|
guydewdney
|
 |
« on: October 13, 2011, 09:56:39 PM » |
|
Doing a property development - not for me - and there is a requirement for a small space water system - so is there a 'mini' hot water cylinder that could be heated to 90? C and then act as the heat bank for a combi boiler (with a temp reduction thingy so the combi doesnt throw a fit)? Dont have space for a conventional cylinder, before you ask.
|
|
|
|
|
Logged
|
|
|
|
|
KLD
|
|
« Reply #1 on: October 13, 2011, 10:20:26 PM » |
|
Guy, What do you try to achieve beyond the combi boiler capabilities? Do you require higher flow rates, or have additional heat sources?
Klaus
|
|
|
|
|
Logged
|
|
|
|
|
guydewdney
|
|
« Reply #2 on: October 13, 2011, 10:28:30 PM » |
|
In a 'conventional' combi boiler with solar, theres a large tank heated by the solar, which feeds pre-warmed water to the combi, reducing the energy required by the boiler. But - we dont have the space for a large tank - so wondered if there was another option. Its adding a 'green' credential to a build in a conservation area.
|
|
|
|
|
Logged
|
|
|
|
|
KLD
|
|
« Reply #3 on: October 13, 2011, 11:31:43 PM » |
|
Ah, you want to buffer some solar heat for later use, possibly topped-up to required temperature by the combi?
It all depends on how much DHW you need. Let's play with a few numbers. Water can store 1.17(Wh/L °C). Say your cold supply is 15°C, hot at 45°C (i.e. dT = 30°C), and you want 100L of it, than that's 3.5kWh. If you were to have a small buffer tank, say 50L, then you'd need to get that tank up to 105°C (half the volume, twice the dT = 60°C, 45+60°C). Hm, not so good then. With less stored energy (lower dT in the buffer), the backup boiler would have to contribute more.
Klaus
|
|
|
|
|
Logged
|
|
|
|
|
guydewdney
|
|
« Reply #4 on: October 14, 2011, 12:01:18 AM » |
|
oil filled buffer? Has to be a 'off the shelf solution' though....
|
|
|
|
|
Logged
|
|
|
|
|
knighty
|
|
« Reply #5 on: October 14, 2011, 02:48:12 AM » |
|
isn't the specific heat capacity of water higher than oil ?
water is one of the highest iirc?
do you have the solar panels yet ? could you use the type that have a tank built onto the top of them ?
I don't know what they're called, but I've seen them on here before !
|
|
|
|
|
Logged
|
|
|
|
|
guydewdney
|
|
« Reply #6 on: October 14, 2011, 11:07:40 AM » |
|
I doubt planning would allow the tank type - plus that means no mains pressure hot water. Oil can be heated to a higher temp than water, so could, in theory, store more therms per cubic foot so to speak, with water at 90C and oil at 400C...
|
|
|
|
|
Logged
|
|
|
|
|
KLD
|
|
« Reply #7 on: October 14, 2011, 11:08:04 AM » |
|
Install pV and use the grid as a buffer store?
K
|
|
|
|
|
Logged
|
|
|
|
|
Iain
|
|
« Reply #8 on: October 14, 2011, 12:33:19 PM » |
|
Hi Guy
A boat calorifier would come in all sizes, but any thing to do with a boat would be more expensive.
Iain
|
|
|
|
|
Logged
|
1.98kWp PV (11 x Sharp 180 and SB1700)
20 x 65mm Thermal and 180ltr unvented
6000ltr rainwater storage
Plymouth
|
|
|
|
renewablejohn
|
|
« Reply #9 on: October 14, 2011, 01:13:31 PM » |
|
Guy
Have a look at the Otag Lion instead of your combi. Could also link in with PV I have posted links on the steam engine thread.
|
|
|
|
|
Logged
|
|
|
|
|
