Need help with piping diagram on simple forced air Xchanger install

[hartkem]

I thought I was really good with figuring technical things out but I guess I just don't know enough about hydronic heating to get this straight in my mind. I was hoping someone could draw me a simple diagram to help me accomplish my goal. All the diagrams on this site have multiple zones and seem to be much more complicated than I need. I am going to order an EKO 40 and the 490 gallon preinsulated storage tank from new horizons. The EKO will be installed in a garden shed 150' f from the house. I will use thermopex(size unknown) to get the hot water into my basement where my 100,000 btu forced air furnace is located. I want to install my storage tank somewhere close to the forced air furnace. I am not bothering with domestic hot water now to keep the install as simple as possible. I will have a water to air heat exchanger in the plenum of my furnace. Since I travel some my storage may go cold more often than most peoples so the ability to heat the house before the storage reaches full temp would be nice if possible. I want to go with a pressurized system. I don't understand all the symbols yet so a key would be nice. Thanks for taking the time to help a future wood burner out.

P.S. I have about 4 cords of wood seasoning right now.

Mike

 

[RobC]

I would reconsider a few things before the pipe layout.
1) That is a long run with insulated pipe. It's very expensive. And you may have to up size pipe diameter or circulator because of the distance.
2) You mention that you travel. You may want to consider more storage ?
3) when you size your water to air HX you need to oversize it so you can heat with water temps less than 180f, That is where most HX's are rated for 180. It would be nice to get heat at 150 or less.

Some folks have added a shed attached to house or, close to house and put boiler and storage there. This cuts down on thermopex and electrical runs. It's tempting to use what's existing but you need to look at all possibilities if you have any alternatives.

When doing the piping I would leave taps on the supply and return for future domestic hot water.

EKO and pressurized storage two thumbs up !!

Cheers Rob.

 

[in hot water]

piping, wiring, and operation are all explained in the i-dronics 10 mentioned in another post.

As Rob mentioned you will need to size the piping, pumps and mixing devices based on the load, distance, etc. Adding a 3 way mixing valve that could have an outdoor reset control added on is a big plus to leverage the energy the buffer tank can supply.

hr

 

[hartkem]

I would reconsider a few things before the pipe layout.
1) That is a long run with insulated pipe. It's very expensive. And you may have to up size pipe diameter or circulator because of the distance.
2) You mention that you travel. You may want to consider more storage ?
3) when you size your water to air HX you need to oversize it so you can heat with water temps less than 180f, That is where most HX's are rated for 180. It would be nice to get heat at 150 or less.

Some folks have added a shed attached to house or, close to house and put boiler and storage there. This cuts down on thermopex and electrical runs. It's tempting to use what's existing but you need to look at all possibilities if you have any alternatives.

When doing the piping I would leave taps on the supply and return for future domestic hot water.

EKO and pressurized storage two thumbs up !!

Cheers Rob.

Ok, I understand where your coming from. I am willing to spend the 2500 bucks on the 1 1/4 thermopex. I can't put the boiler inside since there is no way to add a flue and my outbuilding is my only other option. My wife is never going to allow me to add something on to the house or build something closer so I have to use what I have. I am using that size storage because I am again limited to my space in my basement. I will install the biggest and thickest HX in my plenum that I can fit in there if that will help out. Understanding the piping before I start buying things makes me feel more comfortable and better about the project.

Thanks

 

[stee6043]

What is your goal with 490 gallons of storage? How long do you want/need to be able to heat from storage? I wouldn't recommend adding storage "just to add storage". If 490 is a useful size for you, go for it. But if you're adding it only becuase it sounds like the right thing to do then maybe you should reconsider.

