Wood chip boilers. I tell you how to heat a house for free

Article Heating the house with homemade pellets. Real cost example caused heated discussions among readers. The main problem we saw was the moisture content of the sawdust. They should be of optimal humidity, and ideally dry.

I propose to develop this topic further. But not in the area of ​​the sawdust drying process, but in the direction of obtaining free fuel for solid fuel boilers from chips.

First, let's see if there are boilers that are capable of operating on wood chips. The first thing that came across was powerful boilers operating on chips, sawdust, husks from some kind of production. Example:

Powerful boilers for 100 kW and more. Large automatic boilers. Even for large areas houses 350 m2 it's a lot. It makes sense to install it on two houses with garages. The cost of imported models - up to 500 thousand rub. Are there compact low-power boilers for chips, or even better - automatic boilers with a hopper and a chip feeder auger?

Found the smallest boilers ТМ Froling Т4. Power 7-24 kW.

This is an imported Austrian boiler capable of operating on wood chips and pellets. Its cost is high. It is very similar to the automatic pellet one. The only problem is the supply of chips. The fact is that in the bunker the chips may not spontaneously fall into the auger, they get stuck. It must be constantly stirred during feeding, during operation of the auger. And it is loaded in portions, buckets. Also, the chips should not have a higher moisture content 20%.

I found a video where one craftsman installed a shaft with an electric drive for stirring wood chips in the bunker of a pellet boiler:

Probably, he no longer needs pellets and he heats the house with a cheaper type of fuel (or generally free) - wood chips.

Another type of boilers that can operate on wood chips are long-burning pyrolysis boilers. I found one manufacturer who uses the technology of burning fuel on hot grates made of fireclay bricks - boilers Brick:

These boilers run on any fuel, even with moisture up to 70%.

There is an explanation for this effect on the manufacturer's channel: https://www.youtube.com/channel/UCvd2wpuHZTY6TdI9WUhb95g/videos

About the wood chip boiler here: https://youtu.be/6KXd-hCL7go

Well, these boilers work when the chamber is completely filled with fuel - up to three days. On wood chips and sawdust - 1-2 days.

We decided on the boilers. There are not so many types of heating equipment capable of operating on wood chips, but there are such boilers. Let's move on to the technology for obtaining free chips.

Basically, it is obtained from sawmill waste. The so-called pasta or croaker:

All sawmills don't know how to get rid of it. Someone comes and picks him up for firewood. But even so, it costs $ 2,000. rub for 6-10 m3. Those. in fact it has the cost of storage in a truck and delivery.

If you come to the sawmill, they will give it to you free of charge. At least in Siberian cities. At one time I chose something from a similar heap that looked like a board for a shield. For fixing slabs of permanent formwork foundations. There was an article here over a year ago.

Then there are two options: bring narrow and long sawing waste to your site, dry it and process it into chips. Or process them right away at the sawmill and take them away in bags or MKR in a car trailer. For the second option, you need a chip cutter. The design is uncomplicated and someone can assemble them for their own needs. Factory made look like this:

It is optimal if the engine power is 5 kW and the size of the loading window is 100x100 mm. Under these conditions, the chip cutter can produce up to 2 m3 of chips per hour of operation. There are also petrol models, but petrol costs will be higher. The cost of gasoline models - from 30 thous. rub. Electric - from 50 thous. rub.

If you have purchased a pyrolysis boiler of long burning, negotiate with the owner of the sawmill, bring in a wood chip cutter and recycle its sawing waste. Take it to your place in bags (nets) or in a large bag. Mesh bag cost - 10-15 rub / piece Price for MKR per 1 ton - RUB 250-300

The sawmill will thank you for waste disposal. And you can take away the wide croaker for firewood. Or cut for yourself.

Next, you need to dry the chips. To do this, the nets with chips must be hung under a covered and ventilated canopy.

The bags dry for a month in a suspended position, then we transfer them to the woodshed and dry the next batch.

We count how much chips are needed for the winter. Let's say you have a house up to 120 m2. In practice, on average, a boiler needs 30 kg of pellets or chips per day. More in cold weather, less in thaw. This is about three 10 kg mesh bags. 90 bags per month. Or 720 bags for 8 months of the heating season. Minimum 7 tons. Or in a volume of 22 m3 of wood chips (30 l / bag). These are numbers for a temperate climate. For Siberia, they need to be increased.

For storage, you need a room of 3x3 m. And an open canopy for drying in the summer.

Let's say you make 3 m3 of chips in a day off. This is 900-1000 kg. And bring it to your site in your trailer. You will need a maximum of 10 days of such weekends per year. If the sawmill is nearby, then the cost of fuel and lubricants will be minimal. Electricity for the chipper should be free of charge. You provide a service to the sawmill - you recycle their waste.

So if you have a pyrolysis boiler or a converted pellet boiler (with a turner in the hopper) and with a natural moisture content of wood chips up to 20%, you will receive free fuel for heating. Bags, FIBCs, wood chips - a one-time investment, like a boiler, which will pay off in two years. And if the chip cutter is made by hand, then for the season.

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