Ultra simple storage system
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Seems you will have to get the whole 500G upto temp before you can heat the house. I do it the other way, heat goes to house first - leftover heat goes to the tank. Maybe a little too simple? I don't think you will be happy waiting for a cooled tank to get upto 180 degress before you can start heating the house...I know your wife won't...
Nofossil
Moderator Emeritus
This is schematically equivalent to 'simplest pressurized storage' sticky with the exception that your top and bottom connections to storage are separated by a small distance rather than being connected at a tee. Not a significant difference - the basic hydrodynamics are almost identical.
As long as flow into and out of the tank isn't too turbulent, you'd only have to heat the top few inches before getting hot water to the house. With this approach, there's virtually no chance of ghost flow, though you still need check valves in all circulators to prevent thermosiphoning.
As long as flow into and out of the tank isn't too turbulent, you'd only have to heat the top few inches before getting hot water to the house. With this approach, there's virtually no chance of ghost flow, though you still need check valves in all circulators to prevent thermosiphoning.
Hummm.. I think I am seeing problems with the two circ returning to the boiler. I think one circ with the mixing valve would be a better option. I know you are saying that only one will be running at a time with associated temps but why not run one pump constant and throttle or "mix" the return. You don't see two water pumps on a car.
I was thinking about this a couple threads ago. Do you guys think it would be possible to machine up a inline standard thermostat housing made with NPT or sweat and use a automotive thermostat? You can get them in alot of different temp settings. I think it would be simple reliable and cheap.
I was thinking about this a couple threads ago. Do you guys think it would be possible to machine up a inline standard thermostat housing made with NPT or sweat and use a automotive thermostat? You can get them in alot of different temp settings. I think it would be simple reliable and cheap.
The two circ. method is the way the Econoburn's PLC prevents return temps. below 150. The only concern I have with this is that once the primary is circulating, it will continue to until the control sees that the boiler is below 150. You could be getting a slug of 100 degree water for quite some time. One way to prevent this though is if the control is reading return temps. just outside the boiler before that tee....
With the European thermostatic valve method the valve begins to throttle flow down as soon as it sees temps. below 140. This prevents the boiler steel from ever seeing the thermal shock. The downside to this is the headloss through the valve. Anyone know what it is for say a Danfoss at full open?
With the European thermostatic valve method the valve begins to throttle flow down as soon as it sees temps. below 140. This prevents the boiler steel from ever seeing the thermal shock. The downside to this is the headloss through the valve. Anyone know what it is for say a Danfoss at full open?
sgschwend
New Member
You have a redundant circulating pump, it would be less complex (and take less energy) to substitute a mixing valve.
You can also eliminate the lower check valve by purchasing the pump that includes the check valve.
You can also eliminate the lower check valve by purchasing the pump that includes the check valve.
sdrobertson
Minister of Fire
Garnification said:
I've thought of this myself...I think it would work well, the only issue that I see is how to figure out the head loss going through the auto thermostat and then figuring out your flow rate.
Nofossil
Moderator Emeritus
There are many ways to solve the return protection problem. Some manufacturers (like Econoburn) provide a solution, while others leave it to the installer.
I like the circulator especially if you use a variable speed circ - that would be quite elegant. With a fixed speed circ, I suspect you'd have to throttle it or use a circ that's a good deal smaller than the main boiler circ. In any event, a fixed speed circ is pretty much equivalent to a bypass zone valve (which is what I use) and it's limited in that it provides a fixed ratio of recirculated water. A circ will use a good deal more power than a zone valve, but it doesn't run all that much.
Mixing valves are a more elegant solution, but many of them present a significant flow restriction. They are usually a lot more expensive than a circulator or zone valves. They also have a limited number of different output temperatures, and most aren't easy to change. Still, a good system solution.
In my never-so-humble opinion, the ideal solution is a mixing valve or a variable speed bypass circulator that provides a minimum inlet temp of about 140 degrees, coupled with a variable speed boiler circ that adjusts flow through the boiler to achieve your desired outlet temp (which of course you would vary depending on the needs of the heat loads). Finally, the primary and secondary air flow rates would be managed to accomplish peak efficiency at all phases of the burn.
I like the circulator especially if you use a variable speed circ - that would be quite elegant. With a fixed speed circ, I suspect you'd have to throttle it or use a circ that's a good deal smaller than the main boiler circ. In any event, a fixed speed circ is pretty much equivalent to a bypass zone valve (which is what I use) and it's limited in that it provides a fixed ratio of recirculated water. A circ will use a good deal more power than a zone valve, but it doesn't run all that much.
