Displacing hot water

[Justburnit]

I want to reduce the amount of water inside our boiler so it can get up to temperature quicker when it has cooled down.
I have been thinking of something in the line of tank floats such as used in toilet tanks or larger industrial size floats.

So far I have not found a cost effective supply of something that will hold up to the hot water at the mild pressures inside the heat system.
Any Ideas?

 

[pybyr]

try McMaster-Carr -- www.mcmaster.com-- put "float" in the search function and I think (from looking for floats for another project) that you'll find ones made of various materials, including stainless steel, that might fit your purpose

 

[Justburnit]

I had looked in McMaster last winter but they are cost prohibitive for this task. I am hoping to learn of a surplus supply, if there are any true surplus supplies left, or some other idea.

 

[jebatty]

Is it the Tarm 30 that you want to reduce the water inside? If so, I would be concerned about the impact on heat transfer between the the heat exchanger tubes and the surrounding water jacket. If heat exchange is impeded, you might be shooting yourself in the foot, as there may be less heat transfer. Just a thought.

I have the Tarm 40 and find that the boiler heats fast. The Termovar prevents boiler water from circulating to the system until temp reaches 160F, so when it opens, the system gets 160F water minimum. The amount of 160F water provided depends on the temperature of system return to boiler.

 

[Justburnit]

Hi Jim,
Yes this is in the Solo 30.
In the S30 most of the heat to water transfer is from the firebox. The fastest way to get the temp up in this unit is to not put it into gasifying, basically let it updraft till the circulator turns on. Obviously this is far from ideal operating condition.
If you light a fire and put it into gasifying right away with just a small start load of wood, and then add wood in small amounts, this thing can burn ½ day with 450°+F flue temps without the water climbing from 20°C to 60°C. When it is doing this we open the damper to let the firebox updraft and light all the wood and it puts out heat soon. I find it to be real frustrating to run two loads of wood and not get usable heat out. The firebox on a solo 30 is small, one only gets a 2 ½ hour burn if not idling.
Another characteristic for the S30 is that the water short circuits withing the boiler. The water flow around the firebox is stagnant. I have seen a number of people on this forum questioning knocking in there boiler, this knocking is a hot spot up front in the corner where the blower is. There is no waterflow over there.

So what I am up to.
I do not have the DHW coil in my boiler. This allows me to add a new water outlet through the removable cover up on top of the unit. This will be internally plumbed to draw from the right front corner.
This will induce the waterflow to enter the boiler in the standard location, but rather than just climb and exit it will traverse the whole water chamber and exit at the far end of the boiler providing a much more even cooling of the boiler.

The second goal, since I have a heat storage there is no need for mass storage in the boiler. I will be adding something such as tank floats through this top hatch to displace as much as I can up there. Being that these will probably be floats, they will float leaving a full water flow along the hot surface of the burn chamber but remove unneeded water mass from the upper area of this chamber. This will reduce the startup up time from a cold boiler.

 

[DaveBP]

Justburnit

Yes this is in the Solo 30.
In the S30 most of the heat to water transfer is from the firebox. The fastest way to get the temp up in this unit is to not put it into gasifying, basically let it updraft till the circulator turns on. Obviously this is far from ideal operating condition.
If you light a fire and put it into gasifying right away with just a small start load of wood, and then add wood in small amounts, this thing can burn ½ day with 450°+F flue temps without the water climbing from 20°C to 60°C. When it is doing this we open the damper to let the firebox updraft and light all the wood and it puts out heat soon. I find it to be real frustrating to run two loads of wood and not get usable heat out.

Am I the only one reading this that finds this description a little left of odd?
Sounds more like a miniature OWB burning green wood than a gassifier running on afterburner.

 

[Justburnit]

Dave,
It sounds that way doesn't it?

The first part of last season my wood was not as dry as it needed to be. But by late winter I was into good wood that had been indoors most all winter. We also started working with both soft and hardwood after the cold part of the winter. That is when I based my true learning and spent time on the phone with the importer to back up my experiences.

I have a very technical background and am far more aware than average, therefore I learn more and get deeper into the operation and design than most people ever will.

The Solo 30 has 6 short ~ 3" ID heat transfer tubes that even with turbulators allow for less than 1 second of transfer from the fluegas. In the boiler industry 3-4 seconds is considered the minimum for any efficiency of operation.
There is a total lack of fins or any form of surface conditioning to induce heat transfer from the fluegas. It is no surprise the flue gas temps are in the 500° range during operation. And they call this 90% efficient, Ha.

I make my living improving efficiency on a with variety of items and will be doing so with this boiler.

So if this thread sounds far fetched it is solely because no one has been willing to go where or question what I do. Take the internal knocking to point. It happens with every hot fire in a Solo 30. It can be eliminated without any ill side effects and no modification to the boiler. But no one does. How many years of heat stress can the chamber endure without issues, I choose to cure the problem before a crack forms because we know the crack will not form till the warrantee is out.

 

[Justburnit]

For the most part just with the kindling on startup. I did run some with a load of wood early on but that wood was not up to snuff. I have not blended any later on with good wood.

 

[heaterman]

I want to reduce the amount of water inside our boiler so it can get up to temperature quicker when it has cooled down.
I have been thinking of something in the line of tank floats such as used in toilet tanks or larger industrial size floats.

So far I have not found a cost effective supply of something that will hold up to the hot water at the mild pressures inside the heat system.
Any Ideas?

That's probably not something I would recommend. The water level in your boiler is a pretty critical issue and should not be tampered with for safety reasons as well as the long term integrity of the unit itself.

That being said, if you are talking about the water level in a storage tank, that is a different issue. But I have to say that if you are having problems with water temp getting to low in the first place, you should probably increase your storage not decrease it.

Try looking for a device called a liquid level control as an option to a float valve. WW Grainger has several types.

 

[Justburnit]

I am not talking about lowering the water level in the boiler. As the thread title states I am talking about displacing water to reduce thermal mass.

 

[heaterman]

I am not talking about lowering the water level in the boiler. As the thread title states I am talking about displacing water to reduce thermal mass.

Ok. I'll rephrase my statement. Reducing the volume of water in your boiler is not something I would recommend. Your boiler is designed to function with a specific amount of water volume in it by the manufacturer.