Gasometer / Gas Holder

I was thinking about building a gasometer to run my RV fridge and I had the thought why not displace the water instead of a vessel? This way you can take advantage of the water weight to compress the gas bit to get more energy density pr charge. It would still be relatively safe. (I would never ever consider or endorse pressurizing hydrogen or CO in a sealed container ever.)

So here is what I am considering building. Using one 16 gallon 14 inch diameter barrel drum and a 55 gallon barrel drum. The 16 gallon if it has an open top removable lid you simply invert it and will need to lock in place a few inches above the bottom surface of the 55 gallon drum. Then you have an inlet / outlet placed at the top of the 16 gallon inverted drum.

Ok so if my figuring is correct. 16 gallons you multiple by 2 giving 32 gallons. This is the static water displacement that will do nothing. So this leaves 23 gallons of water of the 55 gallon drum that can actually be displaced. One gallon of water weighs 8.34 so 23 gallons X 8.34 = 191.82 lbs of gravity force. So this will allow some pressurizing of the gas but still with a way to vent out in the case of a flashback and it should only displace the water shooting out. So you would not have a vessel flying through the air. lol If were a really potent flash back that would over come displacement of the water, the 55 gallon drum itself I think would be plenty sufficient to shield it from harming anything.

Off grid refrigeration is only real difficulty in going off grid. Electric refrigerators require a lot of energy. However an LP Fridge is very efficient and I think you could easily run and sustain a large size RV LP refrigeration unit using this contraption. :fire:


I am not understanding your math, Matt. How can 16 gallons displace 32 gallons static in a 55 gallon drum and leave 23 gallons of water? I am not a math wiz by the way.
Like this?


Yeah that makes two of us haha.,

The 55 gallon can only hold 55 gallons. When you fill the 16 gallon drum and then displace it there will actually be 32 gallons or what ever the capacity actually is on the outside of the 16 gallon drum that is static. (if filled only to the height of the inside barrel) But if we take the full capacity (16 gallons of full gas capacity) then fill the rest of the 55 gallon drum to the top; then that would leave 55 - 16 = 39 gallons. Then multiply that by 8.34 that gives us 325 lbs of gravity weight. Does that make more sense

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Matt, I don’t fully understand you either, maybe you think so? … George has something similar for storing cooking gas, but as I understand it, he lifts the inner barrel with a winch. :thinking:


Thats a typical gasometer. This has a 55 gallon drum that is much larger than the 16 gallon drum. The 16 gallon is fastened down inside the 55 gallon drum, so it can not move and the bottom is open. You fill it with gas and the water displaces out into the 55 gallon drum. The 55 gallon drum towers over this inner drum and has more than 3 times the capacity. This capacity equals a lot of weight from the water.

Fill your sink up with water and take a cup and flip it over and try to submerge it. When you have it fully submerged all the water weight above the bottom opening of the cup is applied.


It may not matter how much the capacity is. Only the weight of what is displaced can actually be applied. You could submerge it in the ocean the pressure would be the same as in the 55 gallon drum. :frowning: It would still work for a low pressure system though just would not have that extra weight of the water like I thought it would.

So if you start off with the 16 gallon barrel full of gas and you use up 3/4 of the gas with cooking or whatever, the water level in the 55 gallon drum will lower and the gas pressure will reduce because of the reduced head? That is why Georgio has a floating barrel?


The buoyancy force is equal to the weight of the displaced liquid, and the pressure depends on the height of the water column.

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Yes I believe that is correct and only the weight of the 16 gallons can be applied. So three quarters down leaves 4 gallons = 33 lbs or so.

But its still a good idea considering I want to use the barrels. The 16 gallon drum weighs around 12 or 14 lbs. 16 gallons of water however, weighs 133 lbs

If I go to the 30 gallon drum for the inside drum then thats 250 lbs. But I would not have the full capacity if submerged into the 55 gallon drum

Matt, that’s what physics says …

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Thats a clever way to get a lot gas inside the vessel with out a blower? Get the gasifier up and running then lift that baby up and it will suck in the gas by lifting it right?


That is way over my head lol. But I gather I am somewhat correct that having the height will apply more pressure. But not weight, that is where my logic is probably messed up. There are two different things going on.

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If we filled up a balloon inside there then we would be working with the pressure forces instead of the buoyancy weight correct?

Here’s an ezpz way to make a ~30 gallon gasometer, with very little risk of gas leaks.


