Category: Temporary Accommodations

Repair and Upgrade of Storage Heater Number Two!

Here we are .. just to the start of Winter .. and we are having to service our homemade Storage Heater, to make it fully functional again. Also, we are taking the opportunity to upgrade the control board as we had a proper PCB made earlier in the year when we did some lighting modules so we included a design to allow us to put on a new larger micro-controller chip.

New Stoarge Heater control PCB

We undid all the wiring and devices from the old control board and populate the new PCB with those, plus some new extra ones too.
There were some minor corrections needed to be executed on the PCB and other slight modifications but we now have a new working control board without the forest of looping wires shooting all over the place.

The next job is to get access to the trays of bricks so we undid the front panel, loosen the wire mesh, carefully picked off the glass wool and untangle the inner wire mesh as well and bent them open to the sides. At this point, we discovered that some of the insulation was very fragile and crumbled when we touched the wires coming out of the trays, especially the top ones.
So, it was a case of replacing all the wiring with better high temperature resistant insulated wires which we found on the web. We bought two rolls of 12metres of three layers; one woven glass fibre on the outside, a middle layer of Mylar and an inner layer of more woven glass fibre, protecting a 0.75square millimetres of 10 stranded copper wire. The whole wire is rated for 500°C !!

We also noticed that the spade terminals plugged onto the elements inside the bricks, were not tight anymore and this has caused corrosion, probably caused by electric arcing damaging the surface. So we needed to solder the new wires directly on to the terminals on each element. This meant finding a high temperature solder and it turned out to be a silver copper alloy that has a melting point of 750°C to 800°C which is high enough for our requirements! We bought a tiny little syringe weighing just 5grams costing £10!! Silver is not cheap!
This syringe also has a special flux mixed in with the silver and copper particles.

Once these items arrived in the post, we proceeded to lay in the new wires, a pair for each tray, going out sideways and then up to the top of the cabinet and then up into the control board area where they were terminated with a solid caps and then screwed into a line of terminal blocks. One thing we discovered was that one of the rolls was only 11metres long and not 12metres!! What Cheek of the manufacturer! We had to borrow a short length of our old wiring for the last section going up to the top of the cabinet which is fortunately outside the hottest zones. So should be ok.

Next, by pulling each tray out a few inches, we scrubbed the two iron tabs of the elements using a ‘scotch-brite’ wheel, to clean up the corrosion and rust.
We then expose several inches of the wire, twisted the strands together and then poke the end through the little hole in the middle of the tab and wrap it around twice, before arriving back to the incoming wire where it was twisted together. We had some old flux which we revitalised and applied a blob to the contact area and using a miniature blow torch using liquid propane gas, heated up the tab until it started glowing orange hot. It said on the web that bright red for iron has a temperature of about 730°C and orange is a temperature of 930°C which is high enough to melt the silver solder.
We did the second tab the same way and then to make sure that we got a good soldered connection, we measured the resistant between the two wires up on our control board and if it reads approximately 67ohms which is the internal resistant of the element themselves, we therefore got a good connection.
We repeated this task for the next seven trays (one of them had a resistant of 98ohms which meant the soldering didn?t work terribly well so we redid it again).

Now that is all done, we could reassemble the wire mesh and put back the glass wool. But before putting on the outer layer of the wire mesh, we got some more glass wool and thickened up the two outer vertical edges and also folded a double thick layer for the upper 6inches above the trays of bricks. It was showing signs of being rather patchy.
This will hopefully help reduce various hot spots on the cabinet, especially near the top on the right side. We will see!

The final wire mesh was inserted into place and after double checking all the electrical connections to each tray again, we put the front panel back on.

