Turboburn Monitor Plus

Suggested local user-interface for Turboburn Monitor Plus

With hindsight and a bit of experience behind us, here's my proposed specification for "Turboburn Monitor Plus".  This device does away with all electro-mechanical controls apart from, perhaps, an on-off switch.

Turboburn Monitor Plus specification

The device essentially controls the turbo-fan in any solid-fuel boiler of this type. It does so by monitoring the water-bath temperature, but can also monitor other temperatures. It has a local user-interface for example as shown above, and a remote, web-based interface.

The default local display shows the water-bath temperature in large numerals and the temperature trend in smaller numerals. In the example the water is at 93 degC and is rising at the rate of 3 degC per hour.  A lamp in the large button (or the display) indicates when the fan is running.

Press the small button marked "Display" to cycle though other parameters - after a few seconds the display will revert to the default.

Press the large green button to turn the fan on or off. When the fan is first turned on a period of say 15 minutes grace is allowed before the fan control algorithm cuts in. This is to give a newly lit fire time to get going. The algorithm detects when the water is no longer rising in temperature and turns the fan off and raises an "alert". The algorithm will also turn the fan off when the temperature gets too close to boiling, and raises an "alert".

An "alert" is also raised if the water-bath temperature falls below, say, 50 degC.

The device monitors the water-bath temperature and controls the turbo-fan. It can also monitor up to about six additional temperature sensors and a similar number of electrical circuits (e.g. pump on/off).

The web-interface will be similar to the existing Turboburn Monitor. Thus it also displays the water-bath temperature and its trend, and will also show the last 8 hours of this data in graphical form. The state of the fan and the temperature of other sensors is displayed (e.g. outside temperature), and the fan can be turned or or off remotely. All this data is logged in a file for optional analysis.

The device raises "alerts" to attract the attention of the person responsible for stoking. An alert appears as a banner across the web-interface page. It closes a volt-free relay contact which could be used to activate a siren or high-intensity beacon lamp. It could even send an email or a text.

The device is battery backed so that settings are not lost in the event of a power cut.

I am considering making this technology available in "kit" form. The kit would comprise a partially populated PCB (all the hard bits done for you) including an OLED graphical display and control button, a separate industry-style fan button, a heavy duty enclosure to mount it all in, and full instructions for customising to your own particular boiler set-up.

To register your interest without any commitment please send an email to tb4monitor at gmail dot com (replacing the ' at ' with @ and ' dot ' with . unless you are a robot!)

Turboburn Monitor part 3

Oh - and I forgot say - it is undesirable for the water to boil because the steam causes condensation which wets the insulation, and excessive boiling will discharge water through the overflow pipe, loosing with it the precious inhibitor additive.

Since even the best stoker may misestimate, we have added a feature whereby, when the 95 degC thermostat trips, a one-hour timer is started during which both main-house heating circuits are energised regardless of the room-thermostat. Thus excess heat is dumped to the house to bring the water temperature down.

If I redesign TB4 Monitor then it would be very simple to built this feature in, rather than having to use a separate 95 degC thermostat and one-hour timer with its relays to energise the heating circuits.

Turboburn Monitor part 1
Turboburn Monitor part 2
Turboburn Monitor Plus

Turboburn Monitor part 2

Our TB4 snug inside its shed "in the bleak mid-winter"

This picture was taken just after stoking. Once the fire has got up to temperature the amount of visible smoke emanating from the chimney drops dramatically.

The beauty of the Turboburn boiler is its simplicity. Apart from the amount of fuel, the only boiler user-variable is its fire-box fan. At the simplest level this could simply be left on 24/7, but having the fan on with no fire blows heat out of the chimney. Also, turning the fan off before a fire has burnt out may damp the fire sufficiently to avoid unnecessary boiling.

In Part 1 of this series I mentioned that Frank supplied a 2-hour mechanical timer and a 95 degC thermal cut-out. The idea of the 2-hour timer is to ensure the fan turns off if the boiler is left unattended, 2 hours being a typical time for a fire-box full of logs to burn out.  The cut-out is a fail-safe should the water get to boiling point. So I mounted these two controls in a box, outlined in red in the photograph below, this position being in front of two available thermometer pockets Frank had inserted into the boiler water-bath.

