Principle of heat pump dryer

A heat pump is essentially a heat boosting device. The high-temperature heat pump drying unit uses the inverse Carnot principle to absorb heat from the surrounding environment and transfer it to the heated object (object with higher temperature). Its working principle is the same as that of a refrigerator, both of which operate according to the inverse Carnot cycle, except that the working temperature range is different.

Working principle of high-temperature heat pump drying unit

The high-temperature heat pump drying unit mainly consists of four parts: a finned evaporator (external unit), a compressor, a finned condenser (internal unit), and an expansion valve. By continuously evaporating the working fluid (absorbing heat from the outdoor environment), compressing, condensing (releasing heat in the indoor drying room), throttling, and re evaporating, the heat from the external low-temperature environment is transferred to the drying room, and the refrigerant circulates in the system under the action of the compressor. It completes the gas-phase pressure rise and temperature rise process in the compressor (with a temperature of up to 100 ℃). It enters the internal unit to release high-temperature heat and heat the air in the drying room. At the same time, it is cooled and converted into a liquid state. When it runs to the external unit, the liquid state quickly absorbs heat and evaporates again, transforming into a gas-phase. At the same time, the temperature can drop to -20 ℃~-30 ℃. At this time, the air around the heat absorber will continuously transfer heat to the refrigerant.

When the high-temperature heat pump drying unit is working, like ordinary air conditioning and heat pump units, it absorbs energy from the low-temperature environmental medium in the evaporator QA: it consumes a part of the energy itself, that is, the compressor consumes electricity QB: it releases heat QC through the working fluid circulation system in the condenser, QC=QA+QB. Therefore, the efficiency of the high-temperature heat pump drying unit is (QA+QB)/QB, while the heating efficiency of other heating equipment is less than 1. Therefore, the heating efficiency of the high-temperature heat pump drying unit is much higher than that of other heating equipment. It can be seen that using the high-temperature heat pump drying unit as a drying device can save energy and reduce the emissions of pollutants such as CO2, achieving energy-saving and emission reduction effects.