[TRNSYS-users] Forcing Function Type 14h problem

[Shofolahan, Idris Adewale]

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





________________________________
From: David BRADLEY <d.bradley at tess-inc.com>
Sent: 09 March 2015 17:37
To: TRNSYS users mailing list at OneBuilding.org
Cc: 'idris_ade at yahoo.com'
Subject: Re: [TRNSYS-users] Forcing Function Type 14h problem

Idris,
 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


On 3/9/2015 11:04, Shofolahan, Idris Adewale wrote:

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.

[cid:part1.07070005.02010301 at tess-inc.com]


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



============================================
The LSBU communications disclaimer can be found at http://www.lsbu.ac.uk/ict/legal/


_______________________________________________
TRNSYS-users mailing list
TRNSYS-users at lists.onebuilding.org<mailto:TRNSYS-users at lists.onebuilding.org>
http://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org



--
***************************
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 at tess-inc.com<mailto:d.bradley at 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/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/trnsys-users-onebuilding.org/attachments/20150310/673cee98/attachment-0003.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: ATT00001.png
Type: image/png
Size: 192661 bytes
Desc: ATT00001.png
URL: <http://lists.onebuilding.org/pipermail/trnsys-users-onebuilding.org/attachments/20150310/673cee98/attachment-0003.png>