The use of heat pump dryers in agriculture

The 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. It continuously completes the thermal cycle of evaporation (absorbing heat from the outdoor environment), compression, condensation (releasing heat in the indoor drying room), throttling, and re evaporation by allowing air to continuously evaporate, thereby transferring heat from the external low-temperature environment to the drying room. The refrigerant circulates and flows within the system under the action of the compressor. It completes the process of gas pressure rise and temperature rise in the compressor (with a temperature of up to 100 ℃). It enters the internal unit to release high-temperature heat to heat the air in the drying room, while being 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 state. 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 in operation, 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 power consumption of the compressor QB: When releasing heat through the working fluid circulation system in the condenser, QC=QA+QB. Therefore, the efficiency of the high-temperature heat pump drying unit is (QB+QC)/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.

The application of heat pump drying is quite complex and lacks significant regularity, unlike central hot water in hotels, which requires different drying items, such as seaweed and seaweed, to be dried using a heat pump. Its drying characteristics are also different. Another type of material, such as tobacco, requires different drying characteristics, so the development path of heat pump drying is still long.

Heat pump dryer is a very practical product with many benefits. It can be well used in many industries, and the reasonable use of air drying machines can help quickly dry products that require drying. It is more widely used in agricultural life.

Taking agricultural drying as an example, in the past, traditional drying methods mainly used natural sun drying, oil-fired coal-fired boilers, electric drying, etc. However, in recent years, with China's attention to environmental protection issues, the use of high energy consumption and high pollution drying equipment such as fuel and coal has been strictly restricted or even prohibited. Traditional drying methods can no longer meet market demand, and green, environmentally friendly, energy-saving, and safe new air drying methods have become the new main force in drying.

The heat pump air dryer adopts the reverse Carnot cycle principle, using a small amount of electrical energy. The compressor absorbs a large amount of heat energy from the air, evaporates the working fluid into a gaseous state in the evaporator after passing through the expansion valve, and then compresses the gaseous working fluid into a high-temperature and high-pressure gas through the compressor. It then enters the condenser to release heat and heat the drying medium, continuously circulating and heating. Compared to electric drying machines, it saves two-thirds of electricity. Whether it's fruit drying, vegetable drying, chrysanthemum drying, grain drying, and so on. Some agricultural products are dried. Air drying machines are a very high-quality choice. It is also possible to carry out work in large quantities.