Re: [TRNSYS-users] help

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

Imen,
 I assume you are using TRNSYS 16 or 17. If so, you can use the PID controller (Type23). Please pay particular attention to the mode setting (parameter 1) and if you use mode zero, set a small time step and make sure that you have some thermal capacitance in your system. Most heat exchanger models ignore thermal capacitance and  compute a steady state solution. Without sufficient capacitance in the system (in the form of pipes and tanks), it might be very hard to control the outlet temperature of your heat exchanger.
Best,
 David

On 6/27/2010 10:17, imen chraief wrote:

Dear

I used a heat exchanger (air /water) the hot side fluid is water extracted from a storage tank connected to solar thermal collector and the cold side fluid is an air.

Hot side inlet temperature and cold side inlet temperature are known and are in function of time, and the cold side outlet temperature is imposed 68°C; how achieve a constant temperature with this model?

Please help me the fastest possible it is very urgent; thank you and  apologize for this bad English  text

Best regards

imen

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