Quadrafire Castile Experiment

[Harvey Schneider]

That IS interesting, Andy. The next time the stoves are down for cleaning or warm weather, I'll pull a couple of the springs and take my inspection camera and feed it in the tubes to see if there is any evidence of corrosion. I would think after a couple of years that, if it's happening, I would see a spiral pattern of corrosion. Thanks for the warning. I'll feed back for the others who have made this mod. Worst cast would be to give the springs a 1/4 turn to put the contact at a different spot on the tubes.
Oh, thanks to one of the other guys, I have the twisted spirals inside of the springs! But filling the space completely with 1 1/4" spirals would be good but you wouldn't get the contact area that the springs afford. We're looking for anything to improve the caveman technology in the standard Quads and many others. All suggestions are welcome.

Thermal contact between a round spring and an enclosing cylinder is never very good. Theoretically there is only a line of contact. As a result heat transfer is not usually through the spring. The spring serves primarily as a means of creating turbulence. The turbulence improves heat transfer from the cylinder to the air. In a design that I worked on many years ago we used a twisted piece of aluminum dropped into the pipe to enhance turbulence. Creating too much turbulence hurts heat transfer because it reduces the volume of air moving through that path. As with all engineering, it's a juggling act.

 

[tjnamtiw]

Andy, what kind of stove do you have? You should put it in your signature so all can see. The high speed convection mod was first done by B-Mod and I copied him and added the springs and 'turbulators'. To get the fan to always be on high, I feed the snap disk for the fan (purple wires) from the infeed side of snap disk #3 instead of from its normal feed.

Thermal contact between a round spring and an enclosing cylinder is never very good. Theoretically there is only a line of contact. As a result heat transfer is not usually through the spring. The spring serves primarily as a means of creating turbulence. The turbulence improves heat transfer from the cylinder to the air. In a design that I worked on many years ago we used a twisted piece of aluminum dropped into the pipe to enhance turbulence. Creating too much turbulence hurts heat transfer because it reduces the volume of air moving through that path. As with all engineering, it's a juggling act.

You're right, it is a line contact but a contact none the less. Most benefit comes from the turbulence. Most of my experience was with heat transfer in water where you wanted ALL the turbulence you can get. My experiments showed that I was removing more heat than before but whether I would gain more or less with more turbulence is a ???. I did add turbulators too, which improved heat transfer even more so I was still moving in the right direction when I stopped messing around.
If I could get springs or spirals made out of square stock, they would provide much more contact area and would really improve heat transfer. Hmmmmm. Anyone have a spring making machine and some aluminum square stock????? You could sell a bunch of springs to people here and maybe even Quad.

 

[Themlruts]

tjnamtiw
I see you have done some mods to your castile. I just picked up a castile this year since i bought a new house. In the old house I had classic bay 1200 and man could that put out some heat. Heated my entire 2000sqft split level.
My wife want to get the castile because of looks. I did know that it put out less BTU. But our house is now a small 1200 sqft ranch. I am just not happy with performance of the stove.
I see a lot of people do the air wash mod. But how do you do it? Do I buy different gaskets? 3 sides of my door have gasket but the bottom doesn't .
What about the springs? I have 10 tubes in my stove. I see people say they have ordered them but what size and where? Link?
Snap disk mod - Can you do it with the existing snap ring or do you have to buy the variable one?
Let me know what else i can do to increase efficiency.
Thanks
Mike
PS I think we should make a sticky with all this info instead of having to fish through the whole thread

 

[tjnamtiw]

Themiruts, all the info is right in this very long post plus use the search tool to look for other threads that speak of 'springs' and 'Quads'. Also, look for threads by a fellow experimenter 'B-Mod' who is the 'author' of the constant blower speed.
Don't mess with your gasketing around the door. You have the latest version. That Castile should be able to heat your 1200 sq ft. Make sure you have the flame height set per the instructions by adjusting the feed gate while on HIGH heat.

 

[rcc]

tjnamtiw said, "That IS interesting, Andy. The next time the stoves are down for cleaning or warm weather, I'll pull a couple of the springs and take my inspection camera and feed it in the tubes to see if there is any evidence of corrosion. I would think after a couple of years that, if it's happening, I would see a spiral pattern of corrosion. Thanks for the warning. I'll feed back for the others who have made this mod. Worst cast would be to give the springs a 1/4 turn to put the contact at a different spot on the tubes."

tjnamtiw ......

