vertical storage

[huffdawg]

Just purchased two used 500 gal propane tanks for $250

Whats the best way to pipe two vertical 500 gal. propane tanks to primary loop . A manifold top and bottom or some sort of series setup.

Huff

 

[Donl]

Huff, two 500 gallon tanks will be great for your EKO 40. Twice as good as my 500 gallon tank, which works well for me.

 

[woodsmaster]

I plumbed mine parallel and am happy with the way it works. I've never had any thing else to compare it with so I can't say it works better than in series. If you go parallel be sure to have the exact length of pipe elbows etc.
to each tank so they charge and discharge evenly. I have to throttle one tank back a little on mine to make them flow even because It didn't get each side even, but it still works fine. I plumbed mine so that I can use only one tank if need be because of repair or something.

 

[in hot water]

Here is a concept that is common with solar thermal, multi tank loading. i've seen this done with up to 6 individual tanks.

The goal is to keep the collectors, or boiler in your case, at it's most efficient operating condition. That being with the coolest return temperature operation. 130F and above of course for wood boilers, solar doesn't have return temperature issues.

It involves a 3 way zone valve with a delta t (solar) controller. The tank with the lowest temperature is supplied first. It is heated until it is 10F above the other tank. then loading will be done alternately.

Furthermore the pump used to load these could be modulated with a variable speed function. The pump would not start loading until the boiler is up to temperature 140F or so, for your "anti dew" protection.

Supply to the loads is pulled from the top of the tanks.

I'd wrap 60 feet of 3/4 copper tightly around the upper part of one tank as a DHW pre-heat.

It depends on what temperature you can use to your heat emitters as to how I would pull that off. Ideally an outdoor reset function would be used to pull only the temperature you need to meet the load. This maximizes your tanks "useable" energy best.

If in fact you could heat the home with supplies of 120F you now have a 60 degree delta T tank range. charge them to 180F, draw down to 120F. I've posted a few different options for low temperature heat emitters in the past. radiant slab best, low temperature panel rads or that low temperature baseboard, or Jaga fan assisted panel rads.

DHW boost could be via an indirect tank if you want, tankless, whatever.

solar could be tied into this arrangement also to cover DHW summer loads for that I would include a mid point port in one of the tanks so a small array 40- 80 square feet would only see part of one tank as it's load.

A bit more involved piping would include a parallel piping that allowed heat energy to go directly to the loads without heating either tank until the load satisfies, then the tanks start their charge. That too could be a priority function that assured the load could always be covered even before the tanks get up to final temperature.

My overheat method, if i even worried about it would be to fire a low priority zone in the home to drop the system temperature to a comfortable point, maybe 190F on, 185F off. This could also be a circ with a battery backup for power outage protection.

hr

 

[in hot water]

Here is the overview of how the control is configured and sensors placed. Also a page to explain loading and priority options.

I'd rather see the 3 way zone valve on the return piping to keep it in a lower temperature condition, the drawing shows it on the hot 9solar) pipe.x

hr

 

[SolarAndWood]

Here is a concept that is common with solar thermal, multi tank loading. i've seen this done with up to 6 individual tanks.

The goal is to keep the collectors, or boiler in your case, at it's most efficient operating condition. That being with the coolest return temperature operation. 130F and above of course for wood boilers, solar doesn't have return temperature issues.

....

I'd wrap 60 feet of 3/4 copper tightly around the upper part of one tank as a DHW pre-heat.

...

DHW boost could be via an indirect tank if you want, tankless, whatever.

solar could be tied into this arrangement also to cover DHW summer loads for that I would include a mid point port in one of the tanks so a small array 40- 80 square feet would only see part of one tank as it's load.

That's intriguing. So, a scheme where you have a smaller array for summer dhw, bigger array the rest of the year and a boiler to supplement when it gets cold? Is the only in tank heat exchanger the summer dhw coil? Or do you have to isolate the array(s) for freeze protection?

 

[chuck172]

A 60' roll of 3/4" l copper tubing cost's about $300.00
I'd love to pre-heat my dhw. but ???