The new micro-controller was tested and the software was modified so that we can now switch on any of the eight trays. The display is working, the menu button and selector is working, the mains electricity sensor to measure the current is working, the 50hz signal is being picked up, the motor for the chimney flap is working and all six thermocouple probes are reading ok too. We double checked all the electrical connections at the relays and the row of terminal blocks and we did discover a left-over wire link in the back of the last terminal block. It was reading 0ohms between the live and neutral lines and only after leaning over and cranking one’s head (a very tight gap between the ceiling and Storage heater) to see behind the terminal block, we could see this rather hidden link! The next test was to measure the resistant of each circuit after all the relays were told to switch over to the ‘on’ position and we discovered another problem. It seems that we may have burnt out the internal contacts as most of them shows very high resistant levels so we had to order a replacement eight-way relay module.

This duly arrived within a day and we did the laborious job of unscrewing all the connections to release the wires off the old module and then slide in the new one, putting all the dozens of wires back.
After testing the new relays, which are all working just fine, we proceeded to a full test where we set the temperature to a low 100°C and set the clock so it thinks it is in Economy 7 mode.
It switched on five of the eight trays at a time, using the pattern of on, on, off, on, on, off, on, off for tray 1 through tray 8 respectively. Then, every five minutes, it would rotate this pattern, one tray position, around the eight trays so that all the trays would eventually get equal amount of charging.

And ..

All is successful! It got to the required temperature and stopped charging in just under an hour. Yippeee!

Now we can reset the clock to the correct time and set the target temperature to 300°C and leave it to run overnight.

18 November 2024
Upgrade and Repair of our Storage Heater

We are facing another winter here in our temporary living quarters, so therefore we needed to service and upgrade our homemade storage heater.
This report was rather late in being created and published- November 2024!!Our first attempts of heating the bricks up was not robust as the heating wire suffered from metal fatigue, caused by the wires glowing red hot one moment and then cooling down during the day. This is what we discovered when we dismantled several of the trays. The wire was broken in one location or another.
So we went looking on the web and discovered some commercial heating elements that are designed to fit in a domestic storage heater out there somewhere, we didn?t care about that, as these would provide a much stronger replacement than our bare wires. So, we took apart the two layers of bricks, chip off the cement and pulled away the heap of heating wires. We then turned the bricks over so that the hollow part is open upwards and we grinded a series of slots to fit the new heating element in so that the second layer of bricks can come back down flat again.

We connected the spade terminals to the existing wiring and push the spade plugs on to the elements. We reassembled the stack of trays. One thing to note, is that we only replaced eight of the ten trays as the supplier were only selling these elements in packs of four and we didn?t want to take the risk of buying another pack and have two spares. We were not confident enough to know whether it will work or not. Another limitation was the power requirements as each element is more powerful than our original setup, therefore we could only connect one tray to one relay and we had only eight relays in total. So, the bottom two trays were two of the old design and we left them in the stack to act as ballast.

We reassembled the rock wool layers, stretched the wire mesh over the wool and put the front cover back on again. We rewired the relays up on the control board so that the mains is switching just one tray instead of a pair it was doing before.

We fired up and everything is running. We then set the temperature to a deliberately low 200°C and waited overnight. The five trays all heated up nicely!! So, we turned up the temperature to 300°C on the following night. All is ok again. We did 400°C and still ok! And finally, we settled on 500°C and lovely!

You may have noticed that we were only heating up five trays and the reason for this was that our micro-controller chip didn?t have enough output control pins to drive the other three trays.

We have our storage heater back again for this Winter!
We are warm again using cheaper Economy 7 prices!!
Phew!

20 November 2023
Designing and Building of a Storage Heater

This is a long awaited blog report to catch up on what we have been doing these last few months since before Christmas last year. We had to come up with a strategy to reduce our commitment on the stupidly high electricity prices. We have already invested in a large array of Solar panels and a Battery system but we found that it was not big enough to cope with our temporary living quarters in keeping us cosy and warm. We found that we needed even more energy during the daytime than what the battery could deliver, even if we charged them up using the cheaper night time rates, which we are already doing.What we needed was another Battery pack but what with the war in Ukraine and the chaos of all the world shortage in materials etc. .. The exchange rates were very poor and it would have costed us another £2000 at least and even a third pack would only bring in additional 15kWh of energy storage. We really needed another 30kWh to 40kWh to cope with the coldest days in our living quarters.

