The main types and characteristics of air energy heat pump dryer

Heat pump dryers can be divided into four types: low temperature, medium temperature, high temperature and ultra-high temperature according to different air outlet temperatures:

1. The drying temperature of the medium and low temperature drying heat pump is between 40 and 65 °C. Basically, all agricultural products and seafood are suitable for drying in this temperature range, and the speed, quality and efficiency can be done better;
2. The drying temperature of the high-temperature drying heat pump is between 65 and 85 °C. Some agricultural products, seafood and industrial products require high temperature to volatilize the bound water inside the items, so a high-temperature unit needs to be selected;
3. Ultra-high temperature drying The drying temperature of the heat pump is between 85 and 105 °C. At present, there are relatively few drying products of this type on the market, which have at least undergone two-stage compression.

According to its structure, it can be divided into 3 types

1. Drying room integrated machine (the unit has its own drying room, which is integrated with the host);
2. Embedded all-in-one machine (there is no drying room, but the unit reserves a fixed space to install the drying room, which is actually another form of the all-in-one machine with drying room. Usually, in order to reduce transportation costs, the drying room is not installed go in);
3. Split machine (split machine only has a heat pump host, and the drying room needs to be built separately).

According to the water removal method: hot air drying type, heat pump dehumidification drying type

1. Hot air drying type. The hot air dryer absorbs the heat in the air outside the drying room through the evaporator, and transfers it to the drying room through the refrigerant and the compressor to heat the air in the room. The device (humidity exhaust fan or air valve) is discharged out of the room to realize drying.
2. Heat pump dehumidification drying type. The closed dehumidification dryer heats the air in the room at the same time, and through the closed cycle, the moisture is reduced to below the dew point temperature through the evaporator,Precipitation of moisture (condensed water is discharged outside the drying room through a drain pipe), and the drying air flows through the material moisture and returns to the evaporator again to form a drying cycle. After many cycles, the material drying operation is completed.

According to the source of its heat, there are 3 kinds of

1. Open loop heat pump. The outer machine absorbs the energy of the ambient air, and the inner machine releases energy in the drying room, heats the items to be dried, converts the moisture of the items into a gaseous state, and discharges the board room.At present, most body heat pump dryers on the market are of this type, with a simple structure.It is suitable for the occasions where the ambient temperature is above 10 degrees and the drying temperature is within 55 degrees. Part of the open-loop heat pump with heat recovery blows the hot air from the dehumidified part to the evaporator of the outdoor unit,This increases the evaporator temperature. However, the open-loop heat pump is not suitable for the occasions where the ambient temperature is low and the requirements for mildew are high.
2. Closed loop heat pump. The evaporator and condenser of the heat pump are placed in the drying room, and the energy comes from the power consumption in the board room, and is 100% recycled in the board room.Through the evaporator, the water in the board room is condensed into water and discharged from the board room, thereby reducing the relative humidity, raising (or lowering) the temperature of the items, and achieving the purpose of fast drying.
3. Closed-loop heat pump with external evaporator (dual energy, air energy drying and dehumidification integrated or drying and dehumidification) - in order to solve the problem of slow heating of closed-loop heat pumps,In addition to electric heating, an external evaporator can also be installed to send the energy in the ambient air into the board room like an open-loop heat pump to achieve the purpose of rapid heating.

The most advanced technology of this type of heat pump dryer is basically suitable for all drying occasions and locations, but the structure is very complicated and the cost is high. This type of heat pump enables rapid temperature and humidity regulation. Therefore, it is especially suitable for drying such as tobacco and meat products.

Based on the above characteristics, there are currently two popular heat pumps on the market: split-type hot air drying type and integrated closed-loop dehumidification type.

Diye Energy has a domestic professional heat pump research and development team, engaged in heat pump structure and function research and development, intelligent control system development, drying process improvement, etc. For many years, it has been committed to providing more efficient, intelligent and environmentally friendly drying solutions for domestic and foreign markets.