6533b7d0fe1ef96bd125abef

RESEARCH PRODUCT

Performance maps for an air-cooled air conditioning system as a preliminary instrument for the diagnosis of evaporator fouling

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Abstract During the past few decades, there has been increased interest in the development of automated approaches for detecting and diagnosing faults in air conditioning systems. Among them, thermoeconomic diagnosis is a technique which involves the use of exergy analysis. As a first step towards improving its performance, this work is focused on the thermodynamic and exergy analysis of a direct expansion air conditioning system used in small commercial building applications. The analysis was carried out by means of experimental activities on a 17.5 kW rooftop unit installed at the Herrick Laboratories, Purdue University, Indiana (USA). The system under investigation was equipped with a variable-speed compressor and variable-speed fans, thus allowing the unit to meet different loads. A detailed mapping of the performance of this system was carried out by considering the effect of the outdoor temperature and the cooling load. In addition, the effect of evaporator fouling was investigated. Results showed that poor exergy performance were achieved due to the exergy destruction occurring in the evaporator. Also, when testing evaporator fouling, results showed that this fault contributed to increase the consumption of the mechanical exergy of the air, thus allowing for an easy detection of this fault.