Heat pump drying is a system project, including the selection of the host, the construction of the drying room, the design of the air duct, the placement of materials, the processing of the process, etc., each link will have an important impact on the drying effect and operating costs of the whole system. And drying of a variety of materials, according to the properties of different materials and drying requirements to scientific design drying system program, to determine a reasonable drying process processing.

Industrial and agricultural drying has the attributes of energy saving, environmental protection, agricultural machinery, HVAC and other industries, highly in line with the national industrial policy and development planning, more and more by the government and agricultural machinery, HVAC, agricultural processing, food, environmental protection and other industries focus on the market development potential is huge. In more than a decade of rapid expansion, the industry is becoming more and more perfect. Industrial and agricultural drying applications through the transformation of product structure, industrial clustering, professional restructuring and other initiatives, the industry continues to expand in size. At present, about 10% of China's heat pump drying equipment sales overseas, exported to Indonesia, Thailand, Vietnam and Bulgaria, Africa and other countries, mainly used in fruit and vegetable heat pump drying, flower heat pump drying.

1, low temperature heat pump - drying temperature between 10-45 degrees heat pump, that is, the drying temperature may be lower than the ambient temperature of the heat pump, in addition to being able to heat drying may also have to cool down cooling drying. Low temperature heat is more suitable for open-loop machines, closed-loop can also be achieved, but regardless of open-loop closed-loop, the drying time is longer and less efficient. Therefore, if there are no special requirements, in general, try not to use low-temperature heat pumps.

2, medium temperature heat pump - drying temperature between 45-65 degrees heat pump, that is, the drying temperature is higher than the ambient temperature. 45-65 degrees this temperature range for agricultural products, seafood and other food is the golden temperature, basically all agricultural products seafood are suitable for drying in this temperature range, and the speed, quality, efficiency can The speed, quality and efficiency can be optimized. Therefore, as long as the drying of food products, should try to consider or try to use the medium temperature machine.

3、High temperature heat pump - heat pump with drying temperature between 65-85 degrees. High temperature has a great impact on the evaporation of water, and some agricultural products, seafood and industrial products must have a certain high temperature in order to evaporate the combined water inside, therefore, there is a great demand in the market.

4, ultra-high temperature heat pump - drying temperature between 85-105 degrees heat pump, complex structure, expensive accessories, high efficiency. As ultra-high temperature heat pumps need to use refrigerants with high boiling points (above 40 degrees) such as R14 or R140, only closed-loop heat pumps can be used. With a drying temperature close to 100 degrees, flash drying is basically achieved and the drying speed is very fast, but there are still very few drying products of this type on the market.

1、Open-loop heat pump - the external machine absorbs energy from the ambient air and the internal machine releases energy in the drying room, heating the items to be dried, turning the moisture of the items into a gaseous state and discharging them from the board room. Most of the heat pump dryers on the market at present are of this type, with a simple structure, suitable for working at ambient temperature above 10 degrees and drying temperature within 55 degrees. When the ambient temperature is lower than 10 degrees or the drying temperature is greater than 55 degrees, the pressure difference between the compressor inlet and exhaust becomes larger, which is not conducive to the energy efficiency ratio and life of the compressor. Therefore, ordinary open-loop heat pump dryers are best used in low-temperature drying and for drying in summer and autumn. Open-loop heat pump dryers heat up faster, but humidity control is very difficult and should be applied very carefully in the drying of items prone to mould and mildew.

2, open-loop heat pump with heat return heat - in order to solve the open-loop heat pump in the ambient temperature is low when the energy efficiency ratio and life problems, you can blow the hot air of the moisture discharge part to the evaporator of the external machine, so as to improve the evaporator temperature, can be more effective in solving the drawbacks of the open-loop heat pump, but in the ambient temperature is very low, or can not fundamentally solve the problem. In addition, the drying humidity problem is not improved in any way. Therefore, any open-loop heat pump is not suitable for working in low ambient temperatures, and for occasions with high mould requirements. Although open-loop heat pumps have some inherent defects, but due to the simple structure and low cost, satisfactory results can be obtained in most seasons in the south, and in the north in the summer and autumn.

3、Closed-loop heat pump - the evaporator and condenser of the heat pump are placed in the drying room, the energy comes from the power consumption in the board room and is 100% recycled and circulated in the board room, through the evaporator the water in the board room is cooled and condensed into water and discharged from the board room, thus reducing the relative humidity and raising (or lowering) the temperature of the items to achieve the purpose of fast drying.

As the closed-loop drying energy all comes from its own power consumption and the energy cycle inside the panel room, theoretically its efficiency has absolutely nothing to do with the ambient temperature and ambient humidity, and its efficiency is relatively high, especially in winter and northern areas, where the closed-loop heat pump has absolute advantages. Due to its closed nature, an external condenser or water-cooled heaters are sometimes required in order to balance the energy input with that of the compressor. When the drying temperature in the slab rises, its evaporating temperature also rises in parallel, so that the compressor has a small differential pressure between the inlet and exhaust air and works easily, with a long life and high efficiency. Closed-loop heat pumps are slower to heat up if they only rely on the power consumption of the compressor and fan to convert heat energy, so there is generally rapid heating of the electric auxiliary heat to cope with the emergency heating required on special occasions, but as the emergency heating consumes only a tiny proportion of the whole drying process, it does not reduce efficiency, but can greatly speed up the drying cycle and extend the life of the compressor. Closed-loop heat pumps have higher technical requirements, more complex structures than open-loop heat pumps, and higher equipment costs than open-loop heat pumps. Closed-loop heat pumps are generally designed to be integrated, very simple to install and can be expanded in parallel at will.

4, closed-loop with external evaporator (dual energy, air drying and dehumidification in one type or drying and dehumidification) heat pump - in order to solve the problem of slow heating of closed-loop heat pumps, in addition to adding electric heating, can also be external evaporator, the same as the open-loop heat pump will be sent to the energy in the ambient air into the board room, to achieve the purpose of rapid heating. This type of heat pump dryer is the most advanced technology and is suitable for essentially all drying situations and locations, but is very complex and costly to construct. This type of heat pump allows for rapid temperature and humidity regulation. Therefore, they are particularly suitable for drying e.g. tobacco and meat products.

1、All-in-one machine with drying room (the unit comes with a drying room, which is integrated with the main machine).

2, embedded all-in-one machine (no drying room, but the unit set aside a fixed space to install the drying room, in fact, it is also another form of performance with drying room all-in-one machine. (usually to reduce transport costs, did not install the drying room into).

3, split machine (split machine only heat pump host, drying room need to be built separately).

Air source heat pump drying, as a potential market for cross-development in the fields of energy saving, agricultural machinery and HVAC, has been in a period of rapid development overall in recent years and is receiving wide attention from the government as well as various industries within the three major fields of agriculture, industry and services.

From the current market pattern, the heat pump dryer industry brand concentration is low, the industry entry threshold is small, no brand pattern has been formed, and it is in the midst of rapid development. But on the other hand, because the heat pump drying materials are very different, the requirements for drying technology are different, so this also puts forward different requirements for the enterprise's own industry experience, program accumulation, technology accumulation and the ability to provide tailor-made programs according to the actual needs of different customers. Of course, the opportunity only favours those people and enterprises that are well prepared for various kinds of work and are good at capturing market demand and customer needs.