Green roof with Ecoroof module in Energy Plus

asked 2019-11-19 21:09:02 -0600

zahro gravatar image

Hi,

I am working on project to see the impact of green roof performance into improvement of building thermal quality. I want to see the impact of different plants strategy to the result. Previously, I read both Engineering References and Input Output Reference to have a reliable modeling process.

The model requires input for minimum stomatal resistance, leaf thermal, solar and visible absorptivity, and plant height to represent the plant species properties implemented in the actual building.

I read in the Engineering Reference that stomatal resistance value will be changed according to solar irradiance, soil moisture content and vapor pressure deficit in the plant itself during the modeling process. Regarding the vapor pressure deficit, there is one property of gd which represent the plant specific characteristic and will only be non-zero for trees as shown in the image below. image description.

However, I didn't see any specific input regarding this coefficient and there is no reference on this value either in the plant database. I want to ask if Energy Plus have some reference value for it, to see whether my type of plants will have significant value of gd or not since I think it will be important to understand the result? How it will work in the algorithm itself to determine the gd for the calculation of stomatal resistance? Is it omitted during the process by assuming that gd will always be zero since the green roof will only have small plants like shrubs and grass?

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