Free Storage Heater Experiment

[Joeboy]

Nowty,

Is this more efficient than say filling a barrel of water and heating the water for the same period and then running the heat pump loop via the heated water ideally on the outside of the tank sandwiched between tank and insulation ?

I suppose it depends on the availability and size of barrel, insulation and space to locate as your current set up is "free" and infinitely flexible as to "as and when needed".

I'm curious I guess as this is a very specific application and seasonal requirement.

Moxi

It might not be any more efficient but I'm not going to be installing another water based heatstore for something which is only going to be used a few times a year.

My application is purely to help run Nowty Towers comfortably without gas in really cold conditions with sub zero temp nights and ONLY using cheapslot leccy.

This means ALL peak period power MUST be provided by my home battery and battery inverter. Therefore total load cannot exceed 6kW and the 50kWh capacity battery cannot be exhausted during peak times. This means the storing of heat is essential as well as battery charging during the cheapslot time.

My solution might end up being something more simple like adding another storage heater, maybe one the newer high performance ones.

One only truly learns what is possible through experimentation of theoretical ideas.

We hid our storage heaters as much as we could and they are the 80's ones that come up on Gumtree at reasonable prices. Last batch I got for £250 and I still have one spare to be installed soon. I'll put my hands up and say that thoughts of thermal mass came after I has already installed two SH. The house itself is a 1980's build and even with all the work I've down it still leaks. If I can get up to the 1/2 metric tonne of thermal mass I think we will be good down into the external minus range. As we are now we can drop to minus 1 outdoors just and gas stays off. That's a massive achievement for us and I'm over the moon at that. We have literally blitzed the shoulder months with innovative thinking, bigger arrays and of course tou tarrifs. Games not over yet! Go for it Nowty!

[nowty]

The top bricks in my oven are still too hot to pick up at 64 degrees, over 8 hours now since the oven switched off. I've opened up the oven door as I need them to cool down so I can cook roast chicken dinner later.

Still using my home grown Onions (running low), Thyme, Rosemary and Bay Leaf.
Sadly the tatties are no more.

[Moxi]

Now now Nowty, oven gloves were purposefully invented for the sole activity of removing cooked brick from the oven so you have no excuse not to get the chuck in the oven in time !

All this talk of thermal mass is taking me back to my apprentice days at British Steel (remember them?) where they used chequer brick recuperators on some of the older furnaces to preheat the incoming combustion air using the hot furnace off gases.

Moxi

[Moxi]

Mind you they used to heat to around 1100 degrees C if I remember my lessons correctly - and this was specific to the open hearth steel making process - alas where i worked on the EAF's the heat was just pushed up the stack and I remember then that we had a 1250 degree high temp alarm at the offtake to ensure we didnt set fire to the bags in the bag filter plant 300 meters away!

Moxi

[Joeboy]

Mind you they used to heat to around 1100 degrees C if I remember my lessons correctly - and this was specific to the open hearth steel making process - alas where i worked on the EAF's the heat was just pushed up the stack and I remember then that we had a 1250 degree high temp alarm at the offtake to ensure we didnt set fire to the bags in the bag filter plant 300 meters away!

Moxi

Where did you work Moxi?

[nowty]

All this talk of thermal mass is taking me back to my apprentice days at British Steel (remember them?) where they used chequer brick recuperators on some of the older furnaces to preheat the incoming combustion air using the hot furnace off gases.

In my apprenticeship at Springfields (BNFL) we casted uranium nuclear fuel rods in vacuum chambers (cos it burns in air like magnesium), heating a 380kg uranium conical block with electrical induction. One night shift they forgot to put the thermocouple in, but the process workers carried on with the furnace run as they could look through a sight glass and look at the colour to know when to turn off the induction heating. Process worker allegedly fell asleep, uranium overheated, crucible cracked, uranium melted through the steel base, lost vacuum. Molten uranium on fire spilled into a pit beneath the furnaces. Very difficult to put out metal fires so in the end they improvised and flooded the pit with argon gas from TIG / MIG welding cylinders. They were hand chiselling the fused uranium from the concrete floor for quite some time after that. And funny enough the temperature trace reading for that run went mysteriously missing.

It was acceptable in the 80's, it was acceptable at the time.

Frightengly we used to do a job right underneath those furnaces changing oxygen sensors, even when some of them were operating.

[Moxi]

Hi Joeboy I worked with the special engineering steels division at Rotherham Aldwarke steel mills in the melt shop as a metallurgist 3rd hand on T, K and N electric arc furnaces.

Nowty, I have heard of that and related incidents, one of the big fears in decommissioning circles is a uranium hydride fire although I have long argued that uranium hydride will decompose in air over a period of years to oxides and given the cladding has sat in bunkers of one description or another for thirty plus years the risk is minimal and tolerable.

The nice thing about clean uranium fuel is it’s literally hands on material with the obvious safe guards for alpha particles - heavy though.

Moxi

[nowty]

The nice thing about clean uranium fuel is it’s literally hands on material with the obvious safe guards for alpha particles - heavy though.

Yes, it was a surreal thing to walk round with a magnox uranium fuel element, cladded or even uncladded as if it was a normal thing to do held at one end with your bare hand and the other resting on your shoulder. We used to use real fuel rods to do some of the machine calibrations as they had to have the correct weight and dimensions.

One thing that was fun (as an apprentice) was there was a really long corridor, like 100 meters long or more and it had small prices of uranium fragments (from the top of the the rod moulds) littered everywhere and we used to kick them as hard as we could and they used to spark like cigarette lighter flints as they bounced along the concrete floor. Although if a foreman saw you doing that you got into trouble.

[Moxi]

Ha ha you reminded me of an incident with that recollection- we were decommissioning a station and the fuel was all offsite when we came across a lead wrapped metal box complete with padlock in an abandoned room - off to a secure cell to unpackaged and surprise surprise it’s a fuel element correct size and cladding arrangement for our station but we are reportedly fuel free. Investigation ensued question raised and eventually we determine that a n element had been borrowed from the sister station to allow sensors at our site to be calibrated - then they forgot to send it home. Both stations got a royal shillacking from those with the big sticks of officialdom. That was not so long ago and goes to show how important it is to not run civil operations with enriched product !

I used to be SQEP with the magnox fuel elements and the variety of cladding types required for different reactors - it never ceased to amaze me how the whole fleet was treat as a design development exercise i bet production at Springfields was a nightmare at times trying to fabricate fuel in all the different arrangements

Moxi

[nowty]

Anyway, been a bit busy today.

I went to have lunch with SWMBO on her work break, she faked going to have an eye test so we could have a leisurely time.

There was a free podpoint charger at the shopping area so I plugged the TM3 in for a free 7kW charge so all todays driving around was cost free if not carbon free.

After I returned home, I found that one of the bricks which was a high density block paving brick was hotter than the other house bricks so I decided to go down B&Q and buy a few more block paving bricks to replace the house bricks. I took out the oven shelf which was buckling under the weight and arranged them into a new configuration all nicely stacked and have increased the mass yet again to 22 bricks, about 46kg so I reckon its all at least 3kWh of heat storage now.



So its not quite free anymore but still very cheap, obviously going to do another test run tonight after cooking the chicken dinner in the same oven (minus the bricks).