Is this enough storage?????

[bulldogbones]

If this has been covered in another thread just paste the link in.

My questions is, will 250-300 gallons for a storage tank do anything. Is it really large enough to make a difference. My problem is the largest tank that I could fit into my basement was a 38"x41" plus the hemispheres on each end. Should I shop around for another one? or make due. Also I read somewhere that standing propane tanks on end was better, why is that and what will I lose if I lay it down?

 

[Singed Eyebrows]

If this has been covered in another thread just paste the link in.

My questions is, will 250-300 gallons for a storage tank do anything. Is it really large enough to make a difference. My problem is the largest tank that I could fit into my basement was a 38"x41" plus the hemispheres on each end. Should I shop around for another one? or make due. Also I read somewhere that standing propane tanks on end was better, why is that and what will I lose if I lay it down?

Yes, 250 gallons of water will hold a worthwhile amount of heat. Can you get three of these? Stand them on end if possible & you got it. You want the hot water to layer(stratify) so you don't need to heat the entire tank to start getting hot water. Your hot water "output" from the boiler goes to the "top" of the storage tank/tanks. If you lay them down it won't stratify as well, many members do use them this way though. An upright tank will resist mixing better. You don't have a gasser so you shouldn't need return water temp protection. Randy

 

[ewdudley]

If this has been covered in another thread just paste the link in.

My questions is, will 250-300 gallons for a storage tank do anything. Is it really large enough to make a difference. My problem is the largest tank that I could fit into my basement was a 38"x41" plus the hemispheres on each end. Should I shop around for another one? or make due. Also I read somewhere that standing propane tanks on end was better, why is that and what will I lose if I lay it down?

If you're able to control return temperature to the boiler so that you can let the storage tank go lower than 140 degF or so, then stratification is more important, and standing on end has somewhat of an advantage. But it's no big deal for hot water. More important would be to avoid jets of water inside the tank that would cause mixing, especially vertical jets.

But your tank sounds like it's not particularly skinny, so horizontal or vertical not so much difference.

If you can't control return temperature to the boiler then you're probably going to want to keep the storage tank over 140, in which case maintaining stratification might not be so important because as long as the water is above 140 it should be reasonably useful for heating assuming your radiators will work with lower temperature water.

Even if your tank can't store 15 or 20 hours worth of heat, it can be used as a buffer to insure that when your boiler lights-up is will keep burning for an hour or so, which is certainly a good thing.

--ewd

 

[Piker]

Stratification of the water in a thermal storage tank is ALWAYS beneficial as it provides the greatest number of USABLE btu's before your supply temperature drops below what your emitters need to maintain a comfortable living space. Many of us use horizontal tanks where stratification is difficult to achieve, and still have good results... those with vertical tanks, experience longer cycle times and excellent results.

cheers

 

[ewdudley]

Stratification of the water in a thermal storage tank is ALWAYS beneficial as it provides the greatest number of USABLE btu's before your supply temperature drops below what your emitters need to maintain a comfortable living space. Many of us use horizontal tanks where stratification is difficult to achieve, and still have good results... those with vertical tanks, experience longer cycle times and excellent results.

cheers

Right, I neglected to keep in mind that on the internet categorical statements ALWAYS prevail over reasoned arguments as long as they are CAPITALIZED! ;->

Cheers --ewd

 

[Piker]

Stratification of the water in a thermal storage tank is ALWAYS beneficial as it provides the greatest number of USABLE btu's before your supply temperature drops below what your emitters need to maintain a comfortable living space. Many of us use horizontal tanks where stratification is difficult to achieve, and still have good results... those with vertical tanks, experience longer cycle times and excellent results.

cheers

Right, I neglected to keep in mind that on the internet categorical statements ALWAYS prevail over reasoned arguments as long as they are CAPITALIZED! ;->

Cheers --ewd

lets say 140° is the cutoff for your emitters, and that at that temperature they produce a 20° delta t at 10 gpms's

Imagine a scenario where no stratification exists, and the water is perfectly mixed... once the thermal storage tank hits 140 - your done... the next gallon of water to return to the tank at 120 drops the temperature of the entire tank to below 140 and the heat load can no longer be maintained.

