[TRNSYS-users] differential controller - Type 2

[Ali Shahrouzian]

Dear TRNSYS users,

Hi,

I'm modelling a solar system to heat a space. It is consisting of two loops: one of them is a water-based solar collector loop as heat source and the other one is an air-based loop included an air-to-water HX, a fan and so forth.
In order to control the solar loop in such a way that it turns off when the incident radiation isn't sufficient (during night), I've used a differential controller (type 2). I connected the collector outlet temperature to Th (parameter 1 for type 2) and the HX outlet temperature to the Tc (parameter 2).
Defining the controller in this same way causes the collector outlet temperature starts from minus temperatures like -25 degrees C over the course of winter days. I face with this issue when I used types 50 (PV/T collector), (538 evacuated collector), 539 and ... , however using type 1 (flat plate collector) as the solar collector doesn't cause this issue.
I would appreciate if anyone help me in this case.

And one more thing, as I've already explained my system also has a secondary loop included a fan, an air-to-water HX and ... . I am wondering whether in order to control the secondary loop when solar loop is off, I should define a new controller (type 2) or I can use the differential controller previous.

Thanks in advance.
Ali
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/trnsys-users-onebuilding.org/attachments/20210808/f03e0e6a/attachment.html>