Help with the choice Sensor Plan Tube

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the middle
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by the middle » 07/05/09, 18:51

Here is a small text which explains better than me :D
The Self-draining System

This particular solar system works differently from other systems. If there is no sun or if the balloon no longer needs heat, the circulation of the fluid stops and all the water contained in the solar collector is emptied into the balloon. The addition of antifreeze products is not necessary because, when the installation is not in service, the sensor does not contain water - an additional point in terms of the environment! This also means that there is no pressure in the circuit, therefore no expansion tank, therefore less risk of leaks!
Unlike other systems, there is no longer a risk of overheating of the fluid containing antifreeze in summer, which can withstand high temperatures very poorly!
Limestone has no chance.
During the first start-up, the accumulator tank is filled only once with running water, without using additives. This water serves as a medium for heat accumulation and will not be changed during operation. On the accumulation water side, there can therefore only be a single deposit of the limestone contained in the volume of water.

Constraint: contact a specialist for this system to be sure of the mandatory slopes for self-draining!

Origin of the text: http://www.neowatt.fr/Chauffage-Solaire.htm
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Philippe Schutt
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by Philippe Schutt » 07/05/09, 18:53

it would be quite a pressure anyway.

If I take for water, 6,5 bars at 160 ° and 16 bars at 200 °.
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by Did67 » 07/05/09, 20:28

Sorry, I'm coming back a little late!

1) I don't know if it boils, I was never at the top of the sensor at that time! I do not think so.

2) Exact, my system is under pressure (2,5 bars in normal operation). It is neither more nor less than a heating circuit ... So very commonplace.

There is an expansion tank. And a safety valve. Who never worked (I have a hose connected to it with a container). So the pressure did not reach the discharge pressure (7 bars I think?).

I happened to notice the circulator "blocking" in good weather (this happens, with the safety of 50 ° - see below, when too much hot water is withdrawn too suddenly in full operation in the middle of the day). I admit not having watched the pressure. I should have. But it never shocked me!

3) It is not pure water but a mixture (50/50 ??? water-antifreeze?). At what temperature under what pressure it boils, I don't know!

4) What I wanted to say: this has been going on for 7 years. I don't know if it's "good", but I'm just testifying that it works. It doesn't seem like a problem. The system crash has happened at least a dozen times! And we often went on vacation in the summer without purging, without bypass in a radiator ...

5) It seems to me that the majority of installations in operation are of this type. That must make a few thousand! Self-draining systems have made a much more recent appearance ...

6) I cannot carry out the test suggested by the correct medium: there is a safety which prevents the circulator from turning as soon as the temperature difference between tank and top of the sensor exceeds 50 ° C. The system does not restart until after be cooled.

This is therefore provided (it is the case which controls the circulator which has this function)

Otherwise, indeed, the arrival of cold liquid in an overheated sensor would be formidable!

7) It is obvious that the developers of self-draining systems will praise it. In the article put above, I still find incredible the argument of the deposit of limestone: as in a self-draining system, in my system, it is always the same liquid which turns. I do not see where the limestone supposed to settle would come from. This makes me suspicious about the pitch, which seems commercial to me. Have you ever seen someone at Peugeot praising a Renault? (even a Citroën, which is however almost the same thing!).

In short: 1) the classic system works; 2) the drainable surely also (with advantages and disadvantages - durability of the filling system? Cost?; 3) I do not believe in the history of limestone; 4) emptying absolutely does not prevent sensor to reach staggering temperatures anyway - the calories absorbed are not removed); 5) with the expansion tank and the safety valve, the pressures in a typical system are those encountered by any heating system - I haven't seen anyone drain it! 6) remains the argument of antifreeze, which seems to me just as "crazy": it is a few liters of glycol I believe, a fairly banal product it seems to me, for life!

