Centralized control Solar-Biomass mixed system with Arduino and TFT Shield

In this post I will share with you the improvements I've made to our biomass/Solar mixed system , which is basically to change the obsolete control system for thermostats with a centralized system based on Arduino fully customizable, flexible and expandable; we will see the assembly, components and source code.

Applied materials:

   1 - Arduino MEGA 2560 (specifically I used a Funduino clone ), because the TFT shield does not leave me enough inputs / outputs Free UNO R3.

   2 - Touch Screen TFT 2.4 "  McuFriend , which will give us great freedom when it comes to display information on screen libraries that have worked best for me. Are the BUHOSOFT ; here you can download the version I used.

   3 - relays to activate solenoid valves, with a fed to 5V that can handle 230V and 10A worth us to spare.Not to stress regulator Arduino board, the food independently with other L7805 regulator (handles between 7-30V and 1.5A max). Being so low consumption, nor need a heatsink:

   - A speaker-buzzer for alarm warning in case of problems, which operates between 7 and 12V 100dB, enough.

   - A relay SSR DC-DC to activate the buzzer ; only consumes between 3 and 25mA so we can turn directly to the Arduino pin. I used one of solid state more than anything because I had left the other, butsince it is an element that is to be activated soon, you better go to a mechanical more economical and compact:

Modifying an insertable wood stove to add double combustion and fans

In this post, which had long been "waiting" for various reasons (my apologies to Alberto, intone the mea-culpa), an animated friend of sustainability we discuss how modified 2014 a stove without too much effort to optimize its performance , having fun how nice in the process.

Alberto tells us who dared to take pictures of it and write it done because it came in handy examples and information I put in this blog.

Adding steel tubes for double combustion and fans increase the combustion efficiency to deliver oxygen where it is needed, and also preheated, and fans are needed to optimize the extraction of heat to the room and extend the life of the stove by reducing the temperature of the structure , which otherwise would be very stressed by extreme temperature changes to increase performance. These modifications are safe (with the only danger plaster smoke, controllable and which will be discussed in detail). 

So, without further ado, let him be himself who tell us (apologies for the quality of the photos):

Presentation and project

The first is to introduce Alberto and I am not a professional in this sector, but I like the tools and I dare all.

I needed an insertable for the house in Ávila, at 1360m above the sea, as the chimmenie fire never could heat the cold granite house. And of course I wanted to double and double combustion chamber. 

I do not remember very well the extent of the gap in his fireplace; would be about 530mm, about, quite recently, I found an insertable fire made ​​of that size. The sides of the fireplace are also granite but the problem is securing a roof beam in the middle of the house and did not make me any grace the walls shake too.

So I Have This Test was willing to custom. I was asking for tempered glass in the door to start ... phew... 'find materials that work !!.

By chance I found a home at a low price approaching the measures, and for 250 euros I found very interesting in Leroy Merlin especially since half the work had already been done.

Centralized control mixed system Solar-Biomass with Arduino and TFT Shield

In this post I will share with you the improvements I've made ​​to -biomass Solar mixed system , which is basically to change the obsolete control system for thermostats with a centralized system based on Arduino fully customizable, flexible and expandable; We see assembly, components and source code.

Used materials:

   1- Arduino MEGA 2560 (specifically I used one Funduino clone ), because the TFT shield does not leave me enough inputs / outputs Free UNO R3.

   2 Touch Screen TFT 2.4 "  McuFriend , which will give us great freedom when it comes to display information on screen libraries that have worked best for me. Are the BUHOSOFT ; here you can download the version I used.

   3 - relays to activate solenoid valves, with a fed to 5V that can handle 230V and 10A worth us to spare. Not to stress regulator Arduino board, the food independently with other L7805 regulator (handles between 7-30V and 1.5A max). Being so low consumption, nor need a heatsink:

Example of installing a coil into a wood stove connected to existing radiators to share the heat to the rest of the home

Your coil makes good use to be able to put the logs inside.