For what it's worth when heating with an in-furnace HX and storage (like I do) I find temps below 140 to be pretty much worthless for two reasons. First, my run-of-the mill HX really does not function well at that temp. But also, and less discussed here, is the fact that once your system RETURN temps drop below 140 degrees you have no choice but to dedicate a certain amount of your heat output to reheating input to mainain proper boiler temps (via Danfoss, etc). So even if you find a coil that will work well with temps down to 150/140 you're still going to have this storage return/supply/return temp efficiency dillema. It's unavoidable.

 

[RobC]

I'm not the one to do the math on the pump and pipe loss going from the house to the boiler and back again. But, "hr" mentioned buffer tank. Having the 490G storage acting as a buffer tank could be a benefit. It might allow for 1" pex to be used ?
Hartkem, here is a table the will give you the idea of why the different size circulator and pipe are important.
http://www.taco-hvac.com/uploads/FileLibrary/SelectingCirculators.pdf
What is important to try to achieve the ability of your pump and pipe combination to pump away enough heat to the house so the EKO isn't cycling on and off or not allowing enough heat to get to house under high loads in winter. ( plus potential for DHW )
One other item.... Outdoor boiler and travel ? What are you going to do for freeze protection ? If you install Glycol antifreeze this reduces you efficiency some and needs to be factored in.
Can you add some other info for us. Like what state you live in ? For example, upstate NY would be completely different than MD. What is your primary heat now? The more the better....
Rob

 

[hartkem]

I'm not the one to do the math on the pump and pipe loss going from the house to the boiler and back again. But, "hr" mentioned buffer tank. Having the 490G storage acting as a buffer tank could be a benefit. It might allow for 1" pex to be used ?
Hartkem, here is a table the will give you the idea of why the different size circulator and pipe are important.
http://www.taco-hvac.com/uploads/FileLibrary/SelectingCirculators.pdf
What is important to try to achieve the ability of your pump and pipe combination to pump away enough heat to the house so the EKO isn't cycling on and off or not allowing enough heat to get to house under high loads in winter. ( plus potential for DHW )
One other item.... Outdoor boiler and travel ? What are you going to do for freeze protection ? If you install Glycol antifreeze this reduces you efficiency some and needs to be factored in.
Can you add some other info for us. Like what state you live in ? For example, upstate NY would be completely different than MD. What is your primary heat now? The more the better....
Rob

I live in kansas city missouri. Im trying to heat a 3200 sq ft cap cod style house with finished basement. House was built in 2002 so it has decent insulation with double pane windows. R15 walls with R30 in ceiling. Currently have a propane 90% efficiency forced air furnace with 90,000 btu output. The furnace runs almost non stop when it is 0 degrees outside but it seems to keep up. I use about 1200 gallons of propane each year with DHW. I didn't do any calculations on the storage size and thought i just needed to add it because I hear so many talking about it on here. Plus its about the biggest I am going to fit in my basement. If the storage isn't going to help me I would much prefer not to spend the 3,000 bucks on it. I am basically using my propane furnace size as an indicator of which size Eko to buy. I do travel but usually not gone for more than 3 nights. I was planning on letting the circulator pump run to keep it from freezing or install small electric heater in garden shed that is insulated. Didn't want to use glycol if i didn't have to.

 

[hartkem]

What is your goal with 490 gallons of storage? How long do you want/need to be able to heat from storage? I wouldn't recommend adding storage "just to add storage". If 490 is a useful size for you, go for it. But if you're adding it only becuase it sounds like the right thing to do then maybe you should reconsider.

For what it's worth when heating with an in-furnace HX and storage (like I do) I find temps below 140 to be pretty much worthless for two reasons. First, my run-of-the mill HX really does not function well at that temp. But also, and less discussed here, is the fact that once your system RETURN temps drop below 140 degrees you have no choice but to dedicate a certain amount of your heat output to reheating input to mainain proper boiler temps (via Danfoss, etc). So even if you find a coil that will work well with temps down to 150/140 you're still going to have this storage return/supply/return temp efficiency dillema. It's unavoidable.

I forgot to add that I would like to be able to go 9 hrs between firing up.

