I am setting up a hot water system for our house using a Sanden CO2 heat pump and our existing radiant floor system and domestic water system.The Sanden uses a 83 gallon tank to store the hot water. It is really important that the water in the tank remain stratified such that when the heat pump turns on it receives cold water rather than hot water to maintain the best performance. The top of the tank is at 150*f.
I will be using a Taco x-pump block to transfer heat from the tank to the radiant floor. If the inlet to the Taco is 140* F or so then the out is 120+- which is too warm for the heat pump. I want the floor water at 85*F
I am thinking if I use a mixing valve to feed the Taco I can decrease the input temperature to 110 and get return water to the tank at a lower temperature.. I would feed hot and cold from the tank to valve, mixed to Taco where pump pulls the water and out from Taco to cold line that feeds the mixing valve and is connected to cold of tank.
Do you see any issues with this setup? Thanks Rod