Modeling and simulation for intelligent control of expansion valve in vapour compression refrigeration system

Conventional control techniques are not able to accomplish the stable cooling in VCRS (vapour compression refrigeration system) of air conditioning system. This article describes the fuzzy modeling and simulation for intelligent control to regulate the opening area of expansion valve for better and stable refrigerant flow even in the presence of operating condition change. Fuzzy logic control of expansion valve can make a quick response to the abrupt changes of operating parameters in VCRS. The expansion valve opening trend depending upon differential pressure across it (delP) and refrigerant mass flow rate is analyzed with fuzzy modeling using ANFIS. Differential pressures in the range of 3-7 bar are sustained across the valve. Flow rates up to 0.15 kg/sec for the refrigerant R-134a have been demonstrated. The performance of the model is evaluated by comparing the predicted results with the standard mathematical model.