If you have COPD, emphysema, or some other respiratory problem, you may have to have oxygen that you can use at home. It doesn't matter if you have to have it on an as-needed basis or all the time; you are going to need to have a good source of your supplemental oxygen. There are several different kinds of tanks or other supplemental devices that your doctor may prescribe for you. Generally, while your doctor has the final say as to which device you will use, they will likely talk to you about the differences and will consider your preferences before they make their final decision.
One device that you might be prescribed by your doctor is an oxygen concentrator. This device doesn't have an oxygen tank that you use. Instead, it utilizes the oxygen in your room. It does this by sucking in room air and then separating the oxygen from the rest of the elements that are found in air. Then the oxygen is concentrated and delivered through tubing to you. This device is not a mobile device. It stays in the room where it is plugged in. It does use electricity in order to do its job, so that may be something that you have to factor in when your doctor and you discuss this.
Liquid oxygen tanks are more portable. They come in a variety of sizes so that there are tanks that you easily move from room to room in your house as well as leave your house and be able to do things like go shopping or go to work. Some of the portable tanks are tanks that you can easily fill yourself; others will come prefilled. Liquid oxygen systems work because the oxygen has been compressed down into a liquid form, which lets more oxygen go into a tank. The liquid oxygen becomes gaseous before it gets to you, allowing you to breathe it in. If you use a liquid oxygen system, you will have to have the tanks delivered on a regular basis. How often that needs to be done depends on how much oxygen your doctor prescribes for you. If you are set at a high flow rate, you are going to need more frequent deliveries. If you are on liquid oxygen, you are going to have to be careful with it, because there is a risk of fire with it. As long as you follow all safety precautions, you should have no problem.
If you have to use oxygen for a respiratory illness, there are different kinds of devices that you could use, so talk with your doctor about different medical equipment options and what will work best for your needs. .