Automated Refrigerant Charge Station for Portable Medical Refrigerators

Project Goal: Improve the precision refrigerant charging station used for a portable medical refrigerator through the design and manufacture of an automated recharging station.

Refrigerant maintains the desired temperature of vaccines, food and living spaces. The less refrigerant a system requires, the more precision in refrigerant charging it requires. Providing an accurate quantity of refrigerant to any cooling system is critical. Most known methods of refrigerant delivery are done manually, introducing the potential for human error in the refrigerant delivery process. Improved methods of supplying refrigerant will ensure proper operation and efficiency.

The team designed a refrigerant recharging process system using electronically controlled pumps, valves and sensors. The system minimizes human involvement and maintains an accuracy of 40g ±0.10g of refrigerant during delivery. The monitoring system consists of load-cell-based weighing stations that continuously collect data on the mass of the refrigerant tanks and medical refrigerator. The system alerts operators of events, such as the need to switch out empty refrigerant tanks or full recovery tanks of excess refrigerant that are ready to be recycled.

This design improves refrigerant delivery accuracy by automating the refrigerant recharge process and monitoring refrigerant mass.