Originally Posted by ennonne
Remember that HEAT does NOT rise. Hot air does. There are homes heated with radiant heat installed in the ceiling. It has the advantage of not having things sitting all over it, as a floor does. So yeah, radiant panels in the walls could work.
The heat in heated water does rise.
Open up an old water heater and you will notice that the cold water inlet has a tube attached that extends down to the bottom third of the tank while the hot out has a tube that barely extends into the top third of the tank.
I do commercial hydronic heating and air for a living and when I have to help troubleshoot a system I can always look at a specific cools temperature readings and tell if one or all are piped in backwards or not.
To the OP. look up heating hydronic coil piping from bell and gosset's little red school house and it can/will explain some/all of your questions.
They are a big company and do continuing Ed. For engineers yearly around the world. Don't meen you have to buy there stuff which is priced comparably and top notch support all the way through for whatever your design and intentions but the little red school house will help your knowledge with air elimination devices,flushing,filling and proper zone valve's for your intentions.
I installed heated almost everything except the roof in 7 working dog kennels for one bases I work around and the piping was pretty straight forward.
The concrete man didn't like me.
The mason's hated me.
But the zone control panels and pumps required kicked my butt?
The system was an Italian manufacturer that I couldn't understand when I talked to and B&g worked with me through the troubleshooting mess.
Yes heat rises and so do air bubbles.
High point air vents whether manual or automatic is needed.
And ethylene glycol is better than water in most hydronic systems but in any closed loop hydronic system with automatic air vents you have to have an automatic feed system to replace what is lost in the air bubbles.
I have and can help build a flush cart system to get all air out of a closed system without vents but that more of the glycol type.
Food for thought?