The Proof is in the Pudding

PMJ

I've observed here for some time that perfectly even heat would mean that the thermostat was never satisfied. So by definition, so long as the temperature of the space does not fall below the cut in of the thermostat, the longer calls go on with the temperature remaining inside the deadband of the thermostat the more even the heat is.

I attach here graphical evidence that my simple control is getting very close to achieving this with a boiler on the bigger end of what is needed. Note - this system was running on a vaporstat when I moved in and banging off its high limit regularly. It was noisy in the basement with air rushing in and out and no the heat was not even...upstairs/downstairs or anywhere else.

The outside temperature for this was about 10F. Shown is a 12 hour stretch where the thermostat was satisfied only 3 times, and only for a total of about 23 minutes. There were 23 even burns of just under 10 minutes each, and waits between burns of 18 minutes or so. During those 18 minute waits the vacuum guides more steam to the colder areas. Each new fire begins in the deepest vacuum and full boil is achieved in 30 seconds or so. So this ends up very close to 2 cycles per hour so the boiler has to run 30% of the time to heat the structure at this temperature. You can see where the thermostat was satisfied and for how long on the wait time chart.

The difference between what this system was and is now is huge. The system is dead silent. My only vent opening is in the garage and no air can ever be heard going in or out. The heat is even everywhere - my upstairs/downstairs difference problem went away.

The control is simple. There is no outside temperature input. There is no high level math. Though it is much easier to do with a PLC one is not necessary. Without the vacuum part all that is needed is two independent timers and one simple temperature switch on a remote radiator. The burn lengths and wait times adjust to the conditions. The colder it gets the longer the calls get as it dials in. I haven't changed the timer values in several years now.

EBEBRATT-Ed

looks remarkably consistent. Now all you have to do is design a factory plug & play system and get a patent

ChrisJ

EBEBRATT-Ed said:

looks remarkably consistent. Now all you have to do is design a factory plug & play system and get a patent

Yeah good luck getting anyone to buy it patent or not.

I've already watched this story play out.

STEVEusaPA

The actual saying is...
The proof of the pudding is in the tasting

HVACNUT

ChrisJ said:

EBEBRATT-Ed said:

looks remarkably consistent. Now all you have to do is design a factory plug & play system and get a patent

Yeah good luck getting anyone to buy it patent or not.

I've already watched this story play out.

But there's "graphical evidence". 

PMJ

EBEBRATT-Ed said:

looks remarkably consistent. Now all you have to do is design a factory plug & play system and get a patent

Consistent, yes, and based on the demand which actually doesn't change that fast.

Fire until steam gets where you want it. Don't fire again until that same spot has cooled a set amount. Length of firings and time in between them then changes as the conditions do because the rate steam is condensed by the system changes. As it gets colder net burn minutes per hour increases but it all stays in even pulses. Obviously in mild weather the tstat gets satisfied more often.

I'm not interested in patents or in selling anything. I'd like folks to just try this on their own. A few are now. It is just so easy, so inexpensive, and very effective.

ChrisJ

No logging of any temperature sensors in any of the living spaces?

PMJ

ChrisJ said:

No logging of any temperature sensors in any of the living spaces?

No.

ChrisJ

PMJ said:

ChrisJ said:

No logging of any temperature sensors in any of the living spaces?

No.

So,
For all we know some rooms are swinging 4 degrees.

PMJ

The logical basis of these control systems is to maintain a temperature at the control point. Hanging in the dead band of the thermostat for long periods is proof that is being accomplished, that is total call time as a percent of total time.

I find that consistency at the control point is consistency everywhere. Ongoing 18 minutes of off time between 10 minute firings with the control point never leaving its dead band no room can possibly swing 4 degrees even in theory.

cross_skier

Interesting, thanks.  I'm planning on trying 18 minutes delay triggered by 0.1 psi trigger and see how it does on my system.  This is simpler than what you did, I am wondering what benefits I am losing by not adding the second timer 

PMJ

cross_skier said:

Interesting, thanks.  I'm planning on trying 18 minutes delay triggered by 0.1 psi trigger and see how it does on my system.  This is simpler than what you did, I am wondering what benefits I am losing by not adding the second timer 

Many ways to do this. I do not claim mine is the only one or the best.

The more people trying things on this the better.

ChrisJ

PMJ said:

The logical basis of these control systems is to maintain a temperature at the control point. Hanging in the dead band of the thermostat for long periods is proof that is being accomplished, that is total call time as a percent of total time.

I find that consistency at the control point is consistency everywhere. Ongoing 18 minutes of off time between 10 minute firings with the control point never leaving its dead band no room can possibly swing 4 degrees even in theory.

I'm sorry but I'm confused. Maybe I'm having a duh moment, it happens.
Where do we see any evidence of how consistent the temperature is in the living space?

All I'm hearing right now is "the thermostat wasn't satisfied most of the time" but that could mean a lot of things. It could mean the temperatures in the space dropped several degrees and then overshot at the end which is exactly what I saw with this setup. repeatedly. It would fall behind more and more, then kind of catch up but not quite, and then overshoot. Then the thermostat would stay off for too long because of the overshoot, and then the system would fire for short bursts, each time falling behind more and more and then again, kind of catch up but not quite, then overshoot. Rinse and repeat.

delcrossv

@PMJ Can you post a diagram of your control setup?

