Heating oil in lieu of water with a wood boiler
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Oil as a heat transfer medium? I suppose ya got the idea from those portable oil filled radiators. Personally I would consider it way to risky with the current state of Owb regardless of make. Never heard or worked on any boiler system that used Oil as a medium. Spring a leak and now ya got a major EPA event. Glycol/ water mix, yes, Even with Glycol the EPA gets all twisted up. If your thinking along the lines of corrosion protection then there are ways to treat the water for neutral PH
Oil has a flash point not a real good idea to get it over its flash point. There are thermal oils like Therminol used for specialty industrial applications for heat transfer. The trade off is usually that its hard to beat water for btu/lb.
If you are worried about freezing protection glycol is the way to go, just don't overheat it or it can go acidic.
If you are worried about freezing protection glycol is the way to go, just don't overheat it or it can go acidic.
maple1
Minister of Fire
I can guess, I have 550 gallons of heating oil storage in my basement. Sure would save money if I could use that oil as storage medium. I expect indirectly it does as I expect the tanks warm up when the basement warms up and provide some heating when the basement temp drops. Of course I haven't had them full for many years.
Well you said OI, not the tanks- question is if it would be possible to get them cleaned out of the oil residue ( a lot of work) to make them useful for storage. My guess would be no, particularly as they have sat empty, I do not think you could ever get all the oil sludge at the bottom out. If you do go that route then I would suggest a low pressure test to check for leaks. Fuel oil is corrosive- sulfer content mixed with water( humididty/condensation internally) even if empty due to the sludge at bottom. Better choice- big barbecue grills.
I'm old enough to remember the days when many who couldn't afford antifreeze for their cars and tractors. They would either drain the radiators at night or use kerosene in the cooling system. There were a lot of cars sitting on the side of the road burning.
Besides that oil won't transfer heat as well as water because oil has a much lower specific heat. A given volume of oil will hold much less heat than the same amount of water.
Besides that oil won't transfer heat as well as water because oil has a much lower specific heat. A given volume of oil will hold much less heat than the same amount of water.
Back in the 70's a bunch of thermal solar systems used Bray boil. It looked and smelled like ATF.
Silicone oil was also used, less toxic than the Bray oil. This was mainly for antifreeze protection. Both required double walled heat exchangers. Sure was a mess to clean up and get off the tools.
In hydronics it would cost you more pumping power, maybe 50- 66% more. It probably has a lower specific heat, so you have both density and specific heat working against you.
Now for storing heat, it may have some additional value, or for super high temperature operation.
The large solar thermal power arrays in the desert use oil based fluid. Nevada 1 runs over 700F temperatures, to flash steam.
Silicone oil was also used, less toxic than the Bray oil. This was mainly for antifreeze protection. Both required double walled heat exchangers. Sure was a mess to clean up and get off the tools.
In hydronics it would cost you more pumping power, maybe 50- 66% more. It probably has a lower specific heat, so you have both density and specific heat working against you.
Now for storing heat, it may have some additional value, or for super high temperature operation.
The large solar thermal power arrays in the desert use oil based fluid. Nevada 1 runs over 700F temperatures, to flash steam.
I want to use oil as a medium to boil mash in my ethanol still, a jacketed pressure tank. If I am correct I don't believe using water for heat transfer will be hot enough to boil liquid. Have considered using wood fuel to fire still, but hard to control temperatures. We have an abundance of wood to fuel the wood gas boiler. I am in the design stage.
OK, now THAT is one of the most interesting posts I've seen in a long time! Looking forward to hearing more about this project - cool!
My two cents - you'll be miles ahead by figuring out how to safely harness the power of steam vs heating oil. I believe most stills and industrial brewing applications will use steam to heat their mash tuns. I'm assuming using oil would be a nightmare. Not only do you need it "hot enough" but you also need to be able to control it. Oil is going to be very slow to react. You'll have a heck of a time maintaining consistent temps (I'm assuming) which will be detrimental (I'm assuming) to the mash profile you're targeting...
What temperatures are you looking for? If you keep it under pressure, say 12 psi, you can take water to about 244F before it boils.
if you have the right heat source, steam is another excellent option, as mentioned above.
if you have the right heat source, steam is another excellent option, as mentioned above.
The solar systems from the 80's that used silicone oil were prone to leaks. That is the first issue. Heat transfer with oil is not as good as water based systems.
And then there is the cost. I do believe it is long lived, but as with many heat transfer fluids, the hotter the system runs, the greater potential of fluid breakdown.
And then there is the cost. I do believe it is long lived, but as with many heat transfer fluids, the hotter the system runs, the greater potential of fluid breakdown.
There were hundreds of those silicone oil systems put in apartment buildings in NW Arkansas back in the 80's. I serviced them until about 10 years ago. I'll bet some are still running. They started taking them down when the roofs wore out!
Dow Syltherm, cost about 27 bucks a gallon when I last bought some, again 10 years ago.
Dow Syltherm, cost about 27 bucks a gallon when I last bought some, again 10 years ago.
I understand that water is the best for btu/lb, but not hot enough. I am looking at vegetable oil.
I need about 300 - 350 degrees for my process, ethanol distillation, typical flashpoint of vegetable oil is well north of 400 degrees. Should be safe with proper controls.
System will be non-pressurized, I think pressurized systems are too cost prohibitive.
Not sure yet how I can heat oil in conjunction with a wood gas boiler.
Not really worried about freezing.
Sounds moderately terrifying. I hope at the very least you're planning to do this out in the barn and nowhere near your place of residence.
People on this site get uptight when folks talk about heating water in a copper coil in makeshift wood burners. What you're discussing hear feels exponentially more dangerous (ethanol, hot oil, DIY). Oiy....
Good luck and stay safe! And don't forget your PPE....
People on this site get uptight when folks talk about heating water in a copper coil in makeshift wood burners. What you're discussing hear feels exponentially more dangerous (ethanol, hot oil, DIY). Oiy....
Good luck and stay safe! And don't forget your PPE....
maple1
Minister of Fire
Something about a flammable fluid in a boiler jacket kinda gives be the willys....
I like the concept of this giving one the "willys".
As an unpressurized system with vegetable oil, there are a LOT of scary parts to this.
Vegetable oil will break down, especially when heated and exposed to oxygen.
The flash point of vegetable oils are nowhere near the silicone oils we talked about used in solar systems.
You want an oil that has a very high flash point and is sealed against oxygen. They all do burn at some temperature.
Keep this operation away from any living things and buildings you do not want to burn down. Think of the videos of turkey frying. Once it starts burning, it makes a great fire.
If you are really serious about this, research the proper oils. Or consider propylene glycol.
As an unpressurized system with vegetable oil, there are a LOT of scary parts to this.
Vegetable oil will break down, especially when heated and exposed to oxygen.
The flash point of vegetable oils are nowhere near the silicone oils we talked about used in solar systems.
You want an oil that has a very high flash point and is sealed against oxygen. They all do burn at some temperature.
Keep this operation away from any living things and buildings you do not want to burn down. Think of the videos of turkey frying. Once it starts burning, it makes a great fire.
If you are really serious about this, research the proper oils. Or consider propylene glycol.
Its all fun until something blows up or catches on fire. I am going to research alternative heat exchange fluids.
Good idea. The Europeans try to avoid the use of high pressure steam heating if at all possible due to licensing requirements. They do thermal oil systems if at all possible. There are some fluids good up to 400 deg F
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