Naval Ship & Submarine Propulsion Systems

[Depot Dog]

Looking into this debate about batteries I was doing research into hydrogen fuel cells. The conclusion was any technology we choose they come with their own fire hazard. AIP stirling engines require liquid oxygen. Li-ion can burn. The hydrogen in hydrogen fuel cells is flamable. As a technologist I think we should go forward and embrace new battery technology. Like everything it is a matter of how you manage the risk.

Japan Goes Back To The Future With Lithium-Ion Battery Powered Submarines

Diesel electric submarines may be on the verge of returning to their simpler roots with the help of lithium-ion batteries.

www.thedrive.com

My preferance would be Hydrogen fuels cells. Attack class designer DCNS is already developing a AIP system with Hydrogen fuel cells. It is the most silent AIP technology. Good trait for submarines The Australian government wants to become a green Hydrogen super power. So access to fuel shouldn't be a problem.

The only draw back is the technology hasn't fully matured. That hasn't stopped the boffins here researching and developing ground breaking technology.

Just my thoughts
DD

 

[ngatimozart]

Well ITER intend to have their fusion reactor running in 2025. They started assembling it last year with the installation of the shell for the worlds largest fridge. This is intended to cool the reactor, making it the 2nd known coldest place in the universe being 4°K (-269°C) The coldest place is some place that is 2°K (-271°C). The reactor will at the same time be one of the hotter places in the universe with the plasma being at 100 million °C. The reason for the cooling is the superconductors in the magnets creating the magnetic field to confine the plasma stream preventing from touching the sides of the reactor. There are 18 magnets and each one is the same weight as a fully loaded B747.

Once they have that running and the bugs sorted out, it won't be long before the reactor size and costs start reducing significantly. The real beauty about it is that it requires tritium and that it can make itself out of water. So whilst at present battery technology is the way to go, possibly in 20 or 30 years we may see the first fusion reactors on subs and ships, and that will change a lot of things.

 

[alexsa]

Pretty much everything discussed in this thread is theoretical. But we've seen similar estimates made for the Japanese subs (see infographic below), so I think it's pretty safe to say that those kinds of ranges are more than just theoretical.

Image courtesy of SSK Soryu Class Submarines

This is not aimed at ngatimozart or Calculus …. I am just following their posts.

I have been trying to behave here… but … endurance is not just about speed. You could build a submarine with a 1950 fire control system and sensors which will burn very little power and give great range …. Is this a good option?

The comparison looks and range and speed not combat profile. It is rubbish. The submarine effective range is driven by absorbed energy and the systems that energy supports. It is also driven by the operational situation is planned to operate in or where are certain contingency capability is required. Tactical manoeuvres also burn power as does the the combat system and sensors.

So…..massive range at slow speed is less desirable and a longer range and better persistence (the ability to remain effective on task for longer).

If you fire an SSM at a ship with limited power reserves in your battery the steaming geyser will let lots of folk know where you are. Your tactical situation will be driven by that consideration.

Info-grapics do not address this. Effective scenario models do. I do not expect that DoD will be show that sort of assessment to the public.

New battery technology will be great …. When it is proven. The time frame on that. Is subjective.

Sorry …. Just my spray

 

[alexsa]

Looking into this debate about batteries I was doing research into hydrogen fuel cells. The conclusion was any technology we choose they come with their own fire hazard. AIP stirling engines require liquid oxygen. Li-ion can burn. The hydrogen in hydrogen fuel cells is flamable. As a technologist I think we should go forward and embrace new battery technology. Like everything it is a matter of how you manage the risk.

Japan Goes Back To The Future With Lithium-Ion Battery Powered Submarines

Diesel electric submarines may be on the verge of returning to their simpler roots with the help of lithium-ion batteries.

www.thedrive.com

My preferance would be Hydrogen fuels cells. Attack class designer DCNS is already developing a AIP system with Hydrogen fuel cells. It is the most silent AIP technology. Good trait for submarines The Australian government wants to become a green Hydrogen super power. So access to fuel shouldn't be a problem.

The only draw back is the technology hasn't fully matured. That hasn't stopped the boffins here researching and developing ground breaking technology.

