IES-VE User Forum

hi every one

is it possible to simulate the effect of tree or number of people on heat movement or exchange using MicroFlo? how? can we see that in the result in viewer? using slides for example?

i have tried to add tree (component) to a room but couldn't see any different in the results between "with tree" and "without tree"

many thanks in advance

Microflo doesn't mesh components that aren't CFD components. Some of the components in the component library are for the Radiance module and are too complicated to be meshed by Microflo.

Components are designated as "standard" or "CFD" (if I remember correctly). Only CFD components are meshed.

You should keep your component geometries as simple as possible (blocky) to allow the mesher to create a mesh with low aspect ratio cells, otherwise you will have difficulty in obtaining a converged solution.

thank you for your reply

in fact, i have use a CFD component of tree , i did't made it , just i use the one in the library

do you have any idea?

The tree components in the VE are for the Radiance module, not for the Microflo module. If you look down in the bottom right of the component modeller window you will see they are called "Object" components, not "Standard" components like I said before. The CFD components are called "CFD".

> is it possible to simulate the effect of tree or number of people on heat movement or exchange using MicroFlo?

Yes if you import a CFD component. The easiest way is to use one of standard CFD components (radiator, source, solid heat source) and to scale it to make the size of component you need. The standard CFD components are just single blocks (hexahedrals) but they can be combined into more complex shapes if needed.

But you should keep components as simple as possible as MIcroflo uses a Cartesian mesh and if you add componnets that are too complex the mesher will produce a mesh with large aspect ratio cells that will make it hard to get a converged solution.

> i have tried to add tree (component) to a room but couldn't see any different in the results between "with tree" and "without tree"

That is because it is not a CFD component so it is ignored by the mesher.

thank you sooooo much

you really taught me new things,

i was confusing about the components in VE, i have changed the tree form "Object" components to "CFD" components
and i got the results!

if you don't mind, i need some references about concept of standard CFD components (radiator, source, solid heat source), especially if i want to analyze the results,

when in see the results, in video slice for example, i really got confused about what are the Velocity, Temperature and Pressure

Components are just a way to add extra geometry, boundary conditions and sources into a CFD model - stuff that cannot be added to one of the surfaces of the main VE zone (wall/ceiling/floors/windows and doors).

There are 3 CFD components in the component library by default, called: 1) radiator, 2) solid heat source, and 3) source.

But these are just arbitrary names and what the components do in the CFD model can be controlled by clicking on and off the check buttons for: solid, heat, temperature, CO2 etc.

If you have the "solid" check button selected then air cannot pass through the component, and importantly you can go down onto individual surfaces in the component and add the same boundary conditions that you can add for the main wall, ceiling etc.

So for example you could add a solid component that acts as an air conditioning unit drawing air out of the domain at the bottom (extract boundary) and blowing back into the domain at the top at a different temperature (a supply or diffuser boundary).

On solid components you can have the following boundaries: heat, temperature, extracts and any of the diffuser/supply boundaries.

Non-solid components on the other hand are there to allow you to have sources of heat, or CO2, or water vapour, or CO within the model. You cannot click down onto their surfaces to add boundary conditions. The heat or other source is added equally to each cell within the non-solid component on a volume weighted basis - e.g. each cell gets the same W/m3 for a heat source component.

So forget about the names of the components and concentrate on what check buttons are selected and how you specify the boundary conditions or sources.