This from Linde’s material data safety sheet for 99% pure compressed carbon monoxide.
Note the compressed gas is stable. It decomposes at 752°
If you are worried about flash back, use Humphrey screens in your feed line.

I like this topic. I have done this in the past. I have a tank of co here somewhere that I labelled with soapstone, but I think it washed off in the rain, so…IDK. The idea was to see if soot came out.
This needs some practical experimentation. Does the pumping losses (in terms of wood) make storing the gas in cylinders, prohibitive versus the low pressure gasometer.
Or was it a case of safety? Riveted tanks seem scary although so does a big hat in a swimming pool.


For me its both, and probably more on the energy losses when using high compression storage. But Ive also blown up a lot of stuff using HHO and know this gas will kill you in a heartbeat. If there is any risk at all Im out and not messing with it. Shoot a container into the sky Im not so worried about and I think for my application a low pressure storage like this will be plenty sufficient.

The idea of displacing the water instead of using the inner vessel to move the gas is to make it safer. So instead of shooting this vessel into the air you simply blow the water out of the lower container.


Hmm … Matt, compressing gas at high pressure (200bar) and storing it as CNG for use has been a challenge for me for some time. True, a lot of energy needs to be invested here for compression, but if the right approach is used in use, this energy is not lost, even more, you have a lot of clean potential energy in the cylinder that you can easily use to drive an air engine before gas ignite.
The most practical use, however, would be to dose the gas into the otto engine just before the piston reaches the top dead position, or before the ignition occurs. Thus, at the same time, we would get the compression energy returned and the full amount of clean air for mixing and combustion with gas … in short, a lot of engine power …:thinking::grinning::roll_eyes:


So, I can see a scuba tank compressor taking the gas up to 1100 psi.
In theory, releasing it into a crappy old engine whose compression pressure is between 125-75 psi.
Do you need an accompanying stream of injected air? Or is this going to run like a diesel with air only being drawn in through the intake.
This would be a good place to show a graph of the increase in pressure due to the increase in “n” (PV=nRT).

The obvious injector apparatus would be some sort of logic controlled solenoid…do you know of any? This could also be used if you wanted a steam engine.


Search term: gaseous fuel injector


I dont plan to run an engine with this. This will used to create charcoal and provide gas to replace LP / NG for running the gas appliances. The charcoal rendered will be for the generator for electric power.

I could very easily automate an on demand gasometer / gasifier system to do this and the gasifier would not need to produce very clean gas. So the gasifier could be made very simple possibly a FEMA or a simplified Imbert.

When gas is needed to recharge the gasometers. Ill use some of the left over gas to light the unit. The blower will turn on and the machine will try to ignite the flare until it lights. Once the controls see a lit flare, the blower motor and flare valve shuts off and the hoist motor will activate and lift the accumulator of the gasometer up sucking in the gas. So very low power requirement. Lighting with the Amteck blowers I expect a 30 second start up time and then the barrel hoist lift will be a few minutes and then a settling time.

So there will be two gasometers that will flip back fourth in this process. One will supply while the other accumulates and settles the gas.

The supply out however will have a small air compressor pump and a small accumulator tank. This is to better maintain a constant presure but it will only need to sustain less than 10 psi. So again very low electrical input.

This will run my Hot water heater, my refrigerator, stove, LP Furnace and cloths dryer. All these appliances can be ran on gas versus electric and would be direct energy conversion from energy waste reclaim of the charcoal process for the charcoal gasifier.

This will help balance the scale as most of the weight the electrical system carried = more wood for process. So with the gas appliances we shift that weight away to a more efficient method. Your wood process efforts are now for the gasometer for energy to run the gas appliances. What you get in charcoal for the electrical power is the bonus. So now your electrical requirement is cut in half if not more so less charcoal is needed. This should actually produce a surplus and that would be great for EV adoption or a CV (Charcoal Vehicle) :fire:

Here is very good example. Note his “gasifier” is actually a closed retort and he is injecting the pyrolysis gas directly into the gasometer and it is clean as can be. Using a compressor with woodgas I cant see working for long duration. The tar will eventually destroy the pump and air will get in at some point. The Pump I will use will be after gas scrubbing and will be small along with a very small volume accumulator. A gasometer if it blows it just shoots out the water and would shoot the accumulator out the water. The hoist will stop it from becoming a rocket. Ive experienced at least 20 catastrophic flash back events in my development history. If any of these events were inside a closed sealed vessel I would be dead!! Never ever put this gas in large quantities in a sealed closed vessel ever especially under presure.