Julian Elizondo, Navarra, has installed a coil embedded in the wood stove with all the necessary security . He says that he works very well considering the stove all day running, get temperatures of 20 ° C throughout the house without much cane put him into the fire, partly helped by the good insulation of the house as outside usually around them 5ºC half the winter. In total has cost about 700 euros between coil, copper tubes, electronic thermostat, valve autofill, another thermal shock, trap, etc, and to install have used the same gas boiler for move water ( as I explained in this post ) and have it plugged into the nearest radiator , eliminating it. Achieve heating elements 55 60 cm (aluminum radiators) and usually kept between 43 degrees and 50 degrees most of the day, Home on since morning.

Most of the installation is done it with the instructions of a cousin who is a plumber, who was the one who installed the auto-fill valve and electronic control of temperature in the boiler. Were turning and after several sketches decided the shape of the coil to better exploit its serious fire in C , as your stove is two doors and did not want to cancel any of the two doors.

The coil steel tube with 2 mm wall. or more will last a lifetime, because as a closed circuit oxygen from water by reacting rusting steel is consumed, until they oxidize more (formerly all radiators were much cast steel wall).

Designing a wood stove: simple, convenient and efficient combustion: Understanding the process of combustion of wood (3)

Picture: Hergóm 

To find an optimal design in an oven, we must analyze and understand the process of combustion of wood; variables involved, phases, each phase processes, better combustion conditions, etc., a theme to spare studied by engineers and encompasses knowledge of different subjects: thermodynamics, fluid dynamics, chemical dynamics, mechanical properties and thermal properties of various materials etc.

When designing an effective, safe and easy to build homemade stove, we find the following dilemma:

As the efficiency of the stove grows, so the complexity of it.

However we must look for a committed performance and simplicity and ease of construction that fits the overall needs in burning wood design , and our goal should be that, later to be implemented improvements (also easy to implement if possible ) that can increase performance.

Wood stoves with secondary combustion: Less smoke and more performance

In this blog we have been analyzing the benefits of using biomass to heat our home for profitability and ecology.

In this post I will discuss something even more beneficial for our pocket and nature: The technology of double combustion wood stoves. With this system, lacking the vast majority of wood stoves, get even greater performance avoiding much maintenance to avoid the generation of smoke, which the outlet tubes accumulate less soot and tar with use, produced by imperfect combustion of the gases expelled by the timber to catch high temperatures.

Soot particles are carbon that failed to burn and did not pass gas as CO and CO2.

How to heat a home with an open fireplace: Adding a cupper coil, by Rafa

Fireplace coil made of copper by Rafael, with added doors

The people are so rigged. Rafa, a Seville plumber of 52 years, residing in Gerona has been kind enough to share with us their system , very similar to mine , which  for heating radiators leverages the built-in fireplace (yes, those that turn you on ahead and I grow cold by behind), achieving a more than worthy result to save wood and heat the house. 
He was not aware of these pots (used in villages of the Basque Country for decades), and their parents save money and gave googled my page, went looking for and found Lacunza, in whose  assembly schemes relied for connecting pumps, thermostats , etc., which sells kits pumps and thermostats ready for its chimneys, and the coil was based on the they have for sale Fireplaces Sierra , but made ​​with 15 mts. welded copper tin / silver . Detail thermometer, thermostat at 45 ° C to activate pumps and sensor of the safety valve 90 (not visible in the picture, touching the tube) which triggers a valve that ejects the last water this temperature outside and in turn enter cold water from a faucet automatic filling (in another photo) set to 1.5 bar:

Detail shot regulating door, right thermostat, thermometer and safety valve sensor

Building a wood-optimal, safe, efficient and easy firewood: Continuation

Example stove with vermiculite plates and air intake to improve combustion

I keep turning the issue of simple and efficient stove burning (low CO2), my goal before automate with Arduino and complicate thing is to seek simplicity.

Everything should be made ​​as simple as possible, but not simpler. Albert Einstein

First of all I will discuss a couple of important things in any boiler or fireplace:

• Pressure of fumes (sub-Atmospheric): It depends on the height of the chimney, caudal (diameter) and flue gas temperature rising by it; more value for any of these three variables shot improvement. If too much heat recovered from combustion, the fireplace is narrow and low rise in output has no anti-wind cap, going to have problems in your smoke fire under; the combustion chamber will be filled with smoke and even put a door will not improve much the problem and the fire may drown in their own CO2. It is important a good shot if you do not want to fill with smoke every time you load wood burning stove.

