How can i solve the warning about water-to-water heat pump

asked 6 years ago

l1023
141 ●2

updated 6 years ago

shorowit

12570 ●220 ●9 https://www.nrel.gov/b...

   ** Warning ** GetDensityGlycol: Temperature is out of range (too low) for fluid [WATER] density **
   **   ~~~   ** ..Called From:CalcWatertoWaterHPHeating,Temperature=[-10.99], supplied data range=[0.00,100.00]
   **   ~~~   **  Environment=SHANGHAI ANN HTG 99.6% CONDNS DB, at Simulation time=01/21 00:00 - 00:15
   ** Warning ** GetSpecificHeatGlycol: Temperature is out of range (too low) for fluid [WATER] specific heat supplied values **
   **   ~~~   ** ..Called From:CalcWatertoWaterHPHeating,Temperature=[-10.99], supplied data range=[0.00,125.00]
   **   ~~~   **  Environment=SHANGHAI ANN HTG 99.6% CONDNS DB, at Simulation time=01/21 00:00 - 00:15
   ** Warning ** SolveAirLoopControllers: Maximum iterations (50) exceeded for DOAS SYSTEM-Y, at RUNPERIOD1, 07/11 20:30 - 20:35

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answered 6 years ago

rraustad

13924 ●82 ●13 http://www.fsec.ucf.edu/

The warnings show that the water temperature is -10.99 C. This is obviously wrong and something in the simulation is causing the water-to-water heating coil to turn on when the plant is unable to sufficiently heat the water loop. To help determine the cause add:

Output:Diagnostics, ReportDuringWarmup;

Then add Output:Variable reports for the plant loop water inlet and outlet nodes, the equipment performance reports for the plant loop equipment, and the water-to-water coil reports for air and water side nodes.

After the simulation is complete open the variables report and review the performance of the HVAC and plant. I suspect you will find that the plant is not operating as expected during the warmup period and the plant temperatures are too low for some reason.