Evaluating the performance of fault detection and diagnostics protocols applied to air-cooled unitary air-conditioning equipment

Fault detection and diagnostics tools are increasingly being applied to air-cooled unitary air-conditioning systems. However, it is not known how well these tools work because there is no standard method of measuring or evaluating the performance of fault detection and diagnostics. This article describes the common faults to which fault detection and diagnostics is applied in unitary systems and proposes a method of evaluating the performance of fault detection and diagnostics protocols. The method involves feeding measurement data through a candidate protocol and collecting and organizing the responses based upon the fault's impacts on performance. A library of faulted and unfaulted measurement data has been built and is described. Standard definitions are proposed for several pertinent terms and quantities. A case study is used to demonstrate the evaluation method, using a publicly available fault detection and diagnostics protocol that is evaluated using the complete library of data. This protocol is found to perform poorly.