A holistic microclimate model

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intro:modelconcept [2017/11/12 20:57] – created enviadminintro:modelconcept [2023/02/26 18:25] (current) – enviadmin
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 ===== Overview in a Nutshell===== ===== Overview in a Nutshell=====
  
-ENVI-met V4 is a holistic three-dimensional non-hydrostatic model for the simulation of surface-plant-air interactions not only limited to, but very often used to simulate urban environments and to asses the effects of green architecture visions.  +ENVI-met is a holistic three-dimensional non-hydrostatic model for the simulation of surface-plant-air interactions not only limited to, but very often used to simulate urban environments and to asses the effects of green architecture visions.  
-It is designed for microscale with a typical horizontal resolution from 0.5 to 10 m and a typical time frame of 24 to 48 hours with a time step of 1 to 5 seconds. This resolution allows to analyze small-scale interactions between individual buildings, surfaces and plants.+It is designed for microscale with a typical horizontal resolution from 0.5 to 10 m and a typical time frame of 24 to 48 hours with a time step of 1 to 5 seconds. This resolution allows to analyze small-scale interactions between individual buildings, surfaces and plants. Depending on computer resources and time, you can also use ENVI-met to simulate complete months or even a whole year.
  
 The model calculation includes: The model calculation includes:
  
-  * Shortwave and longwave radiation fluxes with respect to shading, reflection and re-radiation from building systems and the vegetation +  * Shortwave and longwave radiation fluxes with respect to shading, reflection and re-radiation from building systems and the vegetation. ENVI-met provides high-resolution modelling of all radiative fluxes, including multiple reflections in urban areas and radiation diffusion in tree canopies.
   * Transpiration, Evaporation and sensible heat flux from the vegetation into the air including full simulation of all plant physical parameters (e.g. photosynthesis rate)    * Transpiration, Evaporation and sensible heat flux from the vegetation into the air including full simulation of all plant physical parameters (e.g. photosynthesis rate) 
   * Dynamic surface temperature and wall temperature calculation for each facade and roof element supporting up to 3 layers of materials and 7 calculation points in the wall/ roof.    * Dynamic surface temperature and wall temperature calculation for each facade and roof element supporting up to 3 layers of materials and 7 calculation points in the wall/ roof. 
 +  * Support of wall/ roof greening systems including substrate layer 
   * Water- and heat exchange inside the soil system including plant water uptake   * Water- and heat exchange inside the soil system including plant water uptake
   * 3D representation of vegetation including dynamic water balance modelling of the individual species    * 3D representation of vegetation including dynamic water balance modelling of the individual species 
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 ===== Software Versions ===== ===== Software Versions =====
-The **BASIC/TRIAL** version of ENVI-met V4 is free and comes along as a complete model including the basic simulation core for non-commercial applications, but is restricted in domian and calculation features. In addition to the free version (**"ENVI-met BASIC"**), there are  the **BUSINESS Version** and **SCIENCE Version** which include advanced modelling features and the newest simulation techniques. While the **Basic** version can be downloaded and used freely based on the Creative Commons License  BY-NC-SA, the **BUSINESS Version** and  **SCIENCE Version** need to be licensed and are not free.+The **LITE** version of ENVI-met is free and comes along as a complete model including the basic simulation core for non-commercial applications, but is restricted in domian to 50 x 50 grids and has less calculation features. In addition to the free version (**"ENVI-met LITE"**), there are  the **BUSINESS Version** and **SCIENCE Version** which include all modules of the ENVI-met software and free updates to the newest simulation techniques . While the **LITE** version can be downloaded and used freely based on the Creative Commons License  BY-NC-SA, the **BUSINESS Version** and  **SCIENCE Version** need to be licensed and are not free.
  
  
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- **Wind field**  ENVI-met includes a full 3D Computational Fluid Dynamics [[wp>Computational_fluid_dynamics|(CFD)]] modell. It solves the [[wp>Reynolds-averaged_Navier–Stokes_equations|Reynolds-averaged non-hydrostatic Navier-Stokes equations]] for each grid in space and for each time step. The effects of vegetation are included as drag forces in the wind field. For detailed building physics simulation, the wind flow close to each facade and roof segment is calculated. With the new Single Wall feature, wind patterns inside complex or semi-open structures can be simulated as well. + **Wind field**  ENVI-met includes a full 3D Computational Fluid Dynamics [[wp>Computational_fluid_dynamics|(CFD)]] model. It solves the [[wp>Reynolds-averaged_Navier–Stokes_equations|Reynolds-averaged non-hydrostatic Navier-Stokes equations]] for each grid in space and for each time step. The effects of vegetation are included as drag forces in the wind field. For detailed building physics simulation, the wind flow close to each facade and roof segment is calculated. With the new Single Wall feature, wind patterns inside complex or semi-open structures can be simulated as well. 
  
