Looking for pics or descriptions of how to plump 2 500 Gal. Propane Tanks together.

[Donl]

Very nice diagram Don, the only thing I might suggest on it is that it looks to me like it would be better if you pulled the heat for the storage tanks off before the heat for the floor... I would think that even though the floor might only pull a small amount of water, it is going to return cooler, and thus cool the water in the line going to the storage tanks... If you pulled the tank water off first, you'd be getting the hottest possible water into the tank, and could use the cooler water in the floor, which has a lower temp requirement anyway...

Gooserider

That's not how it works.

During recovery the pump to to the radiant slab does not run. Therefore only heat from the storage tanks is recovered. Heat stored in the concrete slab is released slowly only into the shop via radiation from concrete to air. Once the slab is heated to max it can keep the shop relativley warm for quite a long time. The storage tanks are just required to heat the house. It would have been better to locate the storage tanks in the house basement, however my wife had something to say about that.

 

[stee6043]

At the risk of getting back on topic, here are a few photos of how I setup my two 500 gallon tanks. They are plumbed in series and my heat loads are plumbed "before" the tanks so they get heat first...

And for those who are really paying attention...yes....the taco pumps in these photos are mounted in the wrong orientation...for placement only!

 

[rkusek]

I would think you could use 1 circ & 1 loop if you added 2 3way valves near the circ to reverse the direction of flow but I have not seen that discussed anywhere. The cost of 2 3way valve is probably about the same as adding a 2nd circ with a loop I suppose. The "switchover" process would probably overly complicate things as well. Those with P/S how is your storage plumbed?

Thus diagram shows the use of a 4-way valve to provide correct flow direction to and from storage.

How much did that 4 way valve cost? I came up empty on a quick search of Google and ebay. Yours must be at least 1" if not 1 1/4" or 1 1/2". Everything I found was small and refridgerant type. Could not find anything that large. It might more cost effective for me to use another circ, a few check valves, and some extra black iron pipe. I could probably use the same "pickup" and "return" in my tank just wire circs so only 1 could run at a time.

Don, does your Loop E & B circs (house primary & woodshop primary) run 24/7? I was wondering where to locate my large expansion tank. This (broken link removed) indicates the primary loop is the proper place for the compression tank, system fill, and air separator. I would proably keep my small expansion tank and air separator above the boiler. I am a little concerned that the flow control valves on the circs (as well as any check valves I may add) would not properly equalize the pressure at the storage tank in all situations especially when that circ is not running. Don, this article also suggests that check valves on both sides of the secondary may be a good idea, I know you were addressing a "ghost flow" problem in another thread.

Does anyone see any problem with location of the fill valve, air separator, or expansion tanks. My initial thought was to fill at boiler only and locate the large expansion tank right at the 1000 gal storage tank. I'm guessing Holohan knows what he is talking about but it seems everyone here that posts their schematic has something different. I need to get my schematic on here for review before I plumb anything I guess.

 

[Gooserider]

Very nice diagram Don, the only thing I might suggest on it is that it looks to me like it would be better if you pulled the heat for the storage tanks off before the heat for the floor... I would think that even though the floor might only pull a small amount of water, it is going to return cooler, and thus cool the water in the line going to the storage tanks... If you pulled the tank water off first, you'd be getting the hottest possible water into the tank, and could use the cooler water in the floor, which has a lower temp requirement anyway...

Gooserider

That's not how it works.

During recovery the pump to to the radiant slab does not run. Therefore only heat from the storage tanks is recovered. Heat stored in the concrete slab is released slowly only into the shop via radiation from concrete to air. Once the slab is heated to max it can keep the shop relativley warm for quite a long time. The storage tanks are just required to heat the house. It would have been better to locate the storage tanks in the house basement, however my wife had something to say about that.

I wasn't thinking so much in terms of the recovery cycle, as I was in terms of charging the tank - I would want to have the tank charged to the highest temps possible, which means I would want the hottest water going to the tank during the charge cycle, and then heat the floor with what comes out of the tank... Right now it looks to me like during charge, the floor gets first shot at the hottest water, which means the tank gets something a little cooler (how much cooler depends on the amount the floor pulls out at a time) However if the floor gets up to temp and shuts off before the boiler burns out, it probably doesn't matter all that much.

