AftabRad Revit Add-in -> Export To Radiance -> Type of Sky/Analysis: UTCI based Sunlight Hours

UTCI (Universal Thermal Climate Index) is the temperature that weather forecast media used when they say that the temperature “feels like” something higher or lower than the actual outside dry bulb temperature.

Therefore, this analysis is based on firstly finding the comfortable outside temperature (from a simplified version of UTCI calculation formula) for the selected period and then doing the sunlight hours study for all those hours that people enjoy to be outside.

This analysis is based finding Feel Like Temperature that is based on the Dry Bulb Temperature, Humidity, Wind Speed and Radiation values that can be find for each hour in a year from the weather data file.

Therefore, to do the analysis we should do the following steps:

1-      Press ExportToRadiance button in the AftabRad Add-in

2-      Select UTCI based Sunlight Hours in the Type of Sky/Analysis

3-      When choosing the UTCI based Sunlight Hours as the type of analysis, we need to define the calculation period. By default, by choosing this type of analysis, the calculation duration is automatically changed to a period from 1^st of January to the end of December.

However, we can change the calculation duration to anything else if we want to do this type of analysis for different periods in a year.

4-      Since this analysis needs to know about the Dry Bulb Temperature, Humidity, Wind Speed and Radiation of each hour during the selected period, we need to import EPW (Energy Plus Weather Data File).

One of the most common way to find different EPW file for different cities in the world is to download the weather data file of around 2000 cities in the world from https://energyplus.net/weather website.

The other free option to find an appropriate EPW file for your project is to use this link: http://climate.onebuilding.org/

5-      Press Open EPW File button and import an EPW file that is relevant for the location of your model.

6-      Press Rif Settings button to open the Rif Setting page to define

                                 i.            The 3D views that you want to include when export the model into Radiance. (Here, we will define on which views we want to do the export to Radiance.

However later we will come back to this page and asked to choose only one view to do the UTCI Based Sunlight Hours study)

                               ii.            Image Quality, Model Detail and Light Variability

                             iii.            Image Resolution

                             iv.            Calculation Type (luminance/radiance or illuminance/irradiance) (for this calculation it should be illuminance/irradiance)

                               v.            Indirect Reflection (in this analysis it should be zero)

7-      To create a good view that satisfy our expecatation regarding the view point, view direction, horizontal and vertical field (in degree) or width of the view, we can checked the Open Radiance View Panel checkbox.

8-      Be sure that you checked the checkbox next to the Rif Settings button, and press the Do Export2Radiance button.

9-      After pressing the Do Export2Radiance button, we need to define the acceptable range of UTCI temperature in the UTCI Temperature Specifications page.

10-   After pressing the OK button in the UTCI Temperature Specifications page, we need to specify only one view to continue the UTCI Based Sunlight Hours image based analysis.

So the Rif Setting page appears again, but this time we just have one choice of view. By pressing >>> button we can choose the selected view in the 3D Views panels as the main view to continue the calculation.

11-   If you checked the Open Radiance View Panel checkbox, the Radiance View Panel  will be opened.

In this page, we can change all different Radiance parameters of the selected view, and preview the image by pressing >> Preview >> button. As soon as we are satisfy with the image,

we can save that view parameters by pressing the Save button and then we can press Continue to continue the export to Radiane procedure.

12-   After pressing the Continue button, the calculation process will be start. Here it is worth to metion that, since it does its calculation for hour in the selected period, it can take from a few minutes to few hours.

So, please prepare for a long calculation time.

13-   Now, it is time to make the image based analysis. Therefore, the next step is to press the OpenAftabFC Button.

14-   When the FalseColor Analysis page is opened, it is automatically opend the File Openning page.

Therefore, here we need to open an HDR file that, in this case, should be the one that is created when the UTCI based Sunlight Hours view based calculation is finished.

15-   In the FalseColor Analysis Page, we can measure the values of each point by clicking on the image, or find the average of an area by drawing a rectangular or circle.

In UTCI based Sunlight Analysis, the Multiple No. (Multiplying Number) should be 1.

16-   Moreover, in this page, we can make falsecolor images too.

For example, by changing the Scale value to 1500, and choosing Custom. Under the Label drop down list, and writing Hrs as the Label, by pressing the Do FalseColor button, we can create a falsecolor image.

17-   To know more about different function of FalseColor Analysis Page, you can take a look at this pdf file or this link.