Solar Thermal Install

[gaz1]

A quick Google suggests IBC rating is about 60C. ST panels could happily boil water. For a bulk, low temperature store, great. But needs failsafes to be sure that they can't get too hot if something accidentally got left in the wrong setting while away on holiday for example. If you're limited to under 60C, that's a bit cool as a preheater for tap water but not useless. Could be more useful for space heating but even then, better in a well insulated house with low temperature emmiters/UFH. For most people, where it's going to be retrofitted and space is at a premium, you can maximize kWh/m3 by simply raising the temperature.

they can go higher than that

Storing hot water in IBC tote tanks? - Storage - Fieldlines.com: The Otherpower discussion board

Storing hot water in IBC tote tanks? - Storage - Fieldlines.com: The Otherpower discussion board -

www.fieldlines.com

Most likely these tanks are made of high-density polyethylene. That type of plastic is good for 150 F continuous. It would start melting at about 250 F. I'm sure that it would be some sagging at 130 F, but since they are caged it should be OK. But any plastic could crack, so if you use them to store water, make sure that the water don't do a lot of damage when it spills.

 

[gaz1]

I would not under any circumstances consider putting ibc tanks in the loft. Ground space I have plenty of.

I think I'd rather divert excess to storage for night time, space heating release.

Looking at my plan above...I could bring the kitchen out to encompass that current covered space. I could then hive off the back of the kitchen for a plant room. It'd be nominally dead centre of the house so losses would be internal.

nobody has said put it into the loft

the reference i used is like the black overflow tank in the loft area used with emersion heater

Polytank 190L Cold water loft tank, (L)1185mm (W)510mm (H)490mm

This 190L loft tank is ideal for new builds and as a replacement tank. It comes fully packaged, just add water.

www.diy.com

 

[gaz1]

proper pdf rating

https://www.traconed.com/files/pub/225084_TDS.pdf

Hot filling a IBC.
For short periods (a few hours) temperatures up to 80° Celsius can be reached during filling without effecting the mechanical
characteristics of the package. In case of longer periods do not exceed 60°Celsius.

60c is 140f
80c is 176f

emersion tank:
Electric water heaters should be set at 60 °C to limit the risk of Legionella contamination

solar hot water reference:

a temp. of between 60 deg. F. and about 160 deg. F

 

[knighty]

I think I'd rather divert excess to storage for night time, space heating release.

the only times you're going to have an excess worth storing is peak summer, when you don't need the heat anyway

if you really want to store/use excess heat... add another hot water tank

price up all the stuff you're going to need, pipe, valves, insulation, fittings, heat leak radiator (I'd still add one so system doesen't boil in a power cut), hot water tank etc. etc. etc.

proper solar hot water tanks + fittings etc. will add another £1000 onto the bill - pretty soon you'll end up out of pocket instead of saving money


also, insulate the hell out of your loft!!!!! - that's the best investment/return by far!

 

[Gareth J]

proper pdf rating

https://www.traconed.com/files/pub/225084_TDS.pdf

Hot filling a IBC.
For short periods (a few hours) temperatures up to 80° Celsius can be reached during filling without effecting the mechanical
characteristics of the package. In case of longer periods do not exceed 60°Celsius.

60c is 140f
80c is 176f

emersion tank:
Electric water heaters should be set at 60 °C to limit the risk of Legionella contamination

solar hot water reference:

a temp. of between 60 deg. F. and about 160 deg. F

Thanks, you illustrate the point perfectly; don't exceed 60C long term. Knowing the containers, that feels like a sensible limit to me.

As mentioned, ST tubes can easily boil water. You're not going to want to hook them up directly without some control mechanism to limit the feed temperature into the tanks and consider how to get around a situation where tanks are hot and panels are still generating. A couple tanks with only moderate insulation may leak enough heat to balance out more generation capacity but I'd hope the insulation would be better than that.

An immersion tank is not limited to 60C at all, that's the *minimum* suggested to reduce legionnella risk. The maximum rating of most immersion thermostats is around the 75-85mark. A few can go to 90. A copper tank itself can boil for all it cares. My tank, housing spare PV, gets to about 80C throughout before I either call it a day and export the excess, if it's warm, or automatically fire the towel rails if it's not summer. Regular high temps can have issues, for metal tanks not least, higher losses but also increased scaling risk but fortunately melting isn't one of them!

