Methodology for optimising the heat pump cycle based on a real-life case study

Abstract

This paper presents a new approach to optimising thermal equipment and systems. It is based on a very complex object model in which the heat transfer coefficients and phase transitions of the humid air are calculated, from which only the operation of the heat exchangers is derived, and then the machines and equipment that make up the system. This approach relates, among other things, the operation of the fan inverter to the heat input and thus the amount of liquid condensed on the exchanger, which is linked to the cooling capacity of the heat pump and the refrigerant condensation and evaporation temperatures, and thus also to the compressor output. Under the conditions of a real thermal system with many interconnected components, only such an accurate model allows simulation-based optimisation of the entire system with all interconnections. All real-world units are characterised by their operating efficiency, which is also introduced into the model. The simulation model allows for not only the optimisation of operating parameters but also the selection of system components. The entire process is illustrated using the example of a heat pump supplying a drying cabinet, in order to demonstrate the correctness of the methodology on a real facility in the form of a “case study”. Optimisation was aimed at obtaining the best energy ratings for the unit and minimising drying time. Due to the multitude of parameters to be optimised and the interdependencies between them, the Taguchi method was used for the optimisation analysis. The real efficiencies for the heat pump have been introduced, focussing on the effectiveness of the heat exchanger fins and the compressor. The tests carried out after the optimisation showed a significant improvement in the coefficient of SMER (Specific Moisture Extraction Rate), which increased by almost 44 % at its peak. The factors influencing SMER underwent significant improvements, with drying time decreasing by 45 % and total energy consumption by more than 21 %. The problem addressed in this work is a methodology for optimising the anticlockwise cycle of an industrial unit, taking into account the actual efficiencies of the components. The innovative methodology includes parametric and nonparametric model elements.