 

[in hot water]

Here is a concept that is common with solar thermal, multi tank loading. i've seen this done with up to 6 individual tanks.

The goal is to keep the collectors, or boiler in your case, at it's most efficient operating condition. That being with the coolest return temperature operation. 130F and above of course for wood boilers, solar doesn't have return temperature issues.

....

I'd wrap 60 feet of 3/4 copper tightly around the upper part of one tank as a DHW pre-heat.

...

DHW boost could be via an indirect tank if you want, tankless, whatever.

solar could be tied into this arrangement also to cover DHW summer loads for that I would include a mid point port in one of the tanks so a small array 40- 80 square feet would only see part of one tank as it's load.

That's intriguing. So, a scheme where you have a smaller array for summer dhw, bigger array the rest of the year and a boiler to supplement when it gets cold? Is the only in tank heat exchanger the summer dhw coil? Or do you have to isolate the array(s) for freeze protection?

Tie in a pressurized drainback solar component. Leave about 1 foot of air space at the top of the tanks. This becomes your expansion tank for the system(s).

So the same water that is in the solar is in the wood boiler and heating distribution. It all runs at about at about 12-15psi.

To get serious about solar thermal for heating in cold climate I'd suggest at least 6 collectors. For just summertime DHW 2- 3 is plenty for family of 4. You want 1-1.5 gallons of storage for every square foot of collector. So about lower mid point of the 500 gallon tank is where you pump up to the collectors.

These drainback when the tank gets to temperature and also when the collector drops to 32F or lower. So you get freeze and overheat with plain tap water in the system. It also eliminates the need for large external expansion tanks. You may need to add a shot of air into the tank every 3-5 years as some will be absorbed into the fluid. I know of several of these systems, that have been running for 30 years, including one in upstate NY. Mine is set up this way, combo solar, radiant, DHW.

You can still have an air elimination device on the heating loop, but no air vents on the top of the tanks, that air bubble needs to stay there for DB and expansion

DHW could be accomplished by a large size plate HX as a single pass. Many of the small wall hung boilers use this method.

Here is a link to a I-dronics that shows and explains combi drainback systems with pressurized and un-pressurized tanks. Click on the I-dronics manuals, then choose I-dronics 6. look at pages 36 &37; to show the solar, boiler, heating interface. www.caleffi.us

hr

 

[in hot water]

A 60' roll of 3/4" l copper tubing cost's about $300.00
I'd love to pre-heat my dhw. but ???

I had this idea for a pex heat exchanger girdle. Pretend that garbage can is your tank. Get, or build some of these thin aluminum radiant floor heat transfer plates. I've seen homemade ones from roll flashing with pipe pounded in to form the shape. Then use a loop of pex aluminum pex tubing instead of copper. Attach the girdle around the tank, use some screen door springs to pull the ends together and keep good contact with the tank.

Not as conductive as copper of course, but fairly inexpensive to put together. The large amount of aluminum surface compensates for the plastic tube conductivity, as compared to copper.

Rheem and Ruud have sold solar a tank built with an external wrap around for many years. They still do. Often sold as a Solaraide model. While not as good of performance as a coil inside, they are cheap and easy to construct, and they pass the double walled HX requirement for code with the coil external.

hr

 

[SolarAndWood]

I know of several of these systems, that have been running for 30 years, including one in upstate NY. Mine is set up this way, combo solar, radiant, DHW....www.caleffi.us

Thanks for the insight and the link. I need to read more. I have 1000 sq ft of unshaded solar south roof, room for as much storage as I need and it is conveniently located next to my wood pile. I designed and built that roof for year round optimization of PV net metering but I am beginning to think thermal may be a better use of it.

Back to the OP's two tanks, it sounds like there are advantages to having multiple tanks instead of one.

 

[in hot water]

Got an i-phone? Get this free app from SMA. Take the phone to where you want to locate the solar, it will find the nearest weather station data and recognize the pitch and orientation that you hold the phone to. Then it tells you the kWh.

