The present invention relates to a fire extinguishing system
for a marine vessel comprising an engine room and a fuel cell arrangement according
to the preamble of claim 1.
Engine rooms or machinery spaces of marine vessels, or
other marine structures such as oil drilling platforms, LNG stations, etc., generally
have to be provided with a fire extinguishing system. Typically this is a CO2
system designed for the entirety of the engine room. Furthermore, so-called prime
movers must have a local fire fighting system. In practice this usually means that
water mist sprinklers are provided above the engines or other machinery equipment.
The CO2 system is efficient as such, but it
can not be employed before the entire engine room is evacuated, i.e. cleared from
personnel. This most often means that there is a delay in releasing the CO2,
which increases the impact of the fire. In order to remedy such situations, local
fire fighting systems as discussed above are required. The local sprinklers may
then be deployed as soon as the fire is noticed.
The above is relevant for more conventional machinery arrangements.
However, fuel cell arrangements are becoming more frequent. In case of a fire, deployment
of the main CO2 system for the engine room would result in undesired
delay and increased damages for the fuel cell arrangement. Also the effect of CO2
released in an engine room around the fuel cell arrangement would be inefficient.
Moreover, conventional local fire fighting systems comprising water mist are not
well suited for electrical components, since they would create risks of short circuiting
and cause damage to the fuel cell arrangement.
An object of the present invention is to avoid the drawbacks
of known solutions and to provide an effective and simple fire extinguishing system
for a marine fuel cell arrangement. This object is attained by the present invention
according to claim 1.
The basic idea of the invention is to apply a local fire
extinguishing system within the fuel cell arrangement, which comprises at least
one fuel cell module. Each fuel cell module is provided with at least one fire detection
sensor and at least one internal nozzle for releasing a fire extinguishing medium
into the fuel cell module. Primarily this offers a better fire fighting capability
and a quick response, i.e. a possibility to start the fire fighting earlier with
less damage to the equipment. This also lessens the risk of casualties. Particularly
this offers the advantage to fight a small fire without any risk of additional damage
in connection with a larger fire fighting process.
The fuel cell module normally comprises a number of separate
components, whereby the fuel cell module advantageously may be provided with at
least one auxiliary nozzle for releasing fire extinguishing medium to one or more
of the separate components. Such components typically include a hot box, including
a fuel cell stack, a fuel reformer, an electric inverter, power conditioning, a
process gas heater, a control unit, etc. The benefit would be an increased fire
extinguishing effect focused directly at the actual source of fire. The auxiliary
nozzles may be effective in immediately extinguishing a tiny fire, without incapacitating
the function of the fuel cell module in general.
Preferably the fuel cell module is located within a container
structure, whereby e.g. the dimensioning and the control of the fire fighting system
may be designed more exactly to increase efficiency, also with a benefit of cost
The fire detection sensor advantageously comprises a smoke
detector and/or a heat detector, whereby also detection of gas fires would be sufficiently
The fire extinguishing medium nozzle and, if employed,
auxiliary nozzle may be connected to a fire extinguishing medium supply comprising
a dedicated container and/or a common supply network. This allows for utilising
the general fire extinguishing medium on board the marine vessel, depending on the
substance, and also utilising a specific fire fighting medium when desired.
Preferably the fire extinguishing medium comprises CO2
which is both effective and generally available on board a marine vessel. CO2
is also practical to use in the form of dedicated containers or bottles. In case
the fuel cell arrangement comprises a MCFC (Molten Carbonate Fuel Cell) the CO2
may be made available from the fuel recirculation process of the fuel cell process,
which would reduce the need of an external supply of CO2. As an alternative
to CO2 an inert gas, advantageously N2, may also be used.
These arrangements ensure an improved extinguishing effect, reduced damage as well
as an elimination of risks of electric short circuiting.
Additionally, water mist may be utilised as a supplementary
fire extinguishing medium for specific purposes, such as for cooling a hot box of
a fuel cell module or for cooling the walls and roof of a fuel cell module, or of
an enclosing container structure, from the outside.
