[TRNSYS-users] Type 60 heat exchanger

[Jeff Thornton]

<Recently, I am simulating a system with one heater exchanger in Type60f_2
(thermal
storage tank) connected  to a pump and a solar collector.  But, the value
of UAHx
for this Hx is not convergent. I have used different size and the
conductivity
coefficient, it is still very difficult to converge. So, the calculated
outlet Temp
of this exchanger is wrong.>

You need to account for the difficult closed loop calculations in TRNSYS. 
Try small timesteps, tight tolerances (0.0001), pipes with mass,
collectors with mass etc.  Calculate the amount of time it takes the fluid
to "go around the loop" and set your timestep less than that value.

Jeff



Jeff Thornton
President - TESS, LLC

22 North Carroll Street - Suite 370
Madison WI 53703 USA

Phone: 608-274-2577
Fax: 608-278-1475
E-mail: thornton at tess-inc.com
Web: www.tess-inc.com