Yes, having two water coils on the same plant branch is going to cause problems. A heating coil needs to be connected to a hot water plant loop and a cooling coil needs to be connected to a chilled water plant loop.
From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of stagiaire3@xxxxxxxx
Sent: Friday, September 27, 2013 4:04 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] RE: Water coil meets the load with no water flow rate...
Thank you Brent,
In fact, I don't have any unitary system, but your contribution makes me think that the problem may come from two controllers on the same water branch. Could it be possible?
If that is the case, I don't really know what to do: from what I've seen so far, E+ does not allow water coil without controller... (In my model, the second controller is inefficient (convergence tolerance set to 100°C) since the heating coil water flow rate must be determined by the cooling coil flow rate only).
On top of that, I did not find a way to regroup both cooling and heating coil in only one cooling coil (thus having only one controller) because the air input and output conditions of this "coil system" would be inconsistent with E+ water coil definition : I would get "no apparatus dew-point found" errors... (input condition: 27°C, 15g/kgas, ouput condition: 20°C, 7g/kgas)
What do you think?
---In energyplus_support@xxxxxxxxxxxxxxx, <brent.griffith@...> wrote:
I have seen this sort of thing happen when the input for water coil’s control is set up with both a Unitary system and a Controller:WaterCoil. It needs to be one or the other but not both.
From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of stagiaire3@...
Sent: Thursday, September 26, 2013 7:02 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] RE: Water coil meets the load with no water flow rate...
I must add that this is not only a report problem. With total water coil cooling coil rate and input/output water temperature, I could do the math to determine water flow rate...
The point is that I have 70kW total cooling coil rate, and 0kW chiller electric power, so the 0m3/s water flow rate is really accounted by E+...
Hoping this could help understanding my problem,
Luc
---In EnergyPlus_Support@xxxxxxxxxxxxxxx, <energyplus_support@xxxxxxxxxxxxxxx> wrote:
Dear community,
I have some troubles modeling a dehumidification system that consists of a water cooling coil and a water heating coil in series, for both fluids: the output water from the cooling coil (at approximately 20°C) is used to re-heat the air stream through a heating coil before heading back to the chiller.
As I run simulations, it appears that the loads are met, and that the water temperatures at cooling coil inlet node, cooling coil outlet node (=heating coil inlet node) and heating coil outlet node are coherent: 5/19.3/14.4°C. But there is no water flow rate reported, using both "system node massflowrate" and "system node volume flow rate standard density", while air flow rate is well reported.
I get no warning or errors on this in the err file.
Does anyone have any idea on what is happening here?
Thanks,
Luc
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