imagine a flower-wreathed picture on an easel in the gymnasium, standing to the firefighter's podium, and the bored kids texting each other about what a turkey you must have been to have engendered a perpetually endowed safety assembly in your name). I know that such an ignoble end would be too embarrassing for me by far.
Run the generator outside!
Now it is time to return to work!
Mike Lincoln
On Jan 26, 2011, at 12:59 PM, Shan Rose wrote:
>
>
> My Onan runs like a top, the reason for the smaller gen is 4 fold, one is the fact that it uses about .1 gal an hour at 1/4 load the onan with almost no load burns about .4 gallons an hour. Second is noise, unless running the roof AC, water heater, or some other electrical appliance which demands heavy current, the onan is overkill. Third is portability, I can take the smaller gen with me anywhere without having to drive the coach there. 4th is to reduce wear and tear on the onan, since mantainance costs are significantly more ofor the onan (last oil change for the onan was about $40, compared to just $6 for the yahmaha) the onan is a great genset, once I worked out the bugs, mine has provided me with several hundred hours or reliable service, and by splitting the load with another APU I can make the onan last even longer before a major overhaul will be required, so now I will only need onan under severe usage conditions and not just to nuke something or watch a little TV whe
> n im in my rig...
_______________________________________________
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73 Canyon Lands, (a.k.a. The Yellow Submarine) West Los Angeles CA
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