No, the arguments of the self-draining do not really convince me on reflection. It is certainly not bad. After they try to sell it, it is obvious. So it's the best. For them !
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by I Citro » 07/05/09, 21:45

Did67 wrote:- if it is cloudy, gray or fog, even the tubulars do not give much
A heating engineer in my town has a CESI thermosiphon on display in front of his store. It is very badly exposed. I was surprised to see that despite its flat sensor, in winter on a very overcast day (the fog had not dissipated), the balloon was nevertheless at more than 40 °.
8)
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by the middle » 07/05/09, 21:59

: Cheesy: ok, the history of limestone is phony
But after some research, I found figures on the degradability of glycol.
Some say stop at 120 ° C, others say there is degradation at 160 ° C.
I also saw that there are products to clean the sensors ... because the glycol deposits a "skin" inside the tubes ..
I also saw that the glycol must be changed every three years.
They may be bobars ..
But I say NO to the sensors with glycol, and YES to the drainage systems. : Cheesy:
Very interesting this subject.
That said, it is advisable to change the car brake oil from time to time ... who does?
Ditto for motorcycle suspension oil ...
But that's another subject :D
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by I Citro » 07/05/09, 22:11

lejustemilieu wrote:That said, it is advisable to change the car brake oil from time to time ... who does?
Myself :? But not every 2 years ... :frown:
It is true that even by organizing with ad hoc hacked stuff, it is long and tedious. :frown:
lejustemilieu wrote:Ditto for motorcycle suspension oil ...
Also, but it's much faster and easier. : Arrowl:
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by Philippe Schutt » 07/05/09, 23:05

We are also supposed to change the 4 seasons from time to time. But I never saw the water of an engine go up to 160 ° : Cheesy:

I wonder, their famous T ° of stagnation, it must be dry ...

Did67, in terms of holding at 200 °, I do not see what could hinder your sensor if the welds are adequate. After all the glycol is confined in the copper tubes. So with the strong solder it bathes. I brazed a tube to refill a small bottle of Argon from a large one, it happily exceeds 100 bars and I have never had a problem.
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by the middle » 08/05/09, 08:06

citro wrote:
Did67 wrote:- if it is cloudy, gray or fog, even the tubulars do not give much
A heating engineer in my town has a CESI thermosiphon on display in front of his store. It is very badly exposed. I was surprised to see that despite its flat sensor, in winter on a very overcast day (the fog had not dissipated), the balloon was nevertheless at more than 40 °.
8)

Yes, but...
A tank is built to keep the water hot for several days ...
So these 40 ° c may have been generated 2 days before, on a sunny day.
In addition, if by chance, it does not consume hot water ... then, the 40 ° c are quickly reached. (CESI expo :? )
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by Did67 » 08/05/09, 10:58

Philippe Schutt wrote: if the welds are adequate ...


You are right. here's one capital point : all the fittings are silver solders... With tin, it may actually dissolve ... It was marked in the assembly instructions for the kit. I put this important info in one of my first posts, it seems to me (unless it is on another forum, I do not know anymore ?).

Honestly, I may be wrong, but I'm not too worried about glycol. Filing a film? Perhaps. So what if it doesn't keep calories from passing? Slight decomposition? Same: where is the problem if the antifreeze power is enough ...

You cited lots of examples. There would still be hydraulic fluid from Citrën suspensions. My Xantia is 15 years old. Never changed. No doubt not ideal, but it still works.

And the Rollmops that I ate a few days ago: use by date = 28.12.2008. Not even sick. (I did not do it on purpose, I saw after eating a jar which had remained "behind" in the fridge ...! An oversight, what). This gives an idea of ​​the margins, when it comes to food!

In cloudy or gray weather, it is not the temperature of the tank that should be looked at, but that in the primary circuit. At home, it's clear and clear: gray, rainy, overcast weather, etc. ... it does not "circulate" (the circulator only starts up if the temperature difference between the bottom of the tank and the top of the tank. sensor is 15 ° - from memory; it is programmable). Below, we do not recover enough calories (with the losses in line in addition), for it to be effective.

I believe in time slightly covered, there is a certain diffuse brightness, there the tubulars manage to heat, this is their main advantage. But to put in relation to the costs - and the number of days that it can concern according to the region where we are ...
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by Philippe Schutt » 08/05/09, 16:38

In general, the coolant must be changed every 5 years in cars. I guess the same rule applies to signs.
And nobody does it for cars, and probably not for signs either : Wink:

side performance panels, as long as we have not tested, it's hard to give an opinion. instinctively, I would tend to say that you need tubulars with reflectors, but on the other hand the absorbed radiation gives its energy whether it is reflected on a tube or not, and then only the level of insulation counts. so ???
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