I am not sure if I want to do is feasible and logic. I want to control a constant flow low temp radiant system based on the radiant surface temperature (in my case ceiling surface temperature). I tried to add a EMS sensor for Surface Inside Face Temperature for the Ceiling surface; for the actuator I am using "Constant Flow Low Temp Radiant” with the control type “Water Mass Flow Rate”. My problem is that I am not sure what should be the logic of my program. Basically, I want to provide chilled water only after the heat gains from a room have melted all the phase change material (PCM) in which the pipes of a radiant system is embedded. I am assuming that all the PCM is melted when the temperature of the ceiling is a couple of degrees above the melting point (around 23C). In my case, I want to run the chilled water when the surface temperature (which in the model should be the same as the PCM temperature) is above 25 C, which should be an indication that all the PCM is melted and needs to be regenerated. The chilled water is used to regenerate (solidify) the PCM by reducing its temperature to 21 C. When the temperature reaches 21 C, the chilled water stops and lets the system to work passively by absorbing internal heat gains until the surface temperature (PCM temperature) reaches 25C, when the system starts working again.
Any suggestions???
