Re: [EnergyPlus_Support] Natural Ventilation II

Ana Paula:

The values in example files are used to demonstrate capabilities. They may be real values for different windows. I can't say which one is better, either 0.08 or 0.001. The values are dependent on the windows you would like to simulate, either from testing or manufacturers' data.

Since airflow rate is proportional to the mass flow coefficient when a window is closed, it is expected to get higher air change rates with higher mass flow coefficients.

The zone temperature used to activate natural ventilation can be reported into two variable names: Zone Mean Air Temperature or Zone/Sys Air Temperature. The first is averaged in a zone time step, which can be equal to or less than a system time step. Since the AirflowNetwork model works in a system time step, the program uses Zone/Sys Air Temperature internally. That is why my suggestion is to report Zone/Sys Air Temperature. The Input/Output describes both report variables.

Lixing

----- Original Message -----

From: Ana Paula Melo

To: EnergyPlus_Support@xxxxxxxxxxxxxxx

Sent: Monday, June 30, 2008 2:05 PM

Subject: [EnergyPlus_Support] Natural Ventilation II

Lixing Gu,

I am simulating the natural ventilation.

I am using the value of 0.08 for air mass flow coefficient when opening is closed. I got this value on AIVC book - Lidament. But I noticed that on examplefiles that this value is 0.001.

I simulated with both values and the final results are very different. The air changed is higher in the case that I used 0.08.

Am I wrong to use 0.08 value?

I did not find where in the Input/Output or Engineering that is saying I have to use the Zone/Sys Air Temperatute to activate natural ventilation. Can you help me??

Thanks for all,

Ana Paula.

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