Building an optimal and secure wood-stove: Getting Started

Photo: Lotus Wood stove

In this post I continue my reflexion of the design of a range of "open source" in which all (and indeed some have already sent me mail their designs and tips) can participate and improve. 
When designing a wood burning stove in the optimal fuel consumption and comfortable, we have several options, depending on how we want to extract the heat. 
To do this we use the latest techniques and materials; First I'll build a simple stove that anyone can do only with refractory bricks, refractory cement and a fan (optional for better performance), to then make a more complex and automated fire control, accumulator wood to make it even more comfortable and autonomous.

Example of success: changing oil boiler with wood boiler

If you have boiler heating oil, do as Gregoria and Manolo; consider installing wood boiler

The wood boilers and inserts are increasingly popular and successful, the possibility of getting free firewood (cleaning mountains of fallen trees and dry branches) is an advantage.

Today I will discuss the case of Gregoria and Manolo, from La Rioja (Spain), this winter asked me for placing an insert stove with pan for heating and hot water, they were complaining of bills for diesel fuel (3,000 euros annual) due to poor insulation of their house, the doors and windows are made of iron (discouraging thieves), and while they are thinking to better isolate 150 m2 over two floors, because it requires a very high energy expenditure.

They were Not decided between several models, and models from Baxi Roca, the cheapest they found was Albizia model (70% yield, € 1,200 approx.) unregulated auto shot, and Serval (80% yield of 1,900 €), Portuguese manufacturing.

Update 02/11/14: Gregoria tells us this winter "around here we continue with our hydroboiler running, although at least in our case, has not been as great as expected, due to poor insulation we think of our house (that have not yet been undertaken.) The truth is that when the temperature drops below 5 °, we are still with a bit poor temperature, unless we burn more than 100 kilos of firewood a day ... When the temperature is not so cool if we got a lot more pleasant when we warmed up first with diesel. Lately, we have implemented a mix that works pretty well. As we still have operating the oil boiler when we turn on the stove, once the day we launch the diesel, about 20 or 30 minutes, this causes less firewood needed to heat the entire circuit and we heat faster. The fuel consumption is minimal, we took 70 euros all winter so far . Furthermore, for reasons of lack of time ... we stopped fetching firewood us, so we bought it at a fairly reasonable price 11 cents a kilo, beech and oak. "

Finally, although the choice of pellets is the most convenient, they decided on putting a wood, having the chimney suitable for stove measures, and have free fuel themselves like to enjoy nature and take advantage of clean mountains respectfully with their maintenance, removing broken branches and dead trees, so opted to put the model Albizia Baxi Roca.

And they can not be more pleased with the result: With 50 kg. daily dry firewood, collected directly from the mountain, they get put at 20 all day, your house look new, Gregoria told me enthusiastically.

Spreading the heat from a smokestack with very little money

Low heat with heat removal by natural draft failing to place the drywall

In this post I will discuss the "invention" that has made ​​Jose, the previous entry that heats the house with a Hergóm stove to get more heat from a low fire.

Recently we were invited kindly to spend the evening at home, and we saw how he had prepared the Hergóm and how well it worked, and incidentally told me another idea that seduced me for its effectiveness, which he has kindly left me to share with you.

I had read somewhere on the possibility of putting tubes to extract the heat from the flames to the local, but had never seen implemented as well as it did Jose.

It is an ingenious system that removes most of the heat from the flames by the operation of two principles; that the hot air rises, and atmospheric pressure.

Let me explain:

• On one side is sealed local (almost), because it has more air inlets to the pipe through the home (or stack), so that the flames, while climbing because warm air is lighter, make natural draft, "sucking" air of the room, which has no other site you get the pipe through fire. On the one hand ensures that no harmful cold air currents, and other system efficiency is maximized because we do not need fans. And there is no danger for local air constantly is renewed by the preheated air stream exiting the open tube you see in the first picture. It is also self-regulating, more fire, more shooting, more heat to the room.
• On the other hand, the cold air entering the street at the bottom of the fire itself heat collecting tubes amounts to the upper tubes of the circuit, helping to maximize the siphon effect.

