The core technology for achieving precise temperature control and uniformity in desktop low-temperature storage boxes is mainly reflected in three aspects: multi-sensor collaborative control, optimization of air circulation systems, and independent regulation of refrigeration and heating.
Multi sensor collaborative control is the core of precise temperature control. The equipment usually uses PT100 platinum resistance or NTC thermistor as the main sensor, combined with multiple secondary sensors to form a temperature monitoring network. For example, in the low-temperature storage box control method applied by Gree, when the main sensor detects the shutdown temperature, it will further analyze the data of the secondary sensor and confirm whether there is a local temperature difference through a threshold judgment mechanism. This multi-sensor linkage can effectively avoid temperature fluctuations caused by the failure of a single sensor, ensuring that the temperature difference in each area of the box is controlled within ± 0.5 ℃, meeting the strict requirements for long-term storage of biological samples.
The optimization of wind circulation system is the key to temperature uniformity. The equipment adopts a multi wing air supply fan and air circulation design, forming a forced convection circulation through the reasonable layout of the air outlet and return channels. For example, the Zhongke Duling low-temperature storage box optimizes the evaporation and condensation system and air duct structure to achieve a temperature uniformity of ± 3 ℃ (± 5 ℃ in the full temperature range). Each layer is equipped with ≥ 5 testing points (corners and center), and the entire machine has ≥ 20 testing points to ensure coverage. Some models are also equipped with deflectors, which further reduce the impact of sample placement on the temperature field through airflow guidance design.
The independent regulation of refrigeration and heating systems enhances their dynamic response capability. The equipment adopts dual system intelligent refrigeration technology, such as the single-stage self stacking refrigeration system of Zhongke Duling -86 ℃ ultra-low temperature storage box, which can achieve rapid freezing (up to -86 ℃ in 2 hours); Simultaneously integrating resistance wires or heating plates as heating actuators, dynamically adjusting output power through PID algorithm. This independent control mode ensures that the heating and cooling systems do not interfere with each other, improving efficiency and reducing failure rates, ensuring that the temperature inside the box fluctuates stably near the set value.