This means a more traditional storage heater design, taking electricity and storing it as heat in ceramics. But it is really difficult to find a shape of size that will fit into our existing arrangements and also it seems that the cheapest ones that is big enough for our needs would be also cost us well over £1000 as well.

So we fall back to our usual solution .. Build It Ourselves!!

We had some steel ‘rebar’ that were the left-over from doing our swimming lane so we designed a frame for the heater, an inner cage that will hold trays of house bricks and an outer frame to hold the covering, with space between for insulation. We had a load of clay bricks sitting outside, not doing anything so we grabbed 180 of them and got them all washed in hot soapy water.

Cleaned-bricks-waiting-to-be-used

We then cut up thin steel sheets we had and bent up a narrow edge to form the metal trays then welded the corners, each tray holds 2 layers of 7.5 bricks. Next, we bought some high temperature mortar mix, designed to be used in brick kiln ovens and cemented the first layer of bricks together and then buried the electric heating wire in a layer of cement before sticking down the second layer of bricks on top.

Storage-Heater-Brick-trays

The electric heating wire is the standard industrial type, an alloy called nichrome, which is composed of 80% nickel and 20% chromium. We wanted to end up with a pair of trays drawing 1kWatt of energy from the mains national grid. We made ten of these trays, to fit into the steel cage, to form a tall stack.

The next job was to wrap the steel cage in chicken wire which will hold the glass wool insulation in place without it bending into the inner chamber and touching the trays of bricks. We needed an air gap around all the trays so that the hot air can rise and escape out of the top. We also laid across the chicken wire a layer of aluminium foil to reflect the heat back into the core. Finally, the glass wool, which was 50mm thick, was squashed into place with a second layer of chicken wire and another layer of aluminium foil. That is the basic design of the inner core.

The chimney at the top had an 1inch thick ceramic trap door which can be lifted up using a motor and let the heat out. The whole upper section is 150mm thick of glass wool to minimise the heat losses upwards and avoid overheating our electronic control board as well.

The whole thing was then encased in a mixture of 10mm and 8mm thick cement boards to provide the final human safe outer cabinet shell. There is a small air gap between the cement shell and the insulated inner core, to allow fresh air to circulate up and around the whole unit and keep it cool.

The front panel then had a wooden duct built on it, to form a channel for the hot air to be vented out into the room around the floor level, using three high temperature rated case fans. They are speed controlled so can be adjusted electronically depending on various factors like room temperature, the chimney temperature and mixing chamber at the top. We would like to keep the temperature under control and not allow the shell to get too hot.

The electronic control board has a little microcomputer that has lots of input pins connected to 9 different temperature sensors, 6 of them are high temperature thermocouples and the other 3 are the more normal types. We placed the thermocouples in and around the trays of bricks, three of them actually placed inside a brick, down a small hole and the other three are measuring the air temperature between trays, with one of them up in the chimney itself.

With a combination of all the temperature sensors, we could control the heat output during the daytime by opening and closing the chimney and speeding up the fan to extract the hot air pouring out of the inner core. The control circuit also took the mains grid electricity during the night-time period and ?charged? up the ten trays of bricks, bringing them up to a working temperature of 300°C. Our calculations suggested that we should have been aiming for a much higher temperature of around 450°C to 500°C but we couldn’t get that far. There was too much heat loss out of the inner core, probably a lot of it is going up the chimney, even though the flap is fully closed. We discovered that it seems that our amount of glass wool insulation isn’t thick enough to provide a longer term heat storage.

