# Maximum capacity of Coil:Cooling:DX:SingleSpeed

HI, I am working on a LEED energy model for a data center. The design case model ran through fine but my baseline model crashes with the following error:

```
** Severe ** Temperature (high) out of bounds (202.78] for zone="FLR3_WHITESPACE_A4.03.WS", for surface="6892E3"
** ~~~ ** During Warmup, Environment=AMSTERDAM ANN HTG 99.6% CONDNS DB HVAC Sizing Pass 1, at Simulation time=01/21 15:30 - 15:40
** Severe ** Temperature (low) out of bounds [-101.84] for zone="FLR3_WHITESPACE_A4.03.WS", for surface="DAFECC"
** ~~~ ** During Warmup, Environment=AMSTERDAM ANN HTG 99.6% CONDNS DB HVAC Sizing Pass 1, at Simulation time=01/21 15:30 - 15:40
** Severe ** Temperature (low) out of bounds [-111.87] for zone="FLR3_WHITESPACE_A4.03.WS", for surface="6892E3"
** ~~~ ** During Warmup, Environment=AMSTERDAM ANN HTG 99.6% CONDNS DB HVAC Sizing Pass 1, at Simulation time=01/21 15:30 - 15:40
** Severe ** Temperature (high) out of bounds (210.03] for zone="FLR4_WHITESPACE_A4.04.WS", for surface="B02EB9"
** ~~~ ** During Warmup, Environment=AMSTERDAM ANN HTG 99.6% CONDNS DB HVAC Sizing Pass 1, at Simulation time=01/21 15:50 - 16:00
** ~~~ ** Zone="FLR4_WHITESPACE_A4.04.WS", Diagnostic Details:
** ~~~ ** ...Internal Heat Gain [2114.971] W/m2
** ~~~ ** ...Infiltration/Ventilation [0.224] m3/s
** ~~~ ** ...Mixing/Cross Mixing [0.000] m3/s
** ~~~ ** ...Zone is part of HVAC controlled system.
```

The IT and electrical rooms have very high internal loads as it is a datacenter. These spaces are conditioned by system 4 - PTHP with single speed DX cooling, single speed DX Heating coils and constant flow fan. Based on my sizing calculations, the rated air flow per watt for the zones is 0.000075 m³/s per watt. According to the idd file, I see that this value should be between 0.00004027 m3/s and .00006041 m3/s per watt of rated total cooling capacity. Here is the error that I get:

```
** Severe ** Sizing: Coil:Cooling:DX:SingleSpeed "FLR10_TECHSPACE_A4.10.11_PTHP-CCDX": Rated air volume flow rate per watt of rated total cooling capacity is out of range.
** ~~~ ** Min Rated Vol Flow Per Watt=[4.027E-005], Rated Vol Flow Per Watt=[7.500E-005], Max Rated Vol Flow Per Watt=[6.041E-005]. See Input Output Reference Manual for valid range.
************* SizeDXCoil: Potential issue with equipment sizing for Coil:Heating:DX:SingleSpeed FLR10_TECHSPACE_A4.10.11_PTHP-HCDX
** ~~~ ** User-Specified Rated Air Flow Rate [m3/s] = 7.12000
** ~~~ ** differs from Design Size Rated Air Flow Rate [m3/s] = 13.25438
** ~~~ ** This may, or may not, indicate mismatched component sizes.
** ~~~ ** Verify that the value entered is intended and is consistent with other components.
```

Is there a work around to get this Coil:Cooling:DX:SIngleSpeed component used with ZoneHVAC:PackagedTerminalHeatPump to work?

Thank you, Raghu