Sending the warmth of a fireplace to the radiators with a coil

The cauldron of fireplaces Sierra (Granada)

With the onset of winter, and increasing energy bills (gas, electricity) should look ways to warm up cheaper and more efficient, as the use of biomass (wood, forest waste, olive pits, etc). 

In conventional wall mounted fireplaces, as already mentioned earlier in this blog, 80% of the heat is lost up the chimney if they have no heat recovery system (either by movement of air or water). 
In a wood stove cast iron outdoor setting this is not necessary, already have a lot of performance (depending on the oven). 

Image: Cassette flush with heat fans with 85% yield

Stainless steel biomass heater produced in-house - by Jose

Update: If you wanna make this project on your own, I advise you to not put the horizontal steel sheets to avoid problems with smoke; those sheets cool down the fumes a lot and it is bad for verting, the tar and slag will stick to the tube. To avoid this situation the temperatures of the smokes must be over 300ºC.
If the tube is long, we have to put an insulated tube to maintain the ignition temperature inside of it.

This entry I will devote to the project of Jose, who kindly sent me photos and details of his proposed home in stainless steel boiler., As I am concerned by the crisis and the environment. Hope you enjoy it as much as me.
Project Details

Photo of the stove in operation in the absence of cover with drywall

(This document was translated using Google Translator from the original spanish article) 

Jose, another hands of Toledo has developed a wood boiler full of stainless steel., And assures us that is like a shot, in 10 minutes take the set temperature 60 degrees and starts pumping, the house is large (210m) and 2h hot. Is supercontento, of which I am very happy because it saves money and uses renewable energy such as wood (= 0 Co2) and get some exercise step carrying firewood (with saving him from the gym ;-).
Started commenting on this post , in which he commented that before light was paying € 500 every two months using a heat pump, while the neighbors, heat radiators "blue" spent € 600! per month, an entire salary.

Advantages of biomass
There will be people who think "gas is the most comfortable, give it to the thermostat and forget." And it is true, only that the discomfort comes from the ax € 150 per month, money that goes out of Spain, in addition to increasing climate change.
Wood waste helps the local economy, providing jobs in the collection, cleaning and transporting forest biomass.
Besides these stoves, wood metiéndoles good, they just need loads every 3 or 4 hours, about 15 kg. can heat up a house of 100 square meters, and is a good exercise to eliminate the daily stress, thereby relaxing the contemplation of the fire!

Heat the house with the stove: Place a coil in a Hergóm stove

The stainless steel coil and placed

(This document was translated using Google Translator from the original spanish article) 

Last weekend a friend and I were staying with a friend in Lazagurría . It is a small and intimate, you saw the south of a hill cottages, most over 50, who has managed to survive the decline of population on little towns on Spain (20 km to he city Logroño).
Noa, an impressive skillful woman, intending to heat the house with the fire of the plate in the kitchen, she wanted to better distribute the heat for the house of your old wood stove and saw on my blog, and in the end we put a coil efficiently adapted to your kitchen, with which it heats the radiators. Cost of the modification: 100 € and 200 € coil installed accessories for it.

We have made very good impression, we have been so pleased with their hospitality to revisit more often ;-). (Will accept requests from the entire peninsula, see the email in the top-right of the blog: D).

The kitchen is typical Hergóm still present in many old houses of Spain, which gives considerable heat and uses very good wood for their manufacture refractory brick and reinforced molten metal.

