Low-temperature evaporators achieve energy-efficient evaporation through heat pump technology, centred on establishing a ‘heat recycling’ system that eliminates traditional reliance on external steam, significantly reducing energy loss. The underlying principle comprises three key stages.

Firstly, efficient heat extraction and transfer. The heat pump system comprises four core components: evaporator, compressor, condenser, and throttle valve. During operation, the heat pump first extracts heat from the ‘secondary vapour’ (water vapour produced by material evaporation) within the low-temperature evaporator. This secondary vapour condenses into water as it releases heat, while the refrigerant within the heat pump absorbs this heat and evaporates into a gaseous state. The gaseous refrigerant is then compressed by the compressor, significantly increasing its temperature and pressure to form a high-temperature, high-pressure gas. This gas subsequently enters the condenser, where it transfers its heat to the material awaiting evaporation within the low-temperature evaporator, providing the energy required for evaporation. The refrigerant itself condenses back into a liquid state. After pressure reduction via the throttle valve, it returns to its initial state, completing the thermal cycle.

Secondly, it maximises energy utilisation efficiency. Traditional single-effect evaporation requires continuous input of fresh steam heat, whilst the secondary vapour generated during material evaporation is directly vented, resulting in a heat utilisation rate of merely 30%-40%. In contrast, heat pump technology enables the ‘recovery and reuse’ of heat within the secondary vapour. It achieves cyclical heat transfer by consuming only the electrical energy required to operate the compressor (used to elevate the refrigerant's energy level). Data indicates that low-temperature evaporators employing heat pump technology recover 3-5 kWh of heat for material evaporation per 1 kWh of electricity consumed. This represents a 40%-60% improvement in energy utilisation efficiency over conventional evaporation, substantially reducing external energy consumption.

Finally, there is synergistic adaptation to low-temperature environments. Heat pump technology precisely controls the refrigerant's energy transfer process, ensuring stable material evaporation within the 30-60°C low-temperature range. This avoids damaging heat-sensitive components while eliminating the need for complex multi-stage heat exchange to enhance efficiency, as required in multi-effect evaporation. The equipment features a simpler structure and generates no excess heat emissions during operation, further reducing energy waste and achieving the dual advantages of ‘energy efficiency + low-temperature operation’.