 

[RobC]

Don't know about you wood availability but have you considered a wood pellet set up with a hopper ? These can run unattended for long periods of time. Yes you would be buying pellets but you could shut off the gas and get DHW and home heat. This might give you the best payback because you could use it 24/7 365.....
Might want to check on Hearth's Pellet Forum....
Rob

 

[markmudd]

9 hrs firing time should not be a problem. Pay attention to advice above for pipe sizing, lenth of run (friction losses). This is very important if you want system to work properly.

I have similar situation to you. using non gasser 150K indoor wood boiler with FA water to air heat exchanger, 3000 sq ft home decent insulation (r40 cieling) Have about 450 gallon home built non pressuized storage (My storage set up is not the best and could be improved. Manually controlled storage, but soon to change). In 20 degree night temps 40 degree day (typical mo winter) here is my routine,

No fire im morning, storage maybe 150 -160 at wake up

when return home in evening, storage is typically not below 130. build fire to get house up to temp,and start raising storage temps, (usually doesn't drop more than 2 degrees below t stat setting of 71 on cloudy /windy days. (Obviously depends on day temp, sun etc),

Add more wood at 11:00pm or so, amount loaded depends on storage temp achieved, low temp at night expected etc

next morning, l have hot air blowing at 7:00 am, house at themostat setting, and water temps around around 150,

I have my fan set to run down to 130 degree temp. Fan needs to run longer at lower temps, but it still works tos ome extent to get thru the day.

Colder temps = more wood use, less time between firing etc. I plan to add radiant and go to at least 500 gallon pressurized storage in future.

More than you wanted to know maybe!

 

[hartkem]

I would be happy with 9 hrs firing time. Can anyone tell me if my 500 gallon tank could provide that time? also would I need 1" or 1 1/4" thermopex? I checked my propane furnace and the input is 100,000 btu and the output is 90,000. It almost runs constantly when it is 0 degrees but that doesn't happen but a few times a winter.

 

[stee6043]

I would be happy with 9 hrs firing time. Can anyone tell me if my 500 gallon tank could provide that time? also would I need 1" or 1 1/4" thermopex? I checked my propane furnace and the input is 100,000 btu and the output is 90,000. It almost runs constantly when it is 0 degrees but that doesn't happen but a few times a winter.

I'm not sure you are going to be able to pull off your 9 hour goal based on what you're saying here. If your 90,000 btu furnace is running properly and runs non-stop at 0 degrees, you have a pretty significant heat load.

I can run 16-18 hours +/- from my 1,000 gallons of storage on an average winter day. If temps drop below 0 and stay below zero all day I can only get about half that. And my heat load, on an average day, is right around 20,000 btu/hr. I'm 50k btu/hr on the coldest of the cold days.

If we were to assume your heat load is double mine and you're trying to run on half the storage....I think you're looking at closer to 4-5 hours on storage on an average day. Zero hours on storage below 0.

And an easy answer on your question on pex - you'll regret going smaller. I'd actually suggest you look into two runs of 1" pex if it makes sense. But I'm not an outdoor installation guru...

 

[hartkem]

If I can get 4-5 hours on storage plus the time the fire is burning wouldn't that put me at around 8-9 hours total. If its 0 outside or below which is very uncommon here through the day I would expect to have to continuously load the fire. November and February it is common to see 30-55 degrees so my storage should help a decent amount during that time I would think. Furnace doesn't run nearly as often when its above freezing. Just trying to justify the cost of the storage.

 

[markmudd]

I would think for your area that would be reasonable assumption as long the boiler and piping is sized properly for the heat load. I can do it in average conditions usually without losing any temp to the house between firings. For past few weeks have not had need to build fire in morning before work due to mild winter.
Having storage really helps to spread out the time between burns and allows boiler to operate a full load which helps minimize creosote issues. Very important for gassifiers, as they do best running at full output.