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

Adapt an electric water heater for use as heat storage by adding a coil

Copper coil to heat household water tank

(This document was translated using Google Translator from the original spanish article)

Install a system for using solar energy or biomass to produce hot water in winter is profitable within a few years (particularly in areas where solar power is not enough), but can be very expensive for many, especially in developing countries.
With this tutorial you intend to use an old water heater 200 liters. of 'Cointra' brand and add a coil to heat the water inside. Quite a challenge considering we have to keep the seal and put it in without enlarging the tank ;-)-.
Before deciding on this, I had several options for heating water for hot water in a simple and economical, each with its pros and cons:

• Buy me a plate heat exchanger high performance to bring the heat to the tank. This solution has many drawbacks, it affects the lime, is expensive (between 60 and 300 euros), you need a second engine to circulate the water tank (thereby generating mousse) and if you want to give priority to the ACS have to put a three-way motorized valve to divert excess heat after reaching a certain water temperature.

A copper heat exchanger standard.

Preparation of a stainless steel coil for the Russian stove

(This document was generated using Google Translator and then correcting some errors from the original spanish article).


Recently I showed you how to get better performance from a wood stove, using a Masonry Heater.
Yet I realized I could get even more performance (the accumulator design is not very efficient), and could benefit even more from the heat from the flames by adding a similar coil placed on the other stove my parents to recover more heat for other uses.

Underfloor heating
Hopefully, this floor was rebuilt in 2003 I had the great idea of putting underfloor home heating.


(of which I only keep this photo) made with copper pipes covered with dough and small amount of cement to make it loose and allow expansion of the tubes.
The technique of using the floor instead of radiators is the best way to heat your home for several reasons:

• Being a greater heat-emitting surface the water temperature can be much lower so the energy efficency  is between 15 and 20% higher than with other systems.
• By the same reason, solar energy systems can be used to transfer heat energy from the sun roof to the rooms of the house, for its performance at low temperatures (around 20 to 40 º C).
• The comfort is higher, since heat is evenly distributed and from the bottom up ... it is a pleasure going barefoot with the flagstones at 25 º C! Soil is also the heat accumulator, thus heating it for several days, we will be warmed up for two days.
  
• We eliminated the pesky radiators, usually placed next to windows covered with curtains so the losses through the glass are accentuated. All this is avoided.
• When working at low temperatures we can use cheaper plastic materials and is often used PE.

The disadvantages of this system are almost nonexistent. It may be mentioned that requires more work and labor (if done at the moment of building the house could be even cheaper) and that if there is a leak it is difficult to repair (could involve a large surface lift) and it is inappropriate to use soil with low transmission of heat as wood.

On my system I should have isolated the soil below the radiant tube, since underneath is the rock of the mountain to which is transmitted 30% of the heat and taking longer to reach temperature. The good thing about this is that if the soil is heated to 40º C (which requires several loads of wood in the stove), the soil will remain hot for 24 hours ;-).

Heat accumulator: Increase the performance of the wood stove (Russian Stove or Masonry Heater)

In this post we will see how to get more performance from a wood stove smoke passing through a vertical loop firebricks and do not involve maintenance.

Recently, I spoke of the "Russian stove" , which is simply a low heat oven or built with bricksrefractory and gives a great performance and comfort for heating. 

However I made ​​the mistake of assuming that the narrow passage I left still allow the passage of smoke (considering 4 meters in fire that made ​​shooting), but the smoke is cooled much and slowed both passing the shot was almost zero,introducing a lot of smoke in the room every time the door would have and it was very difficult to remove.

So since I had to disassemble the entire block bricks, took the opportunity to completely change the design because putting cast iron stove out from the wall it was a botched it had more disadvantages than advantages; this time the put-in wall, and on it, the heat accumulator block smoke, leaning against the wall by an arch .

I've always liked the brush fires; when I was little I was soup on the couch in front of the fire in my parents' house; careful with the crackle of firewood and comforting warmth, causes drowsiness;-).

I learned from the mistakes of the previous experiment, with the new design and I hope to have more advantages:

• Avoiding the maintenance, with a simple circuit favoring vertical soot fall within the same range.
• Better take advantage of the space and the brick is flush with the wall, plus it is prettier.
• Increase the shot, making a larger even than the smoke outlet of the stove step, which prevents the smoke comes out of the great door of the stove I have chosen.
• By using more bricks to the accumulator increases the stored heat and hours of comfort.

The only downside is that its performance is reduced by 10% (not recessed stove so easily and quickly releases the heat), heat up more slowly home. Still, a daily charge burning temperature sufficient to maintain at 18 ° C with 7th outside.

