<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto">Berkane,<div><br></div><div>If you have the Tess Libraries, use one of the aquastat models. If you just have type 2, connect the upper input to the load temperature, leave the lower input temperature un-connected and set the initial value to 50. Connect the output control signal from the model back to the input of the same model for hysteresis. Set the upper deadband to 5 and the lower deadband to -5. Now the signal will be 1 when the temperature reaches 55 and stay at 1 until the temperature falls to 45. You can adjust the deadbands if you need tighter control but the tighter you make them the more the system will “chatter”. The likely reason you were getting an error with your equation based approach is that there are times that with the flow off the temperature is greater than 50 but with flow on it’s less then 50. There is no solution so the equation will flip flop until the iteration limit is reached.</div><div><br></div><div>Jeff - TESS<br><br><div dir="ltr">Sent from my iPhone</div><div dir="ltr"><br><blockquote type="cite">On Aug 30, 2020, at 4:12 AM, berkane ahlem via TRNSYS-users <trnsys-users@lists.onebuilding.org> wrote:<br><br></blockquote></div><blockquote type="cite"><div dir="ltr"><div dir="auto"><span style="font-family:arial,helvetica,sans-serif;font-size:small">Dear users,</span><div dir="auto"><span style="font-family:arial,helvetica,sans-serif;font-size:small"><div dir="auto">I want to exploit thermal energy of solar collector when the temperature of the tank T_load exceeds 50 ° C (the tank does't need heating), in which the dividing valve will direct the flow to the tank when T_load <50 and to vertical exchanger when T_load> 50.</div><div dir="auto">how I link T_load tank with controller type 2b to give sign to diveting valve . i use this equation to control the diverting valve c-out =gt(T-loud tank,50) but i get error. </div><div dir="auto">Best regards </div></span></div></div>
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