Mixing valves are a more elegant solution, but many of them present a significant flow restriction. They are usually a lot more expensive than a circulator or zone valves. They also have a limited number of different output temperatures, and most aren't easy to change. Still, a good system solution.
In my never-so-humble opinion, the ideal solution is a mixing valve or a variable speed bypass circulator that provides a minimum inlet temp of about 140 degrees, coupled with a variable speed boiler circ that adjusts flow through the boiler to achieve your desired outlet temp (which of course you would vary depending on the needs of the heat loads). Finally, the primary and secondary air flow rates would be managed to accomplish peak efficiency at all phases of the burn.
here is a new design that uses a mixing valve to moderate the water temp entering the stove. I have a ebw200 econoburn so that is the stove I am trying to install. Econoburn wants to use a near boiler loop but that won't do any good once the water temp reaches 150 and the primary turns on . it will just ingest cold water causing the aquastat to turn the circ loop back on. I figure my system this way. The propane tank is my storage but also my manifold, the stove when fired heats the water in the tank, once the tank is loaded then the stove can be shut down. now when my load asks for heat the load pump will turn on and send water the my water to air heat excahngers and then the hot exchangers will kick their fans on. Now I realize that there might be a day that the house is cold and needs heat but the tank is cold so i included and manual bypass that would allow the stove to be fired and the hot water directly sent to the load and then the leftover would start to recharge my tank, this would also require a manual electiral bypass that would have to be swithced allowing both pumps in the system the run together, but only when the tank bypass has been turned on. Then once everything is heated up I can switch my pumps back to being controled by their aqustats and turn the bypass off and use the system normally. My main goal with this system is that I will only have to fire my stove when my storage becomes cool and when i do fire it I will be able to let it gasify until the fire burns out and then shut it off and prevent and idleing that will cause build up int he unit , I belive this setup will allow me to burn as little wood as possible . I left all the known needed items like exp tanks and suck out of this diagram.
Please let me know what you think, i am 2 weeks from hooking it up and I want to make sure i am not making any mistakes/
Econo burn wants a near boiler loop and a mixing valve .WHY? the loop makes no sense if you going to mix the incoming water anyway
Please let me know what you think, i am 2 weeks from hooking it up and I want to make sure i am not making any mistakes/
Econo burn wants a near boiler loop and a mixing valve .WHY? the loop makes no sense if you going to mix the incoming water anyway
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bowsky, I think they want the boiler loop to get all of the boiler preheated and heated up as fast as possible before it can except colder water form storage. In my opinion these boilers operate just like an automotive engine. When you start your car, coolant is circulated throughout the engine but not through the radiator. once the engine coolant reaches a set temp, thermostat, the thermostat opens up and allows coolant to flow through the radiator. The thermostat regulates the amount of coolant going to the radiator and maintains the engine at a controlled temperature.
I think this is the same principle as the downdraft boilers. Boiler is the engine and the radiator is the storage/load. That way the boiler is up to optimum constant operating temp. just like an engine. No thermo shock, no steam, just steady temp.
I think this is the same principle as the downdraft boilers. Boiler is the engine and the radiator is the storage/load. That way the boiler is up to optimum constant operating temp. just like an engine. No thermo shock, no steam, just steady temp.
Garnie, I would agree it's similar in concept to an engine coolant system.
If you have a 200K BTU boiler 1000 gallons of storage would probably be more useful for you, depending upon your heating load. Something to consider.
If you have a 200K BTU boiler 1000 gallons of storage would probably be more useful for you, depending upon your heating load. Something to consider.
The Econoburn's control structure was designed around simplicity. It will accomplish the desired goal for 90% of the applications in the field... most of which do not utilize thermal storage. Keeping the controls simple and effective allows for lower cost installations.
When it comes to pressurized thermal storage, personally, I love the first drawing. I believe there is a thread floating around here about piping pressurized thermal storage as a hyrdaulic seperator, which in essence is what that is. Like no-fossil said, after the first couple of inches at the top of the tank are hot, any time the load calls for heat, hot water is transferred right across the top of the tank and into the load, while any excess heat is transferred directly into the storage.
The return protection in the second drawing is definitely a good idea. The controls on the Econoburn, as they are set up from the factory, are not intended to operate a system with thermal storage. The thermocouple that measures water temperature and switches between the near boiler circ and the primary circ is about as far away from the return line as it can be. If your tanks were very cold, you would be getting a tremendous cold shot at the return for some time before the water at the very top of the boiler registered the change in temperature. This would produce a generous amount of condensate in the heat exchanger, and put a little more stress in the boiler plate and refractory than you would want.
