Sizing error of Coil:Cooling:DX:SingleSpeed unit in DOAS ystem

asked 2016-03-09 11:12:44 -0600

Yan
1181 ●3 ●14 https://www.linkedin.c...

updated 2016-03-09 13:46:49 -0600

I am simulating DOAS system with an air-cooled DX unit using OpenStudio, and there is an error when sizing the "Coil:Cooling:DX:SingleSpeed".

Based on the "input output reference" of E+, the rated volumetric air flow to total cooling capacity of "Coil:Cooling:DX:SingleSpeed" should be 300 to 450 cfm/ton; for DOAS application, it should be 125 to 250 cfm/ton. My DOAS system is 168 cfm/ton, which locates in the range of DOAS application. However, E+ seems to use the range of 300 to 450 cfm/ton, and it comes out the error:

* Severe * Sizing: Coil:Cooling:DX:SingleSpeed "1 SPD DX CLG COIL": Rated air volume flow rate per watt of rated total cooling capacity is out of range. * ~~~ * ...Air Volume Flow Rate used in calculation = 1.179869 m3/s * ~~~ * ...Air Volume Flow Rate per Watt of Rated Cooling Capacity is also out of bounds at = 2.2566585E-005 m3/s/W * ~~~ * During Warmup, Environment=NEWARK INTERNATIONAL ARPT ANN CLG .4% CONDNS DB=>MWB, at Simulation time=07/21 00:00 - 00:10

How should I let the program know that it is DOAS application?

Here is my setup:

The "Type of Load to Size On" was set as "VentilationRequirement", and both "100% Outdoor Air in Cooling" and "100% Outdoor Air in Heating" as "Yes". As for the "Coil:Cooling:DX:SingleSpeed", cooling capacity is 178400 BTU/h and air flow rate is 2500 cfm

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CoilSystem:Cooling:DX, A11, \field Use Outdoor Air DX Cooling Coil \type choice \key Yes \key No AirLoopHVAC:UnitarySystem, A16, \field Use DOAS DX Cooling Coil \type choice \key Yes \key No

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I didn't find the field of "Use DOAS DX Cooling Coil" in OpenStudio, but I do set both "100% Outdoor Air in Cooling" and "100% Outdoor Air in Heating" to "Yes". I didn't use "AirLoopHVAC:UnitarySystem", instead, I created an empty air loop and add coils, fans. In this case, is there any place I could setup DOAS?