Designing a cooling mechanism for oxygenator compressor

[senior person wearing a nasal cannula, https://www.tripsavvy.com/air-travel-with-portable-oxygen-concentrators-2972594]

---

We all know that the air we breathe only contains around twenty percent oxygen. For some people with respiratory problems, they cannot get enough oxygen just by breathing the air. An oxygenator, then, can be used to delivery a much more oxygen-rich air concentration to the patient’s lungs. Unfortunately, even the cheapest of oxygenators retail for thousands of rands, an amount many in our communities simply cannot afford. This project, I feel is very relevant to the community, especially now that we have seen the devastating impacts the pandemic has had on people who are already struggle with their breathing. It is my aim and desire that through this project we will be able to contribute to the community by designing and building a practical and cost-effective oxygenator which will offer a solution to this challenge.

To achieve its purpose, an oxygenator uses a compressor (motor) to suck in air from the atmosphere and purify it by filtering out the nitrogen, leaving a much higher concentration of oxygen. Oxygenators must run continuously, something motors are not too fond of. From the simple formula E(t) = V*I*t, we can see that when run continuously the temperature of a motor will begin to increase as more energy is dissipated through the windings. The hotter the motor gets, the more the windings will deteriorate, or even worse the windings can completely burnout, leading to a complete failure of the compressor and thus the oxygenator. Normally, the best way of running a motor is to give it time to ‘cool off’ by switching it off and letting it stay idle for some time. This method is not feasible in this case since the oxygenator must run continuously otherwise the user might be starved of oxygen. We need to find a way to keep the motor running and cool at the same time.

For this project, I will design, test, and implement an effective and efficient cooling mechanism for the compressor. This system will include temperature sensors and monitoring devices to keep track of the motor temperature in real time. I am thinking a compensator can be programmed into a microcontroller (maybe a PIC or an Arduino) to create the controller which will drive the plant (the cooling mechanism) in response to the measured temperature. The system should have an appropriately fast transient response and should also allow the user to input an external reference or desired temperature.