In hindsight, we probably should have gone for a smaller tray of bricks and put in twice as much glass wool insulation so we could have gone for a higher working temperature and be able to have a better control over the core temperature during the different periods of the year. On the other hand, it is working well enough to make a fabulous difference to our electricity usage during these cold times, and especially with us only paying 11p for a kWh unit of energy during the night 7 hours period, we are saving enormous amount of money this year. It doesn’t matter what the daytime prices are (actually it is 51p per kWh unit) because we don’t need to use any grid electricity during the daytime hours at all. Our battery is also being charged up during the 7 hours night-time period and we then can power our house from the batteries almost all the time. It is only during a rare occasion that we exceed the 5kW power capabilities of our powerful Solis inverter that we have to draw a little bit off directly off the National Grid.

We completely assembled the heater while still in the garage and did a test run of heating it up just in case something went wrong and burst in flames! First to only 200°C, inspect all side and check the temperature of the outside shell. As this was OK we started heating further and got to about 350°C and checked everything was again OK. The hottest outside parts only reached 50°C.

Then the moment arrives when we had to install the giant thing into our living quarters. You may not appreciate this but this thing measures 550mm wide (nearly 2 feet), 750mm deep (2½ feet) and a massive 2100mm tall (7 feet) and it weighs, with all the bricks and everything, somewhere in the order of 500kg!! That is half a ton!! Smile!

But of course, we couldn’t move 500kg! So we had designed it to allow us to undo the front section of the cabinet, undo the inner core and slide out the ten trays of bricks as well. We could then move the cabinet on a sack trolley into the long corridor of our living quarters and get it positioned into the correct location so that we could slide it into the hole we had made into the floorboards. We knew that 500kg would have been too much for our floorboards so we cut a rectangle segment out and put in some reinforcing wooden beams across the wooden foundations underneath. After a tricky time of moving the cabinet around and aligning it up to the hole, then slowly rotating it upright and at the same time, drop into this hole. We were just about clearing the ceiling but only just!! But we made it .. just ! Phew!

We reassembled all the ten trays of bricks, redid the glass wool and chicken wire mesh to lock up the insulation again and then put the front panel back on. We laid in a new mains high capacity electric cable back to our consumer unit that we had to upgrade .. .. and switch it all on!!

It works!!

As part of our new regime of working, we are doing a lot of computer work and this storage heater has some of the components of managing our equipment and communicating response packets back to our database. We record what the storage heater is doing during every minute of the day .. and night and we can see how the temperature of the various parts of the inner core is doing, and also, measuring what power we extract from the grid, plus what the fans are doing etc.

We learnt to how control the fan speed during the different modes of operation, whether the flap is open or not and we must have reprogrammed the little microcontroller brains a dozen times with new functions and techniques to get what we wanted. It is still a working in progress but ..

We have pretty pretty much finished all what we want to do to this storage heater. There may be minor adjustments as time goes past. But, now we are going to concentrate on getting our computer sorted and start working on the various software libraries for managing our whole house. We will resume our work on the house soon.

1 February 2023
Adding Extra Insulation to our Roof on our Temporary Living Quarters

We were interrupted in doing this task by a bout of Covid and waiting for the weather, but we finally got to install an extra layer of insulation foam boards to the roof of our temporary living quarters. We are suffering from the huge rises in electricity prices and we needed to do something about it and save money.
So we decided to make use of our recent supply of recycled PU foam board pieces and construct 90mm thick panels. We took a heap of random sized pieces, only making sure that they were at least 1200mm wide and put them through the slicing machine to make 90mm wide pieces. We then stacked them into a frame and stuck them together with a little bit of PU spray glue. We stacked them up to a height of 1750mm which covers the majority of the roof surface, leaving a small gap down the ridge line, which will be filled in with other 90mm pieces later on.

Sliced-insulation-glued-into-a-sheet

We proceeded to make sixteen of these panels over the course of several days.

Constructed-sheets-ready-for-install

One of the early jobs we did before we got Covid, was to install a series of 89mm CLS timber pieces up on the roof so that we had somewhere to fit down the roofing felt and also retain the foam panels in. These CLS pieces were screwed down with 150mm screws, all the way around the edge.

