Waste Oil Burner + Sand Battery

I do not know what the appropriate forum for this would be. If this is the wrong one, my apologies.

I have access to a large quantity of waste oil at my current location. Much of it is used motor oil/transmission fluid. Instead of just tossing this "resource" I set out looking for options to utilize it and came upon the subject of waste oil burners. I'm currently constructing a burner that I would like to use in a couple different applications. This post is about a potential design for coupling a sand battery to the system to bank some of the heat for a longer period of time. I'm not 100% sold this is the way I'm going to go but I wanted to at least post the idea and a quick diagram and solicit feedback of the "That's Dangerous and You Should Rethink Now" variety. Preferably with at least some small pointer as to what is dangerous if it should be so.

If anything in the diagram is unclear or if you have questions please don't hesitate to ask.

Thank you!

I have a long thread on the sand battery and this idea hit me recently to combine waste oil + storage in a thermal mass...

To make this even more effective I was thinking insulating the sand battery  with waste styro foam with a combo of styro crete....

The way the gents over in Europe do this is with electrical heated forced air thru the sand to heat / pull the  heat out of the mass.

I started with sand, but I have moved more into metal because of it's density and how easy it is to pull the heat out of it.

This is a proven method of using waste oil, it deals with all the problems of impurities in the oil.     I have seen many attempt using diesel heaters but they clog up big time over time.

Mart Hale wrote:I have a long thread on the sand battery (snip snip)

This is a proven method of using waste oil, it deals with all the problems of impurities in the oil.

Thank you! I will definitely check out your thread and the video. The oil burner design I'm working on is top fed and uses a rear disk break rotor as the base. I will post either a diagram at some point or pictures of the unit itself once it's together if I end up building it. I am mainly concerned with having the sand battery be on the exhaust chimney stack and if I'm going to have issues with backpressure on the system. The exhaust expansion area is a first-thought attempt to mitigate that somewhat while also potentially functioning as a cooking surface. There "might" be a nautilus shell partition in the expansion area that will route the hot gasses around and out. Going to try leaving it open at first and maybe switch later to see the difference.  Planning for ~4" ID on most of the pipework. I will be building and testing this unit outdoors but the hope is to be able to run it inside eventually if it proves safe.

Michael Jacobsen wrote:

Mart Hale wrote:I have a long thread on the sand battery (snip snip)

This is a proven method of using waste oil, it deals with all the problems of impurities in the oil.

Thank you! I will definitely check out your thread and the video. The oil burner design I'm working on is top fed and uses a rear disk break rotor as the base. I will post either a diagram at some point or pictures of the unit itself once it's together if I end up building it. I am mainly concerned with having the sand battery be on the exhaust chimney stack and if I'm going to have issues with backpressure on the system. The exhaust expansion area is a first-thought attempt to mitigate that somewhat while also potentially functioning as a cooking surface. There "might" be a nautilus shell partition in the expansion area that will route the hot gasses around and out. Going to try leaving it open at first and maybe switch later to see the difference.  Planning for ~4" ID on most of the pipework. I will be building and testing this unit outdoors but the hope is to be able to run it inside eventually if it proves safe.

Yes, other things to look out for is don't use wet sand, it gives poor results and steam can be a real issue with the heat source you are using.

I have been thinking that the cob  rocket mass design,  or mason heaters might be a good place to look for design ideas as they already store and release heat  for home heating....    

Oil gives great advantage as you can almost go heat on demand....

Attached is a photo of a guy who uses waste heat for his outdoor spa...      It has  "BOOM SQUISH"  written all over it,  but the concept looks good just needs regulation of the heat   ;-)

Mart Hale wrote:
Yes, other things to look out for is don't use wet sand, it gives poor results and steam can be a real issue with the heat source you are using.

I have been thinking that the cob  rocket mass design,  or mason heaters might be a good place to look for design ideas as they already store and release heat  for home heating....    

Oil gives great advantage as you can almost go heat on demand....

Attached is a photo of a guy who uses waste heat for his outdoor spa...      It has  "BOOM SQUISH"  written all over it,  but the concept looks good just needs regulation of the heat   ;-)

I have been experimenting with little sand batteries in a cast iron dutch oven. Learned about wet sand and about the issue with >1% organic matter from that. The top of the sand battery in my design will not be sealed. There will be space around the edge between the exhaust expansion chamber and the outer wall. No boom squishy designs for me, tyvm. In the photo you attached it looked like there was a pressure regulator on it. At least a nod to safety I suppose. The upside to using a old hot water heater like that is the chance of flashing to steam is largely mitigated. Not completely though.

I actually have an old 40 gallon gas water heater that I planned to use the tank from for the outer hull of the sand battery. Now though I may think about finding something else for that and save the water heater for a safety boosted version of that hot water heater. Why build one waste oil burner when you can make 2 at twice the price... Lol

Around here there are several homemade waste oil burners and they are very simple. A drip tube is made to take the oil down a tube, through a quarter turn ball valve to control the dripping oil entering the fuel box, then it is set at that setting and oil is just added. Other fuel is typically burned, like wood, but the oil just keeps the firebox going.

The sand battery is a nice step but honestly overthinking it I think. If you got free oil to burn, why make something far more complex then it needs to be. It is pretty hard to beat 100% free heat.

I have been considering it myself. I get tons of used hydraulic oil that I could take home for free. Hooking up a drip tube to my wood/coal boiler would allow me to heat a lot of my house for free. I just need to get motivated on the project.

Used motor oil is cheap. I know because I give mine free to the local auto repair shops. They 'recycle' it in winter by burning it to heat their shops.

My main concern is what happens to all the toxic gunk that old motor oil contains. I don't know and I wish I did.