The objective of this study is to test the different features of the software Solene-Microclimat in a district of Prague, Czech Republic, where ECOTEN is located. Diverses variants are studied:
The functionalities tested in this case study are:
The chosen scene is a housing block surrounded by eight other blocks. It is located in the Vinohrady district, close to Prague city centre. To the north there is a park and the rest of the stage is surrounded by the same type of buildings that make up a dense urban environment. The buildings are of average height, between 20 and 30 meters, consisting of 5 to 6 storeys. The walls are pastel coloured and the roofs are sloping. The floors are covered with bitumen, or white and black paving stones. Some of the streets are lined with trees.
To simulate the impact of different albedo on the microclimate, we need to identify each surface composing the ground or the buildings beforehand as well as the albedo level for each of these surfaces. Then, the software will compute.
For the first two variants, the albedo of facades, roofs and sidewalks are modified. In Prague most of the facades are coloured, often light coloured, but sometimes they are darker or have not been resurfaced for some time and are dark.
There are 3 options for setting assumptions on the temperature control for the Building Thermal Tool. Either the temperature is allowed to change freely, or it cools down above a set value, or it cools down all the time. We selected the second option, with a setpoint temperature of 26 °C.
The aim of studying the first 4 variants was to simulate the urban microclimate in the scene in order to assess the outdoor comfort. In order to analyse the results, specific points had to be selected for study. We take as a referal the Point East (Est) and the Point South (Sud) and track their air and surface temperatures.
We gathered the average and max temperatures for both points. The first comparison (V2 – V1) is for a variation of albedo in the scene without vegetation, the second (V4 – V3) compares a variation in albedo in the scene with rows of trees and the third (V2 – V4) compares temperatures between scenes with and without trees and with the same albedo.
Firstly, we notice that the difference in air temperature is greater for the third comparison than for the other two (up to 8 times), this is particulary true for the western point than at the southern point. The maximum value of 7.25 °C for the West street corresponds to the temperature difference of a dark-coloured street with a trees VS treeless configuration.
This is a very important finding that underlines the gain in comfort provided by the shade of rows of trees.
We then notice the smaller differences between the two streets for the cases of albedo variation. This can be explained by the fact that the heat comes from a rise in temperature that is much more evenly distributed between all surfaces, not only those sheltered or not from the sun, by means of inter-reflections and GLO radiation.
