res0wc18
Full Access Member
So as most of you by now know that my vehicle fleet runs on waste vegetable oil and I have some fun engineering that’s actually useful I thought you would get a kick out of.
As I close in on completing my next daily driver the Grease Beast (1985 CUCV M1009 K5 military blazer) I have been considering going to electrical heating of the oil to aid in switch over times and all around better usage. Currently my systems on my other rigs consist of passive coolant based heating(think giant heat exchanger), and although this works good the engine has to be up to 100% temp for a while before you can even use it. Couple this with my relatively short commute(lake stevens) and it makes it a breaking point for the argument of using strictly biodiesel. In the 7 years I have been running alternative fuels I have seen the cost of chemicals needed to make biodiesel more than 5 fold in price. This makes it almost impossible at points to make it worthwhile.
Anyhow this all relates to a factor of sustainable living. I’ve been working more and more to say goodbye to petroleum products and the crooks that own them. This brings us to the current subject. So when most people hear “alternative fuels” they run in horror because it strikes fear in their mind of some backyard scientist with a half ton chevy nearly blowing himself(and the neighborhood) up. That’s not how I roll. I do something once to the best of my ability and don’t touch it again(and I don’t have to tell you that there isn’t any questionable dangerous offshore products involved). So over a conversation lately with one of my long time life mentors and friend who’s old enough to be my grandfather he had some words of wisdom to offer me, and that was to satisfy my mind and see what “could be”. So in short here it is.
I have not dealt with heat loss and btu requirements since I worked at the shipyard over 6 years ago(sometimes I miss that place…a lot more respect for people who could actually do something than here) so these are pretty decent calculations more than good enough for gubment work.
My feedstock is mostly a mix of soybean and canola mixed with some algae and peanut oil. Using facts from one of my favorite engineering sites http://www.ramacorporation.com/engineer/Engineerweb.pdf http://www.tempco.com/Catalog/Section 16-pdf/Section16.pdf i came up with some of these standards for the oil.
When vegetable oil is in the 160 degree F range it is considered to be safe to run in a diesel as it is within +/- 15% of the viscosity of number 2 diesel by the time it reaches the injectors. Considering our average temp around western wa is about 50 degrees and my fuel system flows about 1.5 gallons minute through a system that holds about one gallon we can assume some standards here from the charts above. All this is to figure what it would take to nearly instantly(1 minute or under) heat the oil.
(Flow rate in gal/min)*(specific weight density in lb/gal)* (desired heat rise in deg F)= required BTU’s/min
(1.5 gal/min) * (7.774lb / gal) * 150 deg. F = 576 BTU/min.
(note that .33 BTU = energy to raise 1 lb of veg oil 1 deg F)
576 BTU/min is... in watts (1W = 3.413 BTU/h): 168.76W
(576 BTU/min) * (60min/h) * (1W / 3.413 BTU/h) = 10.125 kW/h aka a lot of juice!
Now this is only part of the equation. I assumed a 150 degree heat rise to account for the 18% dissipation loss from the stainless housing that is about 40 cubic inches to ensure when it reaches the injectors it is 160 degrees or more.
Here is the real kicker though. ASME standards suggest no more than 60 watts/sq inch. Using this we can figure that we could only absorb(safely) 2.4kw of juice in my current housing or about 24% of what we need, not gonna work! So using this relationship I can figure that my housing needs to be 4 times the size or about 8” in diameter by 12” long. Not undoable but defiantly large for most small cars.
So now we move to electrical load requirements. The grease beast has two 100amp 28vdc alternators with two huge batteries that have a combined power of 2.52kw/h rating. These are large batteries but with the consumption of the heating elements they would last less than 15 minutes in the most ideal conditions without powering going to them. As a general rule you can’t take lead acids below 55% or they go kapoot, and even if you could get the oil to temp before starting the current system could only support that rate for about 38 minutes. So in relation we can derive I would need to have a 400 amp alternator system to keep up. When is the last time you saw a 400amp power unit? Welders ring a bell? http://www.zena.net/ this company makes realllllyyyyy nice stuff. Using these units one could produce enough juice to run a house(no joke) which is never a bad situation in a power outage/ rescue situation.
Saving you more boring technical details it is in theory very possible to subsist off of electrical heat but at about 5k in product. A lot more practical would be to have Adam build some custom units(which he said is doable) http://www.nationsautoelectric.com/ but again 2k in product.
