[TRNSYS-users] type22 stability/solarloop

[Michael Stochniol]

Hello to all,

first thanks for the great answers to my last question, it really helped!

i am creating a SDHW -system. In order to do that i combined a variable speed pump with type22 to adjust the massflow trough the pump to reach a certain Tset tempreture from my collector.
My Type 22 has 1 as maximum output and 0.45 as minimum. everything else is on default. The set tempreture is 77 °C and the controlled Variable is the output tempreture of the flat plate collector. 
Also the type 22 is combined with a differantial controller for his on/off function. 

it seems that the controller has problems to find a signal inbetween min and max. most of the time it is just switching between them both. Somtimes very frequently. I tried alot to change this behavior experimenting with all the parameter in type 22 but without luck. I alsp tryed to store the controlled variable input for one timestep, or even for the output.  But nothing seems to improve the stability. the listfile tells me that the controller was stuck for 2,5% of the last simulation. Is that bad? Or normal? 

I am using 1 minute time steps.  There are pipes in the loop with enough capacity. 

Do someone have maybe a advise how to improve stability for the solarloop controll anyhow?

Im no experienced user, bascily everything i do is try and error. 

thanks in advance

Michael Stochniol