--------------

On the subject of plumbing for loops that flow in opposite directions, there was a thread a while back with a lot of debate about how best to do it. It seems the easiest / simplest / least expensive solution that developed was to just have one length of pipe with two pumps in it that face opposite directions, and wired so that only one pump could run at a time... According to Taco tech support, obviously as long as one doesn't use flow checks, the flow resistance of a non-running circ is essentially negligible, so you just run one circ to pump into the tank for charging, and the other to pump out of the tank for discharging... It avoided the relatively high cost of the multi-way valves (in most cases the pump was less), and was a simpler thing to plumb than any of the loops with check valve approaches.

Gooserider

 

[kabbott]

I use a variant of the back to back pumps. The problem is I have a thermosiphen issue not all the time but when it starts it goes on
for a long time. Think hard about how you layout the plumbing if you go this route. I am not sure how I will solve this yet, A single zone valve
that opens when the pumps turn on will do the trick.parallel flow checks facing opposite directions should work as well.

4-way is not an option in my case, I need the flow reversed at my hyd separator as well as the heat ex. coil.

 

[rkusek]

On the subject of plumbing for loops that flow in opposite directions, there was a thread a while back with a lot of debate about how best to do it. It seems the easiest / simplest / least expensive solution that developed was to just have one length of pipe with two pumps in it that face opposite directions, and wired so that only one pump could run at a time... According to Taco tech support, obviously as long as one doesn't use flow checks, the flow resistance of a non-running circ is essentially negligible, so you just run one circ to pump into the tank for charging, and the other to pump out of the tank for discharging... It avoided the relatively high cost of the multi-way valves (in most cases the pump was less), and was a simpler thing to plumb than any of the loops with check valve approaches.

Gooserider

Thanks for the tip, I will search for that link. I was so focused on the pumps with the inline check valves, my mind didn't consider that option. So when boiler is hot the tank will be charging, when the boiler circ is off (ie. boiler less than 140*) and the temp at top of storage is adequate (probably 120* or greater) I could extract from the tank. When both of these are too cool then nothing will run and no reason to care about unwanted ghost flows. The key would be that the house loads would get first crack at the boiler water in the primary loop, then the barn's unit heaters, and finally storage.

I was going to use my 700' of 1.5 underground pex between home and barn as my primary loop but sending the hotest water from the boiler to the house first via pex makes me wonder if that is a good idea in the case of an overheat situation. I would not want to have to replace the underground pex! Plumbing to storage first would alleviate some of this concern, but probably give me cooler water at the water to air HX in the plenum when boiler is running. Question is how much cooler would it be. Unless I misunderstood, Heaterman did not see a problem with the "large" primary loop when we talked about it. Don L's system uses a small primary loop driving 2 more "primarys" but he has 3 locations to deal with. I could add a small primary loop in the barn and have another "primary" in the home similar to Don's but not sure if that is necessary. Anyone have thoughts on this? The basement of the home is located about 15 feet in elevation above the boiler and storage. This shouldn't affect pumping on a pressurized system but I wondered about expansion tank and air separator locations. I just want to do it right the first time.

 

[rkusek]

I use a variant of the back to back pumps. The problem is I have a thermosiphen issue not all the time but when it starts it goes on
for a long time. Think hard about how you layout the plumbing if you go this route. I am not sure how I will solve this yet, A single zone valve
that opens when the pumps turn on will do the trick.parallel flow checks facing opposite directions should work as well.

4-way is not an option in my case, I need the flow reversed at my hyd separator as well as the heat ex. coil.

Haven't looked at a zone valve, does it have a set of contacts that close when the valve is opened. You would want to energize both this valve and the circ simulataneously. Can you explain how the parallel checks would work?

 

[Donl]

I wasn't thinking so much in terms of the recovery cycle, as I was in terms of charging the tank - I would want to have the tank charged to the highest temps possible, which means I would want the hottest water going to the tank during the charge cycle, and then heat the floor with what comes out of the tank... Right now it looks to me like during charge, the floor gets first shot at the hottest water, which means the tank gets something a little cooler (how much cooler depends on the amount the floor pulls out at a time) However if the floor gets up to temp and shuts off before the boiler burns out, it probably doesn't matter all that much.

