David,
Thank you for your response to my query. I understand your explanation on the unit conversions,however,I would have thought that the reason for the availability of other unit options, is to be able to use them without changing the value. Moreover,both models have same value and units,therefore,one would expect the output to be the same.
Well,I have change the unit from W/m2 to the default units (KJ/h.m2)as suggested and yet the output temperature of the models are still at variance. What do you think is the reason for this?Thank you.
Regards
Idris
Sent: 09 March 2015 17:37
To: TRNSYS users mailing list at OneBuilding.org
Cc: 'idris_ade@yahoo.com'
Subject: Re: [TRNSYS-users] Forcing Function Type 14h problem
In the case without the forcing function, there are 700W/m2 of solar radiation incident on the collector surface at all times. In the case with the forcing function there is whatever amount of solar radiation that the forcing function determines there to be. Please bear in mind that when you change the units of an input, TRNSYS does not perform any automatic unit conversions. The Type expects to receive a value in the default units (kJ/h.m2 in this case). If your forcing function is giving a value, that value is being interpreted by Type538 as being given in kJ/h.m2.
kind regards,
David
============================================Hi there,
I'm working on solar water heating system.I wanted to test the performance of the weather file before using it, by replacing it with the generic forcing function type 14h to keep the beam radiation on the tilted surface of component type 538 . I compared the outlet temperature with and without the forcing functions type 14h.
I plotted the output temperature on the online printer,but the model without the forcing function gave an output temperature of 20.8 degrees while output temp. of the model with the forcing function was 15.8 degrees. Find screenshot of the two above. What is the reason for the difference in the output temperature of the models?
Regards
Idris
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-- *************************** David BRADLEY Principal Thermal Energy Systems Specialists, LLC 22 North Carroll Street - suite 370 Madison, WI 53703 USA P:+1.608.274.2577 F:+1.608.278.1475 d.bradley@tess-inc.com http://www.tess-inc.com http://www.trnsys.com
The LSBU communications disclaimer can be found at http://www.lsbu.ac.uk/ict/legal/