Hi Guys,
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I'm just trying to simulate a single, fairly square room with a TABS. The TABS is in the ceiling about 5cm in the concrete. As TABS I use the object "ZoneHVAC: LowTemperatureRadiantSystem: VariableFLow".The interior walls, as well as the ceiling and floor are adiabatically adopted. The outer wall, which faces west, has 2 windows with a sunshade.
The problem I have is the regulation of this TABS, which I want to overwrite via EMS. The standard control according to current outside temperature works. However, I would like a regulation according to an average of the outside temperature, e.g. the last 12 hours. This control regulates the flow temperature according to a kind of heating curve for cooling and heating, which works in principle. For the transitional area between both cases, the mass flow should be set equal to 0. The mass flow actuator is "Hydronic Low Temp Radiant, Water Mass Flow Rate" of the "ZoneHVAC: Low Temperature Radiant System: Variable Flow" object. If I set the Actuator equal to 0 in my EMS program, this happens. If, however, I specify a different number than 0 as the set mass flow, this is ignored and the mass flow regulates again according to the current outside temperature. It seems like, that this actor only controls the maximum possible flow, even tme "Application guide for EMS" says something different. I also tried "System Node Setpoint, Mass Flow Rate Setpoint" of the "Heating Water Inlet Node Name" resp. "Cooling Water Inlet Node Name" of the "ZoneHVAC: LowTemperatureRadiantSystem: VariableFLow" object to specify the mass flow for the respective cases, but this does not work either. I am using version 8.5.0 but have found no clue in the bug fixes of the newer versions that would address this issue. If someone ever had a similar problem and could help me, I would be very grateful.
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Greetings from Cologne in Germany
Tobias
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Posted by: Jean Marais <jeannieboef@xxxxxxxxx>
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