Just my thoughts
DD

Just for context ….current battery technology (lead acid) has a hydrogen issue. When you charge the battlers hydrogen is produced. the charging process deals with this by ventilating the battery compartments during a change while snorting. Nothing new here… expect if the hydrogen is in the boat while removal is not an option.

Hydrogen has very low energy density and heavy containment. LH2 (liquified hydrogen) is not really an option on a submarine when the containment system needs to vent to maintain temperature. The Japanese pilot LH3 gas carrier vessel operating with liquified hydrogen are looking an -269 degrees C (very close to kelvin) …. But still need to vent (what could possibly go wrong with hydrogen in the boat with no way of venting at very very low ignition energy).

This is not a shot at the the discussion(or Deport Dog) but the relevant of the energy density and risk with hydrogen does get lost occasionally.

 

[ngatimozart]

This is not aimed at ngatimozart or Calculus …. I am just following their posts.

I have been trying to behave here… but … endurance is not just about speed. You could build a submarine with a 1950 fire control system and sensors which will burn very little power and give great range …. Is this a good option?

The comparison looks and range and speed not combat profile. It is rubbish. The submarine effective range is driven by absorbed energy and the systems that energy supports. It is also driven by the operational situation is planned to operate in or where are certain contingency capability is required. Tactical manoeuvres also burn power as does the the combat system and sensors.

So…..massive range at slow speed is less desirable and a longer range and better persistence (the ability to remain effective on task for longer).

If you fire an SSM at a ship with limited power reserves in your battery the steaming geyser will let lots of folk know where you are. Your tactical situation will be driven by that consideration.

Info-grapics do not address this. Effective scenario models do. I do not expect that DoD will be show that sort of assessment to the public.

New battery technology will be great …. When it is proven. The time frame on that. Is subjective.

Sorry …. Just my spray

You're not spraying, just adding another line of thought for consideration to the conversation. Something that should give us all reason to include that idea in our thoughts and cogitations.

 

[Depot Dog]

Just for context ….current battery technology (lead acid) has a hydrogen issue. When you charge the battlers hydrogen is produced. the charging process deals with this by ventilating the battery compartments during a change while snorting. Nothing new here… expect if the hydrogen is in the boat while removal is not an option.

Hydrogen has very low energy density and heavy containment. LH2 (liquified hydrogen) is not really an option on a submarine when the containment system needs to vent to maintain temperature. The Japanese pilot LH3 gas carrier vessel operating with liquified hydrogen are looking an -269 degrees C (very close to kelvin) …. But still need to vent (what could possibly go wrong with hydrogen in the boat with no way of venting at very very low ignition energy).

This is not a shot at the the discussion(or Deport Dog) but the relevant of the energy density and risk with hydrogen does get lost occasionally.

As I said previously all battery technology comes with its own unique risks and safety practices. Hydrogen is flamable with a low flash point. It is difficult and expensive to store. Because of its atomic structure it has low energy density. Conversley it is also the highest in energy per weight

As this is a chemical/electrical process there are no moving parts. Making it silent. You can stay submerged up to three weeks. The average diesel subs cost $0.20 to $0.30 per kWh. The fuel cell sub is $0.15 per kWh. Referance see attachment. It requires little maintenance. All these are good for sub operations.

The German and Italian navies do have commisioned Type 212 fuel cell subs.

Source Air Independent Propulsion - an overview | ScienceDirect Topics
The Germans have overcome the obsticals to make this sub. I am not advocating this system. It is a costly and inefficent. To me it is gen one.

The French mob who are building our subs have some exciting fuel cell research. They have a method that doesn't require Hydrogen storage and other risks. Ta Dah!!!!

Naval Group Achieves Breakthrough with its FC2G AIP System - Naval News

Naval Group announced that they achieved a breakthrough with their proprietary FC2G AIP system for submarine: The company demonstrated an 18 days submerged patrol representative of operational conditions.

www.navalnews.com

The process above converts diesel into ultra pure hydrogen. Please read the the document for further information. If it can do what is reported, it is viable alternative for our Attack class subs.

BTW I need to reframe this debate. When I started this I thought the fuel cells powered the sub directly. This is a method of charging the batteries. So the battery technology debate is another subject.

