TemperingValve over cooling water
Hi all,
Long story short, I have a tempering valve that is meant to lower the temperature from a storage tank down to 60 C if the storage tank temperature is too high (storage tank connected to solar collectors). However, when looking at the output data I've found the tempering valve over cools the water from the storage tank (e.g. 67 C water down to 48 C). If only cooled to 60 C, the instantaneous water heater wouldn't need to add any energy.
Here is a picture of my setup with labels:
I was surprised to see the tankless water heater doing as much work as it was and decided to take a look at the hourly data and found many cases where the storage water was > 60 C but the tankless water heater was still heating water. As stated before, it looks like the tempering valve is overdoing it when bringing in cool water. It will nearly always bring the temperature down below 60C. I labeled all the tempering valve nodes in blue to help show what I set the tempering valve parameters to.
Any advice would be greatly appreciated!
EDIT: Is it possibly my setpoint manager? By having my setpoint manager AFTER the tankless water heater, am I telling the loop "make sure the water is 60 C at My colleague suggested a setup similar to this:
So far things look good from an energy use/temperature perspective. I'm going to take some time to more thoroughly analyze the energy results, but appear much better.
If any of you have thoughts on complications that might arise from this node, doesn't matter elsewhere"? If so, it's almost like I want an extra setpoint manager before the tankless water heater to tell the tempering valve to never cool the water get below 60. As it stands, I imagine my setup isn't breaking rules when the tempering valve drops the water temperature down to 48 before heating back up to 60 because the setpoint manager sees 60C regardless.
I hope that is clear, if not setup, please let me know. This is a difficult idea to articulate and I am still learning my way around openstudio.know.