My own system does not use a mixing valve to temper the return water. My near boiler circulator is piped on a simple bypass between the supply and return, and the thermocouple has a new home on the return line at the back of the boiler. The near boiler circ and the primary circ will cycle back and forth between each other using only the controls on the boiler. Each complete cycle runs about 12 seconds with 70 degree water in the tanks returning to the boiler, and the black iron return line cycles up and down about 12 to 15 degrees from 155 to 140... hardly cause for thermal shock. As the return water rises, the cycle time on the pumps increases, and the temperature differential on the return line decreases. The top of the boiler stays pegged at 165* for the entire burn, until of course the tanks approach 165. This method has a few drawbacks... 1) it will use a little more electricity as you pull more amperage with each on/off cycle of the pumps. (Taco assures me that cycling their pumps like this will not harm them in any way.) 2) It may have a negative effect on warranty claims down the road if you've messed with the thermocouple on your boiler. It does have some benefits though, including not having to mess with cantankerous mixing valves, and being very inexpensive while also being very effective.
Eventually, I may want to wire the near boiler bypass circ to run constantly, and use a variable speed pump as the primary pump to maintain 140 or 150 degree return temps... but that won't even be a consideration until after the existing primary pump fails.
cheers
When it comes to pressurized thermal storage, personally, I love the first drawing. I believe there is a thread floating around here about piping pressurized thermal storage as a hyrdaulic seperator, which in essence is what that is. Like no-fossil said, after the first couple of inches at the top of the tank are hot, any time the load calls for heat, hot water is transferred right across the top of the tank and into the load, while any excess heat is transferred directly into the storage.
The return protection in the second drawing is definitely a good idea. The controls on the Econoburn, as they are set up from the factory, are not intended to operate a system with thermal storage. The thermocouple that measures water temperature and switches between the near boiler circ and the primary circ is about as far away from the return line as it can be. If your tanks were very cold, you would be getting a tremendous cold shot at the return for some time before the water at the very top of the boiler registered the change in temperature. This would produce a generous amount of condensate in the heat exchanger, and put a little more stress in the boiler plate and refractory than you would want.
My own system does not use a mixing valve to temper the return water. My near boiler circulator is piped on a simple bypass between the supply and return, and the thermocouple has a new home on the return line at the back of the boiler. The near boiler circ and the primary circ will cycle back and forth between each other using only the controls on the boiler. Each complete cycle runs about 12 seconds with 70 degree water in the tanks returning to the boiler, and the black iron return line cycles up and down about 12 to 15 degrees from 155 to 140... hardly cause for thermal shock. As the return water rises, the cycle time on the pumps increases, and the temperature differential on the return line decreases. The top of the boiler stays pegged at 165* for the entire burn, until of course the tanks approach 165. This method has a few drawbacks... 1) it will use a little more electricity as you pull more amperage with each on/off cycle of the pumps. (Taco assures me that cycling their pumps like this will not harm them in any way.) 2) It may have a negative effect on warranty claims down the road if you've messed with the thermocouple on your boiler. It does have some benefits though, including not having to mess with cantankerous mixing valves, and being very inexpensive while also being very effective.
Eventually, I may want to wire the near boiler bypass circ to run constantly, and use a variable speed pump as the primary pump to maintain 140 or 150 degree return temps... but that won't even be a consideration until after the existing primary pump fails.
cheers
Piker, thats why I'm thinking someone should design a in-line thermostat with housing. It would kill two birds with one stone. I think it would be inexpensive and reliable.
I think the laddomat valve uses small thermostats in that pump block.http://www.newhorizoncorp.com/PDF/Laddomat 21 Manual.pdf
I kinda wish I had a dd setup with storage to try this idea.
I think the laddomat valve uses small thermostats in that pump block.http://www.newhorizoncorp.com/PDF/Laddomat 21 Manual.pdf
I kinda wish I had a dd setup with storage to try this idea.
I like the first drawing also.
to quote nofossil and piker:
"after the first couple of inches at the top of the tank are hot, any time the load calls for heat, hot water is transferred right across the top of the tank and into the load, while any excess heat is transferred directly into the storage."
Diverting excess heat to storage isn't easily achieved. This system does it for nothing and automatically.
Bioheats plan requires a 200.00 tarmovar valve to do this.
There have been other threads about heating storage first. In Sweeden and other countries this is the norm.
to quote nofossil and piker:
"after the first couple of inches at the top of the tank are hot, any time the load calls for heat, hot water is transferred right across the top of the tank and into the load, while any excess heat is transferred directly into the storage."
Diverting excess heat to storage isn't easily achieved. This system does it for nothing and automatically.
Bioheats plan requires a 200.00 tarmovar valve to do this.
