Solar Water Heating

[Théière]

Thanks Nick Trollope,

So from Poolguys original post he rekons that the tube array is around 6KW so to work effectively you would need 2 of the tube arrays?

[Pierre ZFP]

Well I was sort of in the right area, if a little under the 'actuals' .

While I agree it is a desirable thing to do, t's still a long payback for this particular system though.

I'm thinking of all those water heaters you see in Greece for example.  Yes I know its a lot hotter and the systems are probably less efficient but I can't imagine many taverna/holiday appartment  owners paying anything like €2100 per installation.  There must be more affordable alternatives even if they're less efficient.

 

[Benjamin]

Nick

Your professional input if you can.

There are two of us in the house. We each shower once a day. Neither of us stand under a running shower so at a guess we use say, 40 litres of hot water.

How many months/years/decades do you estimate it might take to break even?

Posed against the environmental impact of heating that water from electricity what would you guess would be the environmental impact of manufacturing the equipment  in the first place.

Just another comment not requiring an answer but aren't the jury still out on the cost/benefit of wind farms?

[Chancer]

[quote user="teapot"]

Thanks Nick Trollope,

So from Poolguys original post he rekons that the tube array is around 6KW so to work effectively you would need 2 of the tube arrays?

[/quote]

You need to realise that Nick quoted quite correctly "14 kilowatt - hours" -the emphasis being on "hours", thus under ideal operating conditions and at 100% output (if this is indeed ever possible) the notional 6kw array would raise the temperature of a 300 litre ballon in around 2 and a half hours.

You can make the comparison with a standard 300 litre electrical ballon which uses a 3kw element and will usually be fully heated within 5 hours of charge dependant on the thermostat setting.

[Nick Trollope]

[quote user="teapot"]

Thanks Nick Trollope,

So from Poolguys original post he rekons that the tube array is around 6KW so to work effectively you would need 2 of the tube arrays?

[/quote]

I can't know that. Every installation needs to be specified for the individual circumstances.

Couple of other salient points; 14Kw is the amount of energy needed to do what I calculated it needed to do. The occasions when you need to do this will vary, as will the rate of capture of energy. Which is why solar systems are always backed up with electrical. Right or wrong (green or not, etc etc).

The only way to get a solar system that works for you, is to have it designed by someone who understands this particular black art. The technology is just too new to be bought "off the shelf".

 

[Nick Trollope]

[quote user="Benjamin"]Nick

Your professional input if you can.

There are two of us in the house. We each shower once a day. Neither of us stand under a running shower so at a guess we use say, 40 litres of hot water.

How many months/years/decades do you estimate it might take to break even?

Posed against the environmental impact of heating that water from electricity what would you guess would be the environmental impact of manufacturing the equipment  in the first place.

Just another comment not requiring an answer but aren't the jury still out on the cost/benefit of wind farms?

[/quote]

I don't know. Quite a long time. (and that is the best you are going to get without a) giving lots more info and b) paying me!).

As I say above, I can't justify the installation of any "eco" energy source on cost alone - it can't be done. There are many other reasons (all of them unselfish) for using them. I really don't want to/won't get into the minutiae of the justification of green systems, I'm afraid - I don't have the time.

 

Are regards wind farms - what Jury are you referring to? They are a fact of life the world over. I don't think their green credentials are up for debate but, FWIW, I think they are a superb blend of form and function - the ultimate blend, perhaps.

 

[Théière]

[quote user="J.Rs gone native"][quote user="teapot"]

Thanks Nick Trollope,

So from Poolguys original post he rekons that the tube array is around 6KW so to work effectively you would need 2 of the tube arrays?

[/quote]

You need to realise that Nick quoted quite correctly "14 kilowatt - hours" -the emphasis being on "hours", thus under ideal operating conditions and at 100% output (if this is indeed ever possible) the notional 6kw array would raise the temperature of a 300 litre ballon in around 2 and a half hours.

You can make the comparison with a standard 300 litre electrical ballon which uses a 3kw element and will usually be fully heated within 5 hours of charge dependant on the thermostat setting.

[/quote]

Quite so J.R, teach me to nearly read a post before leaving the house. 2.5 hours sounds plenty, wonder if it is?

[UlsterRugby1999]

Okay - phew - thanks for the thoughts and input so far. Well most of the posts that is.

Setting aside the views of BricoDepot and I understand what La Plombiere means, what is the general view of the system, its cost, and its ability to deliver me, in my house, with a reasonable percentage of my hot water needs.