The house heating system has its own controls of course: the circulating pumps and zone diverting valves are controlled by a room-stat and programmer (timer). The hot water is controlled by a cylinder-stat and the programmer.

Our boiler is located a good 50m walk from the house and that's far enough to make one think twice about checking the boiler especially when the weather is inclement. So my first enhancement was to echo the boiler fan circuit to an indicator lamp and to install at the boiler a thermostat-switch set to about 50 degC which lights a second indicator lamp, these lamps being located by the heating controls in the house. Thus we can see without leaving the house whether the fan is running and if the boiler temperature gets very low.

My next enhancement was to add a relay to automatically switch over to the oil-fired boiler and immersion heaters when the Turboburn temperature falls below the 50 degC. This switch-over only occurs if a switch is set. So far we have used this feature only once - it was in the early days before we had figured out how much wood to stoke and whilst we had a bunch of American visitors (these Americans were allergic to our Irish weather).

With a little experience one can gauge how long the boiler will run on a given amount of timber and about how many degree it will increase the water-bath temperature, all other things being equal. But all other things are seldom equal: during the night when the heating is off the temperature hardly drops at all, but when all heating circuits are demanding the temperature plummets. Even when the programmer has timed the heating to be "on" it is difficult to predict when the room-stat will be demanding. If you have stoked the boiler expecting the heating to stay on, and then the room-stat turns if off, the water-bath temperature might soar. Or conversely you might think there was enough heat to last and then someone hits the "boost" button on the programmer.

Enter "Turboburn Monitor". This is a box of electronics which I created from a dormant work project, mounted on the side of the boiler.  This box is outlined in yellow in the photograph below - double-click the photo to enlarge it. The box is connected to seven temperature sensors around the boiler and two relays in the main control box (outlined in red).

Our TB4 boiler with conventional control box and TurboBurn Monitor

Inside the box a PIC32MX microprocessor acts as a web-server and is connected by CAT5 cable to our local area network (LAN). We were able to pull the CAT5 cable through the 4" duct Frank had thankfully insisted we bury with the pipes for such a time as this.

Any web-browser (e.g. a smart-phone) connected to the LAN can surf this embedded web-site to display the boiler status and optionally over-ride the 2-hour timer.

Turboburn Monitor main screen in the morning

The first screen-shot was taken shortly after 09:00.  The boiler was not fired during the entire period shown. You can see how well the boiler retains its heat during the night when there is no demand, and how the temperature starts to drop as soon as the heating comes on at 06:30.

We have the seven temperature sensors fitted as follows:

•  one in each of two boiler thermometer pockets: the software takes the highest reading
•  one 'outside' in a plastic box mounted on the outside wall of the boiler-house
•  the remainder affixed to the copper flow-pipe about a metre from the boiler on each circuit: main house heating, main house hot-water, courtyard heating (not yet working) and courtyard hot-water, thus a sensor reads high when that circuit is demanding heat.

An hour or so after lighting the fire

The second screen-shot shows a steady decline during the day (today - Sunday - so the heating was on most of the time) until the boiler was stoked at 14:33.  We usually leave stoking until about 4pm - I guess Joe decided to light the fire earlier today because he had noticed, from this software app, that the temperature had dropped as low as 60 degC.

Turboburn Monitor "Settings" page

The web-site has a second page accessed by clicking the 'Settings' button. Here you can turn the fan off if it is on, or on if it is off, and synchronise the web-site's clock which isn't battery backed in this version.

Turboburn Monitor has proven to be most useful and the various people here who stoke the boiler like it. But most of the time it is used only to remotely gauge the boiler temperature.

