Thermoeconomic diagnosis of air conditioning systems: experimental assessment of performance for improved reliability

Thermoeconomic diagnosis is an exergy-based fault detection and diagnosis technique which has been recently extended to air conditioning systems. So far, developments of this technique have relied only on simulation data without being evaluated using real data. For the first time, this work aims at assessing the performance of thermoeconomic diagnosis using experimental data obtained from a five-ton packaged rooftop air conditioning unit (RTU) installed at Herrick Laboratories, Purdue University. The RTU was tested in psychrometric chambers under a wide range of operating conditions and fault levels. The following faults were investigated: (i) evaporator fouling, (ii) condenser fouling and (iii) evaporator fouling along with condenser fouling. The experimental results were used as inputs in the latest thermoeconomic model proposed by some of the authors, in order to verify the results previously obtained. Results showed the capabilities of the technique in detecting faults. As concerns its quantitative performance, it is satisfactory for condenser fouling, but it becomes poor when evaporator fouling and multiple faults are considered.