Temp-Living-extra-insulation-framing

The next task was to slice up some 11mm OSB board to generate fourteen 100mm wide strips and four 75mm ones, all them being 1780mm long. These pieces will be used to clamp down the insulation panels. Eventually, we will laid down a covering of protective roofing felt, so we decided that these OSB strips needed to have their edges chamfered so we put each one through our router. The four smaller strips had a quarter round shaped on one edge and a 45degree slope cut into the other edge. The same 45degrees chamfer was done on both edges of the other fourteen strips.

Then, after ordering a box of 180mm long screws and clout nails for the roofing felt and grabbing a lovely clear day today, we managed to get all sixteen panels up onto the roof, starting at the far end and proceeded to fit each one, sometimes needing to trim them down a little bit and clamping the edges down using the strips of 11mm OSB we made earlier. We had to drive the long screw into the roof, to seek out the old 50mm roof rafter inside the structure, and making sure we found it so we had a solid fixing.
Because the old roof had regular slight hollows, we used lots of spray PU foam to fill this little gap between the new insulation panels and the old roof surface, in order to support the new panels, especially when we walk over the new roof whilst applying the roofing felt.

Foam-under-the-sheet-to-fix-and-support-tehm

We managed to get the entire roof covers by about 4pm and the last job to do was to cover this new covering with a tarpaulin, to make sure that the majority of the rain will be deflected away and keep it reasonably dry. The weather is very wet at the moment and we need to wait until we have a full dry day to get the final roofing felt glued and nail down.

All-boards-installed

Now we wait …
We finally got the roof felt on a week later! It was the first dry day when we did not have other commitments, it turned a to be a very drear day with fog all day.
The felt was rolled onto the roof and nailed around the perimiter and along the OSB fixing strips as well as gluing it to the roof at the overlaps and gluing the overlaps to them selves.

Covering-the-insulation

All-covered

28 November 2022
Storm Eunice Ripped Several Pieces of Roofing Felt Off

This afternoon we took to the sky and repaired a smallish section of roof on our Temporary Living Quarters, damaged by Storm Eunice a couple of days ago. It managed to peel off half a strip of roofing felt down at the far end of the roof and a smaller piece also down that end too. We had some spare felt in the garden shed, some nails and half a tin of bitumen horrible black sticky glue. First of all, we levered up the edge of the next strip of felt up the roof (it was going over the central ridge line), got the nails out and slid under the edge a length of the new felt. We used plenty of the bitumen glue to stick down the edge and then nailed everything together to make sure the wind didn’t pick up the felt and cause more damage while the glue is drying. Then a smaller piece slid under the previous strip we just done and applied more glue to that overlapping edge too, finishing off with another line of nails, plus a dozen nails to pin down the loose edge that bends over the edge of the roof and down the wall a little way.

Temporary-living-roof-repaired

To make sure we did not suffer the same faith again, we screwed down a 6 foot length of batten across the end of the roof, to clamp down the ends of the roofing felt, and avoid the chance of another Storm coming along and ripping more felt off our roof!

23 February 2022
Sun Shield Taken Down and Thrown Away

Today, the first thing of the new week, we went up on our roof of our temporary living quarters to take down the Sun Shield from over our long corridor transparent roof “window”. It was falling apart and splitting in lots of places, we could just tug at the material and it would rip quite easily, so we undid all the clamping piece of wood and unthreaded the rope, folded it up and dumped it into our bin. Looking back in our records, it seems that we created this version of the shield back in April 2018, see Sun Shield Over Corridor Created and Mounted for details of us doing sewing, so it has done just about three and half years of service, coping with the powerful radiation coming from our Sun.
Next year, we will repeat the job of buying a new tarpaulin and making a new sun shield.

20 September 2021
Sun Shield Patched and Installed over our Corridor plus New Waterproof Cover for Header Tank

It is very very hot outside today, we had to repair the tarpaulin that provides a sun shield over our long corridor in our temporary living quarter and also replace one of the tensioning ropes.

