## 2 Materials and Methods
### Simulations Performed in the Study  
The modelling part of the proposed approach consisted in utilizing the very popular EnergyPlus simulation code to run the building's thermal calculations. For this purpose, different scenarios were implemented, specifically:  
* Scenario #1, in which the monitored ceiling temperatures were utilized in the simulation as boundary fixed conditions for the ceiling of the investigated rooms. In this scenario, a detailed schedule for the HVAC was implemented, based on assumptions made of its \"real\" use according to the typical time of occupation of the building, considering a power capacity of 1000 Watt. This value was obtained from simulations previously conducted using the climatic design-day typical of the examined area, characterized by a temperature of 5.2\({}^{\circ}\)C (\(\pm\) 0) for winter conditions and 31\({}^{\circ}\)C (\(\pm\) 6) for summer conditions.
* Scenario #2, in which the simulation was carried out utilizing the green roof configuration provided by EnergyPlus (EP+GR), trying to simulate the previously described six plots as faithfully as possible by using the parameters reported in Tables 1 and 2. In fact, the EnergyPlus green roof simulation tool sets numerical limits for some parameters, which could not therefore have been set according to their real values.
* Scenario #3, in which the simulation was conducted by implementing a standard case (STD), that is, considering the original roof of the building without the presence of green coverage.  
Regarding the HVAC schedule of Scenario #2 and Scenario #3, it was decided to use a simple on/off schedule, with the HVAC working between 7:00 and 17:00, considering the same power capacity as that used in Scenario #1.  
The authors would like to underline here that Scenarios #1 and #2 are characterized by the presence of green roofs, while Scenario #3 refers to a standard roof. The difference consists in the fact that, while  
Figure 8: Layout of the building, green roof plots’ arrangement and positions of probes for the temperature measurement.  
the simulation of Scenario #2 totally complies with the Energy Plus code (by utilizing its typical green roof simulation routine), Scenario #1 is modelled by forcing the Energy Plus code, that is, imposing the monitored indoor ceiling temperatures as boundary conditions. In this way, the model was driven with real data based on the presence of the experimental green roof, avoiding the actual simulation of the green roof element itself. Hence, this allowed us to compare the PMVs obtained from the Energy Plus green roof simulation tool (with its relative assumptions limits) with those calculated on the basis of the real monitored experimental data.  
In order to assess the direct and indirect reduction of CO2 emissions, in this work, a value of 85 kgCO2/ha per year [71] was considered for the direct reduction of CO2 emission, based on the extension of green covering, while a value of 0.531 tCO2/MWh (the average emissions for the current electric Italian energy mix [34]) was used to estimate the indirect reduction of CO2 emission based on energy saving for climatization purposes and having set a COP value equal to 3 for the cooling season and 3.5 for the heating season.