The Coefficient of performance (COP) is the ratio of heat removed to energy input.
The energy input may be obtained by multiplying
Pset_DistributionPortPHistoryGas.FlowRate on the 'Fuel' port of the IfcChiller by Pset_MaterialFuel.LowerHeatingValue.
The IfcDistributionPort for fuel has an associated IfcMaterial with fuel properties and is assigned to an IfcPerformanceHistory object nested within this IfcPerformanceHistory object.