If, as has been suggested, I double the collector size would I expect to have a high percentage of my domestic hot water requirements for a family of 4? I have a friend in the Haute Vienne who has 4msq of collectors and complains, mildly, that his tank bounces it gets so hot and this isnt just in the summer months.

Second question if I may, with the system that is on show at BricoDepot, or any other equivalent system, what back up methods can I use. We use wood burners and reversible air con systems here so nothing can be connected that way so I guess I'll need to be able to connect it to an electrical heating unit. Any thoughts on how I can do this.

I'm sorry but I dont have the technical knowledge and a lot of what has been said here has blinded me. I pay 2500€ plus per annum in electricity bills and I calculate that circa 50% of this may be the cost of heating water. Therefore, a system that costs 2400€ which will produce, as an example, 75% of my water needs will have a pretty decent payback time. So, therefore, I'm quite interested in it.

[Théière]

No expert, but I have seen the tanks with an additional electric heater element. I can't tell from the advert so probably best to check.

Let us all know how you get on please

[herbert]

Hello Ulster..

2nd Question: there is an electric heater included in the Brico offer resistance electrique d'appoint fournie pose et cable

you see the black cubic thing in the middle of the tank, to the left

1st question:I don't know yet, where you live, but as said earlier, with two-three hours of fantastic sun, the 300 Ltr will get warm

but you will not save 50percent of your electricity bill as long as you use reversible air con systems. They consume.

herbert

[Chancer]

[quote user="UlsterRugby1999"] I'm sorry but I dont have the technical knowledge and a lot of what has been said here has blinded me. I pay 2500€ plus per annum in electricity bills and I calculate that circa 50% of this may be the cost of heating water. Therefore, a system that costs 2400€ which will produce, as an example, 75% of my water needs will have a pretty decent payback time. So, therefore, I'm quite interested in it.[/quote]

I think that you are blinding your self, you say that you dont have the technical knowledge yet have calculated that your hot water is costing you €1250 plus per annum, or is that what an eco salesman has told you?

Unless you have four 200 litre ballons being heated on heures creuses and you are using every drop of hot water each day then you are not spending anything like that amount on hot water.

[UlsterRugby1999]

I have an 84 year old MIL who lives with me, who constantly washes things, along with 2 teenage children and my wife and me. The system doesnt run on Heures creuses as we'd never have hot water all the time. So, yes, its running pretty much all the time.

[Nick Trollope]

[quote user="UlsterRugby1999"]I have an 84 year old MIL who lives with me, who constantly washes things, along with 2 teenage children and my wife and me. The system doesnt run on Heures creuses as we'd never have hot water all the time. So, yes, its running pretty much all the time.[/quote]

I'm not convinced, I'm afraid. A 200L C/E running 24/365 will cost about 1500€ per year to run. It is impossible for a C/E to run 24/7 (do the maths - I can't be bothered!).

I reckon that an "average" family uses about 600€ (max) of water heating PA.

Your C/E could be faulty or very old, which could account for some losses, but not 100%+

 

[UlsterRugby1999]

[quote user="Nick Trollope"]

[quote user="UlsterRugby1999"]I have an 84 year old MIL who lives with me, who constantly washes things, along with 2 teenage children and my wife and me. The system doesnt run on Heures creuses as we'd never have hot water all the time. So, yes, its running pretty much all the time.[/quote]

I'm not convinced, I'm afraid. A 200L C/E running 24/365 will cost about 1500€ per year to run. It is impossible for a C/E to run 24/7 (do the maths - I can't be bothered!).

I reckon that an "average" family uses about 600€ (max) of water heating PA.

Your C/E could be faulty or very old, which could account for some losses, but not 100%+

 

[/quote]

While not wishing to throw all my personal data onto the Forum - lets assume that the Chauffe'eau was running 12 hours per day and ours is, as its is, a 3Kw unit then we'd cranck up 36kw per day which would be 13140 kw at (I believe 0.08€) per unit would equate to 1051€ per annum. Not quite 50% but still a large amount.

[UlsterRugby1999]

Whats with this flippin quote thing.??????

[Théière]

[quote user="UlsterRugby1999"]Whats with this flippin quote thing.??????[/quote]

Works for me [:P]

I did the old fashioned test with the meter reading and the difference between on permanent and switching off was only 1 on the meter.

