Heating the House with wood-burning stove: place a coil in a kitchen Hergom

Heating the House with wood-burning stove: place a coil in a kitchen Hergom (updated)

Already placed stainless steel coil
Update  : after the success, José de Madrid asked me one that already has working and discussed in this post, in this case connected to the existing installation of radiators.
The last weekend we were a friend and I in the House of a friend in Lazagurría. It is a town small and endearing, dressing South of a hill of single-family homes, the majority of more than 50 years, which has managed to survive the flight to the cities (with Logroño to 20 kms).
Noa, a friend awesome trotters, intending to heat the home with the veneer of the kitchen fire, I wanted to better distribute the heat for your old wood stove House as seen on my blog, and in the end have placed an efficient coil adapted to its cuisine, which well heat radiators. Modification cost: €200 and €100 coil accessories installed by it.

The cuisine is the typical old Hergóm present in many houses of Spain, which gives a considerable heat and uses wood very well for its manufacture in refractory brick and reinforced cast metal.

In Hergóm are still manufacturing this type of cuisine, with more modern lines:

She had been installed, as you can see in the following images, a copper coil to harness the energy of the flames on the side and fire up the oven, where it passes the smoke and flame heating it.

At the beginning I was using an open circuit with water pressure tank, and told me that I had problems with welds of Tin, which is released if it gave him much candela to fire. I told him that such a bomb could have problems to circulate water if there is no pressure, and that if at any point of the coils air builds up, nearby welds, would excessively warm dropping to reach 300 ° C.

Building stainless steel coil
After an exchange of queries by mail, I decided to make it a coil for a price, like the one built for Barna Manel, and approach it for installation. Gracias_a all the sketches, measures and instructions sent me by mail, just had to adapt one of the outputs of the coil on the balcony of his house;-). So it's nice work!

As lena inlet opening is at the top, in the place of the fire just we have to place coils that collect part of the heat of the fire, so it had to be in the space between the top of the oven and the top, which is a space of 35 x 35 cm and 10 cm high, and where they spend the flames and smoke before you travel on one side and out by the rear.
At first I thought about making a small deposit of rectangular stainless steel to which soldaría some fins on top to collect the heat, after downloading, place it beside the fire due to the lack of space.
As I didn't have enough material to make the deposit, I used a tube 50 mm. and 3 mm. stainless steel thickness that I cut into pieces 35 cm. long.

I placed them to presentation to see what separation could leave between each of them and to me at the same time enter into the space indicated by Noa.
To move water from a pipe to another best would have been to use pieces of the same diameter, cut at 45 ° and soldiers on each side, but chose to use a thinner to save material tube and that gases from the combustion will be better between the tubes.

Pieces of sheet metal which I punteé, then I cut and I ended up soldering I used to cover the sides. Needless to say that we must weld carefully and cover any pore go looking to have the minimum possible problems when it comes to prove it.

The union side and side I did cut a triangle in the corner of the pipe, just enough so that by placing the small tube water passes through it without cutting off the passage to the water with material or welding.

Continue tapping and welding the following tube, joining the tubes little by little to form a circuit by which the water to circulate.
At the end I realized that to put the connections in the center of the tube of 50 mm. I would be air in the upper part of the tube, but it doesn't matter because the tube is quite thick and heat is immediately transmitted to the water of its interior, which covers more than half of the tube.

And as seen in the following image, the tubes are connected by tube Ø20 mm.

In the photo below coil finished with the water outlet hot already welded on one side. I soldé both the entrance and exit of water 'eye of thumb' and that it had more than a few approximate measurements of the location and distance to holes on one side of the sheet.

In the following image, by placing a piece of pipe to the cold water inlet.

Left pending soldier the sheet side which will help to recover the heat of gases from combustion, which I left to do "in situ" once at home of Noa.
I tried your seal to 7 bars, and after plug 4 pores that were left, we went to his people.

By placing the coil

Emilio throwing me a hand with the welds
Once there I checked with satisfaction that just had to change the angle and length of one of the water inlet tubes, so we proceeded to weld sheets of 2 mm. attached to the tubes to improve their efficiency, careful not to exceed the 10 cm. of space that we already have but the CAP does not fit sticking with them.

Welding sheets once placed and dotted
Testing the coil
Said and done, we lit the fire and see how has trouble starting, having to switch roles of newspaper in the shot of the wall so the heat pull the smoke through the chimney, typical of these high-performance stoves. Besides the chimney draught, it also has an adjustable shooting in the drawer of ash, which need to be reduced when the fire has already ignited.

The half-hour two radiators that are installed (14 items total) were at 80 ° C, so it can surely warm the 4 or 6 that you want to install at a good temperature, performance, we said, was much better than with copper tubes, which I was pleased very much.
To increase the area of contact of the gas tubes, the heat is recovered well, always careful not too cool the smoke, because it can give problems of traffic jams in the chimney.

Photo of the coil under the right kitchen top
System Accessories

Noa, with its good to do and learning on the fly, put everything you need to take control of the system. In the photo below you can see the thermostat contact on the hot water outlet pipe (set at 30 ºc to jump fast and avoid the formation of air), barometer with the safety on the left valve. 3 bars, and automatic trap that is not correctly put, as it has a float inside that when it fills with water, closes the passage of air and must be placed horizontally so that it works properly, or however rather inclined upwards, but Noa will correct it as soon as you can.

With the Circulator motor and the expansion tank, we already have all the circuit. Gonna put a UPS if the light goes, but at the moment I mentioned for safety not let on the fire if you are home, and if the light is, be careful to extinguish the fire with water; (unless this is not as dangerous as a nuclear power station , but if it fails the cooling will be cooled as or will begin to pour water through the valve of security;-).

In towns like Lazagurría access to cheap wood or free is easy (ripped out old vines or branches, also called branches), so it is our responsibility to reuse natural resources in the outline.
Thanks to the curiosity and willingness to Noa will save from now much energy in the winter, that's always good with this crisis that doesn't seem to end, while the cares for the environment.
Attention: I do not recommend, by its low performance and endangerment, the realization of similar systems of heat without the knowledge and adequate security systems use. Today we have inexpensive pellet and domestically (EcoForest) stoves and other imported (Brico-Depot, Chinese mainly) that will save you money with great comfort; consult your authorized installer.

Attention: This tutorial or document is shared in an educational way to show from the experimentation of a biomass installation (not approved) not legalized form of heat management system, can be without all the required security measures. They are available to share the knowledge acquired, by way of home experiment; I don't do me responsible for what happens by evil or good use of these instructions if the minimum security measures; are not saved each one should use their common sense and knowledge to safeguard its material and physical goods.