Common energy-saving methods for freeze dryer

Freeze dryers are more widely used nowadays, and can be divided into laboratory freeze dryer, pilot freeze dryer, and industrial freeze dryer according to their uses. Three common energy-saving methods for freeze dryer are as follows.

1. Control the pre-freezing speed and tray load

The pre-freezing speed affects the composition of ice crystals. The faster freezing rate is the smaller the crystals are, which is not conducive to traveling and leads to long  dehydration time, but it dissolves quickly after drying. The slower freezing rate has larger ice crystals, which is beneficial to monotonic dehydration, but dissolves slowly after drying. In addition, on the unit area of material tray, the thinner the thickness of the material accumulation, the faster the heat transfer and mass transfer speed, and the shorter the monotonic time.

2. Control the freezing point vacuum monotonic method

The vacuum monotonic method of controlling freezing point uses the respective advantages of freeze drying and vacuum monotonicity, and strictly controls the temperature of food close to the freezing point, but cannot freeze, which not only saves refrigeration energy consumption, but also avoids the problem of thermal denaturation of food and damage to biological cells during the phase transition process.

3. Change the structure of material tray

The material tray can be improved from the thermal conductivity of material and the contact heat transfer surface between the tray and the material. Selecting materials with good thermal conductivity can effectively strengthen the freezing monotonous process.