Have you checked for corrosion in the tubes? I've got my springs cut to length and ready to install

Thanks.....

 

[B-Mod]

I looked in mine, and the springs have been in for years (check the start of this thread), no corrosion. They were dusty, so I cleaned them, put them back in....

 

[tjnamtiw]

tjnamtiw said, "That IS interesting, Andy. The next time the stoves are down for cleaning or warm weather, I'll pull a couple of the springs and take my inspection camera and feed it in the tubes to see if there is any evidence of corrosion. I would think after a couple of years that, if it's happening, I would see a spiral pattern of corrosion. Thanks for the warning. I'll feed back for the others who have made this mod. Worst cast would be to give the springs a 1/4 turn to put the contact at a different spot on the tubes."

tjnamtiw ......

Have you checked for corrosion in the tubes? I've got my springs cut to length and ready to install

Thanks.....

Just now checked and I, like B-Mod, see no signs of corrosion. Plenty of spider webs and 'future food', though. Spiders were really bad this year.

 

[rcc]

Just now checked and I, like B-Mod, see no signs of corrosion. Plenty of spider webs and 'future food', though. Spiders were really bad this year.

Excellent

 

[B-Mod]

Just now checked and I, like B-Mod, see no signs of corrosion. Plenty of spider webs and 'future food', though. Spiders were really bad this year.

How do they like the heat?

 

[Themlruts]

It starting the heating season here in CT i have my springs on order. I will keep you posted

 

[Themlruts]

I got my springs in i cut them to 9. My question is do you let them fall all the way down? They seem to really cut the airflow down.

 

[Themlruts]

I havent read through the thread so maybe I have already made this suggestion;
WE took a Santa Fe and slowed down the combustion fans as we thought the flue temp wastage was too high.
THis transforms the Santa Fe as the heat exchange tubes absorb more heat. It does make the stove body warmer but not to the point it is alarming. Works perfect as the standard combustion airflow is insanely high.

How did you make that change. I thought the mod was to keep the combustion fan on High while on medium?

 

[SwineFlue]

How did you make that change. I thought the mod was to keep the combustion fan on High while on medium?

Two different quad mods here: chickenman reduced the speed of the combustion blower, while tjnamtiw runs his convection blower on High.

From chickenman's description of warmer stove temperatures, I suspect these two mods (three mods with the springs) would work very well together.

 

[tjnamtiw]

I got my springs in i cut them to 9. My question is do you let them fall all the way down? They seem to really cut the airflow down.

The springs SHOULD be a tight fit! The only way we got ours in was to twist them as we inserted them to reduce the diameter a little. If yours are falling down, then either your springs are too small or they changed the ID of the tubes! As for reducing airflow, you can see in one of my posts how much the airflow was reduced which, combined with more surface area gave time for more heat transfer. Yes, we run our circulating fans on high all the time to get more turbulent flow. Don't judge the air flow as 'really cut down' by feeling a particular tube as you will see some are reduced while others actually increase IIRC. Been a while.

 

[tjnamtiw]

THis offers the best possible heat exchange regardless of the fire. THe noise drives me nuts though!!
I actually put a trim pot. on the convection fan to slow it too. Yes it does cut the efficiency a tad but atleast I dont get a headache from the noise.
Wouldn't putting springs in the tubes make extra wind noise?

My fans are not that bad at all as far as noise goes. I noticed no change in noise level with the springs.

 

[Harvey Schneider]

combined with more surface area gave time for more heat transfer.

I had some experience with using a twisted flat plate to improve heat transfer from a flowing gas to a heat exchanger. The twisted plate was not well coupled to the heat exchanger, but was very effective in improving heat transfer.
It is hard to get good heat transfer from a round coil spring in contact with a cylindrical surface. The contact between the two is basically a line where the curvature of the spring touches the cylinder, not a surface.
In all likelyhood the improvement in heat transfer is caused by the turbulence introduced by the springs.
If I am right about that, it is not necessary to have a tight fit of the spring in the cylinder. A spiral twisted piece of sheet metal placed in the cylinder should do the same thing.
The turbulence caused by any object in the gas flow will cause some back pressure and will reduce flow. So even though you are running the blower at full speed you have, in fact, reduced it's output.