There have been other threads about heating storage first. In Sweeden and other countries this is the norm.
Nofossil
Moderator Emeritus
This is an elegant solution, but all of the caveats that apply to the 'Simplest Pressurized Storage' sticky apply here as well. Automatic diversion to storage is a beautiful thing, but to work well you have to do two things at least reasonably well:
1) Match the flow rate through the boiler to the boiler's output. Too high a flow rate will result in a low output temperature, thereby causing thermal mixing in your storage and a low temp at the top of storage. Too low a flow rate and the load circulator will draw a mixture of hot water from the boiler and cooler water from storage.
2) Match the flow rate through the loads to the total heat demand of the loads. Same issues as above.
Ideally, the flow though the boiler is equal to or greater than the flow through the loads. For instance, a boiler putting out 120,000 BTU/hr with a 20 degree rise would flow 12gpm. If the heat load demand were half of that, then the flow through the loads should be 6gpm.
In this case, this approach will divert precisely the right amount of excess heat (60,000 BTU/hr) into storage.
This is an example of a system where the physical components are simple. The complexity is in the design - invisible to the casual observer.
The good thing is that this will still work pretty well even if it isn't balanced.
1) Match the flow rate through the boiler to the boiler's output. Too high a flow rate will result in a low output temperature, thereby causing thermal mixing in your storage and a low temp at the top of storage. Too low a flow rate and the load circulator will draw a mixture of hot water from the boiler and cooler water from storage.
2) Match the flow rate through the loads to the total heat demand of the loads. Same issues as above.
Ideally, the flow though the boiler is equal to or greater than the flow through the loads. For instance, a boiler putting out 120,000 BTU/hr with a 20 degree rise would flow 12gpm. If the heat load demand were half of that, then the flow through the loads should be 6gpm.
In this case, this approach will divert precisely the right amount of excess heat (60,000 BTU/hr) into storage.
This is an example of a system where the physical components are simple. The complexity is in the design - invisible to the casual observer.
The good thing is that this will still work pretty well even if it isn't balanced.
I think that is the key to the simplicity of it.
I don't know that it necessarily needs to be greater GPM as much as BTU/hr if you are running low temps loads and are mixing down supply water with return water to get the load GPMs. Once again, the lower temperature loads like radiant make it easier to run a system more simply.
Either way, the boiler output still needs to be at least equal to that max load or keep those goose down pajamas close at hand. I don't think a directly-coupled boiler/storage tank can be taken for granted to answer all the problems in every system as some (myself included, at first) might hope As you say the simplicity of the thing can be deceiving and the numbers still have to work in any design.
The manual bypass on the supply and return lines around the tank for the occasional blue norther is a pretty easy backup plan if you miss your calculations and it doesn't stratify as well as you hoped. Probably should be part of every pressurized storage scheme in case your tank sprung a bad leak on one of the cold spells. And nobody would put in a pressurized tank without isolation valves, would they.
DaveBP said:
Btu and GPM are kind of inseperable really. The worst case scenario on my "simplest" setup is that while the primary pump is off for a few seconds, the load circulator will be drawing hot water back from the tank immediately after it has been placed there... not really an issue. This will probably only happen at the beginning and end of a burn cycle when the Btu ouput of the boiler may be less than the load from all 6 zones. Even at that, with a boiler of 200,000 Btu of rated output and a load of no more than 120,000 absolute worst case scenario... I'll be covered.
One cool thing about the simplest method, at least for my purposes, is that while the primary pump is on and the load circulator is running, not only do excess btus get sent to the tanks, but btu's not used by the zones go right back into the boiler, tempering the return water a little. On my system, this smooths out the cycling between the near boiler loop and the primary loop by the boiler control. The only difference between the way I piped my boiler and the "simplest" diagram is that my return lines from the manifold enter the primary return line between the tanks and the boiler instead of the far side of the tanks away from the boiler.
cheers
O-k guys, I am totally new to this. I have been heating my house (3800') with a Volcano add on wood furnace for the past 27 years. Some years not so much, some years nearly strictly with wood. I had a water jacket that I ran in the chamber to pre heat my water for the DHW. My wife has a heart problem and the smoke was bothering her and I hated keeping wood in the house.
I just purchased a used CB Classic and am installing it basically as we speak. I will be using the DHW exchanger as well as the forced air exchanger and she just saw the hydronic heaters and wants one in the bath.
My question for this thread is this: Why add more water storage? Isn't the 180 gallons enough? Will this increase efficiency or reduce burn time? What are the benefits? I have space to add a several hundred gallon tank, but I don't really know why.
If this is a stupid question, I'm sorry.
