Propane Off-grid heat

Shrubsteppe

Hello All.
I am in Central WA. 2000' on side of mtn. Building a 1200 sqft workshop/garage w/ 600 sq ft LOFT studio spartment.
I am 100% off-grid Solar + propane. Well water.
Opinions pls. on propane heating options for LOFT space. The 4 winter months avg 10 - 15° F. (Lows -10).
First I'm going to insulate the s**t out of it!
Then... Rinnai, Martin ? direct connect wall mount propane heater?
Additional Radiant floor heat set-up?
I can site all mechanicals in garage space below loft and just run up piping.
Garage will be insulated also.
Wife and I will be lliving here for 2 yrs. while I build main house. She won't commit if I can't promise her "warm" winters.
Appreciate ideas.

EBEBRATT-Ed

So just concerned with heating the loft at this point??

I would do a heat loss for sure. If it's insulated good you won't need much with it being inside the garage. But will the garage be heated?

Probably the safe bet is to figure the loft heat load as if the garage is not heated.

How many rooms in the loft apartment? If it's open space a wall mounted propane heater or two will work.

Will the loft apartment be used as an apartment once the main house is built?

pecmsg

Be very careful with Super Tight and heat. You need an air change ever 3 - 5 hours. That will add to your calculations. 

Larry Weingarten

Hi, I’m off grid as well. I built using SIP panels that were considered too thick for my location. I also built a tall house, so natural ventilation works. These things together gave me a house that was pretty quick to build the shell for and simple to heat. The best stick built homes try to perform as well as SIPS. My considered opinion 🤓 Your situation sounds like a good fit for these ideas.

Yours, Larry

Jon_blaney

You will need hot water also. Maybe an air handler using a the water heater like a BOCK 32e and an air handler from Firstco or Unico.

Jon_blaney

How about steam, no fans, no pumps, just heat. Just like it was before there was a grid only propane not coal.

Gsmith

Guess you can't get millivolt controls anymore, or you could have the whole old time package.

Shrubsteppe

The loft is complete open floor plan (+ 1ba) in the garage. 1200 sqft Pole built, metal ext.
re:  insulate the s**t out of it".
as in closed cell spray 5" x r6.7/", ext sides & 1 inner wall + floor of loft., 6" roof. I fifigure @ 30,000 btu unit for 600 sqft would be good when it gets too cold. I'll have a 10Kw solar setup for the main house which I can utilize until its built. After we move into house I just need reliable lp heating for the loft when kids visit during winter.
I'll have 2 overhead high efficiency fans (dc / 30w ea) to circulate heat (+ cool in summer) so I figured a central located lp wall unit would work. I'll have a 500 - 1000 gl lp tanks outside the garage (waiting for the main house) to tap into.

as far as steam...well if we have another wildfire during winter 3' of snow, maybe. 

Zman

@Shrubsteppe
I assume you are installing some PV electricity and batteries? A propane backup generator?
You might be a good candidate for a Micro CHP setup. https://www.lochinvar.com/lit/733201XRG-01.pdf

If you plan ahead, the building you are constructing now could be the power plant for the future house.
In the summer, you could run primarily PV solar (and possibly hot water solar). In the winter, you would never run out of hot water heat, or electricity.
Be sure to do all the math and build a heating system sized to run on low temp hot water with plenty of buffer/storage tank.

Shrubsteppe

Thx,
Yes PV + Battery storage. Yes lp backup gen.
Also planning a 5 - 10Kwh wind turbine.
But, you throw out Micro CHP and well...
Here I've been trying to minimize sqft and thermal load, with a micro chp I may have to build a larger house.

PRR

Gary Smith said:

Guess you can't get millivolt controls anymore...

Millivolt thermostats are still around.
https://forum.heatinghelp.com/discussion/comment/1675493/#Comment_1675493
The gas fireplace I have it controlling is 120V optional, a stack of AA cells will spark it. As long as you are on the spot and mark a calendar (or keep spare AAs in the barn), it will be fine.

Derheatmeister

Shrubsteppe said:

Thx,
Yes PV + Battery storage. Yes lp backup gen.
Also planning a 5 - 10Kwh wind turbine.
But, you throw out Micro CHP and well...
Here I've been trying to minimize sqft and thermal load, with a micro chp I may have to build a larger house.

Maybe Not..
I am in talks with this CHP company from WI : https://www.axiom-energy.com/microchp
These units can modulate as far down as 13000 BTU/HR while producing 1.2 KW/HR..On the high side they produce 47 000 BTU/HR at 4.4KW/HR all at around a 55dB level...
If More BTU/HR are required you can Daisy chain multipal units together..
As with any CHP source you should size your equipment on the thermal load and of course add a Buffer tank to the equation.
In my situation i still need to plan on derating this equipment for high altitudes of 8500' to 11200'..
Check it out !

hot_rod

I think your challenge will be summer and shoulder season use of the cogen. What to do with even 13,000 btu per hour with no heat load or sizable dhw?
So then  you run a fan or circulator to dump that heat energy. Or a massive buffer tank. 

So a portion of the electrical energy it is churning out goes to tuning something to dump it to. 

We run into this with large thermal arrays in summer also. The pump and fan coil energy required to dump the excess washes out

You have a bunch of energy change of state going in and efficiency loss at every one
lp to mechanical energy to electrical and thermal, add buffer tank heat loss also. Wear and maintenance and eventual rebuild on the engine needs to be factored

Certainly  not trying to talk you out if the plan, just crunch the numbers accurately.

Off grinders I know use generators sparingly😉

Derheatmeister

Generally when CHP/Generator are used in of grid situation such as your situation we would have a solar thermal system with the proper angle and tilt to produce DHW while in the "Off season"
We do use a software programm to size the the Array/Storage tank so they do not overheat therfore we do not need a Heatdump.
Another way to do this would be using a Drainback system such as the collectors by Sunearth which will just as the name states drain back to a tank once the tank is sadisfied leaving the collectors empty and the tank ready to use, so again no heatdump required.

As per your post in seems that you are also going to install Wind and PV as well..
You have a array of things going on and need to make all these different sources "talk" to each other..
Proper thoughts on what you need and want to accive will take some careful planning..

Derheatmeister

hot_rod said:

I think your challenge will be summer and shoulder season use of the cogen. What to do with even 13,000 btu per hour with no heat load or sizable dhw?
So then  you run a fan or circulator to dump that heat energy. Or a massive buffer tank. 

So a portion of the electrical energy it is churning out goes to tuning something to dump it to. 

We run into this with large thermal arrays in summer also. The pump and fan coil energy required to dump the excess washes out

You have a bunch of energy change of state going in and efficiency loss at every one
lp to mechanical energy to electrical and thermal, add buffer tank heat loss also. Wear and maintenance and eventual rebuild on the engine needs to be factored

Certainly  not trying to talk you out if the plan, just crunch the numbers accurately.

Off grinders I know use generators sparingly😉

BTW : The single cylinder engine from Ecopower requires the following maintenance:

Replacement:40,000 hours (equating to 1.6 million miles on an automobile engine)

​4,000 hour service interval (changing the oil, oil filter, air filter, spark plug and spark plug cable)

It will Probably will be many years worth of operation in this case with Solar thermal ?/PV/Wind as a backup until it needs replaced !

I think that the 4 Cylinder setups such as Lochinvar's setup probably require replacement earlier?..Not sure,Cannot find that infomation on Lochinvars site!