"Intelligent Temperature Control" of Blood Bags: How Do phase change Materials Maintain a Constant Temperature of 2-6℃ during transportation

Blood bags need to maintain a constant temperature of 26 ℃ during transportation. Phase change materials achieve this goal through their unique phase change properties. The specific methods are as follows:

1 Characteristics of phase change materials: During the phase change process of substances (usually referring to the first-order phase change), phase change materials can absorb or release a large amount of energy (i.e., the enthalpy of phase change), and theoretically, the temperature remains unchanged during the first-order phase change process. This characteristic gives it an advantage in temperature regulation, enabling it to absorb or release a large amount of energy during phase transition while maintaining a relatively stable temperature.

2. The application method of phase change materials in blood bag transportation: Encapsulation usage: First, the blood bag is wrapped in a tight bag containing molecular alloy phase change energy storage materials, and then the tight bag is placed in a sturdy plastic handbag. When the insulation equipment encapsulated with molecular alloy phase change energy storage materials is being insulated, first place the tight bag encapsulated with the molecular alloy phase change energy storage materials in the refrigerator to completely transform the molecular alloy phase change energy storage materials from liquid to solid. Then, put the blood bag into the tight bag encapsulated with the molecular alloy phase change energy storage materials for future use. Principle of temperature regulation: At room temperature, the phase change energy storage material in the tight bag absorbs heat from the external environment and undergoes a phase change, thus keeping the temperature of the blood bag within the range of 4℃±2℃. That is, during the phase change process of the molecular alloy phase change energy storage material, it ensures that the blood bag itself remains in an approximately isothermal state all the time. Until the molecular alloy phase change energy storage material in the insulated handbag is completely transformed into a liquid state, the insulation effect is achieved.

3. Experimental verification effect: High-temperature experiment: The phase change material was maintained at 20℃ for 12 hours, the stored blood (in a blood bag) was placed at 4℃, and the ambient temperature was 30℃. Twenty-four hours after the blood was placed in, its temperature was 4℃. After being placed in for 48 hours, the temperature was 6℃. After being placed in for 72 hours, the temperature was 9℃. This experiment indicates that the blood delivery box with temperature regulation by shaped phase change materials can maintain the blood temperature within the range of 4℃ to 10℃ for 72 hours in a relatively hot environment, and the preserved blood is suitable for use. Low-temperature experiment: The phase change material is maintained at a temperature of 20℃ for 12 hours. The stored blood (in a blood bag) placed in is 8℃, and the ambient temperature is 20℃. Twenty-four hours after the blood was placed in, its temperature was 4℃. After being placed in for 48 hours, the temperature was 3℃. After being placed in for 72 hours, the temperature is 1℃. This experiment indicates that the blood delivery box with temperature regulation by shaped phase change materials can maintain the blood temperature within the range of 4℃ to 1℃ for 72 hours in a relatively cold environment, and the preserved blood is suitable for use.