The efficiency of heat pump tumble dryers is closely linked to the interdependence between the moist drying air and the heat pump circuit. In this study, we described the theoretical background of the operation of a heat pump tumble dryer in connection with the operation of the vapor-compression cycle. We designed a measurement station and conducted functional tests with three different laundry loads. A software application with a graphical interface was developed in the Python programming language, allowing for a detailed insight into the operation of the tumble dryer, with a focus on the connection between the thermodynamic cycle of the heat pump in the log(p)-h diagram and the properties of the moist air at the heat pump inlet. The analysis showed that the specific enthalpy of the drying air at the inlet of the heat pump significantly affects the system's operation; higher specific enthalpy allows for greater energy transfer to the heat pump. Additionally, the thermodynamic properties of the refrigerant are crucial for optimizing the efficiency of the heat pump. It was found that the highest coefficient of performance (COP) values are achieved when the heat pump operates at low pressures. These findings are essential for further optimization of tumble dryer operation and can contribute to improving the overall
energy efficiency of the system.
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