I felt heating loads should get first priority. But in this case what you say makes good sense because the radiant floor loop does not require much heat. I set the mixing valve for just over 100F on that loop. Therefore that loop could easily make use of the cooler water coming off the storage tanks. I don't think this would be true in the case of a water/air HX in a plenum. It should get the hottest water before storage in my opinion. I will make the changes as you suggest above.

--------------

On the subject of plumbing for loops that flow in opposite directions, there was a thread a while back with a lot of debate about how best to do it. It seems the easiest / simplest / least expensive solution that developed was to just have one length of pipe with two pumps in it that face opposite directions, and wired so that only one pump could run at a time... According to Taco tech support, obviously as long as one doesn't use flow checks, the flow resistance of a non-running circ is essentially negligible, so you just run one circ to pump into the tank for charging, and the other to pump out of the tank for discharging... It avoided the relatively high cost of the multi-way valves (in most cases the pump was less), and was a simpler thing to plumb than any of the loops with check valve approaches.

Gooserider

I think you are correct on this. I did this design prior to the discussion you are referring to. It works well so no need to make any changes. Besides I think Kabbot thinks I have enough pumps already.

 

[Gooserider]

On the subject of plumbing for loops that flow in opposite directions, there was a thread a while back with a lot of debate about how best to do it. It seems the easiest / simplest / least expensive solution that developed was to just have one length of pipe with two pumps in it that face opposite directions, and wired so that only one pump could run at a time... According to Taco tech support, obviously as long as one doesn't use flow checks, the flow resistance of a non-running circ is essentially negligible, so you just run one circ to pump into the tank for charging, and the other to pump out of the tank for discharging... It avoided the relatively high cost of the multi-way valves (in most cases the pump was less), and was a simpler thing to plumb than any of the loops with check valve approaches.

Gooserider

Thanks for the tip, I will search for that link. I was so focused on the pumps with the inline check valves, my mind didn't consider that option. So when boiler is hot the tank will be charging, when the boiler circ is off (ie. boiler less than 140*) and the temp at top of storage is adequate (probably 120* or greater) I could extract from the tank. When both of these are too cool then nothing will run and no reason to care about unwanted ghost flows. The key would be that the house loads would get first crack at the boiler water in the primary loop, then the barn's unit heaters, and finally storage.

I was going to use my 700' of 1.5 underground pex between home and barn as my primary loop but sending the hotest water from the boiler to the house first via pex makes me wonder if that is a good idea in the case of an overheat situation. I would not want to have to replace the underground pex! Plumbing to storage first would alleviate some of this concern, but probably give me cooler water at the water to air HX in the plenum when boiler is running. Question is how much cooler would it be. Unless I misunderstood, Heaterman did not see a problem with the "large" primary loop when we talked about it. Don L's system uses a small primary loop driving 2 more "primarys" but he has 3 locations to deal with. I could add a small primary loop in the barn and have another "primary" in the home similar to Don's but not sure if that is necessary. Anyone have thoughts on this? The basement of the home is located about 15 feet in elevation above the boiler and storage. This shouldn't affect pumping on a pressurized system but I wondered about expansion tank and air separator locations. I just want to do it right the first time.

What I've heard of being done in some cases is to use the storage tank as a sort of giant sized hydraulic separator... Put a pipe at the top and bottom of each end of the tank (once plumbed together, stacked tanks can be considered as one big tank...) and pump hot in the top at one end, using the boiler pump and pull it out at the other with the house loop pump... If the house is pulling as many BTU's as the boiler is making, the water essentially goes straight across the top of the tank w/ minimal mixing. If the house is pulling less, the surplus automatically charges the tank. You could do the same thing with a big tee fitting at the top and bottom, but IMHO flowing through the tank might be better.... Essentially what this does is separate the house and other loads from the boiler - all the loads or the boiler sees is the tank. Aside from possibly taking a little longer to get heat when doing a total cold start, I think this is a really good way to deal with pressurized storage, as the tank gets the hottest water, but simply passes it on to the load when needed. You can then do copper or black iron between the tank and boiler, and pex from the tank outlets on. It also means that the loop from the boiler to storage should be short and low head so that one could use a small pump (I'd look at one of the temp responsive ECM pumps as that would allow ultra simple return protection as well)... Since the house loop then no longer has to deal with pumping through the boiler, (and the storage tank has virtually zero flow resistance) it might also be possible to downsize the house pump (and again look at some sort of speed control on that pump)

What I would do for expansion and air venting is put the main expansion tanks on the hot side boiler - storage loop, along with an air / dirt separator. I would put a second separator and possibly a small expansion tank at the highest point on the house loop. (The house loop could easily be a second PS loop or hydraulic separator setup depending on the nature of the house loads - but that is a totally separate design from the boiler / storage setup - essentially design it assuming you have a hot water supply and return pipe coming from "you care not where" and build around that...)

