Cheap heat

Dave was pretty darn close with geothermal heating. The problem I have with Geothermal is that is cost a lot to set up. It's more than just pipes underground. They use a mixture of water, bio-degradable antifreeze and water pumps.

In manitoba here the frost depth is 6'. If I dig down 30 inches I hit the water table AND a lot of large rocks and sand. :(
So another type of heating is called 'Heat sinking'...

Fundamentally it acts as a storage heater, you heat up material that then slowly releases the heat back into the surrounding structure. In this application we heat up the storage material not with a heating element, but with hot air pumped down into a chamber under the floor of the greenhouse.

Only I would probably do it on a larger scale like the picture to the right.
The only electricity this system needs is a fan to move air.

The heat sink system isn't good enough to keep you toasty warm in -40 weather but it will help a little and keep other costs down.

How can I make it better?

Well I'm going to have a small wood oven for pizza and bread maybe a wood burning stove. I can pump excess heat from there down into my heat sink.

So the pizza oven heats up the surrounding area and that heat rises.
The pvc pipe near the top of the ceiling sucks the hot air down under the floor into the heat sink. The heat sink warms up and is insulated by the ground.
As the pizza oven cools down the cool air gets pumped down into the warm heat sink and warms up.

Another important part of the system is insulation.
It's better to keep hot air in than to create extra hot air to make up for what is leaking out.

Pink insulation is pretty darn good. I'd like to use some of it on the south side and ceiling.
But for the north facing wall, which will always been in the shade I'm going to try using straw bales. It has a very high R-value and is very cheap in my area of the prairies.

"Research by Joe McCabe at the Univ. of Arizona found R-value for both wheat and rice bales was about R-2.4 (RSI-0.42) per inch with the grain, and R-3 (RSI-0.53) per inch across the grain. A 23" wide 3 string bale laid flat = R-54.7 (RSI-9.64), laid on edge (16" wide) = R-42.8 (RSI-7.54). For 2 string bales laid flat (18" wide) = R-42.8 (RSI-7.54), and on edge (14" wide) = R-32.1 (RSI-5.66)" -Wikipedia

I buy bales (16x32x16) for a dollar to insulate my septic field every winter with an R-value of 40+; compared to about $10 for pink insulation that has R-value of 25 but is 10' thinner.

Building with straw can be different than conventional structures. You usually start with the insulation first and then do a majority of the framing around it. In the end you don't know it is there. I'll have ply wood and aluminium siding on the outside and drywall inside.
The drawback is the walls will be around 18' thick. :(
I'm not going to use the straw as load bearing like most straw buildings; my load will be on the wood frame like a normal shed so I won't need a special permit.

The straw bale idea is still in limbo. I'd 'like' to incorporate it because it is very cheap in my area. I can fit around 20 bales in my truck per trip. But it also takes a lot more time than nailing up walls and insulating it.


Another way to add cheap heat is the use of colour. I want to have large windows on the south side that will allow free light in. If I paint the floor a dark colour it will warm up and help, to a small degree, the heat sink underneath.
Or paint the south side outer wall a dark colour.

Well. There are a few cheap alternatives to using electricity or gas to heat my shed. I don't mind burning wood in a stove. It costs about $60 for a cord of wood out here - enough to last a winter; and I can use the ash so very little is wasted.

But that's all fine and dandy during the -40 winters here. But how am I going to tackle cooling for cheap without an air conditioner...!?
We also have humid summers here. And mosquitoes.

---

Links
Heat Sink - YMCA - BBC
Straw - Straw bale construction