My solar system is a made of a solar loop (pump, solar collectors, tank, differential control), and a load loop (tank, building, differential control).
It serves for a radiant floor heating system.
my solar collector is a type 73.
the only paramter i've changed from the default is the area (45 m2).
Inputs to the collector are: water flow rate and temperature from a single speed pump (the water enters the colllector at 20 C and with a flow rate of 1150 kg/h).
other inputs from the meteo type are: ambient temperature, incident radiation, windspeed, horizontal radiation, horizontal diffude radiation, incidence angle, collector slope.
in the tank i put the derivatives of the three nodes at an initial temp of 20 C.
when i tun the simulation the water always enters the collector at about 20 C but exits at 0 C at the starting point, then it keeps around 4 C (till 8 am), and at 8 am it heats up to aorund 17 C, remaining like that till 18, then it cools down again to 6 C thereabout and remains like that till midnight.
I can't understand first of all why the outlet water temp from the collectors starts from 0, and then the problem is that, even if it heats up during the day (up to 17 C), it always remains lower than the inlet water temp of the collector!
(I've tried to change the water flow, but it doesn't effect the problem)
If you have any suggestion..
Thank you,
Filippo