[TRNSYS-users] differential controller's problem

Vajihe Davoodi v.davoodi91 at gmail.com
Tue Sep 3 22:58:00 PDT 2019


Hi Jeff,
 Thanks for your recommendation.
I have prepared a schematic from my simulation which is attached.
It's a part of my solar absorption chiller model.

Thermal storage inlet water temperature (colder fluid) is 103 C but its
outlet temperature is variable. I should define a differential controller
which prepare temperature more than which enter to the solar collectors
(outlet cod water of thermal storage).
I have changed thermal storage properties to these:
volume of thermal storage= 1800 litr
boiling point= 150 C
and controller with 10 and 2 , upper and lower dead band respectively.
now I want to know why sometimes solar energy is negative in my simulation,
it means that the outlet temperature of collectors is less than inlet
temperature. By this anybody can help me to solve my problem?
[image: image.png]



On Wed, Sep 4, 2019 at 12:43 AM Jeff Thornton via TRNSYS-users <
trnsys-users at lists.onebuilding.org> wrote:

> Vajije,
>
> It's a little difficult to understand from your e-mail what you are trying
> to do with the differential controller.  Can you provide a schematic of
> your system and maybe a diagram of the controls you wish to implement?
> That will help the users here better answer your question.
>
>
>
> Jeff
>
>
>
> ---
> Jeff Thornton
> President - TESS LLC
> 3 N. Pinckney Street, Suite 202, Madison WI USA 53703
> Office: (608) 274-2577  Fax: (608) 278-1475www.tess-inc.com
> E-Mail: thornton at tess-inc.com
>
> On 09/03/2019 1:48 pm, Vajihe Davoodi via TRNSYS-users wrote:
>
> Hi all,
> I have simulated a solar absorption chiller, I should run it for different
> thermal storage inlet temperatures for example with inlet temperature of
> 103 C. then I want the outlet temperature of thermal storage doesn't above
> the inlet temperature. I have defined a differential controller but it
> doesn't effect on outlet temperature, I changed upper and lower dead band
> temperature different times but the outlet temperature didn't change.
> if someone can help me please tell me why it doesn't work?
>
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