Outward discharging wet type two-effect drying heat pump unit

Abstract

The invention discloses an outward discharging wet type two-effect drying heat pump unit which comprises an air flow circulation channel provided with an air inlet and an air outlet and further comprises at least two heat pump units. Each heat pump unit comprises a compressor, a condenser, a throttling device and an evaporator which are connected in sequence, wherein the evaporator is located in environment air outside the air flow circulation channel, and the condenser is located in the air flow circulation channel. The air flow circulation channel is provided with a wet discharging opening and a fresh air opening, and the evaporator of at least one heat pump unit is arranged at the wet discharging opening. The wet discharging opening and an air suction opening are provided with hole plate structures with adjustable hole opening degrees. Part of warm and wet air flows out from the wet discharging opening and then flows through the evaporators at the wet discharging opening, the otherpart of warm and wet air is mixed with fresh air supplied from the fresh air opening, the mixed air then flows through all the condensers to be heated into high-temperature dry air, and the high-temperature dry air is sent by into a drying chamber to be subjected to the new round of drying work.

Description

technical field [0001] The invention relates to the technical field of heat pump system design, in particular to an external moisture-discharging two-effect drying heat pump unit. Background technique [0002] The drying process of moisture-containing materials (such as fresh tobacco leaves) is due to its "isoenthalpic" characteristics, that is, only part of the sensible heat of the dry air is converted into the latent heat of moisture vaporization of the moisture-containing materials during the drying process, and the composition of sensible heat + latent heat The total heat (enthalpy value) has not decreased, and the enthalpy value of the air outlet of the drying device is equal to the enthalpy value of the inlet air under the condition of ignoring the heat leakage of the drying device. Therefore, the recovery of waste heat in the drying process has very important technical and commercial significance. significance. [0003] At present, most of the heat pump units that re...

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Problems solved by technology

[0004] The first problem is that the dehumidification of the drying device is unstable

[0005] In order to save energy, the drying device will open the air door after the wet bulb temperature rises to the upper limit of the target value after a period of time in the closed circuit of the drying air flow, and then fill in the fresh air to discharge the moisture; once the wet bulb temperature in the drying device drops to the lower limit of the target value, it will be closed immediately The damper stops the external dehumidification until the wet bulb temperature reaches the upper limit of the target value again and starts the next round of dehumidification; this kind of periodic and intermittent dehumidification through the opening and closing of the damper will cause "thermal shock" to the heat recovery device, resulting in The heat recovery unit also does not work stably

[0006] The second problem is that the waste heat recovery efficiency is too low

[0007] The warm and humid airflow discharged from the drying device when dehumidifying is intermittent, large and small, and it is difficult to match the air volume required by the evaporator; Stable operation problem, the usual practice is to mix the warm and humid air with the evaporator inlet air first, and then enter the evaporator; and the warm and humid air is mixed with the evaporator inlet air, resulting in a decrease in the temperature of the warm and humid air, a decrease in the concentration of water vapor, and a decrease in enthalpy Value decreases, waste heat recovery efficiency decreases

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