User defined materials in DB Manager

Discussions about the Version 4 concerning the core model simulations
jfguzman24
Posts: 18
Joined: Fri Mar 22, 2019 4:36 pm

User defined materials in DB Manager

Postby jfguzman24 » Sun Mar 31, 2019 1:31 pm

I'm defining several of my own materials within the DB Manager, but I've come across some that I do not understand what do they refer to exactly. In a Plant Material, what does the Transmittance value refer to exactly? Is it the same value taken for the transmissivity of the vegetation which should be a function of the extinction coefficient k and Leaf area index (LAI)? If so, shouldn't it be defined in a Greening Material?

In the case of Greening Material, when there is a substrate the water coefficient of substrate for plant has to be defined. Is this value the same as the moisture content in the soil substrate? Or what does it refer to?

Thank you for your help,
Best,
Francisco

Tim
Posts: 1219
Joined: Mon May 15, 2017 3:46 pm

Re: User defined materials in DB Manager

Postby Tim » Mon Apr 01, 2019 10:43 am

Hi Francisco,

Yes, the Transmittance value is a factor reducing the shortwave radiation going through the plant.
The greening consists out of the simple plants and the soils which can be defined in the database as well. All needed values are taken from these defined plants and soils.
The water coefficient is the amount of the usable field capacity of the substrate which is available for the plant. The value is not lowered during the simulation, greening is assumed to always be irrigitated. If the value is not 0.5 as in default but e.g. 0.1 the plant gets water stress permanently.

Best regards
Tim

jfguzman24
Posts: 18
Joined: Fri Mar 22, 2019 4:36 pm

Re: User defined materials in DB Manager

Postby jfguzman24 » Wed Apr 03, 2019 6:52 pm

Hi Tim,

I'm trying to evaluate the impact that varying moisture contents in the substrate layer will have on the evapotranspiration of the plant. I don't want to allow any wilting of the plant, but evaluate which is the ideal amount of water (within the plants' capacity) in the substrate to improve the effects of evapotranspiration from the plant. If I would modify this water coefficient with a lower boundary set to the permanent wilting point and run several simulations increasing this value, would I be able to evaluate the effects of the moisture content in the vegetation layer without causing any permanent stress? And would this value represent the volumetric water content on the substrate layer?

Thanks,
Francisco

Tim
Posts: 1219
Joined: Mon May 15, 2017 3:46 pm

Re: User defined materials in DB Manager

Postby Tim » Thu Apr 04, 2019 8:05 am

Hi Francisco,

Yes, I'd say that it'll work like that.
No, the value does not represent the volumetric water content. It is a factor between 0 and 1 defining the amount of usable field capacity available for the plant.

Best regards
Tim

zhuzhuzhu
Posts: 25
Joined: Sun Dec 02, 2018 5:33 am

Re: User defined materials in DB Manager

Postby zhuzhuzhu » Tue Apr 16, 2019 8:55 am

Hi Tim
You said that greening is assumed to always be irrigitated. So can I assume that the soil of substrate is always at saturation and the water content in the soil(substrate) equals to the value which is set in the DBManage/soil. As I want to set very vrey wet substrate, I am working on how to realaize that. Thanks.
Best regards
Zhuzhuzhu

Tim
Posts: 1219
Joined: Mon May 15, 2017 3:46 pm

Re: User defined materials in DB Manager

Postby Tim » Tue Apr 16, 2019 9:09 am

Hi Zhuzhuzhu,

Then, I would suggest to set the greening substrate water coefficient to a high valu esuch as 0.9 or 1.

Best regards
Tim

zhuzhuzhu
Posts: 25
Joined: Sun Dec 02, 2018 5:33 am

Re: User defined materials in DB Manager

Postby zhuzhuzhu » Tue Apr 16, 2019 9:16 am

Hi, Tim
Thank you. I will try your advice and check the outputs to analyze the effect.
Best regards
Zhuzhuzhu

mrv
Posts: 1
Joined: Tue Mar 24, 2020 4:58 pm

Re: User defined materials in DB Manager

Postby mrv » Wed Mar 25, 2020 7:07 pm

Hello,
I am defining my own living wall and trying to evaluate the effect of irrigation on living walls thermal behaviour. I have taken 0,05 and 0,5 values as "water coefficient of substrate for plants" but surprisingly I get the same building/dynamic outputs for both cases.

Similarly, when i change the "air gap distance between substrate and wall" for living walls from 1 cm to 40 cm, I recieved the exact same building dynamic outputs again. Where do u think i did mistake?

Thank u very much in advanced. Best regards,
Merve.

Tim
Posts: 1219
Joined: Mon May 15, 2017 3:46 pm

Re: User defined materials in DB Manager

Postby Tim » Thu Mar 26, 2020 8:10 am

Hi Merve,

I made a simple test with 4 buildings containing different greenery and found that there are differences for all parameters such as air temperature in front of facade, greening canopy temperature or facade temperature:

2020-03-26_09h03_53.png


All buildings have the default greening with air gap and sandy loam substrate. Changes are:
Top left building: water coefficient to 0.1.
Top right building: water coefficient to 0.9.
Lower left building: water coefficient to 0.9, air gap 0.02 m.
Lower right building: water coefficient to 0.9, air gap 0.15 m.

Maybe, something went wrong in saving your changes in DBManager or applying the greening in Spaces?

Best regards,
Tim


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