How to control the td_pinch value for Moving boundary heat Exchanger

[ronitd07]

Hello,

When i am using Moving boundary heat exchanger as my condensor even though the ttd_u and ttd_l values are much greater than 0 but the td_pinch is getting below 0. How to control the td_pinch value not getting negative ?

ttd_u : 7.29e+00
ttd_l : 4.84e+00
td_pinch : -2.55e-02

I understand ttd_pinch is the minimum temperature difference between hot and cold fluid that could be within the heat exchanger.
Is there any way for TESPY to also plot the temperature profiles of the hot and cold liquid within the heat exchanger so i can understand where it is going to negative.

Thanks,
Ronit

[fwitte]

You can just impose the desired value for td_pinch, e.g. condenser.set_attr(td_pinch=2.5).

The profile can be retrieved with heat, T_hot, T_cold, _, _ = condenser.calc_sections() and then plot the temperatures over heat exchanged.

[ronitd07]

Thanks.
Also can the temperature profile be retrieved for HeatExchanger for evaporator as well ?

[fwitte]

There is no internal sectioning for those components. You can just use the inflow and outflow temperature information. The sectioning is only available in SectionedHeatExchanger and MovingBoundaryHeatExchanger. Of course you can replace your other heat exchangers with instances of these components.