Geyser temps

[PaulF007]

A while ago I placed a temp probe into the solar geyser and started to log the values very interesting to see how the temps reacts. 
We have a Geyser controller and we dont fill the geyser until after the we have showered . That way if the temps are a bit low we could use the full 200l and wait for the next day to heat the water.

Just for fun

[Chris Hobson]

2 hours ago, PaulF007 said:

We have a Geyser controller and we dont fill the geyser until after the we have showered .

Hi Paul I always love your practical experiments. How do you fill your geyser only after showering? I was under the impression that the cold water displaced the hot water and that this was the mechanism to run a bath/ have a shower. It is done this way to protect the system from running dry. How does your system work?

[___]

15 minutes ago, Chris Hobson said:

How do you fill your geyser only after showering?

I think he has a low-pressure unit, possibly with a boost pump? The draw-off point is probably a little above the tank's bottom, so it never runs completely dry. That's just a wild guess though.

If I had to guess, what you're dealing with is water mixing. In a perfect world the water stratifies perfectly with the hot water at the top, but in reality when cold water flows in the bottom, it mixes a little with the other water and brings down the overall temperature of the tank. The contained energy remains the same, but it is spread over a larger volume of water (1.16Wh per degree centigrade per liter of water). So if you don't refill, you keep the water warmer. That's my guess though.

[PaulF007]

@Chris Hobson The controller itself does all the work , it is very similar to the geyserwize jobbies and yes it is a low pressure system (is there any other system  ).

So basically it works in a few ways.

1. The water outlet is at the bottom of the geyser in comparison to a traditional geyser. Then there is a 12v valve at the geyser that gets controlled by the "geyserwize"
2. The controller will fill twice a day (automatically) at 7h00 in the and 13h00 this gives every body enough time shower clean and do dishes. Then at 13h00 dishes if needed and then there is still plenty time for the geyser to top up. 
3. Nighttime we keep an eye on the temp. So if we have 70 - 90 deg. We will fill the geyser twice maybe 3 times. Else we will be a bit more careful. Then I have a program (Obviously ) that keeps an eye an the geyser temp. If it is below 40 deg by 15h00 it will send me a notification so that I can switch on the element manually. I only have a 1kw element so it takes a bit longer to heat up the water  but in winter it makes quite a difference on how quickly the water gets to temp.
4. If the water level drops to below 25% the value will open automatically ( the element will also not switch on then)

All in all the system runs quite nicely. 

[___]

1 hour ago, PaulF007 said:

The water outlet is at the bottom of the geyser in comparison to a traditional geyser.

That's part of the reason why you don't want to refill it too soon of course. The cold water will drop to the bottom and spoil your shower.

Some heat pumps had that problem in the beginning (perhaps still). You'd go and take a shower, and while you're still in the shower the thermostat turns on the heat pump. This proceeds to take cold water from the bottom of the tank (say 15 degrees), heat it by 5 degrees, and pump it into the top of the tank... instantly spoiling the pleasure of a hot shower.

How I miss the pleasure of a hot shower.

[PaulF007]

14 minutes ago, plonkster said:

How I miss the pleasure of a hot shower.

True those little pleasures. but more importantly that horrible "klonk" sound that a toilet makes when you pull the leaver is much worse. 

16 minutes ago, plonkster said:

That's part of the reason why you don't want to refill it too soon of course. The cold water will drop to the bottom and spoil your shower.

The interesting part is that when you look at the graphs you can see that the water is actually getting hotter when you shower , as the hot water is dropping. Never knew that in the beginning.   

[___]

6 minutes ago, PaulF007 said:

more importantly that horrible "klonk" sound that a toilet makes

I mostly avoided that issue. I plumbed my well water into the one toilet, with a new problem. I knew there was some bad stuff in the water (a small taste test confirmed that many years ago), but since no walls had ever been discoloured in 5 years of irrigation use I assumed the iron content must be low. Well... now I have a horrible red stain in said toilet. It's still early enough to get it off, but that's pushed up the urgency of my treatment project somewhat.

It turns out that while I don't have high overall levels of iron, I do have a high "dissolved" iron level at 76µg/liter (must be below 20, preferably). Fun...