Regards
DD

 

[ngatimozart]

Wouldn't it be easier and better to take the hydrogen out of the seawater, then use the oxygen for crew air? Yes I know that O2 is toxic at 10 Atmospheres, which from memory is 126ft. When I used to dive it was 297ft on a normal air mix.

 

[Depot Dog]

Wouldn't it be easier and better to take the hydrogen out of the seawater, then use the oxygen for crew air? Yes I know that O2 is toxic at 10 Atmospheres, which from memory is 126ft. When I used to dive it was 297ft on a normal air mix.

Agreed You would need to set up an electrolysis apparatus. Then a filtering system to produce ultra pure O2. All the technology is available. Inregards to the sub space availability, power requirements, maintenance, waste disposal etc. These problems would have to be worked out by people into sub design. It can be done but it would be complex and costly.

Or just workout the requirements for submarine operations plus the AIP. Then put in an oxy tank big enough. That is the current plan. As they say in the classics keep it simple.

Source: Keeping Assessor Training Simple

Regards
DD

 

[OPSSG]

Although hydrogen-oxygen propulsion had been considered for submarines as early as World War I, the concept was not very successful until recently due to fire and explosion concerns. In the Type 212A, the Type 214 and the Type 218SG, this has been countered by storing the fuel and oxidizer in tanks outside the crew space, between the pressure hull and outer light hull. The gases are piped through the pressure hull to the fuel cells as needed to generate electricity, but at any given time there is only a very small amount of gas present in the crew space.

Wouldn't it be easier and better to take the hydrogen out of the seawater, then use the oxygen for crew air? Yes I know that O2 is toxic at 10 Atmospheres, which from memory is 126ft. When I used to dive it was 297ft on a normal air mix.

Edit: If further volume is needed, isn’t it better to just store liquid oxygen (LOX) in a tank and regas as needed? To release the hydrogen, waste heat is supplied from the two 120kW fuel cells. Siemens has put every effort into integrating the PEM Fuel Cell stack, valves, piping, and sensors as well as the corresponding module electronics control and the ancillaries into a single container making the best use of the limited space on board. The ancillaries comprise the equipment for supplying H2, O2, and N2 for reactant humidification, for product water, and waste heat and residual gas removal.

Regas can also contribute to the air conditioning on the submarine, if the correct heat exchangers are installed, which reduces hotel electrical load. For crew air, just burn an oxygen candle. It’s scrubbing of CO2 that consumes electric power and contributes to hotel load, right?

 

[Depot Dog]

…In the Type 212A, the Type 214 and the Type 218SG, this has been countered by storing the fuel and oxidizer in tanks outside the crew space, between the pressure hull and outer light hull. The gases are piped through the pressure hull to the fuel cells as needed to generate electricity, but at any given time there is only a very small amount of gas present in the crew space.


Edit: If further volume is needed, isn’t it better to just store liquid oxygen (LOX) in a tank and regas as needed? Siemens has put every effort into integrating the PEM Fuel Cell stack, valves, piping, and sensors as well as the corresponding module electronics control and the ancillaries into a single container making the best use of the limited space on board. The ancillaries comprise the equipment for supplying H2, O2, and N2 for reactant humidification, for product water, and waste heat and residual gas removal.

Regas can also contribute to the air conditioning on the submarine, if the correct heat exchangers are installed, which reduces hotel electrical load. For crew air, just burn an oxygen candle. It’s scrubbing of CO2 that consumes electric power and contributes to hotel load, right?

Source:Air Independent Propulsion - an overview | ScienceDirect Topics
I agree it's not new technology. The history of fuel cell development is over 200 years. The theory was there just had to wait for the technology. The storing of H2 in tanks between the outer and inner hull does minimise crew exposure to the gas. From the diagram you can see the inner hull is surrounded by containers of highly flamable gas. I am guessing the there would be safety devices, MSDS and procedures in place. However humans are inventive in find ways of making mistakes.

