Kristall AIP Submarine an Alternative

December 22nd, 2007  

Topic: Kristall AIP Submarine an Alternative

Kristall AIP Submarine Power Plants


the IHD-AIP Alternative

(Modified – 22nd Dec. 2007)

Part 1

Throughout this address, IHD-AIP is considered to be an address of an Integrated Hydraulic Diesel - Air Independent Power Plant operating in a Re-Cycle Diesel mode.

Russian-made submarines, equipped with the Kristall electrochemical generator AIP plant are not expected to be inferior to their foreign counterparts in performance, especially in comparison with the German Project 212 submarines and as such, there is an expectation the Russian vessels will be able to successfully compete in the international market. The Kristall-27E AIP plant, with its alkali matrix electrolyte, intermetallid storage of hydrogen, cryogenic storage of oxygen and low-temperature electrochemical generator, reportedly fully meets all requirements including those of fire/detonation safety, and is claimed to be superior to the AIP system of Project 212 submarines, surpassing these in terms of fuel efficiency. These Russian submarines are likewise more advanced, in that, shore-based support facilities are already a functional reality, with a number of these units already existing and operational; these are again reportedly available as dedicated autonomous shore-based refueling complexes.

Although the shore-based refueling complex is not considered an integral component of the AIP system, it can be supplied to a client as an option: this optional feature contributes to the attractiveness of the Russian project vessels. Customers can be supplied, as a single package, an autonomous refueling complex able to provide hydrogen and oxygen for the submarine's AIP system. As the characteristics of the second-generation air-independent propulsion systems based on these electrochemical generators are claimed to have not yet reached the limit of their development, there is believed considerable scope for improvement, although this improvement is believed to be mainly related to a refinement of the organization of the hydrogen storage and associated feed system, within the submarine.

Within the AIP system development concept, evolved by SKBK, third-generation shipborn AIP systems are believed to be undergoing development. These are expected to enter service with conventional submarines after the year 2010.

Under normal circumstances, equipping non-nuclear submarines with AIP systems increases their costs due to the following factors:
· the cost of power plant's pilot (series) production model can account for approximately 15-20 percent of the total submarine's cost;
· requisite R&D and engineering costs also increase a submarine's price tag.

This is not likely to be the case, with regards the introduction of IHD-AIP plant to either new build or existing submarine fleets. This is essentially a result of the ability to import a mature powering technology, as a result of the power plants development within the various current Russian armored vehicle programs and an ability to utilize aspects of the existing AIP program. The availability of a mature and fully scalable powering technology, readily adaptable as the core of an IHD-AIP plant in combination with the existing technology of the diesel/LOX/argon systems of a re-cycle diesel power plant, ensure rapid and cost effective introduction of such power plants. It should also be recognized, the introduction of IHD-AIP plants in submarines, represents a significantly simpler approach to AIP submarine powering and eliminates the usually costly requirement to develop advanced materials and systems, such as are found in the various forms of existing electrochemical generator AIP technologies. Nor does the IHD-AIP plant require an ongoing supply of exotic mediums for through life operation. Essentially, the IHD-AIP system’s requirements, will be limited to diesel fuel, LOX and argon, none of which are exotic and all are readily available commercial commodities, in any country likely to operate such submarines. As such, the introduction of IHD-AIP submarines does not introduce either a requirement for an additional production facility or an unusual logistic capability. Moreover, there is potential to integrate within the system, parasitic energy production for low voltage systems, control, monitoring and hotel services, providing a substantial energy gain and improved fuel economy of the type.

As has been identified in the existing literature on the subject, the operation of submarines equipped with AIP systems, in conjunction with diesel-electric submarines is cost-effective, because the total number of submarines can be reduced owing to the considerably enhanced combat efficiency of the fleet. FRG projections result in the expectation of an ability to replace 18 diesel-electric submarines of Project 206/206A with 4 Project 212 boats, equipped with AIP systems, based on electrochemical generators. Although this is a practical peace time policy, a more forward thinking policy is that IHD-AIP submarines can be more readily integrated into existing submarine fleets and rather than replace the existing units, the existing units can be re-powered as IHD-AIP units and held in reserve as either training units or for times of need.

