Food dehydrators work differently than conventional dryers. For both systems, air is heated to the desired drying temperature and then circulated over the product to absorb moisture. However, instead of exhausting this hot, humid air like a conventional dryer would, a dehumidifying dehydrator draws the air over the cold coil of a refrigeration system. Moisture condenses from the air and drains away. In addition, air is drawn over the hot coil in the system to reheat it. It is then sent back onto the wet product.
This cycle is repeated until the product has reached the desired moisture content. The energy used is only that necessary to operate the refrigeration compressor, blower and circulation fans. It uses up to 60% less energy than conventional dryers.
High temperature heat pump drying unit is mainly composed of four parts: evaporator (outside machine), compressor, condenser (inside machine) and expansion valve. The refrigerant continuously evaporates (absorbs heat from the outdoor environment) → compression → condensation (heat is released in the indoor drying room) → throttling → re-evaporation thermal cycle process, thereby transferring the heat in the low-temperature external environment to the drying room, and the refrigerant circulates in the system under the action of the compressor.
Complete the process of increasing the gas pressure and increasing the temperature in the compressor (the temperature is as high as 100 °C). It enters the internal machine and releases high temperature heat to heat the air in the drying room. At the same time, it cools down and transforms into a liquid state. When it runs to the external machine After that, the liquid quickly absorbs the heat and evaporates and transforms into a gas state again, and 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 working, like ordinary air conditioners, it absorbs the energy in the low temperature environment in the evaporator. (QA) and consumes part of the energy, that is, the compressor consumes electricity (QB) and thus , the condenser heats (QC), QC = QA + QB, so the efficiency of the pump drying unit of high temperature heat is (QB + QC)/QB. The heating efficiency is greater than 1, so the high temperature heat pump drying unit is much more efficient than other heating equipment.
It can be seen that using a high temperature heat pump drying unit as the drying device can save energy and at the same time reduce the pollutant emissions produced by combustion.
TROCKNNER heat pump dryer working process
1) During the fruit drying process, the high-temperature and high-pressure gas produced by the compressor enters the condenser to release heat, and the heat is sent to the room through the circulation fan. The temperature will reach 10-80°C.
2) The air at outdoor ambient temperature is heated by the heat recovery device before entering the drying room, and then enters the drying room after heating. This design can save 60-70% energy consumption and ensure the temperature stability of the fruit drying room.
3) The hot air circulates by convection throughout the fruit drying room through a large air volume circulation fan so that the drying is more uniform and complete.
4) The fruit delivery cart is made of galvanized square material or stainless steel, which is resistant to high temperatures.