An example was the P3B fire at Edinburgh in 86. This involved a routine procedure with the oxygen tanks. The system was charged to 1800 psi. When they started to remove the nuts holding the tube oxygen escaped. Debris escaping with the gas became red hot. Red hot debris and oxygen not a good combination. The loosening of the nut was the catalyst that started the chain of events. The three airmen defence was none of the maintenance procedures required the gas to be bled. All charges were dismissed. Common sense would dictate to bleed the system. As they say common sense is not that common.

Human error could happen on the Type 212 involving stored hydrogen. On that day something nasty could happen.

My take from Alexsa post was the storage of Hydrogen on subs is dangerous. Before I answered I did some research into how the Germans did it. During my research I came across the French system. The French system looks a more modern approach to sourcing hydrogen.

This is why I highlighted the French system. There is no storage of H2. There are no handling issues. The only thing the sub needs is diesel and oxygen. Two liquids the navy already has storage and handling procedures. It just eliminates some of the risks.

If the French perfect this then I hope the Navy looks at it. If they think it is worthwhile we get it. If not cést la vie.

Regards
DD

 

[StingrayOZ]

liquid hydrogen and liquid oxygen raise heaps of problems. Hydrogen is particularly problematic, hydrogen embrittlement/high temperature attack is a thing and the more hydrogen pipe work, the greater the complexity, cost and maintenance. While the Germans are pushing the technology, the Germans aren't exactly known for creating simple solutions, and the German sub fleet isn't exactly a blowing the world away with availability and efficiency. While there is no evidence that that is due to AIP systems, it also doesn't dismiss the issues, who is operating a high frequency high use AIP system. AFAIK the only one was Japan, and they quickly jumped to battery technology.

There are other systems that can carry "hydrogen" that are suitable for marine or submarine use. Methanol and ethanol reformers for example.

Methanol reformer – The next milestone for fuel cell powered submarines

All submarines with fuel cells built until today are based on hydrogen storage in metal hydride storage cylinders. This technology offers many advanta…

www.sciencedirect.com

You can dissolve the CO2 into seawater, making no bubbles. Evaporation and pressurisation of methanol tanks is much easier and simpler than a hydrogen or oxygen tank. Obvious boil off isn't an issue either.

All of this takes money, weight, volume, complexity, risk from a project. There is also significant ongoing costs.

Something like improved battery technology becomes increasingly attractive, particularly when you scale systems. Particularly for a submarine.

 

[OPSSG]

liquid hydrogen and liquid oxygen raise heaps of problems. Hydrogen is particularly problematic, hydrogen embrittlement/high temperature attack is a thing and the more hydrogen pipe work, the greater the complexity, cost and maintenance.

Sorry did a quick literature search and found that no liquid hydrogen is used in the Type 212A. The German submarine designers store hydrogen in metal hydrides (which uses waste heat from the fuel cell to release); this is the safest method known for storing flammable hydrogen gas (as it is more dense than liquid hydrogen). If your hydrogen system develops a leak, SOLID-H immediately releases a small fraction of its stored hydrogen.

An alternative hydrogen storage is in boron nitride nanotubes — which is still not widely used and needs to mature.

 

[kato]

The German submarine designers store hydrogen in metal hydrides (which uses waste heat from the fuel cell to release); this is the safest method known for storing flammable hydrogen gas (as it is more dense than liquid hydrogen).

Dang, you ninja'd me there while i was writing that.

From the diagram you can see the inner hull is surrounded by containers of highly flamable gas. I am guessing the there would be safety devices, MSDS and procedures in place. However humans are inventive in find ways of making mistakes.

The hydrogen onboard U212A is not carried in liquid or gaseous form in tanks, but in metal hydride solid solutions. Hydrogen is extracted from such storage with heat; onboard U212A waste heat from the fuel cells or diesel generator is used for that (partially also because this heat system is designed to not require cooling at all (!), thus not bleeding waste heat into the water unlike the infrared candles that most other subs running engines are).

In theory such metal hydride tanks can explode if they are subjected to sufficient heat over a sufficient period to extract their stored hydrogen uncontrolled, but unless you literally light a fire in that hull section that's basically not possible.

The downside of such metal hydride storage is that it's rather heavy, which is partly why they are arranged in a relatively flat ring like that.