In short you can buy one heck of a lot of fuel to get up to temp before switch over for 2k and electrical heating is to me at this point is only an option for the rich.
As I close in on completing my next daily driver the Grease Beast (1985 CUCV M1009 K5 military blazer) I have been considering going to electrical heating of the oil to aid in switch over times and all around better usage. Currently my systems on my other rigs consist of passive coolant based heating(think giant heat exchanger), and although this works good the engine has to be up to 100% temp for a while before you can even use it. Couple this with my relatively short commute(lake stevens) and it makes it a breaking point for the argument of using strictly biodiesel. In the 7 years I have been running alternative fuels I have seen the cost of chemicals needed to make biodiesel more than 5 fold in price. This makes it almost impossible at points to make it worthwhile.
Anyhow this all relates to a factor of sustainable living. I’ve been working more and more to say goodbye to petroleum products and the crooks that own them. This brings us to the current subject. So when most people hear “alternative fuels” they run in horror because it strikes fear in their mind of some backyard scientist with a half ton chevy nearly blowing himself(and the neighborhood) up. That’s not how I roll. I do something once to the best of my ability and don’t touch it again(and I don’t have to tell you that there isn’t any questionable dangerous offshore products involved). So over a conversation lately with one of my long time life mentors and friend who’s old enough to be my grandfather he had some words of wisdom to offer me, and that was to satisfy my mind and see what “could be”. So in short here it is.
I have not dealt with heat loss and btu requirements since I worked at the shipyard over 6 years ago(sometimes I miss that place…a lot more respect for people who could actually do something than here) so these are pretty decent calculations more than good enough for gubment work.
My feedstock is mostly a mix of soybean and canola mixed with some algae and peanut oil. Using facts from one of my favorite engineering sites http://www.ramacorporation.com/engineer/Engineerweb.pdf http://www.tempco.com/Catalog/Section 16-pdf/Section16.pdf i came up with some of these standards for the oil.
When vegetable oil is in the 160 degree F range it is considered to be safe to run in a diesel as it is within +/- 15% of the viscosity of number 2 diesel by the time it reaches the injectors. Considering our average temp around western wa is about 50 degrees and my fuel system flows about 1.5 gallons minute through a system that holds about one gallon we can assume some standards here from the charts above. All this is to figure what it would take to nearly instantly(1 minute or under) heat the oil.
(Flow rate in gal/min)*(specific weight density in lb/gal)* (desired heat rise in deg F)= required BTU’s/min
(1.5 gal/min) * (7.774lb / gal) * 150 deg. F = 576 BTU/min.
(note that .33 BTU = energy to raise 1 lb of veg oil 1 deg F)
576 BTU/min is... in watts (1W = 3.413 BTU/h): 168.76W
(576 BTU/min) * (60min/h) * (1W / 3.413 BTU/h) = 10.125 kW/h aka a lot of juice!
Now this is only part of the equation. I assumed a 150 degree heat rise to account for the 18% dissipation loss from the stainless housing that is about 40 cubic inches to ensure when it reaches the injectors it is 160 degrees or more.
Here is the real kicker though. ASME standards suggest no more than 60 watts/sq inch. Using this we can figure that we could only absorb(safely) 2.4kw of juice in my current housing or about 24% of what we need, not gonna work! So using this relationship I can figure that my housing needs to be 4 times the size or about 8” in diameter by 12” long. Not undoable but defiantly large for most small cars.
So now we move to electrical load requirements. The grease beast has two 100amp 28vdc alternators with two huge batteries that have a combined power of 2.52kw/h rating. These are large batteries but with the consumption of the heating elements they would last less than 15 minutes in the most ideal conditions without powering going to them. As a general rule you can’t take lead acids below 55% or they go kapoot, and even if you could get the oil to temp before starting the current system could only support that rate for about 38 minutes. So in relation we can derive I would need to have a 400 amp alternator system to keep up. When is the last time you saw a 400amp power unit? Welders ring a bell? http://www.zena.net/ this company makes realllllyyyyy nice stuff. Using these units one could produce enough juice to run a house(no joke) which is never a bad situation in a power outage/ rescue situation.
Saving you more boring technical details it is in theory very possible to subsist off of electrical heat but at about 5k in product. A lot more practical would be to have Adam build some custom units(which he said is doable) http://www.nationsautoelectric.com/ but again 2k in product.
In short you can buy one heck of a lot of fuel to get up to temp before switch over for 2k and electrical heating is to me at this point is only an option for the rich.
