We ran microclimate simulations on the two sites through the use of two different programmes: ENVI-met and Autodesk's Forma. Both with their own strengths and limitations, we use a balance of the various outputs for our site analysis. The programs were approached with little to no prior knowledge within a limited timeframe. Hence, we consider these analyses tools fairly accessible for people to learn and use.
Abbreviations:
GAT - Gustav Adolfs Torg
MT - Möllevågnstorget
ENVI-met is a relatively long standing and commonly used 3D microscale simulation software. It provides flexibility in analyzing the temperature, humidity and wind conditions of a model. The freely accessible ENVI-met LITE version which we will be making use of, is slightly less flexible and allows for a maximum domain of 50x50x40 grid cells for analysis, lowering our resolution. Despite the greater range of options, it has a comparatively steeper learning curve.
Autodesk's Forma on the other hand is a very recent, cloud-based program available for use through a browser providing almost instant results, intended for early-stage planning proposals. It is still under development, of which we used a 30-day free trial. The resolution is significantly higher, and the output allows for specific wind and sun analyses. However the models are far less flexible, as there are fewer parameters in terms of material, surfaces, vegetation, etc. (see Table.1).
Table 1 - Our data sources used for modelling the simulations in each program.
Both GAT and MT show very similar temperature fluctuations throughout the simulations, having the lowest temperatures at 10:00 and the highest at 16:00. Due to the outer parts of the model containing outliers the exact minimum temperature is not determined, yet roughly known to be similar to what is presented below. The simulations show less heat increases on the open squares specifically. For both GAT and MT these central open spaces contain less asphalt, and more varied soil types including basalt brick or permeable soil. Furthermore, for GAT this open square has more concentrated vegetation. These spaces still reach higher temperatures yet differ up to 3°C to the surrounding, unshaded asphalt road depending on the hour.
All Forma microclimate simulations regardless of site or wind conditions set reach a very similar maximum temperature to the ENVI-met simulations. The significant difference lies in the minimum temperatures reached. This may be due to the centimeter-level resolution analysis showing the smaller colder points in comparison to ENVI-met’s 6m and 4m resolutions for GAT and MT respectively. The warmest and coolest areas are less impacted by the vegetation, and rather most influenced by wind flow and sun position which could be attributed to Forma's limited vegetation parameters. As surface material cannot be accounted for, the temperature difference between the main square and its surroundings are less compelling.
The wind analyses were all run through an assumption of a southwest originating wind as the prevailing direction. Different wind speeds are visualized. According to all comfort scales employed and the wind speed analysis, GAT hosts amplified wind corridors around and between some of the buildings. Ventilation is still very present in the open square, with some buildings providing shelter. MT additionally has some corridors which amplify the wind flow, however much more significantly lowers wind flow in the main square, showing higher levels of comfort but less ventilation.
Both GAT and MT show very strong solar access during July, with the squares having 9+ hours of direct sun. This is in heavy contrast to the winter months, where the January analysis shows half of GAT and near the entirety of the MT square having no sun access. This in combination with the higher concentration of cloudy days shows the strong seasonal contrast present. The impact of sunlight on thermal conditions is further emphasized in the microclimate analysis where the cooler areas follow the shade case by the buildings, which are made especially clear in the 1m/s microclimate video. However it should be noted that Forma has very limited vegetation options, and hence this output likely does not reflect tree shade to a satisfactory degree.
GAT Sun hours availability
(15th June)
GAT Sun hours availability
(15th January)
MT Sun hours availability
(15th June)
MT Sun hours availability
(15th January)