JB
I just purchased a used CB Classic and am installing it basically as we speak. I will be using the DHW exchanger as well as the forced air exchanger and she just saw the hydronic heaters and wants one in the bath.
My question for this thread is this: Why add more water storage? Isn't the 180 gallons enough? Will this increase efficiency or reduce burn time? What are the benefits? I have space to add a several hundred gallon tank, but I don't really know why.
If this is a stupid question, I'm sorry.
JB
The reason I am installing storage is mainly for the fall and spring months - my hope is that i will fire my stove once a day for maybe 4-6 hours and heat up my storage , then when my house needs heat it will draw heat from my storage. The point is that you don't have to run a constant fire- thus you burn less wood .
This is really important with the new gasifier stoves like my econoburn . These stoves do not like to idle -they want to be ran at wide open or shut off.
ALSO ___ ATTENTION ANYONE WHO WANTS TO USE A PROPANE TANK FOR STORAGE_______
I just got my 500 gallon tank the other day and WOW did it stink. THe smell is from the adative in the propane that is a oily substance that sticks inside the tank.
My solution to this problem was to first add 3 gallons of degreaser to 30 gallons of water and roll the tank around , this removed alot of the oil and made me confident there was no propane left in the tank then step two was I used my tractor to hoist the tank onto cement blocks around my fire pit. I then started a large fire under the tank and filled it with water- Once I had 400 gallons of water boiling in the tank i added 10 large bottles of ajax liquid dish soap to the boiling water . The boiling water stripped the oil from the tank and then the soap traps the oil to prevent it from sticking back to the tank. Oncce I had this mix boiling for 1 hour I poped the drain -VERY CAREFULLY
- and let out all the water - My tank is now very clean and smells like lemons!! 
.
So anyone who is going to use a tank like this I recomend this procedure to reduce the smell involved and it also makes sure your tank is clean.
JUST MAKE SURE THERE IS NO PROPANE LEFT IN THE TANK!! :bug:
This is really important with the new gasifier stoves like my econoburn . These stoves do not like to idle -they want to be ran at wide open or shut off.
ALSO ___ ATTENTION ANYONE WHO WANTS TO USE A PROPANE TANK FOR STORAGE_______
I just got my 500 gallon tank the other day and WOW did it stink. THe smell is from the adative in the propane that is a oily substance that sticks inside the tank.
My solution to this problem was to first add 3 gallons of degreaser to 30 gallons of water and roll the tank around , this removed alot of the oil and made me confident there was no propane left in the tank then step two was I used my tractor to hoist the tank onto cement blocks around my fire pit. I then started a large fire under the tank and filled it with water- Once I had 400 gallons of water boiling in the tank i added 10 large bottles of ajax liquid dish soap to the boiling water . The boiling water stripped the oil from the tank and then the soap traps the oil to prevent it from sticking back to the tank. Oncce I had this mix boiling for 1 hour I poped the drain -VERY CAREFULLY
- and let out all the water - My tank is now very clean and smells like lemons!! .So anyone who is going to use a tank like this I recomend this procedure to reduce the smell involved and it also makes sure your tank is clean.
JUST MAKE SURE THERE IS NO PROPANE LEFT IN THE TANK!! :bug:
Medman
Feeling the Heat
Bugzapper, extra storage is not really necessary for your conventional boiler. It also isn't necessary for many of us who own gasification boilers, like the EKO, Econoburn, Tarm, Wood Gun, etc. Storage for us is more a matter of convenience and a modest increase in efficiency. Since your boiler already has storage built in you have the convenience factor.
In the case of gasification boilers storage allows me to decide when to build a fire, since my boiler does not fire continuously except on the coldest days. Your CB will most likely be fired continuously, so timing isn't as much of a factor.
There is a lot of info here on both systems, so look around and do some reading, and don't be afraid to ask questions - we were all in your shoes, once! This really is the best place to find the information you need.
Welcome to the forum!
In the case of gasification boilers storage allows me to decide when to build a fire, since my boiler does not fire continuously except on the coldest days. Your CB will most likely be fired continuously, so timing isn't as much of a factor.
There is a lot of info here on both systems, so look around and do some reading, and don't be afraid to ask questions - we were all in your shoes, once! This really is the best place to find the information you need.
Welcome to the forum!
This is a thorough and fun way to clean out a propane tank but please anyone else tempted to try this: FILL IT WITH WATER BEFORE YOU LIGHT THE FIRE. The only way to make sure you have removed enough propane to prevent an explosion in a tank that is new to you is to fill it completely with water. If you know for certain this has been done then you're safe but don't assume it has been done.
But jeez, it does sound like fun.
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