fluid expansion tanks

Most SHW systems have an expansion tank inline. How much do those cost???
also, if you plumbed in a 5 gallon tank inline in a drainback set up and put it at the correct height, would that work for expansion of fluid?? or even a 3 inch pipe straight up for 6 ft or so..
also, if you plumbed in a 5 gallon tank inline in a drainback set up and put it at the correct height, would that work for expansion of fluid?? or even a 3 inch pipe straight up for 6 ft or so..
Comments
It does depend on the size of the hot water tank, piping, solar thermal collectors, etc.
Here is a really interesting and well written website about a solar heated office/barn project--I think it will answer many questions:
http://www.arttec.net/Solar/BarnHeat.html
-Bill
I have this brand for my heating system:
http://www.amtrol.com/extrol.html
There is a sizing:
http://www.amtrol.com/support/extrol_com_sizing.html
http://www.pexsupply.com/Amtrol-101-1-15-Extrol-Expansion-Tank-2-Gallon-Volume-2556000-p
small and cheap