navitron
 
Renewable Energy and Sustainability Forum
Welcome, Guest. Please login or register.

Login with username, password and session length
News: Anyone wishing to register as a new member on the forum is strongly recommended to use a "proper" email address - following recent spam/hack attempts on the forum, all security is set to "high", and "disposable" email addresses like Gmail, Yahoo and Hotmail tend to be viewed with suspicion, and the application rejected if there is any doubt whatsoever
 
Recent Articles: Navitron Partners With Solax to Help Create A More Sustainable Future | Navitron Calls for Increased Carbon Footprint Reduction In Light of Earth Overshoot Day | A plea from The David School - Issue 18
   Home   Help Search Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: Using tank water for cooking?  (Read 8438 times)
Greenbeast
Hero Member
*****
Offline Offline

Posts: 2303


WWW
« on: July 28, 2009, 08:54:45 AM »

Does anyone use their tank want for cooking or tea coffee?

Is it a bad idea?
I've got a brand new cylinder
Logged
Flamethrower_
Hero Member
*****
Offline Offline

Posts: 745



« Reply #1 on: July 28, 2009, 10:01:27 AM »

Depends what you are calling a tank (cylinder)?
Logged
Greenbeast
Hero Member
*****
Offline Offline

Posts: 2303


WWW
« Reply #2 on: July 28, 2009, 10:06:46 AM »

sorry, i'm talking about the hot water cylinder
Logged
Flamethrower_
Hero Member
*****
Offline Offline

Posts: 745



« Reply #3 on: July 28, 2009, 10:32:48 AM »

If its a unvented cylinder / or thermal store with direct mains water, I personally see no problem but I wouldn't used the hot supply from an open vented system (possible contaminants from storage tank in roof?)

I think there was another thread previously on the Navitron forum all about this I see if I can find it!
Logged
Greenbeast
Hero Member
*****
Offline Offline

Posts: 2303


WWW
« Reply #4 on: July 28, 2009, 11:37:28 AM »

We're open-vented
Logged
plumbskill
Full Member
***
Offline Offline

Posts: 147


« Reply #5 on: July 28, 2009, 12:51:43 PM »

If you have a bylaw 30 tank set up [no risk of contamination] cant see the problem as you would be boiling the water anyway for cooking and making tea.
The only possible financial gains would be if you had short runs of pipework from your cylinder to the kitchen tap.
Cannot see the point of pulling off lots of cold water before it gets hot just to fill a kettle, unless all your hot water is solar heated and you have plenty of it.
Logged
Greenbeast
Hero Member
*****
Offline Offline

Posts: 2303


WWW
« Reply #6 on: July 28, 2009, 01:00:17 PM »

the cylinder is in the bathroom next to the kitchen and i have an unused hot outlet on the cylinder, so there is no cold run at all
Logged
Ivan
Guest
« Reply #7 on: July 29, 2009, 04:23:01 PM »

The other thing to consider is copper in the water. Acidic water will leech some copper from the cylinder, particularly if the tank is very hot. (I guess most water is slightly acidic due to the chlorine). I don't think Monmouth is particularly acidic, but if I run hot water into the bath (without bubblebath!), it's easy to see a greenish tinge. Won't do you any harm bathing, but it might not be so good for you if you ingest it regularly. A better option might be to use a stainless steel plate heat exchanger, and a pump - recirculate the hot water through the heat exchanger, and run domestic cold water through the heat exchanger at the same time. In fact, in Germany this is fairly standard practice with big heatstores.
Logged
kristen
Hero Member
*****
Offline Offline

Posts: 2022


« Reply #8 on: July 30, 2009, 12:12:52 PM »

We have mains-pressure DHW (i.e. through a coil in the Thermal Store) and we use it to save a bit of time cooking / boiling kettle. And with solar hot water its cheaper off course, provided that it doesn't cool the tank to the point where the boiler is triggered ...
Logged
oliver90owner
Hero Member
*****
Offline Offline

Posts: 2064


« Reply #9 on: July 30, 2009, 08:15:36 PM »

I guess most water is slightly acidic due to the chlorine

Ivan,

Soft water perhaps, but not any water with temporary hardness (contains bicarbonates (or hydrogen carbonates)), so will be the alkaline side of the pH scale.

Regards, RAB
Logged
Ivan
Guest
« Reply #10 on: July 30, 2009, 10:24:58 PM »

Good point, RAB.

I've just calibrated my pH meter and checked our mains water - pH7.8 from the kitchen tap - so that's slightly alkaline (presumably due to water hardness, as RAB points out). But we still get slightly green bathwater when the cylinder gets really hot     Huh
Logged
Jonzjob
Full Member
***
Offline Offline

Posts: 125



« Reply #11 on: July 31, 2009, 06:55:24 PM »

The last time I chucked any chlorine into our pool I had to put some sulphuric acid in too because chlor is very alky..
Logged

kristen
Hero Member
*****
Offline Offline

Posts: 2022


« Reply #12 on: July 31, 2009, 07:41:39 PM »

There's some chemistry about swimming pools that I have no recollection of learning at school.

pH and Total Alkalinity.

We had a situation with our pool last year where the pH was fine, but the total alkalinity was sky high (except we weren't measuring it, so we didn't know).

This is apparently caused by a build-up of the stabilizing agent in the Chlorine (to stop it just bubbling off, I presume).

What happens is that it becomes very difficult to control the pH, and that leads to the Chlorine not doing its stuff, which in turn leads to algae growing easily.

To adjust the Total Alkalinity we had to put a shed load of Hydrochloric acid in - about 30 or 40L IIRC.  But I couldn't just chuck it in, I had to reduce the alkalinity, which involved vigorous agitation of the pool.

So:

Add a bit of acid
pH falls
Vigorously agitate the water
ph climbs
Add a bit more acid, and repeat.

Each time we got to the "Add a bit more acid" step the Total Alkalinity had fallen.

Last year, and this, having got the Total Alkalinity "perfect" we have used so little Chlorine, relative to previous years, I can scarcely believe it. Haven;t used any Algaecide at all.

Sorry, probably not relevant to this discussion at all.
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.20 | SMF © 2013, Simple Machines
SMFAds for Free Forums
Simple Audio Video Embedder
Valid XHTML 1.0! Valid CSS!