Clearly it could do more.  It was built "upon" Frank's existing 2 hour timer control but, if I were starting from scratch, I would replace the mechanical timer.  Thus the new Turboburn Monitor would do all that the existing version offers PLUS:

• local display of boiler temperature and trend
• local control buttons to activate / deactivate fan
• software algorithm to detect when fire goes out, kill fan and send prompt to designated stoker-person
• software algorithm, taking as inputs the flow-pipe temperatures and outside temperature, to estimate
• send prompt when boiler temperature drops below say 55 degC
• automatic kill fan when temperature exceeds say 95 degC and send prompt
• provide battery backup at least of the real-time-clock

The prompts could be by text or email as well on a banner (that has to be dismissed) across the web-site main page.

I imagine the same concept would apply equally to any solid-fuel boiler that needs monitoring from a distance. We have it in mind to further develop the idea as outlined above and to make it available in "kit" form (since inevitably every installation will have differing requirements). To register your interest without any commitment please send an email to tb4monitor at gmail dot com (replacing the ' at ' with @ and ' dot ' with . unless you are a robot!).

Turboburn Monitor part 3
Turboburn Monitor part 1

Fever

One's literacy tastes mature with age, they say, but there are several books that make the same impact when I read them now as they did when I first read them. One that I have already mentioned in a post is Kipling's Jungle Book. Another is Laurie Lee's autobiographical "Cider with Rosie" which was a set book in the early years of secondary school. Laurie Lee's way of expression strikes a chord with me and I find myself identifying with him. Whilst I cannot claim to have suffered such childhood illness as he did, nevertheless much of what he described tallies with my own childhood illness experiences:

"With the fever still fresh …by nightfall I was usually raving. My limbs went first, splintering like logs, so that I seemed to grow dozens of arms. Then the bed no longer had limits to it and became a desert of hot wet sand. I began to talk to a second head laid on the pillow, my own head once removed… Such a night of fever slowed everything down as though hot rugs had been stuffed in a clock… Between this sleeping and waking I lived ten generations and grew weak on my long careers, but when I surfaced at last from its endless delirium the real world seemed suddenly dear. While I slept it had been washed of fever and sweetened, and now wrapped me like a bell of glass. For a while, refreshed, I heard its faintest sounds: streams running, trees stirring, birds folding their wings, a hill-sheep’s cough, a far gate swinging, the breath of a horse in a field. Below me the kitchen made cosy murmurs, footsteps went up the road, a voice said Good-night, a door creaked and closed – or a boy suddenly hollered, animal-clear in the dark, and was answered far off by another. I lay moved to stupidity by these precious sounds as though I’d just got back from the dead."

I can remember laying in bed and considering the proposition of my head, as if it were outside of me, a great spherical ball immensely heavy and dense and with a frightening pressure inside as if it should explode. And the eventual recuperation, painted so well by Lee: the first taste of dry cream-cracker and Ribena (I can still hardly allow myself to drink Ribena unless I am sick) and, later, the first proper meal of boiled fish, so soft, so good.

And so I find myself writing from bed - I am suffering (along with several others here) from a particularly virulent cold that brought with it about 24 hours of fever now more or less subsided. I still have the thick-head-feeling and head-ache that reminds me of those times. Ali told me to stay in bed so I obediently obeyed. And so here I am...

Turboburn Monitor

Turboburn heat exchange coils

Living as I do in a Christian community our "home" is large. Its ancient construction makes it a very inefficient building for heating and our past electricity and fuel oil bills have been horrendous. Enter Frank Murhill who manufactures the Turboburn range of wood-burning boilers in Ireland for the European market. I had been looking for some time for a solid-fuel alternative and liked the idea of a heat accumulator, but had been put off by complex controls, complex terminology and convoluted flue passages with implied cleaning difficulties. And then there was the choice of wood chip, pellet or logs. When I was shown a Turboburn flier I was pretty sure it was the answer to my quest.  It took a year or so to finalise our decision and several more months to install our Turboburn TB4, the TB4 being the largest model that Frank sells.

Turboburn inners - from their website

The purpose of this post is partly to give a testimonial of how Turboburn met our heating requirements and partly to point out what we had to contribute to make the system work the way we wanted.  I figure that our experiences may help the next person who chooses to install this kind of system.