Now imagine this scenario where the 120° return water coming back to the tank from the emitters is perfectly stratified apart from the 140°... you would still have an additional 20*8.35*(300 gal.)= 50,000 usable btu's left to maintain the heat load before the supply water from the tank dropped to 120° and the emitters could no longer meet demand.


I understand that trying to achieve absolute perfection in these systems is not very practical... Lots of factors like budget, space, time, etc. dictate whether or not trying to glean every last btu from a system is worth it, or whether it's "no big deal," and ultimately compromises must me made at some level. That having been said... stratification in a thermal storage system truly is beneficial to some degree - ALWAYS. Your comments above regarding return temps are reasonable, and perhaps by capitalizing "always" it appeared that my intention was to disagree just for the sake of disagreement... not so... just pointing out the benefits of stratification with respect to usable btus.

You also have to keep in mind that on the internet, intent and emotion are often misconstrued.

A 250 or 300 gallon buffer properly piped and insulated is a great feature for a wood boiler.

cheers

 

[DaveBP]

Bones, if you are trying to get this all set up for this coming heating season, I understand how you might feel under pressure to get going as soon as possible. But I suggest you sit down and use the search function to read through at least a few dozen (of probably hundreds) of the past posts on this very subject.

How your system is piped will determine what kind of fittings on the tank you will want (or how you will use the fittings that are currently on the tank). There are more than a few different ways to do it, but I assume you are going with pressurized storage. If you are just adding a boiler and storage tank to an existing hydronic system you might have some of your decisions narrowed down.

The slower your hot water from the boiler enters the tank, the less stirred up with cooler water it will be and that improves stratification. If 250 gallons is what you can get down there, then use it. I don't know what fittings are on the tank but try to plumb to it with capped-off tees or something so when you get the whole show going and you think you want more storage it will be easier to add it on.

Nothing magic about stratification. Capitalized or not it makes it easier to use whatever heat you have stored in the tank. Why this is so is kind of like driving a stick shift. It seems terrifying at first but suddenly you just get it. Take it on faith until then.

And search out "stratification" and "propane tanks" and "storage" and terms like that.

 

[bulldogbones]

Bones, if you are trying to get this all set up for this coming heating season, I understand how you might feel under pressure to get going as soon as possible. But I suggest you sit down and use the search function to read through at least a few dozen (of probably hundreds) of the past posts on this very subject.

How your system is piped will determine what kind of fittings on the tank you will want (or how you will use the fittings that are currently on the tank). There are more than a few different ways to do it, but I assume you are going with pressurized storage. If you are just adding a boiler and storage tank to an existing hydronic system you might have some of your decisions narrowed down.

The slower your hot water from the boiler enters the tank, the less stirred up with cooler water it will be and that improves stratification. If 250 gallons is what you can get down there, then use it. I don't know what fittings are on the tank but try to plumb to it with capped-off tees or something so when you get the whole show going and you think you want more storage it will be easier to add it on.

Nothing magic about stratification. Capitalized or not it makes it easier to use whatever heat you have stored in the tank. Why this is so is kind of like driving a stick shift. It seems terrifying at first but suddenly you just get it. Take it on faith until then.

And search out "stratification" and "propane tanks" and "storage" and terms like that.

Getting the system up and running before it gets cold would be nice but not completely neccisarry, as I have forced air/oil as a back up. I like your idea of adding T's and capping them before filling everything up with water.

I have done and still do search the forum reading threads that pertian to my situation and ones that peak my interest. But I hadnt found a thread pertaining to such a small storage unit.

From what I have read and what you guys have been saying about stratifying the water it sounds like my tank is already setup for that and I need to take back my statement about my tank being Propane. The reason I say that is one of the holes in the tank has a pipe that goes almost to the bottom of the tank. So I would make that my ( used/cold ) return and I would draw my ( fresh/hot ) water from that hole.

So now I will have to search and find out what speed I should be using as to not creat anti stratification.