We are happy to announce the following new features in ENVI-met V4.1 Winter1617

• Support of water spray and water fountains (PRO/ SCIENCE only)
• New advanced radiation transfer modelling using Indexed View Sphere (PRO/ SCIENCE)
• Support of temperatures below 0° C

In addition, a number of smaller bugs have been fixed.

Water spray sources can be either of the Fountain-Type ranging from ground to the given height z or of the Spot-Type, only emitting in the given height z.

To use Water Spray, define one or more type of sources in the Database editor. Set Special ID= 1 for a spray source of the Fountain-Type or set Special ID= 2 for the Spot-Type. All spray emissions are given in g/s. In the Project Wizard, go to the “Pollutant Dispersion” Section, enable pollutants and set “Chemical species or type of pollutant” to “SPRAY”. Enter the particle diameter of your spray source (you do not need to set the density). Finally, add the sources to your model area input file.

In the standard radiation modelling scheme of ENVI-met, the reflected shortwave radiation and the longwave radiation emitted from the soil and from the buildings are calculated using an average value over the complete model domain weighted with local view factors. So, if you “see” 40% of building walls, you will always get the same average amount of reflected and infrared radiation, regardless if the walls you actually see are in the sun or in the shade, are white or gray, concret or wood.

Using the new IVS (Indexed View Sphere) method, each grid point now receives the radiation based on the conditions of the walls and soils this specific grid point actually “sees”. The new IVS method is more computation time expensive, as the individualized view factors for each grid point needs to be stored with a 10 degree resolution. ENVI-met needs to use a temporary swap file in your model results folder to store this information. If you have receptors in your model, additional high-resolution data (1 degree resolution) of the view horizon are generated.

As this method is new, it is considered as “BETA”- Please give feedback. If you use the IVS, make sure to update to Version 4.1.1

To use IVS, add the following section to your .SIM file: