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For all surfaces, you can set the exterior temperature that the surface sees by setting the surface's Outside Boundary Condition to "OtherSideCoefficients" and then defining a SurfaceProperty:OtherSideCoefficients object with the desired temperature. Set the air temperature as your Zone Thermostat Setpoint.
Finally, you can use an ZoneHVAC:IdealLoadsAirSystem to calculate the amount of heating/cooling energy that needs to be delivered or use a real HVAC system to calculate its energy consumption.