The input Load for ElectricEquipment:ITE:AirCooled did not suitable

asked 2021-04-22 23:53:26 -0500

tri.ton99 gravatar image

updated 2021-04-23 08:19:42 -0500

Hi everyone,

I am modeling a data center in EnergyPlus based on 2ZoneDataCenterHVAC_wEconomizer model with DX Cooling Coil. My total load of server racks is 300kWh (100 server racks with 3kWh for each of them). In EnergyPlus, I used ElectricEquipment:ITE:AirCooled for modeling racks and my area is 176 m2 so I should put 1704 Watts/m2 to Field Watts per Zone Floor Area like below.

WestDataCenter_Equip,    !- Name
West Zone,               !- Zone Name
FlowFromSystem,          !- Air Flow Calculation Method
Watts/Area,              !- Design Power Input Calculation Method
,                        !- Watts per Unit {W}
,                        !- Number of Units
1700,                     !- Watts per Zone Floor Area {W/m2}
Data Center Operation Schedule,  !- Design Power Input Schedule Name
Data Center CPU Loading Schedule,  !- CPU Loading  Schedule Name
Data Center Servers Power fLoadTemp,  !- CPU Power Input Function of Loading and Air Temperature Curve Name
0.4,                     !- Design Fan Power Input Fraction
0.0001,                  !- Design Fan Air Flow Rate per Power Input {m3/s-W}
Data Center Servers Airflow fLoadTemp,  !- Air Flow Function of Loading and Air Temperature Curve Name
ECM FanPower fFlow,      !- Fan Power Input Function of Flow Curve Name
15,                      !- Design Entering Air Temperature {C}
A3,                      !- Environmental Class
AdjustedSupply,          !- Air Inlet Connection Type
,                        !- Air Inlet Room Air Model Node Name
,                        !- Air Outlet Room Air Model Node Name
West Zone Inlet Node,    !- Supply Air Node Name
0.1,                     !- Design Recirculation Fraction
Data Center Recirculation fLoadTemp,  !- Recirculation Function of Loading and Supply Temperature Curve Name
0.9,                     !- Design Electric Power Supply Efficiency
UPS Efficiency fPLR,     !- Electric Power Supply Efficiency Function of Part Load Ratio Curve Name
1,                       !- Fraction of Electric Power Supply Losses to Zone
ITE-CPU,                 !- CPU End-Use Subcategory
ITE-Fans,                !- Fan End-Use Subcategory
ITE-UPS;                 !- Electric Power Supply End-Use Subcategory

However, simulation did not work and warned that my zone temperature was too high. I confuse that my area was not fit with the server racks load or my HVAC (DX Coil) did not have enough cool air to minimize the zone temperature (heat from racks).

************* Beginning Simulation
** Severe  ** CalcHeatBalanceInsideSurf: The temperature of 58130.37 C for zone="WEST ZONE", for surface="ZN001:WALL001W"
**   ~~~   ** 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 12:45 - 12:46

When I put the value 200 Watts/m2 and I ran, but it not enough for my rack load.

I tried to separate load to Electric Equipment to increase the load for racks and I ran, but I think that ElectricEquipment is not suitable for rack modeling (not realese heat like ElectricEquipment:ITE:AirCooled).

West Zone_MiscPlug_Equip,!- Name
West Zone,               !- Zone or ZoneList Name
ALWAYS_ON,          !- Schedule Name
Watts/Area,          !- Design Level Calculation Method
,                      !- Design Level {W}
300,                        !- Watts per Zone Floor Area {W/m2}
,                        !- Watts per Person {W/person}
0.0000,                  !- Fraction Latent
0.2500,                  !- Fraction Radiant
0.0000,                  !- Fraction Lost
MiscPlug;                !- End-Use Subcategory

This is my model. Can anyone have a look and give me some advices with this problem.

Thank you, I really appreciate ... (more)

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@tri.ton99 your IT load is 300 $kWh$ (energy) or 300 $kW$ (power)? You should enter the power to that EnergyPlus object.

Also, the 176 $m^2$ is for the server rack floor area or the total floor area of the zone where the server racks are located? If you use the $W/m^2$ input option, it should be based on the total floor area of the zone where the server racks are located.

Aaron Boranian gravatar image Aaron Boranian  ( 2021-04-23 08:23:39 -0500 )edit

@Aaron Boranian My IT Load is 300 kW power and my total floor area is 176 m2. However, it still had severe errors like above. Can you give me any advice about my Electric Equipment or my HVAC System?

tri.ton99 gravatar image tri.ton99  ( 2021-04-23 11:12:42 -0500 )edit