Sun-corridor-cover-Jun-2021

The rope had frayed quite badly in the middle point where the whole cover is hoisted up to provide two sloping surfaces to shed the rain water. So we had to thread a new piece of rope through which was a bit fiddly. For the large tear, we found two thin oak strips and while pulling the tear closed, used the two pieces of timber and clamped across the tear using six screws alternatively driven from each side and holding everything together, hopefully for another year or so.

Sun-corridor-Cover-repaired

Then, we replaced the 10 year old waterproof cover, protecting our header tank that sits on top of our garage to provide a temporary water supply to the kitchen, shower and toilet downstairs. We cut another piece of DPM plastic measuring 2.1metres by 2.7metres long and rewrapped the rectangular structure and re-tied the rope back into place.

Water-tank-recovered

Next, we had a quick survey of our roof surfaces to make sure that there were no holes or wearing patches that might look troublesome for us in the future and we can report that it is looking good.
That concludes this year’s annual maintenance for our temporary living quarters.

14 June 2021
Patched Hole in Corridor’s Roof, Caused by a Firework!

Today, we discovered a leak in our corridor in our temporary living quarters while it was raining outside! Upon closer inspection, there was a hole right through the outer layer of the clear corrugated plastic sheet, and we found a little spent firework payload, only measuring about 12mm by 18mm!
Our neighbour, yesterday, decided to celebrate Guy Fawkes Night really early this year and was letting off some fireworks which included these mortar shells that pumped sparkling displays up into the air. One of those empty payload capsules must have went straight up and came down hard on our roof.

Hole-in-the-roof

But to be fair, our corrugated plastic roof is getting rather old and it is becoming more and more brittle as the years roll by. But, it was still amazing that such a little thing could punch clean through the first layer of our roof, and bounced off the second layer inside, we now have a permanent souvenir visible until such a time in the future when we dismantle our temporary living quarters!
So the solution was to thoroughly clean the surface, with sand paper and chemicals, and lay down aluminium tapes to try and make a waterproof patch. We will see !

We will have to keep an eye on this roof and hopefully, it will survive for another couple of years.

26 October 2020
Sun Shield Over Corridor Removed and Two Fence Panels repaired After Storm

Today, Sunday, under a very grey sky, we got up on to the roof of our temporary living quarters and rolled up our Sun Shield tarpaulin covering over our long corridor and put it away for this year.
We did a quick inspection of the rest of the roof, including the garage roof, to make sure that it is looking good and solid.
Plus also, we put in fresh batteries into our weather station transmitter as it was reporting a low battery indication.
After that, we went over to our temporary wooden fence along the Loke to repair two panels that had been blown down by the storm we had a couple of days ago. The rain gauge reported a total of 50mm of water fallen out of the sky! Fortunately, it was not all concentrated in one sharp downpour but spread right across the whole day. Phew!
Anyway, we screwed some pieces of 2 by 1 battens (recycling so old pieces used for the dunking tank) to reinforce the broken vertical edges of the panels and slid them back in between their posts. This time, we also screwed the panels to the posts to stop them falling out of their brackets.

Repaired-Loke-fence

That concludes the 2 hours of Sunday chores!

27 September 2020
Sun Shield Covers Corridor and Cold Water Header Tank Inspected

Today, we reinstalled our usual Sun Shield over the long corridor of our temporary living quarters. It was quite late this year, perhaps we got used to the heat coming in, or perhaps it is not so hot this year as it was last. Anyway, it now stretches across the 10 metres of the corrugated plastic roof.

While we were up on the roof, we inspected the roof surface to make sure that there were no cracks or holes.

And finally, we opened up our cold water header tank to inspect inside. It was all crystal clear and all fine. We did test our two electronic water level switches to make sure they are working. We are planning to start using them, in conjunction with a sterilising and filtration module, to draw up water from our underground rain water tank and start making use of it for domestic use.

20 June 2020