Solutions to Exo7

1. Cf. the file cabin_hvac.json where the heating/cooling systems are specified.
2. In the design_space_cabin.py file, the search space is specified through :

      (...)
      choices_hvac_systems = ["Boiler_WoodPellets_10kW", "heatpump_air_water_10kw", "heatpump_air_air_HE_10kw"]
      (...)
   

   and the names of these products is linked to the rest of the product characteristics in products_catalog_modeified.py.