What forms the circulation system in a heat pump dryer?

The heat pump dryer utilizes an air source heat pump, which consists of several components, including a compressor, heat exchanger, throttle valve, and heat absorber. The system operates by circulating a refrigerant through these components under the compressor’s action.

The refrigerant undergoes a process of pressure and temperature increase in a gaseous state within the compressor (reaching temperatures up to 100℃). It then enters the heat exchanger, releasing high-temperature heat to heat the water while cooling and transforming into a liquid state. As it reaches the heat absorber, the liquid rapidly absorbs heat, evaporates, and transforms back into a gaseous state with temperatures dropping to -20℃ to -30℃. During this stage, the air surrounding the heat absorber continuously transfers low-temperature heat to the refrigerant. The refrigerant circulates continuously, converting low-temperature heat from the air into high-temperature heat and facilitating the heating of cold water.

From the above explanation, we can understand that the air source heat pump utilizes the heat energy present in the air. As long as there is sufficient heat in the air, it can absorb this energy and produce hot water. Therefore, the use of an air source heat pump is not affected by weather conditions, such as cloudy days or rain, and can operate day and night.

Unlike traditional fossil fuel-based energy sources, which generate electricity and produce numerous combustion by-products (e.g., CO2, SO2, NOX, dust), air source heat pumps provide an environmentally-friendly alternative. They help reduce pollution, greenhouse gas emissions, and their associated negative impacts on the environment, including acid rain and land degradation. Moreover, they also have positive effects on people’s physical and mental health. Thus, the use of air source heat pumps represents an effective and energy-saving solution for air conditioning, heating, and cooling, offering a promising direction for sustainable development in China.