Closed loop Heat Pump Dehydrator

A closed-loop heat pump dryer is a device that uses a refrigeration system to cool and dehumidify the hot and humid air, while recovering the condensation latent heat of the humid air to heat the air through the heat pump principle. It is a combination of dehumidification (drying materials) and heat pump (energy recovery).

By repeatedly circulating and heating the hot air in the drying room to absorb the moisture in the material, the heat pump evaporator condenses and removes water while absorbing the heat in the hot and humid air, providing heat for drying and dehydration, and repeating the cycle to ultimately achieve continuous drying of the material.

During operation, the closed-loop heat pump dryer only discharges water, without energy loss, and the heating efficiency is several times higher than that of the open-loop heat pump dryer. Its operation has nothing to do with the outside temperature and humidity, and it always maintains high energy efficiency throughout the year, suitable for any climatic conditions. It is generally more suitable for dehydrating materials with low evaporation temperature and high humidity, and for use in areas with low ambient temperature in winter. However, the operating conditions of the closed-loop heat pump dryer are completely affected by the changes in the internal working conditions of the drying room. The dry bulb temperature ranges from room temperature to 80°C; the relative humidity ranges from <10% to >90%, and the stability control of the refrigeration system is complex.

At the same time, its operation relies on dehumidification to obtain the latent heat of steam condensation to improve the heating COP. The high temperature and low humidity and low temperature and low humidity working conditions seriously restrict its operating energy efficiency. The early heating of the material and the later maintenance of the constant temperature of the drying room require the participation of electric heating assistance, which directly increases its manufacturing cost, so the market price is relatively high compared to the open-loop heat pump dryer.