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EnergyPlus™ is a whole building energy simulation program that engineers, architects, and researchers use to model both energy consumption and water use in buildings.
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The program was corrected so that Refrigeration:AirChiller units served by Refrigeration:CompressorRack now work properly. (CR #9247) #4018

Closed axelstudios closed 10 years ago

axelstudios commented 10 years ago

Refrigeration:AirChiller served by Refrigeration:CompressorRack not working

Added on 2013-06-13 11:57 by @mjwitte

Description

MJW 13 Jun 2013 From ticket: I am working on modeling a refrigerated warehouse using the same method as illustrated in the Refrigerated Warehouse example IDF. The only substantial difference is that instead of using the Refrigeration:System (and associated compressor/condenser components) I am using the Refrigeration:CompressorRack object since details about the refrigeration system are not available currently. However, I am currently getting no cooling from any of the Refrigeration:AirChiller objects to any of the corresponding zones and the temperature in the zones freely fluctuates as if I have no cooling system.

MJW comments I've reviewed the idf and it seems fine. Also looked in the source code for some clues. Noticed this section that sets up different output variables if the compressor rack serves air coils:

RefrigeratedCase.f90, starting at line 8042 IF(RefrigRack(RackNum)%CoilFlag) THEN !rack serves chillers and is solved on HVAC time step CALL SetupOutputVariable('Refrigeration Air Chiller Compressor Rack Electric Power [W]', & RefrigRack(RackNum)%RackCompressorPower,'HVAC','Average',& RefrigRack(RackNum)%Name)

These output variables don't show. RefrigRack(RackNum)%CoilFlag is never set anywhere else and not checked anywhere else, either, so looks like maybe the connections to compressorrack are just missing a few links?

Inputs: 9247-* Weather: None, design days

MJW/RHH 06 Nov 2013 Transitioned the test file to v8.1 and got fatal error

* Warning * GetRefrigerationInput: Refrigeration:AirChiller="PUBLICSTORAGE_AIRCHILLER", invalid Capacity Correction Curve Type="LINEARSHR60". * ~~~ * The "CapacityTotalSpecificConditions" Capacity Rating Type has been specified for this air chiller. This rating type requires * ~~~ * the "TabularRHxDT1xTRoom" correction curve. Verify that a valid "TabularRHxDT1xTRoom" curve is specified in "Capacity Correction Curve Name". * Severe * GetRefrigerationInput: Refrigeration:AirChiller="PUBLICSTORAGE_AIRCHILLER", invalid Capacity Correction Curve Name is blank, required.

I changed the Curve Type from LinearSH60 to TabularRHxDT1xTRoom and the Curve Name from to RackCOPCurve and reran. It CRASHED.

Need a working test file to verify this.

Fix

The load on the Refrigeration:AirChillers was not included as part of the total system load in the Refrigeration:CompressorRack object, and the RefrigRack(RackNum)%CoilFlag was not set if air coils were present on the system. Hence, the energy consumption of the CompressorRack was reported as zero if air coils were used, and the output variables were not called. Code is now included in the Refrigeration:CompressorRack object to sum the coil load and set the CoilFlag if air coils are present on the compressor rack.

External Ref: Ticket 8205 Addressed in 13.10.03 V8.1.0.005 by @frickeba Last build tested: 13.06.11 V8.1.0.001

mjwitte commented 10 years ago

MJW/RHH - Per Brian Fricke, use the revised example file. From RHH: Whereas previously the test file crashed, the RefrigeratedWarfehouse_v8.1_CompRack test file that was attached to this email does run successfully and the compressor rack is showing energy consumption and cooling output at the evaporator. So this CR is FIXED. Last build tested v8.1.0.009