In EnergyPlus the end use category InteriorEquipment is an Output:Meter object that combines either ElectricEquipment or GasEquipment objects from all zones.

In OpenStudio these are found in the Loads tab under Electric Equipment Definitions and Gas Equipment Definitions. These internal gains are essentially rolled up to the building level and reported as monthly totals in the Results Summary tab bar chart.

Assuming your building type is not dominated by internal equipment gains, a couple questions I would have are:

1. Does the interior equipment end use seem too large in absolute terms? If so look at the values used in the model for the Electric Equipment Definitions.

2. Does the interior equipment end use seem too large in relative terms? If so, then your model may not be well tuned (i.e. have unreasonably high unmet hours, say >300 heating or cooling hours not met by the HVAC system). If so then take a look at the HVAC system parameters.

For reference, here's the output from a primary school:

The existing answers are very good but I just wanted to touch on a few other things to look at. In OpenStudio an internal load instance consists of three parts. The load definition, a fractional schedule, and a multiplier. The load instance can exist as part of a space type description or can be applied directly to a space.

If an internal load seems high (or low) check the definition, but also check the schedule and multiplier. Generally the definition represents either the peak load or often a typical usage load (typical usage is of course a bit fuzzy of a term). The schedule define the.usage as a fraction of the definition value throughout the year. The multiplier the quantity of obj ctd that exists. If you are using an electric4 power density such as 1.2 W/soft then the multiplier is typically 1.0. But if your definition is an 80W computer, then the multiplier may be 20 or 50 (representing the actual quality of that specific equipment type in the building).

Interior equipment includes any equipment that requires electricity, that is not already accounted for by HVAC, refrigeration, or lighting objects. For example:

• Computers
• Refrigerators and freezers (non-commercial)
• Printing/copying
• Vending machines
• Laundry appliances
• Televisions
• Elevators
• Swimming pool/ hot tub heaters and pumps

The actual composition will depend on space type.

The EnergyPlus mtd output file documents all of the meter connections. Assuming the OpenStudio bar chart is based on the ABUPS table output, then Interior Equipment is everything on the InteriorEquipment:Electricity, which is essentially all of the ElectricEquipment objects in the idf. Similar, for gas and other resources.