Re: [TRNSYS-users] questions about type 56 building model and chiller

[David BRADLEY <d.bradley@tess-inc.com>]

Zhuo Li,
 Without seeing your project files, it is not possible to determine the cause of the unrealistically high temperatures. I would recommend that you send your project files to your distributor's technical support hotline for assistance.

  The warnings that you are receiving may well be related to the high temperatures. Performance maps in TRNSYS usually contain data for a range of inlet conditions. For example the samp_c.dat file contains performance data for chillers whose return chilled water temperatures are between 4.4C and 10C. If the water returning to the chiller is above 10C then the performance data returned from the map may not be valid. If the problem happens only a few times during the simulation then it can usually be ignored. If the situation arises often then either the system configuration or the data file need to be changed so that valid performance data is returned.

kind regards,
 David

On 09/14/2015 01:00, Zhuo Li wrote:

Dear Trnsys users,

 

I am using type 56 to model an air conditioning system for a three-story building. In my program, each floor has an air handling unit and the external air relative humidity ratio, mass flow rate, and temperature are obtained as ventilation inputs to building model from Type 607, which is connected to cooling coils (type 508).  The temperatures of thermal zones of 1st floor are within acceptable range, whereas temperatures of thermal zones of 2nd and 3rd floor are going infinitely high. How can I solve this problem?

 

In addition, I encountered problems with chiller and ducts. The warning messages are written below:

 

1) The file\Trnsys 17\Tess Models\SampleCatalogData\AirCooledChiller\Samp_C.dat was called with a first independent variable value below the range supplied in the data file. Data is interpolated within the data file range but is not extrapolated beyond  the range. Performance of the equipment modeled by this unit may be incorrect.

2) The referenced UNIT\ (Type 607)\ has called the PSYCHROMETRICS routine with a humidity ratio above the saturation humidity ratio for the given dry bulb temperature. The air was assumed saturated at the given dry bulb temperature and the humidity ratio set for this condition.

For the chiller, parameter of rated capacity was changed and other parameters remained as default values.

Thanks in advance for your help.

Best regards,

Zhuo Li

 

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David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

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d.bradley@tess-inc.com

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