 

[StingrayOZ]

Hydrogens problems are even worse as a gas, it still dissolved into steels and can dissolve through other metals. At some point its a gas. There is likely a big long hydrogen gas line in the sub from outside to inside. Its not just cryogenic hydrogen that is a problem. Storing with hydrides can have other issues, submarines are often the technology leaders here, although the Japanese have a big vision for the technology (surprisingly outside of submarines).

As kato points out it takes volume and weight in a sub. Many systems still have cryogenic oxygen. That alone is a huge issue as well. Taking volume and mass. Neither is also rechargeable at sea. So again, CONOPS comes into play with whom this is going to be particularly attractive to.

It has advantages for some applications, if you are trying very hard to control thermal output, then its an excellent solution. If you only require low loads from the system, again, excellent. If you do not require recharge at sea, excellent. This can then sometimes drive overall design to make the most out of this type of technology. Smaller crew = smaller hotel load.

However, many different countries and companies have competing solutions with various advantages and disadvantages. Last I heard the French and the Spanish were talking hydrogen reformers. Germans loved h + o fuel cells, swedes liked sterling, which the Japanese licensed for a while.

The western nation (any nation?) with the largest AIP conventional fleet with high usage operations moved quite quickly from sterling based AIP to lithium battery technology. Lithium has other advantages, its rechargeable at sea, it can release high current efficiently, take deep discharge, modular, scalable etc. However, it doesn't provide a thermal sink, but in some applications that isn't a huge deal breaker. It has different safety issues that need to be addressed.

Some of these technologies don't exclude each other. No one has ever said you can't have a lithium battery sub with an additional chemical AIP.

However, I am a bit biased here. My wife was involved in a hydrogen explosion at her work, while she is fine, it wasn't an enjoyable experience. I'm not a big fan of the gas personally. I've seen the damage it can do.

I know Japan has a huge liquid hydrogen carrier that will operate between Australia and japan. There are issue of hydrogen storage at scale that makes hydride storage unattractive for large storage and transport.

World's first liquid hydrogen carrier ship launches in Japan

Kawasaki Heavy's vessel will transport the next-generation fuel from Australia

asia.nikkei.com

 

[kato]

Neither is also rechargeable at sea. So again, CONOPS comes into play with whom this is going to be particularly attractive to.

Worse - you need specific infrastructure for the recharge with the system, can't just pump hydrogen in there. Most of the users operate 2-3 refueling stations at naval bases in their countries.

Offhand among users of the system Germany - to my knowledge - is the only one also running a mobile recharging station (onboard submarine tender Main) in order to extend deployed operations virtually indefinitely using low-infrastructure allied ports in-theater.

The western nation (any nation?) with the largest AIP conventional fleet with high usage operations moved quite quickly from sterling based AIP to lithium battery technology. Lithium has other advantages, its rechargeable at sea, it can release high current efficiently, take deep discharge, modular, scalable etc. However, it doesn't provide a thermal sink, but in some applications that isn't a huge deal breaker. It has different safety issues that need to be addressed.

I would see the batteries as completely separate from AIP. The AIP system simply replaces/supplements the diesel genset for recharging the batteries.

Typical lithium-ion installations unless vastly oversized tend to be good for 24 hours at 12 knots (that's what DCNS offers as a hull plug solution, i.e. extended-range for its subs), providing sufficient air-independent evasion capability - instead of a few hours on a standard lead-acid pack.

They however do not provide for air-independent operations over any significant period beyond such an evasion, like an AIP system does. A U212A does those same 12 knots air-independent for 18 days. Continuously. Interestingly that seems to be a benchmark too, since DCNS tested MESMA to exactly the same duration.

On the next two U212 projects (U212NFS for Italy and U212CD for Germany and Norway) you'll get lithium-ion batteries plus fuel-cell AIP btw. Plus for U212CD presumably a similar extended-range diesel tank for longer air-dependent operations that German U212A Batch 2 got as a mobility upgrade compared to Batch 1.

 

[kato]

The downside of such metal hydride storage is that it's rather heavy, which is partly why they are arranged in a relatively flat ring like that.

P.S. On that, just to make it clear: I'm refering to the image posted earlier with the "ring", not the actual submarine which may differ with regard to the actual location, extent or relative size or visual misinterpretation of certain components including these.

