Help on design of boiler in shop with forced air furnace's in home and unpressurized storage

[dcowan]

I've read a lot of posts on this site and am wanting to get some confirmation/opinions one my current best thoughts on my setup. I have a 4000 sq feet home I have calculated at peak btu loss of 90k btu's / hr. Last year I burned 1400 gallons of propane which seems to be in line with those numbers. My current heating is a propane furnace for basement and first floor and electric furnace for second floor. In the past I usually only really run the propane furnace because the upstairs is very open to the first floor and gets most heat from there. I am thinking for this year I will probably only by a heat exchanger for the propane furnace. It is 19x20 which show peak #'s of 150k btu / hr. I have a 30x40 shop that I plan on putting the boiler in. My current plan is an EKO 60. I will heat the shop a couple days a week probably. I have access to 500 gallon stainless containers for free so I plan on using 2 of those for storage. These could take about 10psi only so I plan to use them unpressurized. My house and shop are separated by about about 80 feet. I plan to buy 1 1/4" thermopex to install between them and also run some conduit for control wires and any other wires. I plan to by a water to air heat exchanger with fan for the shop. Based on my propane usage I am planning on 7 cords / year. My main questions are is any of this out of line or dumb? Also I plan on running a small pressurized loop from boiler to storage and use a flat plate heat exchanger to go to the 2 x 500 gallon storage tanks. I see a lot of schematics for hydronic heat but not a lot for forced air. I know they are similar but the heat requirements on water to air heat exchangers are much higher so I want to have priority to it before storage. I am up in the air on if the loop from shop -> house -> water / air heat exchanger should be off the pressurized loop of the boiler or from the storage. Hoping someone hear can give some advice / example schematics on that. Thanks in advance for any advice!

 

[jebatty]

I am up in the air on if the loop from shop -> house -> water / air heat exchanger should be off the pressurized loop of the boiler or from the storage.

Water/air heat exchangers normally require hotter water to get rated btuh output. Check the rating on the heat exchanger against your requirements. Supplying the heat exchanger from a pressurized source rather than unpressurized to a pressurized loop with a plate hx usually results in about a 10F temperature drop, which may not give you the hot water you need for best performance of the water/air heat exchanger.

 

[dcowan]

I should have also mentioned I plan on putting the storage next to the boiler in my shop. Not in the house.

 

[dcowan]

I'm going back and forth on if I should do storage. I know there are benefits but I'm not sure it is worth it since I will be using water -> air heat exchangers which require > 150 and prefer 180 to be fully effective. Any guidance on this?

 

[goosegunner]

I'm going back and forth on if I should do storage. I know there are benefits but I'm not sure it is worth it since I will be using water -> air heat exchangers which require > 150 and prefer 180 to be fully effective. Any guidance on this?

I have a very similar situation but my house is smaller at 2850 finished sq ft. I live in Wisconsin and my heat loss is 48k at -15.

I am just piping my storage after running an Econoburn 200 last year without. It worked great but as warmer temps came it was harder to manage without excessive creosote.

I have the same size heat exchanger and I can tell you with my house I can heat down to 130 degree water. Is it as comfortable as 175, no but it can get me by. I have mine piped with an auqua-stat and time delay at the exchanger that is set for 130, if the water is not 130 after 3 minutes the time delay kills the zone pump and the lp furnace kicks on. It is a great set up with no additional thermostats.

I will know more about my storage soon but I expect it to be a nice addition to my system, adding some convienience factor during shoulder season, one big load to storage vs many small loads.


Gg

 

[dcowan]

Good to know. Do you plan on going pressurized or non pressurized? Also what size storage are you planning? Is your boiler in the house or in a shop / building?

 

[goosegunner]

My boiler is in a separate boiler room from my new shed, 1000 gallon pressurized lp tank storage is there also. It is a 115 foot run to my attached garage on the house. I also used 32 mm Logstor, which is the same as 1-1/4" thermopex. I put in a 2" conduit for power and two 1-1/2" conduits for low voltage wiring.

Building, Tank is in the enclosed area behind 12X16 boiler room.

https://www.hearth.com/econtent/index.php/forums/viewthread/63522/

Inside boiler rm

https://www.hearth.com/econtent/index.php/forums/viewthread/67361/

gg