 The wind flow is updated at given time intervals. ENVI-met also supports a real-time flow calculation which means that the flow field is treated as a normal prognostic variable and calculated each step. Due to the very small time steps needed here, this way of calculation need very powerful computers.  The wind flow is updated at given time intervals. ENVI-met also supports a real-time flow calculation which means that the flow field is treated as a normal prognostic variable and calculated each step. Due to the very small time steps needed here, this way of calculation need very powerful computers. 
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 **Radiative fluxes** **Radiative fluxes**
-ENVI-met contains newly developed analysis modules to model the fluxes of shortwave and longwave radiation inside of complex environments. The scheme takes into account shading by complex geometries, reflections by different surface and building materials and the effect of vegetation on all radiative fluxes. The Expert Version introduces the new IVS method, in which each urban element is considered using its actual state (sun reflection, thermal radiation) instead of averaged fluxes.+ENVI-met contains newly developed analysis modules to model the fluxes of shortwave and longwave radiation inside of complex environments. The scheme takes into account shading by complex geometries, reflections by different surface and building materials and the effect of vegetation on all radiative fluxes. The full versions of ENVI-met include the new IVS method, in which each urban element is considered using its actual state (sun reflection, thermal radiation) instead of averaged fluxes.
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 ** Pollutant dispersion ** ** Pollutant dispersion **
-The pollutant dispersion model of ENVI-met allows the synchronous release, dispersion and deposition of up to 6 different pollutants including particles, passive gases and reactive gases. Sedimentation and deposition at surfaces and vegetation is taken into account as well as the photochemical reaction between NO, NO<sub>2</sub> and Ozone (O<sub>3</sub>). The Expert version of ENVI-met also allows to simulate the effects of photocatalytic activated surfaces on air quality.+The pollutant dispersion model of ENVI-met allows the synchronous release, dispersion and deposition of up to 6 different pollutants including particles, passive gases and reactive gases. Sedimentation and deposition at surfaces and vegetation is taken into account as well as the photochemical reaction between NO, NO<sub>2</sub> and Ozone (O<sub>3</sub>). 
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 =====Soil model===== =====Soil model=====
  
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 ** Soil water content ** ** Soil water content **
-Simulating the water balance of the surface and the soil is a crucial aspect in urban microclimatology. While humid soils can act as cooling devices, dry soils are often hotter than asphalt. In addition, the cooling effect, and -on a longer time perspective- the vitality of vegetation depends on available soil water. ENVI-met dynamically solves the soil hydraulic state of the soil based on [[wp>Darcy's_law|Darcy's law]] taking into account evaporation, water exchange inside the soil and water uptake by plant roots.  The consulting version of ENVI-met can also handle complex types of irrigation methods or subsurface water sources.+Simulating the water balance of the surface and the soil is a crucial aspect in urban microclimatology. While humid soils can act as cooling devices, dry soils are often hotter than asphalt. In addition, the cooling effect, and -on a longer time perspective- the vitality of vegetation depends on available soil water. ENVI-met dynamically solves the soil hydraulic state of the soil based on [[wp>Darcy's_law|Darcy's law]] taking into account evaporation, water exchange inside the soil and water uptake by plant roots.  
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 ** Vegetation water supply ** ** Vegetation water supply **
-Plants are living organisms and will only contribute in positive way to the local microclimate, if enough water is available in the soil within the root zone. Together with the simulation of the soil water content and the new sophisticated 3D root model, the dynamic water supply of the plant and the resulting water extraction from the soil can be calculated. +Plants are living organisms and will only contribute in a positive way to the local microclimate, if enough water is available in the soil within the root zone. Together with the simulation of the soil water content and the 3D root model, the dynamic water supply of the plant and the resulting water extraction from the soil can be calculated. 
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 =====Vegetation Model===== =====Vegetation Model=====
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 ** Foliage temperature** ** Foliage temperature**
 The temperature of the leafs is calculated by solving the energy balance of the leaf surface with respect to the actual meteorological and plant physiological conditions for each grid box of the plant canopy. The health status of the plant and the water supply by the soil regulate, beside other factors, the plants transpiration rate and thereby the leaf temperature.  ENVI-met uses a sophisticated model to simulate the stomata behaviour of the vegetation in response to microclimate, CO2 availability and water stress level. The temperature of the leafs is calculated by solving the energy balance of the leaf surface with respect to the actual meteorological and plant physiological conditions for each grid box of the plant canopy. The health status of the plant and the water supply by the soil regulate, beside other factors, the plants transpiration rate and thereby the leaf temperature.  ENVI-met uses a sophisticated model to simulate the stomata behaviour of the vegetation in response to microclimate, CO2 availability and water stress level.
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 ** Exchange processes with the environment** ** Exchange processes with the environment**
 Vegetation interacts in various ways with the environment: Heat and vapour are exchanged between the plants leafs and the atmosphere. Transpired water will be -if possible- extracted out of the soils hydraulic model using the plant root distribution.  Vegetation interacts in various ways with the environment: Heat and vapour are exchanged between the plants leafs and the atmosphere. Transpired water will be -if possible- extracted out of the soils hydraulic model using the plant root distribution. 
 A complex raytracing algorithm is used to analyse the plants impact of solar radiation (shadow casting) and on longwave radiation exchange (thermal shielding). A complex raytracing algorithm is used to analyse the plants impact of solar radiation (shadow casting) and on longwave radiation exchange (thermal shielding).
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-**Vegetation health assessment/ TreePass/ Wind Risk Assessment** + 
-The impact of vegetation on the microclimate is only one side of the story. To grow and live, plants also need adequate local climate conditions fitting to their individual demand profile. Too much or too little sun, to heavy wind loads on the trees or stagnating air: Many aspects of the microclimate can interfere with the plants requirements and hinder a healthy and robust growth. Using our TreePass technology, the local growing conditions and the plants profiles can be matched to provide an optimal placement. Our wind risk assessment simulates the tree mechanics in order to assess the risk of wind and storm damage depending on the crown structure and the tree location. (Consulting only). +**TreePass: Understanding vegetation health requirements and simulate Wind Risk Assessment** 
 +The impact of vegetation on the microclimate is only one side of the story. To grow and live, plants also need adequate local climate conditions fitting to their individual demand profile. Too much or too little sun, to heavy wind loads on the trees or stagnating air: Many aspects of the microclimate can interfere with the plants requirements and hinder a healthy and robust growth. Using our TreePass technology, the local growing conditions and the plants profiles can be matched to provide an optimal placement. Our wind risk assessment simulates the tree mechanics in order to assess the risk of wind and storm damage depending on the crown structure and the tree location.  \\ 
 +**The TreePass Module is still in development together with different cities and NGOs.**  
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 ===== Built environment & Building system===== ===== Built environment & Building system=====
  
