Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
Per above comments, I moved the pump(s) to the splitter inlet rather than mixer outlet, and put a tempering valve rather than pipe as the bypass branche(s), to get flow through all of the radiant branches. Not sure why demand loops would be affected by having pump discharge on one end or the other of the supply loop but...
I realized that meeting Zone temp targets (i.e. Autosizing of the radiant component flowrates) was also affected by: 1.) SizingPlant:loop design delta T is a fixed constraint in sizing - flow rates are limited to ensure the set dT. My dT was too much; and flow rates couldn't increase enough to ensure enough hxfer to maintain needed temps. 2.) Switching from non-coincident loop sizing to Coincident loop component sizing option didn't change rad. floor tube length or diameter or max flow rates. It is not clear to me if this option works for low t radiant variable flow. 3.) PlantLoop object: Volume/ loop residence time impact ability to meet heat targets. Larger volumes/longer residence times permit more hxfer. 4.) Further to above, increasing hydronic tubing diameter, and allowing multiple circuits in the ZoneHVACLowTRadVarFlow object allowed me to put more heat in the zones
With these parameters understood, I am starting to be able to acheive targeted design temps with autosizing
| | 2 | No.2 Revision |
Per above comments, I moved the pump(s) to the splitter inlet rather than mixer outlet, and put a tempering valve rather than pipe as the bypass branche(s), to get flow through all of the radiant branches. Not sure why demand loops would be affected by having pump discharge on one end or the other of the supply loop but...
I realized that meeting Zone temp targets (i.e. Autosizing of the radiant component flowrates) was also affected by:
1.) by:
With these parameters understood, I am starting to be able to acheive targeted design temps with autosizing
