No clay and want to heat not water - would a sawdust stove work?

Hi,

We are wanting to heat a very badly insulated 3 bedroom 90's kitset wooden house with no wood stove - we are in NZ so in the midst of winter. To put in a wood stove to council regulations is beyond our budget, and would be sitting in a closed-off lounge room anyway. (we bought the property for the 8 acres and farm set-up NOT the house!) We are playing at heating water through a compost heat, and have an unlimited supply of stable sawdust. We have the system working, but find it espensive to get enough pipe to heat our hot water, let alone to heat water for house radiators too. We are also looking at making a stove in an outbuilding (we have a few unused well ventilated buildings with cement or dirt floors and metal sides) and heating the water in some sort of heat eschange and bringing it into the house.
Something like this sort of thing. http://www.youtube.com/watch?v=YTnr8ua54Uw&feature=player_detailpage

The problem is that we are 5 km from the sea, and have sandy soil. We don't have the clay to make the adobe surrounds. What are our options otherwise? As we can have access to free sawdust/manure and dry it off in our outbuildings - we could make a sawdust stove and boil water on that with a heat eschange in it. Or we could make a portable rocket stove with gravel, and run water piping through it. We want something that is low emissions (no chimney smoke for the council to see driving by), and also safe to burn with little supervision.

Thanks in advance.

I am basically a coward, and when it comes to heating hot water with a solid fuel stove you need to be very careful, and do lots of research. If it's a kettle on a stove, that's one thing, but if it's a hot water tank, they can be dangerous, and they do kill people. A sawdust stove can work unattended. Even if you are with it, there's not much you can do. Other types of wood stoves (except chip or pellet) seem to need frequent attention.

This is something we are cautious about too. We were also wondering about stacking bricks on/round the oven, and then putting them on a trolley and bringing them in the house once or twice a day.

We could also try to make a hot air ezchange rather than water, but it seems harder to pull it and insulate it for long distances.

I think the first thing to do is to insulate the house. This pays for itself fairly quickly. What about building a masonry stove, or Russian fire. That way you can heat the bricks directly and you don't have to move them around. It also gets rid of the wet heating system.

Hi,

Thanks for the advice on the insulation. We are looking into window film and bubble wrap for the windows.

Because we are on a wooden chipboard flooring, ezcept for the add-on laundry (which is concrete), I don't know if it would take the weight of a masonry stove. It would also be a long and costly process (and maybe impossible) to get a self-designed wood stove approved through the town council, and there is talk that in 2015 even rural property fires will have to be high efficiency rated for emissions (at present houses in urban areas already have strict controls.

We need something that we can light outside and bring the heat indoors through some sort of heat ezchange. Water seems the easiest and most effective way to transfer heat 50-100 ft from an outbuilding to the house.

One key to safe heating of water is PRESSURE RELEASE!!! Either an open-top tank or pressure relief valves.

The other is to make sure you don't super-heat steam while still in contact with the fire--that is from making the water tubes too small or not made to purge any bubbles quickly.

If I were you, I would try to buy a truckload of clay to work with. I have clay, but have to buy sand. One truckload of the right clay (or even a couple trunkloads hauled in your car) will go a long way when you can mix it sand heavy.

Masonry stoves are VERY low emmision, but you need a SERIOUS footing for them. Good long term project.

I would put down in floor heating system now. you can hook up to one of these solars now, and get a Brillouin heater in a couple years.

These are pretty cheap out of China, usually 500 bucks, a lot of em available on eBay, and they work pretty dang fab.
Most of the new ones are 4 or 5 inches, and catch the light at all angles, so very efficient, without having to have moving panels.

http://www.dudadiesel.com/solar.php

I used to see a "remote wood heater" setup advertised in the back of the Backwoods Home magazine. No idea how it was set up tho.