Here are some links to some smart-phone videos Frank has taken of our system:
Video#1,  Video#2,  Video#3

First a brief explanation of how the Turboburn works.

The Turboburn is basically a huge tank or "bath" of stagnant water completely surrounding a fan-driven firebox connected via "fire tubes" to a smokebox and flue - rather like a steam locomotive. Coiled copper-pipe heat-exchangers towards the top of the tank deliver hot water to taps or central heating as required.

Frank says that having the firebox totally surrounded and thus cooled by water makes it virtually impervious to being destroyed by heat. The fan makes the fire burn at a high temperature and thus very efficiently and with little ash and no build-up of pitch in the flue.  We fire our TB4 boiler once per day and let it burn out after 2 to 6 hours. The idea is to raise the temperature of the water bath to as near to boiling point as is practicable and thus to store enough heat to last until the same time the following day.

For example, at the moment it is 9pm and I last topped the boiler up an hour or so ago. The water temperature is now at 97 degrees C and the fan has just turned off. It may rise another degree but by experience I know it is unlikely to reach boiling point. This is just how I want it - plenty of spare heat to last through tomorrow until stoking time which, for us, is usually around 4pm.

Our monitoring software

We turn off our heating demand at night - the hot water cylinders store enough hot water for washing. The graph above shows just how good the TB4 insulation is - just a couple of degrees drop over 4 hours. And then the sudden plummet when the heating comes on at 06:30 a.m.  More about our monitoring software in my next TB4 post.

If demand is low, as it would be in the summer, we are told it will suffice to stoke every other day.

The beauty of the boiler is its simplicity. Provided ash is occasionally cleaned out (we do this once every couple of weeks) there is nothing to go wrong. The water bath is vented to the atmosphere so, whilst undesirable, boiling is entirely safe. Corrosion inhibitor prevents rusting which an open tank would otherwise suffer from.

We used to spend thousands a year on fuel oil and had three 3kW electric immersion heaters running 24/7. Since the Turboburn was installed we have not used the immersions or oil boiler at all.

We installed our TB4 boiler on a concrete pad some 40m away from the house and have subsequently built a shed around it. We have made a wood-processing yard surrounding this shed.

Because of the geometry of our buildings we have two separate central heating circuits and two separate hot water systems.

Having multiple heat exchangers made is easy to connect these up with minimal changes apart from the obvious underground link from the house to the boiler.

Even though the cost of wood is significantly less than that of oil or electricity, this type of boiler will not suit everyone. We have had three truck loads of timber in eight foot lengths delivered so far. That's a lot of wood. The first task is to chain-saw into rounds about 2ft long. Larger rounds have to be split. The timber then has to be stacked to dry for as long as possible - we plan to have about a year's supply of wood drying. All this takes a fair bit of hard labour and a fair bit of space.

Other fuels are possible - before making the purchase we visited a Turboburn owner who grows elephant grass as fuel. And it is possible to fit an oil burner though I cannot imagine why anyone would so that.

We told Frank that we wanted him to supply the boiler but we would do all other installation work ourselves. And this is exactly what happened.  We laid the concrete slab for the boiler, Frank placed the boiler onto this slab, added insulation, cladding and flue (chimney), supervised the filling of the tank and did a test burn. We erected the shed around the boiler and did all the plumbing and electrical hook-up. Since then Frank has made several return visits to make sure everything is running correctly, and has lent us a hydraulic log splitter.

Frank's log splitter in action

For boiler control, Frank supplied and fitted the fan and then simply handed over a 2 hour timer switch and a thermostatic trip switch for me to fit. He gave advice on how to lay the underground pipes, but we did this work. So here's a list of what we did:-

• We hired a digger to cut trenches 1m deep for our pipes, one trench for each of our two central heating systems. The longer trench was about 60m in length.

The shorter trench to the main house

The longer trench meanders to avoid an ESB duct

• We insulated and then laid our feed and return pipes in the shorter trench to the main house:

Three circuits in 3/4" pex for heating each pipe insulated with19mm thick Armaflex.