And yes, i'm aware that one only needs about 5 minutes on Google to find the real thing. In which visual misinterpretation may still occur.

 

[kato]

Sorry did a quick literature search and found that no liquid hydrogen is used in the Type 212A. The German submarine designers store hydrogen in metal hydrides (which uses waste heat from the fuel cell to release); this is the safest method known for storing flammable hydrogen gas (as it is more dense than liquid hydrogen). If your hydrogen system develops a leak, SOLID-H immediately releases a small fraction of its stored hydrogen.

An alternative hydrogen storage is in boron nitride nanotubes — which is still not widely used and needs to mature.

There is extensive research into possibly developing a similar storage method for oxygen over the last two decades btw, which seems to be a lot more complicated. Nanocrystals looked somewhat promising for a while, but have relatively recently been found to degrade in the sense of considerably reducing their storage capacity within only ten or so fill-up/discharges.

 

[MARKMILES77]

Hydrogens problems are even worse as a gas, it still dissolved into steels and can dissolve through other metals. At some point its a gas. There is likely a big long hydrogen gas line in the sub from outside to inside. Its not just cryogenic hydrogen that is a problem. Storing with hydrides can have other issues, submarines are often the technology leaders here, although the Japanese have a big vision for the technology (surprisingly outside of submarines).

As kato points out it takes volume and weight in a sub. Many systems still have cryogenic oxygen. That alone is a huge issue as well. Taking volume and mass. Neither is also rechargeable at sea. So again, CONOPS comes into play with whom this is going to be particularly attractive to.

It has advantages for some applications, if you are trying very hard to control thermal output, then its an excellent solution. If you only require low loads from the system, again, excellent. If you do not require recharge at sea, excellent. This can then sometimes drive overall design to make the most out of this type of technology. Smaller crew = smaller hotel load.

However, many different countries and companies have competing solutions with various advantages and disadvantages. Last I heard the French and the Spanish were talking hydrogen reformers. Germans loved h + o fuel cells, swedes liked sterling, which the Japanese licensed for a while.

The western nation (any nation?) with the largest AIP conventional fleet with high usage operations moved quite quickly from sterling based AIP to lithium battery technology. Lithium has other advantages, its rechargeable at sea, it can release high current efficiently, take deep discharge, modular, scalable etc. However, it doesn't provide a thermal sink, but in some applications that isn't a huge deal breaker. It has different safety issues that need to be addressed.

Some of these technologies don't exclude each other. No one has ever said you can't have a lithium battery sub with an additional chemical AIP.

However, I am a bit biased here. My wife was involved in a hydrogen explosion at her work, while she is fine, it wasn't an enjoyable experience. I'm not a big fan of the gas personally. I've seen the damage it can do.

I know Japan has a huge liquid hydrogen carrier that will operate between Australia and japan. There are issue of hydrogen storage at scale that makes hydride storage unattractive for large storage and transport.

World's first liquid hydrogen carrier ship launches in Japan

Kawasaki Heavy's vessel will transport the next-generation fuel from Australia

asia.nikkei.com

"Rechargeable" hydride storage systems for hydrogen are available. All you need is a supply of water and electricity to hydrolyse the water. You can now have them at home.


40 KWH Hydrogen hybrid batteries for use as an alternative to Li Ion Batteries for home solar electricity storage have just gone on sale.
They have a life of 20,000+ charge/discharge cycles. They are also designed and made in Australia.

https://mk0lavositensamqu8jl.kinstacdn.com/wp-content/uploads/2020/10/LAVO%E2%84%A2-Residential-Unit-Brochure.pdf

 

[MARKMILES77]

LAVO

lavo.com.au

This is the website for the Australian company who makes them.
They are the world leaders in this technology.

 

[Calculus]

Another interesting description of the propulsion systems aboard the Korean KSS-III Batch 2 subs: South Korea's KSS-III Batch 2 Submarine to Feature both AIP and Li-Ion Batteries - Naval News

The article focuses quite a bit on the safety aspects of the Korean batteries. The Koreans (and the Japanese) seem to have mastered the Li-ion chemistry for use in submarines.