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In OpenStudio, choosing the Ideal Loads System results in this IDF input for each zone:

ZoneHVAC:IdealLoadsAirSystem,
  Thermal Zone: P1- Sl. Empresa 1 Ideal Loads Air System,  !- Name
  ,                                                        !- Availability Schedule Name
  Thermal Zone: P1- Sl. Empresa 1 Ideal Loads Supply Inlet,  !- Zone Supply Air Node Name
  ,                                                        !- Zone Exhaust Air Node Name
  50,                                                      !- Maximum Heating Supply Air Temperature [C]
  13,                                                      !- Minimum Cooling Supply Air Temperature [C]
  0.0156,                                                  !- Maximum Heating Supply Air Humidity Ratio [kg-H20/kg-air]
  0.0077,                                                  !- Minimum Cooling Supply Air Humidity Ratio [kg-H20/kg-air]
  NoLimit,                                                 !- Heating Limit
  ,                                                        !- Maximum Heating Air Flow Rate {m3/s}
  ,                                                        !- Maximum Sensible Heating Capacity {m3/s}
  NoLimit,                                                 !- Cooling Limit
  ,                                                        !- Maximum Cooling Air Flow Rate {m3/s}
  ,                                                        !- Maximum Total Cooling Capacity {m3/s}
  ,                                                        !- Heating Availability Schedule Name
  ,                                                        !- Cooling Availability Schedule Name
  ConstantSensibleHeatRatio,                               !- Dehumidification Control Type
  0.7,                                                     !- Cooling Sensible Heat Ratio
  None,                                                    !- Humidification Control Type
  ,                                                        !- Design Specification Outdoor Air Object Name
  ,                                                        !- Outdoor Air Inlet Node Name
  None,                                                    !- Demand Controlled Ventilation Type
  NoEconomizer,                                            !- Outdoor Air Economizer Type
  None,                                                    !- Heat Recovery Type
  0.7,                                                     !- Sensible Heat Recovery Effectiveness
  0.65;                                                    !- Latent Heat Recovery Effectiveness

Notice that the Design Specification Outdoor Air Object Name field is empty. Per the Ideal Loads System documentation, "If this field is blank, this system will have no outdoor air, and all outdoor air control and heat recovery options will be ignored.." Outdoor Air is typically a large part of HVAC loads, so not having OA in your model might be the cause of the unexpectedly low loads you are seeing.

In OpenStudio, choosing the Ideal Loads System results in this IDF input for each zone:

ZoneHVAC:IdealLoadsAirSystem,
  Thermal Zone: P1- Sl. Empresa 1 Ideal Loads Air System,  !- Name
  ,                                                        !- ,!- Availability Schedule Name
  Thermal Zone: P1- Sl. Empresa 1 Ideal Loads Supply Inlet,  !- Zone Supply Air Node Name
  ,                                                        !- ,!- Zone Exhaust Air Node Name
  50,   !- Maximum Heating Supply Air Temperature [C]
  13,   !- Minimum Cooling Supply Air Temperature [C]
  0.0156,   !- Maximum Heating Supply Air Humidity Ratio [kg-H20/kg-air]
  0.0077,   !- Minimum Cooling Supply Air Humidity Ratio [kg-H20/kg-air]
  NoLimit,  !- Heating Limit
  ,                                                        !- ,!- Maximum Heating Air Flow Rate {m3/s}
  ,                                                        !- ,!- Maximum Sensible Heating Capacity {m3/s}
  NoLimit,  !- Cooling Limit
  ,                                                        !- ,!- Maximum Cooling Air Flow Rate {m3/s}
  ,                                                        !- ,!- Maximum Total Cooling Capacity {m3/s}
  ,                                                        !- ,!- Heating Availability Schedule Name
  ,                                                        !- ,!- Cooling Availability Schedule Name
  ConstantSensibleHeatRatio,    !- Dehumidification Control Type
  0.7,  !- Cooling Sensible Heat Ratio
  None,                                                    !- None,!- Humidification Control Type
  ,                                                        !- ,!- Design Specification Outdoor Air Object Name
  ,                                                        !- ,!- Outdoor Air Inlet Node Name
  None,                                                    !- None,!- Demand Controlled Ventilation Type
  NoEconomizer,                                            !- NoEconomizer,!- Outdoor Air Economizer Type
  None,                                                    !- None,!- Heat Recovery Type
  0.7,  !- Sensible Heat Recovery Effectiveness
  0.65;                                                    !- 0.65;!- Latent Heat Recovery Effectiveness

Notice that the Design Specification Outdoor Air Object Name field is empty. Per the Ideal Loads System documentation, "If this field is blank, this system will have no outdoor air, and all outdoor air control and heat recovery options will be ignored.." Outdoor Air is typically a large part of HVAC loads, so not having OA in your model might be the cause of the unexpectedly low loads you are seeing.