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Re: [TRNSYS-users] Problem with type60

Matteo,
 You need to use a smaller timestep; something on the order of 5 to 15 minutes would be appropriate. I'm actually somewhat surprised that the simulation runs at all - the data file has hourly values in it and with a two hour timestep, it would have to skip every other point in the data file. I didn't think Type15 could do that. I would also recommend that you put some pipes between the tank and solar collector. You need to make sure that the total volume of liquid that the pump can transfer in the space of one timestep is smaller than the volume of the loop itself. The pump and solar collector models neglect the volume of liquid that they contain. I believe that the Type60 internal heat exchanger calculates the liquid volume. However that volume may be smaller than the pumps rated flow rate times the timestep which, from a simulation point of view, means that the liquid would make more than one complete circuit within the space of one timestep. That can cause numerical instability in your simulation.
Kind regards,
 David


Matteo DF wrote:
Hi,
I'm trying to simulate a small project with a solar collector, a pump and a storage tank. I used 12 m^2 of panels which flow goes directly to the heat exchanger of the tank... The circulation pump provides the correct flow.
I have some difficulties as I get some convergence warnings (warning 441) The convergence error is between the solar unit and the tank one.

I attach my little project. Can you tell me were I'm going wrong?

Many Thanks.
Matteo.

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pensare ciò che nessuno ha mai pensato.
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