SteamingatMohawk

This feels like a modern way to simulate how the coal fired systems maintained temperature. The main difference is that you vary the heating rate by the on/off cycles vs. relatively steady burning of coal. I believe the vapor function tends to minimize the cooldown of the system by not drawing in room air between firings.

Can it work in a non-vapor system?

Shahrdad

STEVEusaPA said:

The actual saying is...
The proof of the pudding is in the tasting

I believe the actual saying is "The proof of the pudding is in the eating," but tasting also sounds awfully good.

PMJ

@chrisj,

The temperature at the control point stays in the deadband for hours at a time in the cold. I set a recording thermometer on top of it to verify several times in the past. I live in the space and don't need to do that any more. The wild swing events you describe are not happening.

You have a one-pipe system and I have a two pipe system. From what I understand about one-pipe systems this is dramatically easier to accomplish in 2 pipe. I stay away from commenting on one-pipe stuff because I have no first hand experience. It is no secret that this data is all on a 2 pipe vapor system.

ChrisJ

PMJ said:

@chrisj,

The temperature at the control point stays in the deadband for hours at a time in the cold. I set a recording thermometer on top of it to verify several times in the past. I live in the space and don't need to do that any more. The wild swing events you describe are not happening.

You have a one-pipe system and I have a two pipe system. From what I understand about one-pipe systems this is dramatically easier to accomplish in 2 pipe. I stay away from commenting on one-pipe stuff because I have no first hand experience. It is no secret that this data is all on a 2 pipe vapor system.

Aye.
I feel the size of the system and the size of the building also have a large effect on the performance, perhaps more so than the type of system. Your system has 4 times the mass of mine and I assume so does the building.

My "preheat" times as it's called on the Ecosteam are 90 seconds on a cold night.
That's the time from when the thermostat calls for heat, until the steam hits the end of my long main. Right about that time, or within a few seconds steam will get to all of the radiator inlets as well.

On most days minutes. if not seconds matter on my system. If it runs for a minute longer or shorter than it should it on a typical winter day will cause issues.

Point being, your system may be perfect the way it is, but it may not work right on smaller setups at least not without some tweaking.

PMJ

SteamingatMohawk said:

This feels like a modern way to simulate how the coal fired systems maintained temperature. The main difference is that you vary the heating rate by the on/off cycles vs. relatively steady burning of coal. I believe the vapor function tends to minimize the cooldown of the system by not drawing in room air between firings.

Can it work in a non-vapor system?

Bingo.

Thank you @SteamingatMohawk. That is exactly it.

I can't say I know the answer to your question but my guess is yes.

PMJ

delcrossv said:

@PMJ Can you post a diagram of your control setup?

I will get you something in the next few days.

PMJ

ChrisJ said:

PMJ said:

@chrisj,

The temperature at the control point stays in the deadband for hours at a time in the cold. I set a recording thermometer on top of it to verify several times in the past. I live in the space and don't need to do that any more. The wild swing events you describe are not happening.

You have a one-pipe system and I have a two pipe system. From what I understand about one-pipe systems this is dramatically easier to accomplish in 2 pipe. I stay away from commenting on one-pipe stuff because I have no first hand experience. It is no secret that this data is all on a 2 pipe vapor system.

Aye.
I feel the size of the system and the size of the building also have a large effect on the performance, perhaps more so than the type of system. Your system has 4 times the mass of mine and I assume so does the building.

My "preheat" times as it's called on the Ecosteam are 90 seconds on a cold night.
That's the time from when the thermostat calls for heat, until the steam hits the end of my long main. Right about that time, or within a few seconds steam will get to all of the radiator inlets as well.

On most days minutes. if not seconds matter on my system. If it runs for a minute longer or shorter than it should it on a typical winter day will cause issues.

Point being, your system may be perfect the way it is, but it may not work right on smaller setups at least not without some tweaking.

I think your Ecosteam would be a fine control. But as you know it was not well received here either.

There is nothing perfect about my system. It is an ongoing work in progress.

ChrisJ

PMJ said:

ChrisJ said:

PMJ said:

@chrisj,

The temperature at the control point stays in the deadband for hours at a time in the cold. I set a recording thermometer on top of it to verify several times in the past. I live in the space and don't need to do that any more. The wild swing events you describe are not happening.

You have a one-pipe system and I have a two pipe system. From what I understand about one-pipe systems this is dramatically easier to accomplish in 2 pipe. I stay away from commenting on one-pipe stuff because I have no first hand experience. It is no secret that this data is all on a 2 pipe vapor system.

Aye.
I feel the size of the system and the size of the building also have a large effect on the performance, perhaps more so than the type of system. Your system has 4 times the mass of mine and I assume so does the building.

My "preheat" times as it's called on the Ecosteam are 90 seconds on a cold night.
That's the time from when the thermostat calls for heat, until the steam hits the end of my long main. Right about that time, or within a few seconds steam will get to all of the radiator inlets as well.

On most days minutes. if not seconds matter on my system. If it runs for a minute longer or shorter than it should it on a typical winter day will cause issues.

Point being, your system may be perfect the way it is, but it may not work right on smaller setups at least not without some tweaking.

I think your Ecosteam would be a fine control. But as you know it was not well received here either.

There is nothing perfect about my system. It is an ongoing work in progress.

Yeah.........
Still very not impressed with how that all went over. I'll probably never forget it.