I now solved the input temp "misbehavior", it was just a wrong connection... However, the issue of a rising Quse while increasing the flowrate (in a extreme manner, i.e. that Tout is almost Tin) still confuses me. How can I determine the optimum flowrate for a maximum of Quse (I try to figure out an optimization for a polymer unglazed flat plate collector, so I am trying to understand the behaviours and parameter sensitivity of the different collector types.)? Is the solution for that may be linking the pumpcontrol to a designated Tout? I guess that's the standard way to do it and the standard SDHW uses this control as well. I tried that and when I used this pumpcontrol strategy I gained: Quse=2.6 *10'6 with Toutmax in summer around 130 deg C for a flowrate of 200 Kg/h Quse=3.7 *10'6 with Toutmax in summer around 55 deg C for a flowrate of 20 Kg/h Quse=2.1 *10'5 with Toutmax in summer around 200 deg C for a flowrate of 2 Kg/h (those high temperatures probably occur only for a short timestep whenever the pump starts running...) Here again the question, how can I maximize the Quse of my system? The dependency of Quse and flowrate seems not to be linear and the resulting Touts are strange as well. I used the standard efficiency coefficients eta0=0.8 and efflope=13 I try to figure out an optimization for a polymer unglazed flat plate collector, so I am trying to understand the behaviours and parameter sensitivity of the different collector types. Any thoughts on that? Best, Philip -----Original Message----- From: Philip Horn Sent: Thursday, May 26, 2011 4:15 PM To: 'trnsys-users@cae.wisc.edu' Subject: SDHW template Tin and Useful energy gain- strange behaviour Hi All, I played around a little bit with different efficiency equations for the collector, and wanted to compare the results. Therefore I used the SDHW template (with TYPE1 as collector), which uses the outlet of the Tank as inlet temp to the collector. I erased this connection and set the inlet temp to a fixed 10 deg but in fact is it still varying when I plot it (from 10-13deg). How come? Another thing that I experienced: when I used the system in the normal mode (Tout tank connected to Tin collector), the useful energy gain of the collector is higher than with a fixed (and in average 10 deg K lower) input temperature. Shouldn't it be the opposite? As Q=m*cp*(Tout-Tin) , the smaller Tin, the higher Quse (assuming that Tout is not that heavily affected)? Clarification highly appreciated!! Best, Philip _______________________________________________ TRNSYS-users mailing list TRNSYS-users@cae.wisc.edu https://mailman.cae.wisc.edu/listinfo/trnsys-users |