Exploring the Slow Adoption of HT Superconductors: Advantages and Challenges

In summary, the uptake of HTSC technology has been slow due to its high cost and limitations such as low current density, sensitivity to magnetic fields, and reduced supercurrent density at elevated temperatures. These limitations have made the technological application of HTS challenging, despite its potential for high efficiency and increased capacity. While there have been some limited applications, progress in fabrication technology is needed to fully utilize the potential of HTS. However, the study of HTS continues to yield new and exciting discoveries in physics.
  • #1
Art
Given that HTSC cables have been commercially available for some time now why has the uptake of this technology been so slow. Even allowing for the extra cost I'd have thought the advantages such as 140x the current carrying capacity, far higher efficiency etc. would outway any possible disadvantages?
 
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  • #2
how high a temp are we talking about..?
 
  • #3
willib said:
how high a temp are we talking about..?
I believe around 40K which is the big advantage over LTS which require cooling to 10K. Thus instead of requiring liquid helium which is expensive they use liquid nitrogen which is cheaper than bottled water. As I understand it the coolant is built into the cable in some permanent way.
 
  • #4
Art said:
I believe around 40K which is the big advantage over LTS which require cooling to 10K. Thus instead of requiring liquid helium which is expensive they use liquid nitrogen which is cheaper than bottled water. As I understand it the coolant is built into the cable in some permanent way.

Er.. no. LN2 has a boiling point of 77 K. So the operating temperature will have that as the maximum Tc for the superconductor to use LN2 has a coolant.

HTS such as YBCO has Tc of around 92 K. So this isn't the problem. The problem with most HTS is that it has a low current density, and so a low critical current density, beyond which, it becomes normal, when compared to conventional superconductors. Furthermore, as a Type II superconductor, there's problem with migrating vortices and flux lines when there's any significant magnetic fields (as there usually is when there's current carrying conductors or if it is placed in RF fields). These tend to cause many parts of the superconductor to not be superconducting.

One should also note that the higher the operating temperature, the less the density of supercurrent there is in the superconductor. What this means is that even if one is still below Tc, at elevated temperature, there will be more normal-state charge carriers present than at very low temperature close to 0K. While the DC resistivity of the superconductor will still be zero (since any potential applied will be "shorted" by the supercurrent), the AC resistivity of ANY superconductor is not zero. Here, the normal charge carriers/electrons also participate in the AC resistivity. So if you have a larger density of normal electrons at elevated temperatures, even if you're still in the superconducting state, you still lose power in AC transmission. For HTS, this is made worse because it is not a good normal state conductor in the first place - all HTS are doped ceramics.

This, among other things, have made the technological application of HTS very challenging.

Zz.
 
  • #5
ZapperZ said:
Er.. no. LN2 has a boiling point of 77 K. So the operating temperature will have that as the maximum Tc for the superconductor to use LN2 has a coolant.

HTS such as YBCO has Tc of around 92 K. So this isn't the problem. The problem with most HTS is that it has a low current density, and so a low critical current density, beyond which, it becomes normal, when compared to conventional superconductors. Furthermore, as a Type II superconductor, there's problem with migrating vortices and flux lines when there's any significant magnetic fields (as there usually is when there's current carrying conductors or if it is placed in RF fields). These tend to cause many parts of the superconductor to not be superconducting.

One should also note that the higher the operating temperature, the less the density of supercurrent there is in the superconductor. What this means is that even if one is still below Tc, at elevated temperature, there will be more normal-state charge carriers present than at very low temperature close to 0K. While the DC resistivity of the superconductor will still be zero (since any potential applied will be "shorted" by the supercurrent), the AC resistivity of ANY superconductor is not zero. Here, the normal charge carriers/electrons also participate in the AC resistivity. So if you have a larger density of normal electrons at elevated temperatures, even if you're still in the superconducting state, you still lose power in AC transmission. For HTS, this is made worse because it is not a good normal state conductor in the first place - all HTS are doped ceramics.

This, among other things, have made the technological application of HTS very challenging.

Zz.
Thanks Zz,
I misread the article, it referred to the first HTS material discovered operating at 40K but the critical temperature for the material they are using is 108K. :blushing: Where I am coming from is I was looking at a company as an investment opportunity and I wondered why if they had what reads like such dream products they weren't flying out the door. For example their literature boasts of ships engines they're developing for the US navy 1/4 the size and 1/5 the weight of equal power conventional engines. It sounded too good to be true :smile: .
With current technology limitations do you think it is likely the applications for superconducting products will always be limited or would straightforward solutions such as RF shielding around the cable alleviate some of the problems you described?
 
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  • #6
Art said:
With current technology limitations do you think it is likely the applications for superconducting products will always be limited or would straightforward solutions such as RF shielding around the cable alleviate some of the problems you described?

There have been limited applications of HTS - I think cell phone stations use them in some form or another. Any application that doesn't require a large current would tend to be more suitable. However, unless they can make major progress in the fabrication technology (and recent developements appear to make headway), the use of HTS will be technologically hampered by the limitations I've mentioned.

From my perspective, as a physicist, the physics of HTS is more interesting since that has been what I've focused on. Even if we solve the technological issue, I don't think we'll ever see the end of new and exciting physics coming out of the study of HTS.

Zz.
 

1. What is the main advantage of HT superconductors?

The main advantage of HT superconductors is their ability to conduct electricity with very little or no resistance at relatively high temperatures. This allows for more efficient and cost-effective use in various applications, such as power generation and transmission.

2. Why are HT superconductors not widely adopted yet?

Currently, the slow adoption of HT superconductors can be attributed to several factors. One major reason is the high cost of producing these materials, which makes them less economically feasible compared to traditional superconductors. Additionally, there are still various technical challenges that need to be addressed, such as stability and reliability issues.

3. What are the challenges in using HT superconductors?

Some of the main challenges in using HT superconductors include their fragility, which makes them difficult to handle and manufacture, as well as their sensitivity to external magnetic fields. There are also challenges in achieving high critical current densities and maintaining superconductivity at higher temperatures.

4. How do HT superconductors compare to traditional superconductors?

HT superconductors have the advantage of being able to operate at higher temperatures, typically above 77 K, which is the boiling point of liquid nitrogen. This makes them easier to cool and maintain compared to traditional superconductors, which require much colder temperatures. However, traditional superconductors have been used and studied for a longer time, so there is a more established understanding of their properties and behavior.

5. What are the potential applications of HT superconductors?

HT superconductors have the potential to revolutionize various industries, including energy, transportation, and healthcare. They can be used in power generation and transmission systems to improve efficiency and reduce energy loss. In transportation, they can enable faster and more efficient magnetic levitation trains. In healthcare, they can be used in medical imaging devices such as MRI machines.

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