Hello everyone,
I added several rotary heat exchangers sensible and latent in my air system model. In fact, I have 5 heat exchangers, one after the other. I only use one of each at each time step of calculation (for one time step, only one of the 5 heat exchanger schedules is ON, depending on some conditions).
For each heat exchanger, I desactivated frost control and economizer lockout.
It works fine, but I noticed something strange that happens from time to time in my annual simulation: sometimes, when the heat exhangers number 1, 2,3 and 4 are inactive, and heat exchanger number 5 is active, I notice by looking at the temperatures at each spot that the first heat exchanger has created a temperature and humidity difference!
I checked everything at least 3 times: the heat exchanger number 1 is indeed inactive, schedule is off, I ploted the output sensible effectiveness of the heat exchanger and it is 0, but the temperatures and humidity at the inlet and outlet of the component on the supply side are different!! on the exhaust side, no thermal exchange!
I notice that it happens when the mass flow is high, but I have no explanations, the value I gave for nominal air flow rate parameter is also correct... I tried to raise this value, it has an effect because the moments in which the problem occurs change if I change the value but still it happens from time to time and I don't understand what is happening.
What can I do to correct this issue?
Thank you,
Pauline.