*2.1. Description of the Thermal System*

Two symmetrical HVAC systems (named HVAC-1 and HVAC-2 in the following) are installed on the roof of the building, and each system is used for thermal conditioning of half of the building. Both systems are equipped with heat pumps (model CLIVET WSAN-XEE 302 [37]), having the following technical specifications (Table 1).


**Table 1.** Characteristics of the heat pump CLIVET WSAN-XEE 302 [37].

Finally, each HVAC unit supplies three pipelines, through which the heat transfer fluid is pumped:

