Choose solar collectors: plans or vacuum tubes?

[jessle]

F.MYKIETA wrote:

But to interest self-builders, this sensor must also not be "too expensive" compared to Chinese or Turkish sensors.

Christophe wrote

Yes, but the auto construction market is biased by subsidies ...

although DIY materials have increased in my opinion.

[F.MYKIETA]

Hi Christopher,
Just a quick memo:

"
F.MYKIETA wrote:
Practical or aging conditions, it is indeed a test that is difficult to conduct but that we will do soon. The best aging remains the state of stagnation with very strong radiation. We are well placed in the South of France to do this.

CHRISTOPHE wrote:
You are the pro but here are 2 suggestions: iradier with UV rays and "simulate" more or less violent rams ...
"

Water hammer does not seem a relevant test because we do not have excessive pressure in the sensors.
On the other hand, UV is a good thing and what could be better than putting the gear in full sun. This is the worst, believe me.
We will soon do a stagnation test of several sensors (tubes and plan) that we will put in the Sun for the summer.
The next test will be to compare the performances obtained after aging with the performances obtained before.
Normally, we will have a drop in performance which will be explained by the degradation of the sensor in stagnation.

Pk,

[loop]

Hello

Some vacuum collectors use heat pipes
If I have understood their functioning, the sensor transfers the heat to a gas (acetone in a closed tube) which will condense, releasing additional energy at a specific location (the top point of the tube)

This system is comparable to a heat pump but with the great advantage of not requiring a circulator or pump

Is it possible to envisage such a system in series with conventional flat solar collectors, and in which the heat pipe is placed at the place where the heat is exploited, that is to say in the dwelling or the water heater?
Targeted benefit: lower temperature in the collectors (less radiation to the outside) and cooler return circuit water
The efficiency would be improved and a higher operating temperature for DHW or radiator heating

A+

[Christophe]

Water hammer does not seem a relevant test because we do not have excessive pressure in the sensors.

Yes but it would simulate premature wear of the welds ... right?

On the other hand, UV is a good thing and what could be better than putting the gear in full sun. This is the worst, believe me.

Well, otherwise there are UV tubes in the tanning booths ... or worse: a water disinfection system ...

We will soon do a stagnation test of several sensors (tubes and plan) that we will put in the Sun for the summer. The next test will be to compare the performances obtained after aging with the performances obtained before.
Normally, we will have a drop in performance which will be explained by the degradation of the sensor in stagnation.

Yes but the problem is that your test is "in real time" ... something should be found to accelerate aging ...

[F.MYKIETA]

Hello,
After a little silence, I give you my latest aging results:
A stagnant solar thermal collector ages approximately 1 year per month of exposure.
Pk,

[Kalash01]

Being new to these forums I introduce myself I am an apprentice technico commercial in heating, enr, and water supply and I work within one of the leading companies of the distribution of these products.

I hope to be able to contribute to all of these posts and share with you all!
@ later.

Kalash

[Did67]

Plan or tubes, that was the question.

Part of the answer: a recent severe hailstorm. The tubular sensors were exploded; the flat collectors resisted.

[chatelot16]

hail resistance is really the main risk: there was a big hail storm at my place: all the plastic parts outside were broken: all the tempered glass panes were resisted, car door stored flat. .: I conclude from this that the flat solar panel will also resist

the tempering of the glass gives a very high impact resistance

vacuum tubes are pirex but not hardened

the tubular form gives more impact resistance than the flat form: which is the strongest?

[Kalash01]

From experience, the flat collector is the less effective of the two but the more profitable in the long term (in terms of impact resistance) since it resists rather bad weather, for example.
(this winter hail showers on one of my sites -> destruction of 40% of the tubular collectors installed ...)

so plan sensor I would say!

[Christophe]

An "unexpected" problem: the icing of vacuum tube solar panels in winter under our lattitudes!

Can be already mentioned above on this subject, I know more!