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 ** Full 3D building geometry & Single walls** ** Full 3D building geometry & Single walls**
-Complex buildings and other structures can be constructed in full 3D with no limitations in complexity as far as the cubic base structure allows. This allows the simulation of semi-open spaces such as the soccer stadium shown in the icon and in this example. Moreover, ENVI-met Expert allows the usage of single thin walls that can be applied to any grid which can be used to represent spaces wich are enclosed by walls but do not behave like a building e.g. bus stop shelters, shading structures...+Complex buildings and other structures can be constructed in full 3D with no limitations in complexity as far as the cubic base structure allows. This allows the simulation of semi-open spaces such as the soccer stadium shown in the icon and in this example. Moreover, ENVI-met allows the usage of single thin walls that can be applied to any grid which can be used to represent spaces wich are enclosed by walls but do not behave like a building e.g. bus stop shelters, shading structures...
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 ** Building energy performance ** ** Building energy performance **
 ENVI-met dynamically calculates the development of the building indoor temperature as a result of the incoming and outgoing fluxes through the associated wall and roof segments. This building energy simulation is executed parallel to the outdoor microclimate simulation for each building in the model domain so that a constant feedback between the outdoor and indoor climate conditions and of the interactions between buildings is provided. The recent version allows an initial zoning model to define building sections and thermal zones. ENVI-met dynamically calculates the development of the building indoor temperature as a result of the incoming and outgoing fluxes through the associated wall and roof segments. This building energy simulation is executed parallel to the outdoor microclimate simulation for each building in the model domain so that a constant feedback between the outdoor and indoor climate conditions and of the interactions between buildings is provided. The recent version allows an initial zoning model to define building sections and thermal zones.
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 ** Green Wall and Roof Systems** ** Green Wall and Roof Systems**
-ENVI-met Expert allows a detailed simulation of the energy and vapour exchange processes take place at green walls and green roof tops. The //Green Wall System// (GWS) integrates seamlessly into the dynamic calculation of the building energy performance and the facade/ wall temperature and supports a wide range of different systems from simple climbing plants up to living wall systems.+ENVI-met allows a detailed simulation of the energy and vapour exchange processes take place at green walls and green roof tops. The //Green Wall System// (GWS) integrates seamlessly into the dynamic calculation of the building energy performance and the facade/ wall temperature and supports a wide range of different systems from simple climbing plants up to living wall systems.
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 +=====Data Analysis and Workflow Managment ===== 
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 +** It's the format that matters...** 
 +Starting with the WinterRelease 2019, we have added the option to export ENVI-met datafiles into the NetCDF format. This standard allows you to use ENVI-met datafiles directly in several other applications such as ESRI ArcMap or any other geospatial software. In addition, starting with Version 5, ENVI-met has also changed ALL outputfiles to be readable by standard CSV conventions, including Python Pandas. 
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 +**Visualisation and Analysis without bondaries** 
 +ENVI-met ships with a large range of intuitive visualisation and analysis tools within LEONARDO. However, there is always a Dashboard never thought of and an AI routine that might discover new insights. Maybe you simply want to add some ofyour personal preferences to the grafic layout.  
 + 
 +Python has this all and using the our **DataStudio** implemented in several ENVI-met apps gives you access to this endless world of possibilities. **DataStudio** will be added to all ENVI-met applications Step-by-Step, not only linking to Python itself, but also allowing the user to control most of the ENVI-met app logic by her or himself. 
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 =====Internals===== =====Internals=====