The Eco save power/solar/diy Nuclear Fusion plant thread

Zimmerframe

MUPPET
Subscriber
Jun 12, 2019
13,883
20,573
Brittany, France
This thread won't be for everyone, but a place to share some ideas if you do like the idea of using less power (gas/electric/oil) and ways to achieve that. If you're a leave all the lights on "because you can afford it" type of person, well, don't read on !

My latest foray into using less electric was re-evaluating my hot water usage. My present house shows evidence of previously running instant gas hot water (from bottles) and Instant electric hot water, from a three phase electric hot water heater. It presently uses a 200 litre insulated electrically heated tank.

The first thing I did was double insulate this with polyurethane. This certainly helped, but as someone presently living alone with no bath in the house, a 200 litre tank is excessive as it will ultimately loose most of it's heat to the atmosphere around it. The tank also had quite a long run to the main water usage areas in the house. In France the present regs say that is a 10 meter limit to avoid wastage, it fell within that, but you still waste a huge amount of water waiting for warm water to arrive and a huge amount of warm water that then goes cold sitting in those pipes.

I was talking with some friends last night. Their house is setup so when you turn a bathroom light on, it starts to circulate hot water around the pipes to that room so you get hot water straight away. She has cold showers for various reasons, so ultimately wastes energy as the pipes will radiate that hot water into the house without it being used :)

I looked at instant hot water heaters as these would ultimately be the most efficient for low use - with no water heated which wasn't used.

Unfortunately, here, you can't have a 24kva supply (which is what you'd need to run one) on a fixed rate tariff, only on day rate and night rate, so when you showered, you'd be using peak electric rates which then makes the system no longer economical.

Instead I went for a 45 litre twin tank system with "intelligent" ?!?! usage monitoring. Basically, instead of one large tank, there are two smaller ones, so if it works out that most of the time you only need 20 litres for instance, it only heats one of them. Then based on how much you do use, it will vary the temperature it heats the water too. For example, if you used 20 litres in a shower - say 40 degrees. It would just heat 1 tank to 45 degrees. If you used 4 showers at 40 degrees with 80 litres of usage, it would heat both tanks to 80 degrees so once you'd mixed with cold, you'd have enough water.

The other "sales pitch" of the twin tanks is that they're slim. Two smaller tanks don't stick out as much as one large round one ! Sadly, this obviously became a high point in the development process, so SLIM ! became a priority over ecology and economy. The actual insulation thickness over the tanks at the front and back is minimal. Add in that with a plastic case, the support brackets are attached straight to the tank chassis, you have a perfect thermal bridge !

So, for example .. your very expensive super eco hot water tank .... looks like this :

1676748609001.png


It's effectively become a storage heater !

And the wall brackets are perfect radiators !

1676748661450.png


Or when it heats just the first "output" tank (you can even see the tank linkage pipes):

1676749462308.png


As I'll be boxing the unit into a cupboard eventually, the "attractive wall mounted" aspect was irrelevant for me, so I boxed the whole thing with a foil backed polyurethane.

1676748765888.png


This made a vast difference to heat loss and instantly HALVED it's operating cost !

1676748807287.png


This is with the little cover removed to access the control panel - you can see the heat without the insulation. The strange heat wobble down and left of the square is the reflective heat of me, showing the effectiveness of the foil for reflecting heat.

1676748886154.png


This next image also shows pipe insulation. The Right pipe is the cold feed. The left pipe at the top is double lagged/insulated pipe on the hot exit and the brighter/hotter is single lagged pipe.

1676748938541.png
 
Last edited:

fenwick458

Active member
Oct 6, 2020
295
187
Cumbria
hats the brand of water cylinder you have?
I was looking at upgrading my combi boiler setup to an unvented cylinder (heated by the same boiler) and was thinking of getting one of these Mixergy cylinders. main reasons for upgrading :
  1. how water as soon as the tap is opened or nearly(the combi takes ages)
  2. it claims to be very efficient and is "smart"
  3. I'll probably install PV soon and with a cylinder there's always somewhere to put the extra energy
  4. by doing the cylinder now It'll be heat pump ready for 10 years time when I think we'll all need them anyway
  5. if I get an EV and a good tarrif I could take advantage of the cheap rates overnight to heat the water
 

Zimmerframe

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Jun 12, 2019
13,883
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Brittany, France
hats the brand of water cylinder you have?
The Ariston Velis Evo Dry. It's slightly slimmer than most of the alternatives, so presumably they have more insulation !