Gooserider


Gooserider

 

[kabbott]

On the subject of plumbing for loops that flow in opposite directions, there was a thread a while back with a lot of debate about how best to do it. It seems the easiest / simplest / least expensive solution that developed was to just have one length of pipe with two pumps in it that face opposite directions, and wired so that only one pump could run at a time... According to Taco tech support, obviously as long as one doesn't use flow checks, the flow resistance of a non-running circ is essentially negligible, so you just run one circ to pump into the tank for charging, and the other to pump out of the tank for discharging... It avoided the relatively high cost of the multi-way valves (in most cases the pump was less), and was a simpler thing to plumb than any of the loops with check valve approaches.

Gooserider

Thanks for the tip, I will search for that link. I was so focused on the pumps with the inline check valves, my mind didn't consider that option. So when boiler is hot the tank will be charging, when the boiler circ is off (ie. boiler less than 140*) and the temp at top of storage is adequate (probably 120* or greater) I could extract from the tank. When both of these are too cool then nothing will run and no reason to care about unwanted ghost flows. The key would be that the house loads would get first crack at the boiler water in the primary loop, then the barn's unit heaters, and finally storage.

I was going to use my 700' of 1.5 underground pex between home and barn as my primary loop but sending the hotest water from the boiler to the house first via pex makes me wonder if that is a good idea in the case of an overheat situation. I would not want to have to replace the underground pex! Plumbing to storage first would alleviate some of this concern, but probably give me cooler water at the water to air HX in the plenum when boiler is running. Question is how much cooler would it be. Unless I misunderstood, Heaterman did not see a problem with the "large" primary loop when we talked about it. Don L's system uses a small primary loop driving 2 more "primarys" but he has 3 locations to deal with. I could add a small primary loop in the barn and have another "primary" in the home similar to Don's but not sure if that is necessary. Anyone have thoughts on this? The basement of the home is located about 15 feet in elevation above the boiler and storage. This shouldn't affect pumping on a pressurized system but I wondered about expansion tank and air separator locations. I just want to do it right the first time.

What I've heard of being done in some cases is to use the storage tank as a sort of giant sized hydraulic separator... Put a pipe at the top and bottom of each end of the tank (once plumbed together, stacked tanks can be considered as one big tank...) and pump hot in the top at one end, using the boiler pump and pull it out at the other with the house loop pump... If the house is pulling as many BTU's as the boiler is making, the water essentially goes straight across the top of the tank w/ minimal mixing. If the house is pulling less, the surplus automatically charges the tank. You could do the same thing with a big tee fitting at the top and bottom, but IMHO flowing through the tank might be better.... Essentially what this does is separate the house and other loads from the boiler - all the loads or the boiler sees is the tank. Aside from possibly taking a little longer to get heat when doing a total cold start, I think this is a really good way to deal with pressurized storage, as the tank gets the hottest water, but simply passes it on to the load when needed. You can then do copper or black iron between the tank and boiler, and pex from the tank outlets on. It also means that the loop from the boiler to storage should be short and low head so that one could use a small pump (I'd look at one of the temp responsive ECM pumps as that would allow ultra simple return protection as well)... Since the house loop then no longer has to deal with pumping through the boiler, (and the storage tank has virtually zero flow resistance) it might also be possible to downsize the house pump (and again look at some sort of speed control on that pump)

What I would do for expansion and air venting is put the main expansion tanks on the hot side boiler - storage loop, along with an air / dirt separator. I would put a second separator and possibly a small expansion tank at the highest point on the house loop. (The house loop could easily be a second PS loop or hydraulic separator setup depending on the nature of the house loads - but that is a totally separate design from the boiler / storage setup - essentially design it assuming you have a hot water supply and return pipe coming from "you care not where" and build around that...)