One circuit in 3/4" for direct hot-water each pipe insulated with19mm thick Armaflex.

These insulated pipes wrapped in builder's polythene

One 4" duct for future services laid on top

A manhole is needed to give access to joints
because pex pipe comes in 50m lengths and the trench
was over 60m long

• Likewise for the longer trench to the house extension:

Two circuits in 1" pex for heating each pipe insulated with19mm thick Armaflex.

One circuit in 3/4" for direct hot-water each pipe insulated with19mm thick Armaflex.

These insulated pipes wrapped in builder's polythene

One 4" duct for future services laid on top

Threading the insulation onto the pipe

• Each circuit terminates in its own heat-exchange-coil at the TB4 end, each with its 1" thermostatic mixer valve. The later is necessary because the TB4 temperature varies up to boiling point, whereas the heating water needs to be at around 70 degC and the hot-water around 55 degC. In any case pex pipe is not rated for much more than 80 degC.

• At the main house end, the three 3/4" circuits each have a 6m head circulating pump and NRV (non-return-valve) and then are connected in parallel and join the main house heating trunk circuit behind our existing oil-boiler (also with NRZ). We have retained the oil-boiler as a backup.

Three 3/4" circuits in parallel drive the existing
main house heating load

• At the main-house end, the 3/4" direct-hot-water feed connects via a bronze circulating pump  to the tops of our existing twin HWC (hot water cylinders), and the return is taken from the bottom. These HWC's serve four bathrooms and several other hand-basins. In operation the pump pushes water heated in the TB4 from top downwards into the HWC's. A thermostat near the bottom of one HWC turns the pump off when above about about 40 degC, at which point the tank is virtually full of hot water. A detail is that the feed flows via a 3-port valve into the HWC's - when the pump is first turned on the valve diverts water directly back to the return and thus avoids the trench-worth of water, which by this time may be cold, from entering the HWC's. After a timed delay of several minutes the valve is energised so that the water, which by this time will be hot, is fed into the HWC's.  This system provided endless hot water and its efficiency is evident in that the return pipe is usually cold or just warm - so that I have not needed to lag it where it runs above ground within the house.

• At the house extension end of the longer trench, the two 1" heating circuits will be connected in parallel in a manifold feeding various radiators pending renovation work. The 3/4" hot-water circuit will serve bathrooms in this extension to be as well as at present being connected to the third existing HWC which serves the main house kitchen.

• We prepared the boiler site and laid a 150mm thick, reinforced concrete slab

Here comes the boiler !

Frank unloading the boiler

Positioning on our slab

On goes the second chimney section

Various layers of insulation, about 9" in total

The first fire is lit

Now it is burning hot !

Part 2 deals with the electrical installation.
See also Turboburn Monitor Plus

Ran home from Naas

Naas to home 10.6 miles according to google.maps in 110 minutes, barefoot - felt more like 20

Two fingers

When I was very young my mother told me to clean some part of my shoe, the heel maybe. I asked her what she meant. She said I knew very well and not to be impertinent. But I really didn't know...

When I started in 1st form at secondary school I was only aware of one other Christian and he was in the 2nd form. When I saw him use the two fingers sign, clearly in a derogatory way, I asked him what it meant. I had seen other kids using the sign and thought that he, at least, would not mock me for not knowing. But he wouldn't say - he said that everyone knew what it meant. But I didn't.

I assumed therefore that it was sexual, hence the reticence, and could only suppose it was meant to look like a woman's legs apart.  But then I found the same sign being used for Victory - which confused me. Apparently it depends not only on the hand position and context, but also the nationality: it is only rude in the British Isle although my etymology may not be quite right see here.

My point being - why do people assume that the other person knows what they are talking about?

I remember my father for his sayings. One of them was that, if you are with others and are not sure you understand what they are talking about, you will learn faster if you ask what they mean even if you think so doing will make you look stupid. I regret that I sometimes despise folk when they don't know what I consider everyone should know. Not good...