It's horses for courses really. Lots of low grade heat in cheap tubs that are big and have to live outside or a smaller volume of more useful, more energy dense hotter water that is compact enough to live inside but you'll have to pay a premium for the tank. Both options have advantages/disadvantages.

 

[Onoff]

Both options have advantages/disadvantages.

One advantage being I didn't pay for the ST panels!

 

[gaz1]

the prices have shot up

these prices are before youve even decided on the plumbing thats needed for them so is rather costly

solar cylinders

835.00 inc vat 300 litre

Telford Tempest 300 Litre Unvented Indirect Twin Coil Solar Cylinder

UK Manufacturing at its best, the Telford Tempest is Telford's flagship cylinder made from some of the highest grades of stainless steel on the market today, up to 40% thicker than some products. Twin coil solar models are supplied with two internal coils suitable for two heat sources, gas/oil...

www.discountheating.com

1400.00+

Joule Cyclone Unvented Cylinder | TCIMVG-0200LFC | Indirect | 186 Litres

Buy Joule Solar Twin High Gain Un-vented Standard Cylinder - 200 Litre today. Joule Part No: TCIMVG-0200LFC. Free UK delivery in approx 15 working days.

www.heatandplumb.com

vs hot water cylinder

210.00

Error 410 | Screwfix

Thousands of products at low trade prices | FREE next day delivery available | 30 day money back guarantee on all orders.

www.screwfix.com

ibc tank 30.00

for a start up costs you can use tempest 300 litre tank and an ibc tank as an extra water dump tank until another can be bought

you can even use the hot water cylinder to do the same

the ibc tank would give 2-3 years of life before replacement was needed this would stager the replacements needed in future years as you may need to replace both tanks on the initial purchase

you can still use the ibc tanks heated water via another coil

 

[Trevorleach]

I might take you up on that! Reminds me I've an invite to go and see a lad in Deal who did his own external wall insulation.

Just let me know.

 

[gaz1]

A copper tank itself can boil for all it cares. My tank, housing spare PV, gets to about 80C throughout before I either call it a day and export the excess, if it's warm, or automatically fire the towel rails if it's not summer. Regular high temps can have issues, for metal tanks not least, higher losses but also increased scaling risk but fortunately melting isn't one of them!

It's horses for courses really. Lots of low grade heat in cheap tubs that are big and have to live outside or a smaller volume of more useful, more energy dense hotter water that is compact enough to live inside but you'll have to pay a premium for the tank. Both options have advantages/disadvantages.

a copper tank cant boil certainly not on a closed circuit as it would need to blow off or be subjected to fresh cold water being run through it and straight to a drain

you can use an ibc tank thats stored water within it to cool it though instead of mains water

a closed circuit loop with a presure vessel on it the pressure vessel would get damaged really quickly due to the pressure of the steam build up

old emersion tanks always had a header tank for boiling of water if they didnt that tank would explode due to steam build up due to over boiling

 

[Onoff]

I do have a spare copper hot water cylinder from someone who fitted a combi. Maybe use that as a pre heat tank?

 

[Gareth J]

a copper tank cant boil certainly not on a closed circuit as it would need to blow off or be subjected to fresh cold water being run through it and straight to a drain

you can use an ibc tank thats stored water within it to cool it though instead of mains water

a closed circuit loop with a presure vessel on it the pressure vessel would get damaged really quickly due to the pressure of the steam build up

old emersion tanks always had a header tank for boiling of water if they didnt that tank would explode due to steam build up due to over boiling

Open vented is still very much a thing. Think I mentioned this earlier. As for pressurised getting damahed by pressure build up, maybe, but not if the PRV was functioning as it should. I'm not saying you ought to boiler a copper cylinder, just that if it does happen, won't be catastrophic.

 

[Gareth J]

I do have a spare copper hot water cylinder from someone who fitted a combi. Maybe use that as a pre heat tank?

Might as well consider it! Although getting the heat from the ST working fluid to a cylinder without a ST coil will be a bit inefficient. Obviously using the in tank coil previously used for the boiler will be the next best thing but these have much lower heat transfer area that proper ST coils.

Other consideration is connecting the preheat tank to your existing one. Pretty straightforward if both open vented or pressurised but mix and match not so simple.

 

[owas]

£££

You should see how much we scrap

 

[pedrobedro]

Open vented is still very much a thing. Think I mentioned this earlier. As for pressurised getting damahed by pressure build up, maybe, but not if the PRV was functioning as it should. I'm not saying you ought to boiler a copper cylinder, just that if it does happen, won't be catastrophic.