Similarly, it would be highly cost effective to re-power a few existing and recently into service diesel electric submarines, as an interim measure and use these as training vessels, pending their subsequent replacement by new construction IHD-AIP submarines, in a complete fleet up-grade. With the re-powered vessels subsequently sold off to an export market and the returns from these sales, off-setting the cost of the new-build vessels.

Given the expectations of the FRG projections and the superior operational characteristics of IHD-AIP vessels, this would allow a substantial reduction in operational fleet units, whilst improving over-all fleet efficiency, exceeding the previous level of functionality. Achieving this with vessels of notably less cost than the current technology fuel cell vessels and providing a highly cost effective method of improving a submarine fleet.

Also mentioned in the literature on this subject, none of the countries involved in the production of AIP systems for submarines, are expected to restrict supply of such vessels to their own Navies and owing to the highly desirable nature of AIP technology, there is considerable export potential for such vessels. As well as Russia, currently the more notable countries developing such submarines, includes Germany, Sweden, and France, with the latter believed to be developing AIP-equipped submarines exclusively for this export market.

Apart from Russian projects, current projects of interest, include the four vessels of the Project 212 submarine program, equipped with electrochemical generator AIP plants and being built in Germany; with a projected per-submarine cost of about U.S. $370 million.

With regards current Russian AIP submarines fitted with first or second generation AIP systems, these powering systems are believed to be limited to functioning as secondary powerplants, operating as the power source at economic speeds and basically functioning as a means of providing increased submerged range and duration of submerged operation. They are claimed to improve submerged endurance of a submarine by approximately 10-15 days. It is expected the third generation AIP plant, currently under development, will allow production of a functional single power source AIP submarine, with the AIP system providing both underwater and surface propulsion, as well as auxiliary power. This would appear consistent with the projected mode of operation of the Kockums submarines, with further development of their Sterling cycle AIP system.

It is expected, the third-generation Russian AIP systems will increase underwater endurance of non-nuclear submarines to some 60-90 days and provide operational characteristics more consistent with nuclear powered submarines. It is not expected, however, that submarines optimized with these third generation AIP systems will enter service prior to 2010.

December 22nd, 2007  
Kristall AIP Submarine Power Plants
the IHD-AIP Alternative
(Modified – 22nd Dec. 2007)

(Continuation - Part 2)

As mentioned in the literature on the subject, the Special Boiler Design Bureau (SKBK) JSC is believed to be Russia's only enterprise involved in shipborne AIP plant development and production, with genuine experience in developing electrochemical generator plants for naval submarines. It is also believed SKBK has the capability to develop, manufacture and deliver, AIP plants rated at 10 to 600 kW (up to 4,000 kW for short time), having 100 to 100,000 kWh power capacity, 150 to 200 Wh/kg or 200 to 250 Wh/l specific power capacity, complete with all support systems, both for marine and on-shore applications.

In a direct comparison with the existing AIP type submarines above and using the Kristall powered vessels as a specific example, there is significant advantage in the in-parallel introduction of IHD powered types. This is especially the case when considering the LOX cryogenic storage system developed for the Kristall AIP system, it is believed this would be readily adaptable as a component of the IHD-AIP powered vessels. It should also be apparent, the integration of an IHD-AIP submarine into an existing diesel electric fleet is, logistically, a less demanding exercise; given the common and readily available fuel type already supplied for the existing vessels and recognition, existing maintenance staff will not require much re-training to address the maintenance of IHD-AIP vessels, as the actual power plant is still functionally a diesel power plant. More-over, the supply of LOX in the amounts required would not be an undue load on commercial suppliers of LOX in many areas in which such submarines would be deployed. This is similarly the case with regards the supply of argon for such submarines.

