How to define a good strategy for natural ventilation with Airflownetwork(AFN) in Energyplus?

asked 2016-08-25 02:48:15 -0500

updated 2016-08-27 11:19:59 -0500

Hello, I try to simulate the cooling load conserverted by natural ventilation. The model is an one story residential building with IdealLoadsAirSystem.The heating setpoint and cooling setpoint of Ideal loads air system are 18℃ and 26 ℃. The natural ventilation temperature setpoint for the openings is 19℃ in Apr, May, Jun, Jul, Aug and Sept, and 60 ℃ in all other time. However, the simulation results shows that the heating rates with AFN during the intermediate season(as Apr, May,Sept ) are much higher than without it.The problem is most probably in the control strategy for the opening. I want to know how to solve this problem.

Thanks a lot in advance for your help! Lei

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answered 2018-12-02 12:33:58 -0500

Haohan Sha
279 ●6

Your description is too ambiguous. You should show more details...This is a simple answer, and may be not correct. As you said above, the natural ventilation setpoint is 19C, and heating setpoint of ideal loads air system are 18C. So, the when outdoor temperature is lower than 19C, the openings of natural ventilation will open, and the natural ventilation of course could make your indoor temperature lower than 18C. For example, it will bring 15C outdoor fresh air into room. And so, the ideal loads air system will start to warm the indoor air and generate the heating load and higher heating rates. If you just want to know the cooling load, you should not set the heating setpoint in the HVAC: templates.