The nice thing is big refractory bricks which are highly resistant to shock, so I could disarm them,removing the refractory mortar with a pickaxe or hammer. It took me six hours to clean every drop and a Chinese work.

After placing the stove in place and discussing how to support the brick arch, I saw that I couldput bricks in the space between the concrete wall and the stove, so I have decided to support the weight distributed between the bricks and wall, to minimize the cut to be made ​​in the wall.

To the right I have chosen to put two vertical bricks instead of lying, and I think it will be well placed enough to support the weight and stress.


More mass must be put on top of the curve to be doing. It is better and stronger if purchased or prepared bricks wider on one side than the other, but it takes more money or work.


To hold the bricks as you would have used by placing pieces of brick. It would have been much better if he had made ​​a wooden template which then could remove, but I hoped to do guesswork and has been my right hand a little fall lr. so there is a lag of one centimeter. Although it has not been so bad for the first time I do one.

Attention: In my case this solution is suitable for the wall on which rest the 250 kg.Brick is solid concrete and stone. If you want to do the same and the wall is brick,build good columns on both sides with refractory bricks lying, supporting the arch in them.

The part of the center, with the mouth of the chimney is the most difficult, leave the hole but putting bricks wide as possible for resistance to the whole arc. Then the weight of the bricks will go around the center, so I'm not worried that the area can support less weight.

A note: It would have been stronger still mixing short and long bricks to prevent the continuation of the line of cement in the binding of both rows, as has been weaker for that part.

Do not forget to place fiberglass or rock wool (an insulating support that high temperatures) in the gaps left between the flue outlet of the stove and bricks.

We hope one day it has begun to harden the dough and we can lay bricks until a flat base, with bricks cut in half to reduce the use of mortar as possible.


We're raising the tower, laying bricks in the path of smoke, forcing him to go out and toward the center, so that the entire block into contact with the heat of the smoke, yes, always keeping the minimum smoke evacuation step.


I have been very conscious step to do so sufficiently to favor the natural fall of excess sootinto the mouth vent the stove itself. This way I avoid having to put records accessible for cleaning.Although there is also the possibility of getting dirty enough to stop smoke freely, I think it will take several years and can always drop the last row of bricks for cleaning.



The width of the passage for the smoke I have left is greater than before; but does not have to be excessive, the bricks must go coil supported at least two centimeters; heat may crack but between the weight of the other and mortar will not fall.


You have to leave a little space between the wall and the bricks that allow them to cool and heat the room, an inch is enough. I have not stopped and the heat is not released from the bricks so easily, making it less efficient.
Furthermore, in the mortar spare not used; it is important that there are no gaps where the smoke escape. You can always pick up the remains after the palette. It is also important not to leave any meeting without mortar and use a rubber mallet to set them right.


Finally arriving at the fire escape, I closed with big old bricks, using fiberglass to seal the gapsbetween the pipe and the bricks.
In this post I have not repeated some of the advice given or information on the Russian stove, I invite you to also read the above for more information.



Between the stove and the arch is a hole through which emits a lot of heat and partially shut, putting a grill with holes for the top. Keep in mind that the metal expands more than the mortar or refractory brick, so that should not be put between the stove and bricks.

Try to remove all that is between the stove and let the bricks to dilate freely.

And in this video you can see how it works; shoots much better and use is practically the same. I do not he could have ended at a better time: is back to snow in my area.
I hope that it do not give me any more problems for many years.

Ya just need to finish placing firebricks around beautify and clean them. Probably take the heat of this stove and to heat the water, but that later ...

What has been good to me, and how proud one is left watching your project and illusion performed, priceless!

Greetings to all and see you soon! Suggestions and comments are allowed, do not be shy!

Related links:
Russian stove in Bioclimatic Architecture blog (very good page on sustainable architecture)
Manual for the manufacture of a Russian stove - ( source )
"As a Russian stove is manufactured" on Forosolar of SolarWeb.net
Stoves high performance or "Kachelofen" in the German wikipedia ( translated into Spanish )
Masonry Heater in North America