I did actually buy a different brand first, but whilst the box looked ok, it seemed to have been dropped out of a plane at some point in it's life so the control panel was destroyed and even the inlet and outlet pipes were deformed :) The Ariston was nicely packed !

  1. how water as soon as the tap is opened or nearly(the combi takes ages)
  2. it claims to be very efficient and is "smart"
  3. I'll probably install PV soon and with a cylinder there's always somewhere to put the extra energy
  4. by doing the cylinder now It'll be heat pump ready for 10 years time when I think we'll all need them anyway
  5. if I get an EV and a good tarrif I could take advantage of the cheap rates overnight to heat the water

That looks like a great setup and future proof. 25 year warranty looks great too. Everything I looked at had all the words to say how amazing they'd made it and how it would have improved longevity - but they still all only came with 2 year warranties.

Maybe @dobbyhasfriends would have some experience with it ?
 

dobbyhasfriends

🌹Old Bloke 🎸
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Sep 19, 2019
3,228
4,609
Llandovery, Wales
Maybe @dobbyhasfriends would have some experience with it ?
Kind of but without the smart element. More of a conventional cylinder with multiple pocket stats that just feed info back to the boiler about when to turn on and off etc. I rarely do electric only systems and if I do I just install a direct unvented cylinder.
Came across an article the other day about a guy who wired the output of his solar panels directly to his immersion heater, might have been a wind up but you never know
 

fenwick458

Active member
Oct 6, 2020
295
187
Cumbria
Came across an article the other day about a guy who wired the output of his solar panels directly to his immersion heater, might have been a wind up but you never know
Where was the article? I don't understand why it isn't more common, it gets rid of the need for an inverter and makes the system so much cheaper to install and maintain. and it would be much better than solar thermal in this country I think. I believe really small systems exist like that for use on campervans but I've not seen a kit for a house yet and I can't see why, obviously there needs to be some sort of protection built in to the circuit not just wired direct
 

dobbyhasfriends

🌹Old Bloke 🎸
Subscriber
Sep 19, 2019
3,228
4,609
Llandovery, Wales
Where was the article? I don't understand why it isn't more common, it gets rid of the need for an inverter and makes the system so much cheaper to install and maintain. and it would be much better than solar thermal in this country I think. I believe really small systems exist like that for use on campervans but I've not seen a kit for a house yet and I can't see why, obviously there needs to be some sort of protection built in to the circuit not just wired direct
I agree, I imagine that the inverter and changerover relay methods we use are for safety as the DC from a solar panel cant be shut off without something similar. if there was some sort of DC regulator and overtemp/overvoltage shut off it would be fine but I wonder how many panels you could run in series before it caused problems.. they are usually 'about' 50v output each
 

Zimmerframe

MUPPET
Subscriber
Jun 12, 2019
13,883
20,573
Brittany, France
was thinking of getting one of these Mixergy cylinders. main reasons for upgrading :
The only strange thing I can see on that link is that the proposed savings are only 12 to 20 %

A lot of that must depend on how it's calculated. They can't say you'll save 50% if they work their model that you use less water.

Heating water from one temperature to another will always take a fixed amount of energy.

In my case a 200 litre tank takes 12kw to warm 12 degree water to 65 degree water (you need to goto that to kill of lf the legonella bacteria.)

The standard french tanks work a little like the one you've shown with boundary layers, so the whole tank doesn't have to be at temperature to have hot water.

In my case switching to the smaller tank (it's questionable if the fancy twin part makes any difference) dropped from 12kw to 4 kw (heating 45 litres from 12 to 45-it does a hot cycle once a week. And re heating through the day to maintain that temperature)

Insulating dropped that to 2kw a day.

For me, it's been a huge reduction. Obviously the old tank (which I've kept) didn't use 12 every day. But it's still a larger volume with more area to shed more heat.

One option I also looked at were the tanks with integrated heat pumps. The negative side to these is they use "heat" from their surroundings. As I wanted to install it in a small ish bathroom, it would have meant the room would have been chilled in the process. Would have been ideal to install in a larder 🙂🧐
 

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