I was at a friend's house and there was a loud rumbling coming from upstairs, it was the bathroom tank boiling as the thermostat on the immersion had failed. He just ran some hot water off and kept an eye on the length of time it was switched on till he got a new one installed and no problem as you say

 

[Onoff]

You should see how much we scrap

Stainless Uni-strut?

 

[owas]

Stainless Uni-strut?

Yup,
I'm not allowed to take anything stainless though.

 

[Onoff]

Yup,
I'm not allowed to take anything stainless though.

I'll send you some galv spray and collect it later!

 

[Onoff]

I know what I want but quite how I get there I've no idea.....

My house is mish mash of construction techniques as aforementioned. What I would like is a plan of the house that can show real time temperatures from rooms, DIY solar panels etc. I'd like to be able to view on a phone or by logging onto a "website". Max, Min, Average would be good. Historical data would be good.

Cheap, remote, wireless sensors would be good.

Where to start?

@brewdexta and others have the smarts I'm sure! I don't for sure. Are there any freebie platforms that offer this?

I've Gone and Done Something Mental

Anyone had any luck splicing PLA filament together? How did you do it? I've kept all the roll ends, some are two or three metres long. Not spliced but I have fed a new length of filament in part way through a print a few times and all were successful

www.mig-welding.co.uk

Cheers

 

[brewdexta]

I know what I want but quite how I get there I've no idea.....

My house is mish mash of construction techniques as aforementioned. What I would like is a plan of the house that can show real time temperatures from rooms, DIY solar panels etc. I'd like to be able to view on a phone or by logging onto a "website". Max, Min, Average would be good. Historical data would be good.

Cheap, remote, wireless sensors would be good.

Where to start?

@brewdexta and others have the smarts I'm sure! I don't for sure. Are there any freebie platforms that offer this?

I've Gone and Done Something Mental

Anyone had any luck splicing PLA filament together? How did you do it? I've kept all the roll ends, some are two or three metres long. Not spliced but I have fed a new length of filament in part way through a print a few times and all were successful

www.mig-welding.co.uk

Cheers

I don't use wireless sensors. I have very thick walls with a high iron content and lots of foil backed insulation. I tried and they were unreliable and expensive so went for wired as I had flood wired the house with both alarm and cat5 cable when I gutted it. Wired one wire sensors are cheap. This shows £3 each but I pay less than a quid by shopping about.

One Wire Digital Temperature Sensor - DS18B20

DS18B20 One Wire Digital Temperature Sensor measures temperature in degrees C (9-12bit precision, -55C - 125C).

www.hobbytronics.co.uk

 

[jmp49]

You will need some kind of mains power backup for summer to run all these pumps sensors etc. I have a large solar array (8m2) with these panels and a 1000L tank with multiple coils in it. In summer if you loose the power for 45 minutes in summer its enough to take the 1000L tank to boiling temperature and boil the fluid out the circulation circuit. We have a UPS capable of running the pumps for a hour, and after that its just a question of replacing failed components after the boil over (the safety valves we use dribble after they have released steam and need replacing each time), I've seen melted normal solder on joints too during this. Also be cautious where the valves point, the jet of steam will be impressive.
In winter it underperforms by far the predictions given to us by the solar design company. So it produces too much energy in summer when you don't need it, and in winter nowhere near enough. Also we're on the 3rd set of pumps in 12 years of operation, they wear and begin to stick occasionally at a certain age and that can be really bad. Also we had a commercial deltasol controller for the solar circuit control, and it has brain dead defaults. If its power cycled it forgets any bespoke settings and it defaults to disabling warming the panels in very cold temperature to avoid frost damage. So if it gets power cycled in winter, we have to go back in to the config and set it to enabled or risk frozen panels. I don't know if newer ones are any saner...
Another note on the tubes, they're fragile as someone already said. We lost the vacuum in quite a few due to hail stones and wind.

I would stump up the extra for the pv, solely on the basis that when it over-generates you don't have to get rid of the excess, and its not dangerous shooting boiling fluids or steam out if things fail. In fact we'll refresh this system by replacing the collector with pv shortly. And this is from having a similar set up running for 12 years. Right now its drained and the property vacant so I don't have to mess around trying to service it thankfully. If I sound bitter, that's because I am. We paid a lot of money to a professional company to spec and supply for our custom requirements, and I feel that it was a massive mistake.