[TRNSYS-users] energy balances on the tanks

[Napolitano Assunta]

Dear TRNSYS users,

I am using type 4a to yearly simulate both a cold tank supplied by an
absorption machine and a heat tank supplied by a cogeneration unit. 

For the cold tank the following happens:

 

The heat entering the tank is 0.3% higher then the heat removed from the
tank by the absorption machine. Losses heat are negative, thus an
additional amount of heat is supposed to enter the tank. The difference
between the entering heat and the removed heat amounts to 1% of the
latter. However, the temperature in the top and in the bottom of the
tank is the same at the beginning and at the end of the simulation.  Can
anybody suggest me what I can chek to solve the matter?

 

For the heat storage, I have what I expect about the charging and
discharging. I mean the heat entering is higher then the one outgoing
and losses are positive so heat is supposed to go out from the tank.
However, the energy balance is not zero and it amounts to 2% of the
inlet heat.

 

Yearly Simulations are carried out with a timestep of 10 minutes with 

tolerance integration=0.001 and

 tolerance convergence= 0.001

 

21 timesteps, inputs have not converged.

 

Thank you

 

 

Assunta Napolitano

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