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Dear Michael, Try the following solutions and advice: 1, Set the input 7 of type22 "Tolerance of tracking error" to for example 0.001 instead of 0 2, Set the 2nd parameter of Type 22 "Max number of oscillations" to for example 50 instead of 0 Sometimes, when the flow rate in the solar water loop is too low, Type 22 will be very difficult to converge. So also adjust the flow rate to avoid the low flow rate. If all the above solutions fail, then maybe you can consider adjusting the configuration of your system in TRNSYS simulation and add a tempering valve+mixer to control the outlet temperature of the mixer instead of the outlet temperature of the solar collector. The algorithm of tempering valve Type 11b takes both the heat source temperature and the set-point temperature into account, which will converge better than Type 22. Hope it helps. Kind Regards, Sunliang Cao > From: stochnio@mail.hs-ulm.de > To: trnsys-users@lists.onebuilding.org > Date: Thu, 27 Nov 2014 09:24:52 +0100 > Subject: [TRNSYS-users] type22 stability/solarloop > > 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 > > > > > _______________________________________________ > TRNSYS-users mailing list > TRNSYS-users@lists.onebuilding.org > http://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org |