Unlike the third generation Kristall-AIP submarines, the IHD-AIP submarines could be rapidly introduced and also unlike existing AIP submarines, would not be limited to brief periods of operation at maximum power, but would only be limited in this respect by the fuel, LOX and argon reserves available to the vessel. Effectively, an IHD-AIP submarine could depart its operational base and proceed submerged at full speed to an interception point, prosecute an attack and subsequently rendezvous with a replenishment vessel and restock its depleted fuel, LOX and argon reserves and either return to its base or undertake a further deployment. It should also be apparent, if there is no other option available, such a submarine can be refueled and return to its base using its snorkel, with its engine operating as a diesel/air power plant. Although the former may be considered an unlikely scenario, it is a good example of an extreme mode of action able to be undertaken by an IHD-AIP submarine. In a more usual mode of operation, an IHD-AIP submarine would function much as any existing or proposed AIP type, but with the exception that it may at any time operate at significantly higher power levels than any other AIP type, the Captain secure in the knowledge that replenishment at sea is a practical and readily available option.

It should also be remembered, an IHD-AIP submarine can considerably extend its range by snorkeling and running its power plant as a diesel/air engine, conserving its supply of oxygen and argon for later use. This has the added advantage that such a submarine is operable on less expensive consumables and able to make extended voyages during redeployment, even to the most remote regions, without a need to consider the logistics or cost of the re-supply of either oxygen or argon. Any shortfall in diesel fuel resulting from such an extended voyage, can be simply made good at any existing facility, able to re-fuel a diesel-electric submarine. Once its diesel supply is replenished, the IHD-AIP submarine is again a fully capable AIP submarine. It should also be recognized, at any time during its previous voyage, should the need arise, the IHD-AIP submarine could revert to a full AIP format and undertake any action required within the normal scope of its operation in that mode. This is not an optional mode of operation for any other AIP system where the AIP system is the sole powering source of the submarine.

As has been mentioned, SKBK is prepared to develop, manufacture and deliver to customers, AIP plants:
rated at 10 to 600 kW (up to 4,000 kW for short time),
having 100 to 100,000 kWh power capacity,
150 to 200 W h/kg or 200 to 250 W h/l specific power capacity

By comparison, IHD-AIP plants could be produced as submarine power plants:
rated significantly in excess of 4,000 kW continuous power,

IHD-AIP plants also have the considerable advantage of being variable displacement power plants offering unprecedented levels of flexibility, redundancy and efficiency.

Given the highly compact and light weight nature of IHD power plants and that they, generally, have the potential to provide significant reductions in fuel use and are expected to provide as good as a threefold improvement in fuel consumption figures, in specific applications, operational range of an IHD-AIP submarine will be significantly better than competing types, firstly from the improved fuel economy and secondly from the greater effective reserve of diesel fuel, LOX and argon, such a submarine will be capable of storing. This improved consumables capacity, is further enhanced by the IHD-AIP system resulting in a single power plant vessel, effectively eliminating the usually large battery requirement of conventional diesel electric submarines and contemporary AIP submarines, with this resulting in both a lighter displacement vessel and an ability to assign a greater in-hull volume to the storage of consumables, including munitions.

It is worth emphasizing, the ability to use a reciprocating engine of 1/3rd the combustion space volume of a contemporary engine of equivalent power, allied with the fact that this form of power production develops neither a torque nor thrust effect upon the engine, implies the mass of the machinery supporting structure can be substantially reduced, needing to basically address the weight of the power plant only and such dynamic variables as G-forces and incidental accelerations; substantially reducing the mass of the supporting structure and space taken by same; this is also of considerable advantage with regards submarines, as it allows the power plant to be rafted as part of the vessels noise attenuation program.

With specific regard to a re-cycle diesel power plant of the proposed type, the greatly reduced swept volume for a given power level and better than threefold increase in fuel economy, allows an equivalent reduction in fuel, LOX and argon for an existing level of endurance. Such a situation provides opportunities to build more formidable combat submarines within a given displacement or combat submarines with notably reduced displacements and capabilities equivalent to existing vessels; in either case, the client gains far greater value for a given cost, with regards both capital expense and all combined through life expenses. It is also worth mentioning, there is considerable potential to improve both engine efficiencies and propulsion aspects, associated with this powering system, in AIP submarines.
August 11th, 2008  
AIP is the way to go with submarines just wish the USN would get on the band wagon.

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