Dear all,

I am working on a Solar Thermal combi-system with lanced storage and for
this I am using two double ports in the storage for a single loop i.e. the
input and output of the loop is connected in a different double port. I
have connected the pump from a one of the double port outlet and the outlet
of the pump to the loads and the return from the loads to the inlet of the
other double port. The problem i face in this system is that since the loop
is not fully a closed loop, the input value to the pump is no longer fully
functional i.e. the normal pump type 3d, 110 and the tess library pump 748
does not draw the water out of the tank. It just takes the temperature from
the tank and creates a mass flow rate specified in the pump while the
connection between the tank output and the pump input shows zero mass flow
rate.

In terms of energy, when I see the power through this double port, it shows
zero. Did anyone already experience such problem? It would be great if
anyone can help me finding a solution. I think if I have a pump which can
really draw water from the tank at a specified given flow rate, the problem
will be solved. But all the pump models in trnsys just sets the flow rate
to to the input mass flow rate rather then drawing water at this flow rate.

Thanks in Advance and hope someone might be able to help me.

With Regard,
Muthalagappan Narayanan
Research Assistant and PhD Student
Ulm University of Applied Sciences
Germany