# Questions about ventilation and humidity settings

Hello, all!
I have several questions about the simulation.
1.I didn't really know the settings here.
What is the meaning of the setpoint temperature? Does  the hourly air changes mean the maximum ACH?
Does hourly air changes mean  the air volume added to or removed from a space divided by the volume of the space or 100m3/h?
Becasus in one tutorial showed on the website, the teacher said it was 100m3/h, it made me confuse.
What I want to do is that the hourly air changes suit my own definition using both natural and forced ventilation. How can I achieve this？
2. Also I hope to keep the room relative humidity between 60%-90%. But after I set the condition, the result of the simulation was not the situation that I hoped. But I didn' t know why.Here is the result picture.
Thank you indeed.
Zhuchen

Views: 63

### Replies to This Discussion

Dear Zhuchen,

The scheduled ventilation setpoint temperature controls the scheduled ventilation will reduce flow rate when the setpoint is reached.

The ACH is the maximum flow rate that is then modulated by the schedule.

Hence, the scheduled ventilation module is useful if you have measurements or simulation results from CFD that you would like to bring into Energy Plus.

The natural ventilation module creates a flow rate based on buoyancy and wind driven models. Using both the scheduled and natural ventilation together to then match a total ACH is difficult. If you know what the flow rate is - or should be - I would use just the scheduled ventilation module.

Maintaining the relative humidity levels is then done with the schedule. You can generate and hourly array schedule with Archsim using weather data and some larger or smaller conditionals to compose a control schedule.

I hope this helps.

T

Thank you very much!
Well,I have another question.
When I input my schedule about ventilation the minimum value of which is 0.1,and the maximum ACH is90,but after I run the simulation, the output ventilation ACH had thousands of 0, not the value that I want.
I didn't know why. So could you please explain that for me.
Thank you indeed!