 

[tjnamtiw]

I had some experience with using a twisted flat plate to improve heat transfer from a flowing gas to a heat exchanger. The twisted plate was not well coupled to the heat exchanger, but was very effective in improving heat transfer.
It is hard to get good heat transfer from a round coil spring in contact with a cylindrical surface. The contact between the two is basically a line where the curvature of the spring touches the cylinder, not a surface.
In all likelyhood the improvement in heat transfer is caused by the turbulence introduced by the springs.
If I am right about that, it is not necessary to have a tight fit of the spring in the cylinder. A spiral twisted piece of sheet metal placed in the cylinder should do the same thing.
The turbulence caused by any object in the gas flow will cause some back pressure and will reduce flow. So even though you are running the blower at full speed you have, in fact, reduced it's output.

This is true. The main reasons for the high speed blower and the springs IS to cause turbulence and prevent laminar flow in the otherwise smooth tubes. Yes, there is not a lot of surface contact between the springs and the tubes but THERE IS SOME and every little bit counts. Oh, and don't forget I also have 'turbulators' in the middle of the springs for even more help. You can't knock success and all my measurements prove success.

Themiruts maybe just needs to figure a way to 'suspend' the springs such as a tab on their ends or a bar across the end.

 

[Harvey Schneider]

You can't knock success and all my measurements prove success.

I wasn't knocking it, I was trying to explore understanding of what is going on in the heat exchanger.
I'm not suggesting that you undo what you have, but I am curious if you have tried just turbulators and if the results were similar. The turbulators are cheaper and easier to fabricate.

 

[tjnamtiw]

I wasn't knocking it, I was trying to explore understanding of what is going on in the heat exchanger.
I'm not suggesting that you undo what you have, but I am curious if you have tried just turbulators and if the results were similar. The turbulators are cheaper and easier to fabricate.

No problem, Harvey. You know, I don't remember if I just tried the turbulators. They came from a fellow burner whose name escapes me right now (sorry). They certainly have been proven effective in industrial and military applications but these are pretty small in comparison to the diameter of the tubes.

 

[Themlruts]

This is true. The main reasons for the high speed blower and the springs IS to cause turbulence and prevent laminar flow in the otherwise smooth tubes. Yes, there is not a lot of surface contact between the springs and the tubes but THERE IS SOME and every little bit counts. Oh, and don't forget I also have 'turbulators' in the middle of the springs for even more help. You can't knock success and all my measurements prove success.

Themiruts maybe just needs to figure a way to 'suspend' the springs such as a tab on their ends or a bar across the end.

I may just try to to widen one end. That should do it.

 

[tjnamtiw]

I may just try to to widen one end. That should do it.

Yea, you could just spring one end open so it would not fit down in. Good idea. I still think that there is enough contact to transfer heat, though, but what do I know, I'm just a 'dumb Dutchman'.

 

[Themlruts]

K so not to sound like an idiot but i'm looking at b-mod mod.
1. Convection blower is what blows the air into room
2. Combustion blower is what feeds air to the fire. Is this also the exhaust blower?
If I understand his mod correctly is that the convection blower will always be set to hi even when you switch it to medium?
Will I have to change my feed rate if i put it on medium?

 

[tjnamtiw]

The combustion blower and the exhaust blower are the same thing. Just two terms for the same blower.

When you put it on medium, you ARE changing your feed rate and the combustion blower speed. Only the convection blower remains on high. You don't need to adjust the feed gate except when you change pellet lots or you see a change in pellet length from the last bag. Always adjust that on HIGH, but in most cases you will only do this a few times a season unless you are looking for something to play with.

 

[B-Mod]

B-Mod? Did some one ring? Lol, 12 degrees here this AM, snowed yesterday, the heating season is on. Hauling corn in today!

 

[tjnamtiw]

Hi BMod. 24 here tonight in sunny Georgia! You can keep that 12 degree crap!