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2018-05-23 03:02:29 -0500 | marked best answer | Chiller on SetpointManager:FollowSystemNodeTemperature reports error with no cooling load I am experimenting with using a setback scheme for supply air and chiller water temperatures, using Energy Plus's standard "RefBldgLargeOfficeNew2004_Chicago_SA_setback.idf" building model with weather file "USA_IL_Chicago-OHare.Intl.AP.725300_TMY3.epw". This is in Energy Plus 8.3. The plan is that the supply air temperature setpoint will be regulated to match the warmest zone's requirements, rather than always set at 12.8 deg C. Then the chiller water temperature setpoint will be follow at 6.1 deg C below the supply air temperature setpoint, rather than being held at 6.7 deg C all the time. The idea of this strategy is that the chiller water can rise to a higher temperature when there is low cooling load, increasing the efficiency of the chiller. In addition, if the zone air setpoints are raised, the setpoints for the supply air and chiller water will follow, and the chiller will reduce its work or even shutdown for a while. This would be useful for cutting electricity use and "coasting" in response to a short period of high electricity prices. Concretely, I'm planning to implement this strategy in Energy Plus by replacing the As a first stage, I have inserted the I'm not surprised that the part-load ratio would drop to 0.000 under this control strategy, but I am concerned that Energy Plus isn't recognizing this and just turning off the chillers. I think it is handling part-load ratios between 0 and 0.1 by cycling the chillers and between 0.1 and 0.2 by hot gas bypass (using the 0.2 point on the performance curve). In the default setup, I think it also manages to turn the chillers off on cool days without complaining. But for some reason, when the Is there anything I can do to avoid this message? Or should I just ignore it? Or follow some different strategy entirely? |
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2018-05-22 20:45:20 -0500 | commented answer | Chiller on SetpointManager:FollowSystemNodeTemperature reports error with no cooling load @rraustad I think from the docs that the chiller should run normally for PLR>=0.2 (Minimum Unloading Ratio), use hot- |
2018-05-22 20:12:35 -0500 | commented answer | Chiller on SetpointManager:FollowSystemNodeTemperature reports error with no cooling load @TomB In the timestep with the first error, Chiller Part Load Ratio, Chiller Cycling Ratio and Chiller Electric Energy a |
2018-05-22 19:46:40 -0500 | commented question | Chiller on SetpointManager:FollowSystemNodeTemperature reports error with no cooling load @Julien-Marrec Yes, the only change from the standard example is the SetpointManager:FollowSystemNodeTemperature that I |
2018-05-22 03:47:41 -0500 | received badge | ● Student (source) |
2018-05-21 23:07:34 -0500 | asked a question | Chiller on SetpointManager:FollowSystemNodeTemperature reports error with no cooling load Chiller on SetpointManager:FollowSystemNodeTemperature reports error with no cooling load I am experimenting with using |