What would be the specific applications of a room temperature superconductor?

Ok, I see a lot of false info in here. EE chiming in here.

Minor efficiency improvements: consumer electronics, batteries, solar panels, CPUs/GPUs

Major efficiency improvements: power transmission, wireless power transmission, electric motors, high density electro-magnets (used in fusion, MRI, etc), 'traditional' energy generation techniques that spin a thing to produce electricity (wind, nuclear, hydro, gas, (even coal, but let's pretend coal doesn't exist)).

Outside of my expertise, but I'm speculating major improvements: wired and wireless data transmission (antenna tech)

The implications that excite me the most are mostly around transportation.

-Realistically, of existing technologies I think electric motors are the biggest winner with superconductors. For the most part, the size and power of electric motors are constrained by how to get the electrical waste heat out. With superconductors you don't have electrical waste heat. You can create incredibly small, powerful, efficient electric motors with super conductors. This means efficiency gains in so many of our big 'energy sinks' right now. Transportation, air conditioning, manufacturing... I mean it would be a largely unnoticed improvement to almost every aspect of our modern lives.

-Cars with close to 100% regenerative braking (superconductors+capacitors for temporary energy storage) You could stop at a red light and accelerate back to the same speed 'for net-zero energy'. THAT IS BANANAS! A current conventional gas car burns fuel for ~30% efficiency, the other 70% is waste heat. Then after you've done all that inefficient work to get moving you hit the brakes and USE FRICTION TO TURN YOUR MOMENTUM INTO MORE WASTE HEAT! Bugs the bajesus out of me! Superconductors would make it much more practical to recoup energy when stopping a vehicle.

Then you can get into cool new technologies:

-Mag-Lev trains would be super cool. I don't see a huge practical benefit since the mechanics of train wheels on rails are pretty efficient as is, but come on... levitating trains? so cool!

-Rail gun style space launch systems (unfortunately, this comes with rail gun style weapons too, sorry everybody!)

-Tokamak nuclear fusion reactors are currently constrained by the strength of the magnetic fields they can produce using electromagnets. The limiting factor is largely cooling for these electromagnets and the associated superconductors. Room temp superconductors allows for much more compact designs for the magnetic confinement infrastructure used in these facilities.

-You could make a friggin mag-lev skate park. Hoverboards! REAL FRIGGIN HOVERBOARDS could be produced!

-(I think) We can actually start talking about 'active support' structures. Buildings that would not be possible because of the compressive or tensile strength of known materials can be supplemented by active support through electromagnets!

-This removes probably the biggest constraint in electrical engineering and design. We will see amazing technology come out of this that none of us can predict.

EDIT (I'm just gonna keep adding these as they get mentioned elsewhere):

-Magnetic energy storage. Similar to how an electrical transformer works: You induce a current to flow which 'stores' the energy in a magnetic field. In the case of magnetic energy storage you just leave that current flowing. No resistance means it will flow indefinitely. You can then extract it directly or through interaction with the magnetic field.

Anything electric would be dramatically improved. Electric car range, consumer devices like computers and phones would have a huge jump in efficiency, etc. You name it basically.

In theory, the cost of getting an MRI would come way down due to not having to keep the coils crazy cold. In practice, we have capitalism, so it'll probably go up

The potential for tech miniaturization alone is a massive deal.

Right now, one of the biggest obstacles toward packing more transistors into a given space is the fact that they radiate a shit ton of heat which must be removed by close to immediate contact with the heat sink.

Without the need to deal with a shit ton of waste heat, instead of only having one, or only a couple layers of transistors in a processor, you can stack that shit high. Volumetric processing. Instead of wider chips, we could have taller chips. Hell we could stop calling them chips, and start calling them blocks!

If our processors could be as dense vertically as they are horizontally, we would see entire orders of magnitude more processing power, and, because a lot of energy is not being lost to heat, it's actually being used productively. Or in other words, you need less energy and yet can accomplish even more work.

If I am recalling an article correctly - superconductors mean zero resistance electric transfer. Currently anything using electricity loses power due to resistance when travelling - partly why a CPU gets so hot for example. By having zero resistance, far less power is lost to resistance and heat which means more power efficiency

Everything that has lots of wired coil (motors, generators, turbines, wireless charging)

Less resistance = less energy lost in these endless wire coils.

Wireless charging of mobile devices generates lots of heat which then degrades the battery. If we had superconductors, the charger wouldn’t heat up at all no matter how high the current is. The chemical reactions inside the battery might still generate heat, but the rest of the system wouldn’t.

The chemistry obviously has its limitations too, but as far as the charger and internal electronics of the device are concerned, having superconductors would speed up the process.

It's a zero resistance environment. Usually you would have to use liquid nitrogen to freeze something lime a hockey puck. There are some really cool things you can do then. Especially with magnets. Lay out a track of magnets and something thar is superconducting will hover over then. If you push it it will keep its speed unless acted upon by other forces. Now imagine we don't need to freeze the material...

More efficient battery technology. Imagine being able to have a battery in your laptop that lasts for weeks.

Home mag-lev. Build the super-conductor into the flooring of your home. Equip heavy furniture and appliances with electromagnets in the feet. Dial up the power on the magnets and the furniture will float up and you can slide it to it's new location. Dial down the magnets and furniture will settle back to the ground.

Last I read, current solar panels were only about 8% efficient. That number would skyrocket...

All computers becomes instantly outdated by what amount to 50 years of speed increase.