Post by SpeedEvil on May 5, 2011 21:28:58 GMT -5
After buying a pump...
Anyway - here is an overview of my plans.
My problem.
I have a limited income, and am likely to not have much coming in for the forseeable future.
I want to spend what I have on fun stuff, not bumping up the profits of npower et al.
Most of the below is subject to change - but it's my current thinking.
I don't understand stratified thermal stores well enough to design one. This is the reason for not using one.
At the moment, I have a 40l plastic barrel in the garden, in a kingspan box, hooked up to a 1800mm*57mm*18 tube collector, with the aforementioned pump. This is mostly for data collection, and does not reflect the final system.
Bits are being picked up on ebay, on a 'can I use this' basis, rather than a 'I need x now' basis.
Hence for example instead of speccing the ideal heat exchanger, I'm using random spares for boilers.
Basic design is two thermal stores. Warm and hot. These will not be stratified to a significant extent.
The panel is either connected to the warm, or the hot store. When the pump is turned on, it pumps water into the panel - when it's off, it drains out into the tank - to drain it when it's cold.
Future plans are a flat panel collector, hooked up to the warm tank, and probably a gas fired instant heater on the output to bump it up when solar isn't cutting it.
In normal use, when hot water is demanded, it will run mains cold through two heat exchangers - one connected to the warm tank, one to the hot tank.
Secondary circulation will be two old CH pumps I happen to have, which work fine.
There will be a fair amount of fernox, or equivalent in the system, along with filters, to prolong the life of valves and pumps.
In the case that both stores are too hot - the panel is connected to a radiator in the roof-space.
The stores are not pressurised, and the worst case control failure would lead to the hot panel not being cooled by water at all, but no dangerous failure modes.
Initial plans were to use old hot-water cylinders, from the scrapyard, with additional insulation in the form of a ~20cm or so thick box of kingspan.
However - I got to wondering if it's sane to use steel drums.
Clearly - any oxygen in the system will be extremely bad - and they would require periodic
inspection to ensure that they are not corroding.
If it's treated as a sealed system - with expansion vessel - though at atmospheric pressure - with lots of stabiliser in the system, and no oxygen where might failures occur?
Probably not sensible - though steel drums are very cheap!
Anyway - here is an overview of my plans.
My problem.
I have a limited income, and am likely to not have much coming in for the forseeable future.
I want to spend what I have on fun stuff, not bumping up the profits of npower et al.
Most of the below is subject to change - but it's my current thinking.
I don't understand stratified thermal stores well enough to design one. This is the reason for not using one.
At the moment, I have a 40l plastic barrel in the garden, in a kingspan box, hooked up to a 1800mm*57mm*18 tube collector, with the aforementioned pump. This is mostly for data collection, and does not reflect the final system.
Bits are being picked up on ebay, on a 'can I use this' basis, rather than a 'I need x now' basis.
Hence for example instead of speccing the ideal heat exchanger, I'm using random spares for boilers.
Basic design is two thermal stores. Warm and hot. These will not be stratified to a significant extent.
The panel is either connected to the warm, or the hot store. When the pump is turned on, it pumps water into the panel - when it's off, it drains out into the tank - to drain it when it's cold.
Future plans are a flat panel collector, hooked up to the warm tank, and probably a gas fired instant heater on the output to bump it up when solar isn't cutting it.
In normal use, when hot water is demanded, it will run mains cold through two heat exchangers - one connected to the warm tank, one to the hot tank.
Secondary circulation will be two old CH pumps I happen to have, which work fine.
There will be a fair amount of fernox, or equivalent in the system, along with filters, to prolong the life of valves and pumps.
In the case that both stores are too hot - the panel is connected to a radiator in the roof-space.
The stores are not pressurised, and the worst case control failure would lead to the hot panel not being cooled by water at all, but no dangerous failure modes.
Initial plans were to use old hot-water cylinders, from the scrapyard, with additional insulation in the form of a ~20cm or so thick box of kingspan.
However - I got to wondering if it's sane to use steel drums.
Clearly - any oxygen in the system will be extremely bad - and they would require periodic
inspection to ensure that they are not corroding.
If it's treated as a sealed system - with expansion vessel - though at atmospheric pressure - with lots of stabiliser in the system, and no oxygen where might failures occur?
Probably not sensible - though steel drums are very cheap!
