Sounds to me that you are spending $160/month on heating, which I think is very good. That also means a 5 ton heatpump is not running very much, so you should have capacity left for and addition. How much capacity? That is hard to say but it appears to me that your 5 ton system is not even running at 50%. We would need more data such as running time at certain outside design temperatures etc. What makes you think your loops are not balanced?
Assuming you have antifreeze in your source loops, your heat extraction is only 26,500 BTU, but you should see about 34,000 heat extraction. Heat capacity at those temps should be around 55,000 BTUs, which is what you push out into your floors.So I think your measurement on your source side is not correct.
I would not touch your source side, what makes you think it is not balanced? 13.7 gpm is fine for the 5 ton heatpump, you would not see much efficiency gain. Nor should you try to restrict flow with the intention to balance the loops.
Your radiant floors are not optimal. You should shoot for 10 degrees delta T, try to close the bypass valve. Bypassing your flow to the radiant system makes no sense and might explain your very high (and inefficient) temps on your radiant side. They probably designed you radiant floors like a boiler system with mixing capabilities between supply and return on the radiant side, but this is not how a geo system should be designed.
Onix is not a great material since it requires a higher supply temperature (it is rubber which is an insulator) so your system runs less efficient. It is good for boiler applications where you do not pay a penalty for higher supply temperatures. Not much you can do about it now. You would probably benefit most from an outdoor reset. 119 F supply temperature for radiant floors is very high.
The pressure fluctuations you might see due to
Where are you located? IRR supply sounds familiar. IRR is a plumbing supply chain, with limited geo design experience, which provide limited design service for installers who are not able to design a system by themselves. All with the goal to sell the equipment to them.
So the actual geo part of your system sounds OK, but your radiant system appears to be designed for a high temperature like for a boiler system.
Did I ask if you have a buffer tank for the radiant?
Last edited by docjenser; 04-24-2012 at 06:17 AM.