It also has a screen for Yield and $return. Both thermal and PV collectors have output charts in Kwh, so you could compare cost to output between the two.

hr

 

[SolarAndWood]

As much as PV feels good, I can't stomach the ROI. You can't do any of the work yourself and the state certified guys have more than enough people buying to bother dealing with me. Thermal on the other hand, I can do myself and buy my own materials. Makes a big difference in the analysis. My gut also says PV is going to see some big technology leaps while thermal is probably pretty close to mature.

 

[Hunderliggur]

"Got an i-phone? Get this free app from SMA. " Its called Solarchecker or just search for SMA.

 

[huffdawg]

Here is a concept that is common with solar thermal, multi tank loading. i've seen this done with up to 6 individual tanks.

The goal is to keep the collectors, or boiler in your case, at it's most efficient operating condition. That being with the coolest return temperature operation. 130F and above of course for wood boilers, solar doesn't have return temperature issues.

It involves a 3 way zone valve with a delta t (solar) controller. The tank with the lowest temperature is supplied first. It is heated until it is 10F above the other tank. then loading will be done alternately.

Furthermore the pump used to load these could be modulated with a variable speed function. The pump would not start loading until the boiler is up to temperature 140F or so, for your "anti dew" protection.

Supply to the loads is pulled from the top of the tanks.

I'd wrap 60 feet of 3/4 copper tightly around the upper part of one tank as a DHW pre-heat.

It depends on what temperature you can use to your heat emitters as to how I would pull that off. Ideally an outdoor reset function would be used to pull only the temperature you need to meet the load. This maximizes your tanks "useable" energy best.

If in fact you could heat the home with supplies of 120F you now have a 60 degree delta T tank range. charge them to 180F, draw down to 120F. I've posted a few different options for low temperature heat emitters in the past. radiant slab best, low temperature panel rads or that low temperature baseboard, or Jaga fan assisted panel rads.

DHW boost could be via an indirect tank if you want, tankless, whatever.

solar could be tied into this arrangement also to cover DHW summer loads for that I would include a mid point port in one of the tanks so a small array 40- 80 square feet would only see part of one tank as it's load.

A bit more involved piping would include a parallel piping that allowed heat energy to go directly to the loads without heating either tank until the load satisfies, then the tanks start their charge. That too could be a priority function that assured the load could always be covered even before the tanks get up to final temperature.

My overheat method, if i even worried about it would be to fire a low priority zone in the home to drop the system temperature to a comfortable point, maybe 190F on, 185F off. This could also be a circ with a battery backup for power outage protection.

hr

I have all ready plumbed in a primary loop for my system . If you click on the link in my sig. you can see a pic. of it. I have plumbed in closely spaced tee 's off my primary loop for the boiler storage heating and load supply. Would the system your suggesting work for me . I like the idea of having one storage tank for dhw and the other for lower temp heating loads .

Thanx Huff

 

[airplanes20]

I have a Scandic Solo 40 with two 220 pressurized tanks in the basement. I would like to add a 500 gallon storage tank to the system, how would you pipe that in? Also can't get a tank that size vertically into my basement, i didn't know how other people where putting them up vertically. Any pictures would be great.

 

[afblue]

Airplanes,
I dont think most people put 500 gals vertical, they are typically 330 gal or 250 gallon tanks that they stand up on end. For your system if you have the 2-220 gallon tanks in parallel to your boiler, I would connect the 500 gallon tank to your heat output line with a 3 way zone valve, and an aquastat on the 220 gallon tanks to control the valve.

 

[benjamin]

A 60' roll of 3/4" l copper tubing cost's about $300.00
I'd love to pre-heat my dhw. but ???

I tried about 20' of 3/4" copper tightly wrapped around the base of an 80 gallon electric tank, completely ineffective. The solar is also tied to space heat so it never gets that hot either. Now I need to make some aluminum/graphite/epoxy/silicone heat exchange gunk to throw in the mix... Of course with a longer pipe you have a couple of gallons in the pipe that will heat up over time and be more effective, but the point is that some heat exchange compound (or the Al plates) will dramatically improve the performance.

I now use a 20' 3/4" inside of 1" heat exchanger that will make dangerous hot water with the boiler and decent hot water with the solar. Just need to finish the controls.