That was without using any hot water for a day. (washed in cold water that day)

[herbert]

[quote user="UlsterRugby1999"]Whats with this flippin quote thing.??????[/quote]

and I thought only I was too stupid to press the quotation button

Herbert

[Nick Trollope]

[quote user="UlsterRugby1999"][quote user="Nick Trollope"]

[quote user="UlsterRugby1999"]I have an 84 year old MIL who lives with me, who constantly washes things, along with 2 teenage children and my wife and me. The system doesnt run on Heures creuses as we'd never have hot water all the time. So, yes, its running pretty much all the time.[/quote]

I'm not convinced, I'm afraid. A 200L C/E running 24/365 will cost about 1500€ per year to run. It is impossible for a C/E to run 24/7 (do the maths - I can't be bothered!).

I reckon that an "average" family uses about 600€ (max) of water heating PA.

Your C/E could be faulty or very old, which could account for some losses, but not 100%+

 

[/quote] While not wishing to throw all my personal data onto the Forum - lets assume that the Chauffe'eau was running 12 hours per day and ours is, as its is, a 3Kw unit then we'd cranck up 36kw per day which would be 13140 kw at (I believe 0.08€) per unit would equate to 1051€ per annum. Not quite 50% but still a large amount.[/quote]

If your C/E is heating (as in drawing current) for 12Hrs a day, then there is something wrong with it, I'm afraid. As soon as I have a moment, I will do the maths and prove it to you. Alternatively, this should be your opportunity to fit a properly-designed solar system with a 300L ballon - solve all your problems in one go! Don't buy it fom BD, though.

 

[Chancer]

I agree Nick. The family and MIL would need to be using 800l of hot water a day for it to be drawing current constantly, actually probably twice that allowing for the blending effect of the incoming cold (which I have only just learned about thanks to this thread).

I have witnessed first hand (and was responsible for) a ballon heating continously for 12 hours, it kinda gets your attention, and the pompiers [:-))]

[UlsterRugby1999]

Thanks all - I'm still not sure I understand all thats being said here but I get the gist of it.

Just a thought - our water is seriously hot as if its a degree or teo below boiling. Can I turn the heating element down. Surely this would have a positive effect on the electricity used. [8-)]

Nick - can I get access to an online method of calculating what my needs would be for a solar domestic hot water system?

[Clair]

[quote user="UlsterRugby1999"]Just a thought - our water is seriously hot as if its a degree or teo below boiling. Can I turn the heating element down. Surely this would have a positive effect on the electricity used. [8-)] [/quote]

Do be careful lowering the temperature. Hot water should be stored at a temperature of around 60°C / 140°F to prevent the growth of Legionella bacteria.

I thought our hot water was too hot and it would be worth adjusting the thermostat. I checked the water temperature, which is 64°C / 147°F.

[UlsterRugby1999]

[quote user="Clair"][quote user="UlsterRugby1999"]Just a thought - our water is seriously hot as if its a degree or teo below boiling. Can I turn the heating element down. Surely this would have a positive effect on the electricity used. [8-)] [/quote]

Do be careful lowering the temperature. Hot water should be stored at a temperature of around 60°C / 140°F to prevent the growth of Legionella bacteria.

I thought our hot water was too hot and it would be worth adjusting the thermostat. I checked the water temperature, which is 64°C / 147°F.

[/quote]

Thanks Clair - good advice although I think our water would be well above that. I'll test it this evening and see what its showing.

[Théière]

Can you test the temprature so you can be more accurate 65 degrees feels very hot but a long way from boiling.

[Nick Trollope]

[quote user="UlsterRugby1999"]Nick - can I get access to an online method of calculating what my needs would be for a solar domestic hot water system?[/quote]

Not that I am aware of, I'm afraid.

Where are you? I can probably find you someone to design a system for you.

[UlsterRugby1999]

[quote user="teapot"]Can you test the temprature so you can be more accurate 65 degrees feels very hot but a long way from boiling.[/quote]

Just tested it this morning. I got 37.8 degrees Celcius which equates to 100.04 degrees Farenheit. Errr - that'd be pretty hot then and possibly why the C/E is working so hard. Does that sound about right. [Www]

[quote user="Nick Trollope"]Not that I am aware of, I'm afraid.

Where are you? I can probably find you someone to design a system for you.[/quote]

Thanks Nick - I'm in the south east Vienne area - Montmorillon is the nearest largest town.