Gooserider


Gooserider

That is the "hot" setup in my mind right now, although the "best setup" seems to change month to month with me as I learn new ideas.
Use the tank as the separator and if you have multiple pumps for loads you can use one tap on the tank and a manifold or multiple taps, one
for each pump.

Same on the charge side if you have more than one boiler. For fossil fuel boiler you can tie into the load side manifold so it will not heat the storage.

I'm sold...... now if I could only get a big tank in my basement!

 

[Gooserider]

(much snipped)

I'm sold...... now if I could only get a big tank in my basement!

I agree... Same problem here, it will be tough enough just getting a boiler into the basement, no way I could get any sort of pressurized tanks in... I'm going to have to do non-pressurized storage, which looks like it would be a lot easier, but has a different set of issues to deal with...

Gooserider

 

[rkusek]

Thanks for feedback Goose & Kabbot. I had not read about this option yet. I think I will start a new thread on this.

 

[Medman]

Jim, how is the top fitting with the 90* bend physically accomplished? Copper or black pipe?

 

[DenaliChuck]

My plumbing schematic is based on Bioheat USA's plans. However, instead of their tanks, I have two 500 gallon propane tanks on their sides and next to each other.

I plumbed from the boiler to one end of the top of tank 1 using a 6" long by 3" diameter dip tube. This lays the hottest water gently on the top of the tank. From the other end I installed a 36" long x 3" dip tube that delivers cooler water into the top of one end of tank 2 using a 6" long by 3" diameter dip tube. From the other end of tank 2 I installed a 36" long x 3" dip tube that returns the coolest water to the boiler.

My 1-1/4 inch copper is plumbed into the 3" pipe and there doesn't seem to be much turbulence/mixing as I get stratification of about 25-35 degrees routinely.

 

[chuck172]

I get about a 25-40* stratification with my 500 gallon tank. Is this about the norm?

 

[Grapenut]

Any pipe that needed to be welded in place I used heavy wall or schedule 80. This doesn't include the 1/2" black used for sensors. On upper tank the 2" nipple just goes in and is flush with top of tank and makes a 90 and reduces to 1.5". The bottom nipple is 36" X 2" and goes almost to bottom of tank. I welded a piece of flat stock to the end of this to act as a diffuser so water is pushed to bottom of tank. The way that pipe goes into tank it's at an odd angle, it looked like the incoming water would push up the side of the tank causing mixing. I used a dip tube on the side for easier access for threading and to keep pipe off the floor, but the pipe is inside the sides of the 2 tanks, out of harms way. I add a support frame after tanks were slid into place for extra stability, and to take some of the weight off the legs of the lower tank. After the tanks are insulated the frame will give me a place to attach some sheet rock / fire retardant material. I have had success with a 100G propane tank for the expansion tank for the system.

Rob,

Can you tell me more on the 1/2" black pipes you welded to the side of your tanks for your temperature sensors?

Thanks,
Rob

 

[RobC]

They are just regular 1/2" black pipe tacked on to tank. I used them to slide in digital temp probes. I separated the tanks into quarters and added an extra one close to the top. I used this setup so I could insulate over the top or close off tanks behind wall but still have access to temp sensors with out taking everything apart.

 

[Grapenut]

Rob,

How did that setup work for you? Do you feel you get precise readings without actually having the thermowells inserted into the tanks? Is your data useful for verifying stratification? What brand and model thermometers did you wind up purchasing? Would you do anything different if you were going set them up again?

Rob

 

[RobC]

These are the thermometers that I used. I also use a solar controller on boiler which monitors 3 other temps.
http://www.azeltec.com/images/brochure.pdf
Stratification, yes you can see the temps climb while loading, to the tenth of a degree. It works well for a monitoring tool. The other temps I look at are the return to mixing valve at boiler, post mixing into boiler and system supply (boiler out).
I would not do any extra cutting into tanks than necessary.
The ends of the 1/2" pipe are welded in with a continuous bead for heat transfer and then a couple of spot welds out on the ends. Everything was sprayed with foam.
Any changes. No. Not with the thermometers or the tank set up in general. Been very happy.