charging storage tank

[sootsucka]

I was wondering does anyone charge there storage by supply/return pipe temps. If so, what are your supply/ return temps as your charging and when its done.I just hooked up my 500 gallon tank and I am not sure if I am charging all the way. I was also curious to know if anyone using a flate plate exchanger for dhw. if so what size and do you circulate the water all the time or have some sort of relay. last question, what is the lowest storage temps you can get away with before recharging tank with a flat plate exchanger because i need a new one as mine is too small as i can only get down to about 165 before the water is getting cool

 

[emesine]

Arrrgggghhhh! Too many questions.

Let's just concentrate on the first one. Can you give us some more info on your system? What type of boiler do you have? I take it the storage is pressurized? Can you scribble out a piping diagram so we know how you are filling the tank?

Andrew

 

[sootsucka]

ok Im sorry I have a old non-gasser boiler (energy-mate) . 500 gallon propane tank pressurized. the piping is supply to top left of the tank and return to middle bottom all piping is 1" black iron about 30' boiler to tank and back. the circulator is taco 007

 

[emesine]

It often helps to draw a diagram and take a picture of it to post here. I still don't understand exactly what is going on. I take it the circulator is located right next to the boiler. Is the storage tank in parallel with the load (heat exchangers)? Is it in series? There are a few ways of doing it.

Andrew

 

[leaddog]

I was wondering does anyone charge there storage by supply/return pipe temps. If so, what are your supply/ return temps as your charging and when its done.I just hooked up my 500 gallon tank and I am not sure if I am charging all the way. I was also curious to know if anyone using a flate plate exchanger for dhw. if so what size and do you circulate the water all the time or have some sort of relay. last question, what is the lowest storage temps you can get away with before recharging tank with a flat plate exchanger because i need a new one as mine is too small as i can only get down to about 165 before the water is getting cool

I think it sounds like you are charging the tank and it's not getting to temp?????????? This could be caused by several things. You maybe drawing off heat faster than you are charging, or you are circulating so fast you are mixing and so the whole tank temp is the same thru-out so it has no stratification. This makes it harder to get to the last few degrees as it's efficiency goes down as the higher the temp gets to the stove temp. If you continue to run the pump after you have the tank charged and you aren't putting in heat then that also mixes the water. There are just as many btu's in the tank but a tank with water at say 180*at the top and 120* at the bottom has more USABLE btu's than a tank that is 145* thruout. You probably need some sort of cold water return protection also so that you keep your return water above 140* to protect your boiler from cold water condensation.
A very good way to monitor the tank temps is to use some cheap digital thermometers at the top, middle, and bottom. Search, digital thermometers here and you should find ideas.
As far as using a timer, relay, etc it depends on how much water you need, when, and how fast your hx works. I have my pump to my dhw hx on a timer. I used to run it all the time but that was a waste of elect and it tended to mix the water in the tank. It could be set up with a thermostat also. Most people using a sidearm just have it on the return side going back to the tank and it charges when ever the supply for heat calls for heat. I separated mine as I run it year around so made a separate zone.
hope this helps
leaddog

 

[sootsucka]

sorry can not do pics internet card not very good. I'm just trying to find out what folks are getting when charging by supply/return pipe temps. I am just waiting for temp senders to come. Fairly simple piping. no flo-checks,zone valve's or primary,secondary loops. My system uses two circulators and a couple of ball valve's. I just installed a couple of tees and valve's. I charge the tank from the boiler to top of tank and the return comes from bottom of tank back to return on boiler. When the boiler burns out I just shut a valve, un-plug circulator, and then it draws from the top of tank to the heat exchangers and back to the bottom of tank. pretty simple

 

[sootsucka]

thanks that helps alittle bit Im just wondering when charging do supply/return temp need to be even for the tank to be charged. so say i have 195 feeding tank and 190 return does that mean tank is bewteen 190 to 195 or could half the tank still need to be charged

 

[emesine]

That helps a lot on your description of your system. If you have 195F water going into the top of the tank, and there is 190F water coming out of the bottom, that sounds fully charged to me. Any cold water in the tank is going to sink to the bottom, so you would see it coming out of the bottom as cooler water coming out of the bottom pipe. You could have a lot of fun automating that system. There is a great article at the top of the boiler page on "simpliest pressurized storage design." No, I don't understand it I have unpressurized storage so I have concentrated on mastering that.

Andrew

 

[ManiacPD]

What you state is correct, the feed to the tank (top) should always be hotter than the return (bottom). Once they start to equalize your tank is "charged". How are you taking these temp measurements now? I have thermometers on my supply and return lines which work well but can be deceiving once the circulator stops. Just because the supply pipe is 190F about 3" above the tank does not mean the tank is 190F, it is usually 10-15 degrees warmer (again, circulator is not running).

 

[in hot water]

you could be short cycling through the tank. Do the S&R connections on the tank allow for mixing of the entire tank? It may need a diffuser tube.

Do you have a return protection device, or valve on the boiler. You don't want to run them for long periods with below 140F return temperatures.

hr

 

[sootsucka]

I am temporary unemployed at the moment so the whole system is piece together right now.I take temp reading right now with a IR thermometer as I am waiting for my real sensors to come in the mail. I cant be getting wrong temps because the circulator only stops when i unplug it.I am however taking temps about 15 feet from tank.I know a little getto right now but limited money at the moment I am a hvac technician by trade so when I return to work I will automate everything for now it works. As for as cold water return protection would that stop creosote from forming on the boilers inside walls. I just wire wheeled them 2 weeks ago and a little is forming again.Again this is probably at least a 40 year old boiler (free) I have at the moment

 

[cheapsx]

I have a couple questions:
1- I have acquired one of these boilers for free also that I am setting up with 500 gallons of storage. How long does it take to heat that water with your boiler?
2- I plan on setting up automated system and will put a mixing valve on the return to keep the return temp up to decrease creosote hopefully, but I haven't built the storage tank yet. Do I need to have the water coming in on top sideways, or with a diffuser of sort or does it not matter? If you keep the top inlet to the opposite end of the tank of the bottom outlet can you just run the boiler till you see the bottom temps get close to the top inlet temps? Then does stratification happen after everything shuts off and sits idle for a while?
3- I am going to put temp wells in the tank, is one top and bottom enough or do I need them on the inlet and outlet pipes as well?

I am new to this whole boiler/storage thing and I don't want to have to add to many thing later, I would like to get it correct the first time I hope.

 

[sootsucka]

#1 It usually takes about 4 hours to go from 150 to 200 on tank return to boiler pipe#2 the return temp protection I am waiting on a answer myself, the diffuser is also a good question#3 from what I read so for the wells would be the most accurate

 

[Singed Eyebrows]

This is not a gassification boiler like you said & you aren't going to have the corrosion worries of one. The walls are exposed to radiation from the coal bed & the smoke does not stay in this boiler long. I owned one of these for about 12 years, the original was made in Tomah,Wisconsin. This is a 50 percent efficient boiler as stated by manufacturer. Watch the creosote when idling this one, you are doing the right thing with a tank. I only charge to about 170 on the top of my tank, it is 720 gallons though. Good luck, Randy