Electric flask heater thermosiphon

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Philippe Schutt
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Electric flask heater thermosiphon

by Philippe Schutt » 03/01/21, 20:29

Hello,
I made a very simple and economical assembly which heats up my electric balloon. I find it to work neat, so I'm sharing here.
circuit ecs.jpg
thermosiphon circuit
circuit ecs.jpg (88.54 KiB) Viewed 650 times


Primary
just bypass the hot outlet of the boiler and pass it through a small plate heat exchanger (less than 100 €). Finally the size of the exchanger will depend on the diameter of the pipe, the flow should not be slowed down either. For me, 11kw boiler so 25kw exchanger and 3/4 '' fittings (not found smaller)
Secondary
At the exchanger outlet I put a thermostatic V3V set at 25 °. Note that I use it in reverse flow. Indeed it measures normally at the output while I want to measure the input. So the exit becomes the entrance and vice versa : Cheesy: . I also blocked the hot water inlet, in fact it only has 2 ways. Well, it would be an outing if I hadn't plugged it. : Cheesy:

So when it heats up on the exchanger side it opens on the blue side the red / blue side being always open and a thermosyphon is established up into the tank. When hot water is drawn at low flow, it comes from the tank and through the exchanger; suddenly the balloon cools less quickly. With a cold balloon, I manage to have water mixed at about 35 °. If we pull at high flow, the exchanger cools, the V3V closes and everything comes from the balloon.
With only 80cm of hot column, my 150L tank heats up in + -2h and I don't realize anything about heating.
My son made the same assembly on a 300L on the ground, hot water outlet on top, so column height 2m. There it laughs more, there is not much left for heating as long as the balloon is not half hot. On the other hand, it goes quickly, like a classic valve system or 2 circulators, just much cheaper and more reliable.

Restriction: the boiler must emit water at 65 ° or more, because of legionella. So ideal for wood and pellet boilers, less for gas ...

As I was very happy, I did the same for the solar panel:
IMG_20210103_200948.jpg
IMG_20210103_200948.jpg (446.24 KB) Viewed times 650
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IMG_20210103_201009.jpg (466.36 KB) Viewed times 650
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Forhorse
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Re: electric balloon heater thermosiphon

by Forhorse » 03/01/21, 22:43

You should not have hard water or you should be able to descale the exchangers regularly.
Otherwise yes in principle it can only work.
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Philippe Schutt
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Re: electric balloon heater thermosiphon

by Philippe Schutt » 03/01/21, 23:49

In fact, there is space between the plates. I had made the 1st cut 2 years ago and so far it's clean.
I drained the solar circuit for the winter and it's clean too. Well this one does not exceed 50 ° therefore less risk.
I also plan to add a softener one of these days. I just have to find one cheap ... I was able to test the addition of CO2 in the water, it improves the taste but not the lime deposits at the taps. Maybe I hadn't left it long enough ... to see
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