The Cooling System can't maintain proper air temperatures in the room

asked 2021-05-04 01:08:32 -0500

tri.ton99 gravatar image

updated 2021-05-04 02:41:59 -0500

Hi everyone,

I am modeling a data center in EnergyPlus based on 2ZoneDataCenterHVAC_wEconomizer model with DX Cooling Coil. When I increase the value in the Field Watts per Zone Floor Area (from 200 W/m2 to 1500 W/m2) in ElectricEquipment:ITE:AirCooled, I got the following errors:

** Severe  ** CalcHeatBalanceInsideSurf: The temperature of -16350.21 C for zone="WEST ZONE", for surface="ZN001:ROOF001W"
**   ~~~   ** very far out of bounds during warmup. This may be an indication of a malformed zone.
**   ~~~   **  During Warmup, Environment=WHOLEYEARDAY, at Simulation time=01/01 07:30 - 07:31 
**  Fatal  ** Program terminates due to preceding condition.
...Summary of Errors that led to program termination:
..... Reference severe error count=1
..... Last severe error=CalcHeatBalanceInsideSurf: The temperature of -16350.21 C for zone="WEST ZONE", for surface="ZN001:ROOF001W"
************* ===== Final Error Summary =====
************* The following error categories occurred.  Consider correcting or noting.
************* Nominally Unused Constructions
************* ..The nominally unused constructions warning is provided to alert you to potential conditions that can cause
************* ..extra time during simulation. Each construction is calculated by the algorithm indicated in the HeatBalanceAlgorithm
************* ..object. You may remove the constructions indicated (when you use the DisplayExtraWarnings option).

image description

I change that value to 1500 because my model has more power than the example file (approximately 300kW and total zone are where contain the server rack is 176 m2 (= 22 m * 7.6 m). My total power of server racks is 300kW (100 server racks with 3kW for each of them).

After searching about the problems, I think that my cooling system can't maintain proper air temperatures in the room. My cooling system currently has only DX Cooling Coil, Can someone give me advice to change which parameters of my cooling system to maintain the temperature?

Or this error may relate to the Construction for Surface?

Here is my model. I have tried a lot but it did not work.

Thank you, I really appreciate all your supports.

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I have same issues like you. Did you find any solution?

christon gravatar image christon  ( 2021-05-05 01:37:07 -0500 )edit

@christon I still have not found the answer.

tri.ton99 gravatar image tri.ton99  ( 2021-05-05 11:05:11 -0500 )edit

Is the HVAC equipment hardsized or autosized?

mdahlhausen gravatar image mdahlhausen  ( 2021-05-05 14:09:44 -0500 )edit

@mdahlhausen I used the default Coil:Cooling:DX:SingleSpeed in 2ZoneDataCenterHVAC_wEconomizer.idf file of EnergyPlus example files. Gross Rated Total Cooling Capacity {W}, Gross Rated Sensible Heat Ratio, Rated Air Flow Rate {m3/s} field are autosize, the Gross Rated Cooling COP {W/W} is 3.0 and Curves I use is defined by EnergyPlus (DXSysACCoolCapFT,...). Can you help me to remodify it? Does it have problems in Sizing:System or Sizing:Zone with these severe errors?

Thank you.

tri.ton99 gravatar image tri.ton99  ( 2021-05-05 22:56:38 -0500 )edit