Re: Heat Recover, was: RE: NODE 0 Heat

[Jim Noble <yahoo-groups@xxxxxxxxxxxxxxxxxx>]

Ian wrote:

> >From: Jim Noble [mailto:yahoo-groups@xxxxxxx]
> >
> > What happens when you're not feeding cold water into the cylinder
> though?
>
> When are you ever not feeding cold water into the cylinder?


When it's full?

> Surely the hot water tank is always under pressure, so that if usage
> outstrips capacity you just get cold water from the tap, rather than
risk
> the boiler running dry?


Either from the head of water in the tank (vented cylinder), or the
incoming mains pressure (unvented) yes, but I'm not sure I see the
relevance of that...?

> > Do you have a small secondary tank in the supply pipe?
> That's what I said. ;)
> Rather than this: http://tinyurl.com/6ecex
> You have this: http://tinyurl.com/4zca2


Hot water supply doesn't work quite like that :-? The water heated by
the boiler runs in a continuous loop that never goes anywhere near your
hot taps (unless you like the taste of corrosion inhibitor...?)

You could have a small header tank between the cold water tank and the
cylinder that is gently warmed by your waste heat though. That would work.

> Only in countries prone to freezing, where the externally exposed loop
> typically contains anti-freeze. In hotter climes, it seems that the
> tank is
> fed directly.


Got any links to suppliers of that type of system? I've not found any
like that yet...

> Either way, the concept is the same - you preheat the water to make it
> easier for the boiler so you consume less fuel.


Yep, that makes sense.

> Whether it's practical to
> use PC heat as a heat source is the real question I guess.


Possibly not the most efficient form of hot water heating :-) Better not
to waste any heat you do produce if possible though.

Jim