hamish05
Member
In the latest issue (119) of ReNew there is among other great ideas on page 23 an article introducing Valvcosy.
I purchased one this morning because it looks to be not only a simple and good idea, but an attachment for water heater storage cilinders that makes lots of sense.
Although the ReNew article doesn’t say, it is available from the ATA Webshop, and is shown on their webpage. http://shop.ata.org.au/
TonyT
Member
How many years will it take for the cumulative kWhr of saved heat energy to be worth the $20 price of a Valvecosy ?
Calculations to determine the optimum thickness of insulation for a hot pipe are shown at
http://www.ata.org.au/forums/topic/290#post-25320
hamish05
Member
Just went and checked how the Valvecosy was performing. Tank water temp 68deg, outside temp 14 deg, the Valvecosy is certainly cold to the touch, it’s doing a fine job.
Now I ask, where could you have that much fun for just $20? - Btw, only $17 if you are an ATA member!
I like the idea and just saw it in ReNew also. $20/$17 isn't too bad and when I thought about making one myself I realised there is a little more to this design than simply wrapping the valve in insulation. The design needs to be able to cope with occassional water release without getting wet and soggy and it needs to be easily removable so that you can test the valve without destroying the cover. I might just go ahead and buy one rather than attempt to recreate it DIY.
TonyT
Member
A "tank cosy" and estimates of the kWh of heat that is lost from a hot water tank are discussed in the thread at
http://www.ata.org.au/forums/topic/2687#post-25784
from
http://www.rehau.com.sg/files/Technical_Information_RAUTITAN_Water_Services.pdf
For a copper pipe with OD=12.7mm and wall thickness 0.91mm that carries water at 60degC through air at 20degC the heat loss is 27.2Watts per metre.
In 24hrs the heat loss is (24 x 27.2) = 650Watthours per day per metre
= 0.65kWh/day per metre.
For electricity costing 20cent/kWh, 0.65kWh/day per metre costs 13cents/day per metre.
Pipe insulation 9mm thick reduces this heat loss to 10.0W/m, 13mm to 8.5W/m and 25mm to 6.5W/m
For copper pipe with OD=19.05mm and wall=1.02mm the heat loss is 38.3W/m.
With 9mm insulation this reduces to 13.0W/m, 13mm to 10.7W/m and 25mm to 8.0W/m
andarm
Member
If I'm not mistaken, the ValveCosy only insulates the PTR valve. That being said, while the heat loss values stand as described above, that loss is per metre of pipe and therefore the total distance of pipe at 60-65oC is quite possibly only a few hundred mm in total due to the good job being done by the ValVeCosy.
(Not designed as negative comment in any way just as complete disclosure of data)
