Product characteristics of heat pump dryers

Characteristic

1. It can achieve low-temperature air enclosed circulation drying, and the material drying quality is good. By controlling the operating conditions of the device, the temperature of the hot dry air in the drying room can be kept between 20-80 ℃, which can meet the high-quality drying requirements of most thermosensitive materials; The closed cycle of drying media can avoid impurities and pollution that may be caused by the exchange of external gases, which is particularly important for food, medicine, or biological products. In addition, when materials are sensitive to oxygen in the air (prone to oxidation or combustion explosion), inert media can be used instead of air as the drying medium to achieve anaerobic drying.

2. Efficient and energy-saving. The heat for heating air in a heat pump dryer mainly comes from the sensible and latent heat contained in the warm and humid air discharged from the recovery drying room. The energy required for input is only the power consumption of the heat pump compressor, and the heat pump has the advantage of consuming a small amount of work to produce a large amount of heat. Therefore, the SMER (water content removed by consuming unit energy) of the heat pump drying device is usually 1.0-4.0 kg/kWh, while the SMER value of traditional convection dryers is about 0.2-0.6 kg/kWh.

3. Convenient temperature and humidity control. When the material has high requirements for the temperature and humidity of the air entering the drying room (such as wood), the material's requirements for texture, appearance, and other aspects can be met by adjusting the evaporation temperature and condensation temperature of the working fluid in the evaporator and condenser.

4. Useful volatile components in recyclable materials. Some materials contain volatile components (such as fragrance and other volatile components). When using a heat pump for drying, the volatile components and water are vaporized and enter the air in the drying room. When the air containing volatile components is cooled by the evaporator, the volatile components are also liquefied and discharged together with the condensate. Collect the condensate containing volatile components and separate them using appropriate methods.

5. Environmentally friendly. The drying medium in the heat pump drying device is enclosed in a closed loop, and there is no pollution caused by material dust, volatile substances, and odors emitted into the environment with the drying exhaust gas; The waste heat in the exhaust of the drying room is directly recovered by the heat pump to heat the cold and dry air, without causing thermal pollution to the environment by the unit.

6. It can achieve multiple functions. The heat pump in the heat pump drying device also has refrigeration function, which can be used to achieve low-temperature processing (such as quick freezing, refrigeration) or preservation of various materials in seasons with less drying tasks. It can also expand the heating function of the heat pump to provide heat for planting (such as greenhouses) or breeding places in cold seasons.

7. The heat pump dryer is suitable for a wide range of materials. The suitable materials for drying are mainly a large category of materials that can withstand temperatures between 20 and 80 ℃ during the drying process, or materials that can withstand higher temperatures but are more energy-efficient or safe to dry using heat pumps. Materials that have been extensively studied and applied include wood (such as oak), grains, seeds, edible mushrooms (such as mushrooms and fungus), medicinal herbs (such as ginseng), seafood (such as fresh oysters and scallops), bioactive products (such as cells and enzymes), tea, paper, etc.

8. Compared with other low-temperature drying devices (such as microwave drying, vacuum drying, and freeze-drying) where the air temperature in the drying room is less than 40 ℃, the heat pump dryer device has obvious economic benefits due to its small initial investment and low operating costs. The equipment cost of the heat pump drying device mainly includes the heat pump part and the drying chamber part, among which the drying chamber part has the same requirements as the ordinary convection drying chamber, without special air tightness and pressure resistance requirements.

9. Compared with ordinary drying devices (air temperature entering the drying room>40 ℃), the initial investment of heat pump dryers is generally higher than that of air electric heating devices, gas or coal-fired hot air stoves. Therefore, the initial investment of drying devices is generally higher than that of ordinary drying devices. Heat pump dryers have high energy efficiency, low operating costs, and still have certain advantages in comprehensive economy.