The fire extinguishing medium nozzle and, if employed,
the auxiliary nozzle, are advantageously provided with a manual and/or automatic
For further security, the fire extinguishing system is
advantageously provided with automatic shutdown of e.g. air inlets, fuel feed devices,
exhaust outlets, and any other connections of the fuel cell module to the surrounding
in order to limit any spreading of the fire and to close the fuel cell module from
In the following the present invention is described in
more detail, by way of example only, with reference to the attached schematic drawings,
- Fig. 1 shows a first embodiment of a fire extinguishing system according to
the invention, and
- Fig. 2 shows a second embodiment of a fire extinguishing system according to
Fig. 1 shows a general view of a fuel cell arrangement
in the form of a fuel cell module 2. The fuel cell module 2 is located in an engine
room 1 of a marine vessel. In this embodiment the fuel cell module 2 is enclosed
within a container structure 3 provided with side walls 4 and a roof 5. The fuel
cell module 2 comprises a number of components. Fig. 1 only generally indicates
some components as an example, i.e. a fuel cell stack 6, auxiliary equipment 7,
including e.g. a fuel reformer, heat exchangers, pumps, etc. and a power conditioning
apparatus 8, including e.g. an electric inverter and a transformer.
The fuel cell module is provided with a fire detection
sensor 9 inside the module. The fire detection sensor 9 advantageously comprises
a smoke detector and a heat detector in order to ensure the detection of gas fires.
Furthermore, the fuel cell module 2 comprises an internal nozzle 10 for releasing
a fire extinguishing medium into the fuel cell module. The fire detection sensor
9 and the internal nozzle 10 are located in the vicinity of the roof 5 of the container
structure 3. The internal nozzle 10 is in fluid communication with a fire extinguishing
medium supply 12 outside the container structure 3 by means of a pipe 11.
The fire extinguishing medium supply may be a dedicated
container or bottle or alternatively a supply network onboard the marine vessel.
This depends on the circumstances and the choice of fire extinguishing medium.
A preferable fire extinguishing medium is CO2
which provides excellent fire extinguishing qualities, and in addition, is generally
found onboard marine vessels since it is commonly used for fire fighting, particularly
in engine rooms, on marine vessels. In the latter case there usually is a CO2
supply network onboard, to which network the fire extinguishing medium supply pipe
11 may be connected. CO2 may of course by supplied in dedicated containers
or bottles as well, which are connected to said pipe.
An alternative fire extinguishing medium could be an inert
gas, such as N2.
The fuel cell module 2 is further provided with a fuel
feed device 13 with a fuel shutdown vent 14, an exhaust outlet 15 with an exhaust
shutdown vent 16 and an air inlet 17 with an inlet shutdown vent 18.
Basically the fuel cell module 2 thus provides a closed
structure with respect to the surrounding engine room 1 where the fuel cell module
2 is located, except for means such as the above mentioned fuel feed device, exhaust
outlet and air inlet, and possible other inlets and outlets to the engine room.
In the case of a fire in the fuel cell module 2, the fire
detection sensor 9 reacts and may be programmed to immediately release a fire extinguishing
medium from the fire extinguishing medium supply 12 through the pipe 11 to the internal
nozzle 10, which then sprays the fire extinguishing medium, indicated by reference
numeral 19, over the fire 20, which in Fig. 1 has started in the auxiliary equipment
7. The response is immediate and gives excellent fire damage control. By choosing
a suitable fire extinguishing medium, any other damage to the pertinent component
and any other components may be avoided.
The release may also be arranged to be manual, if so desired.
The signal to release the fire extinguishing medium is
advantageously coupled to an automatic shutdown of the connections of the fuel cell
module 2 to the surrounding. In this embodiment this would mean the automatic closing
of the fuel shutdown vent 14 of the fuel feed device 13, the exhaust shutdown vent
16 of the exhaust outlet 15 and the air inlet shutdown vent 18 of the air inlet
17. These measures would ensure the isolation of the fire to the fuel cell module.
These kinds of control systems and shutdown arrangements
are not discussed in detail in this connection, since they are known to a person
skilled in the art.
The embodiment according to Fig. 2 generally corresponds
to the embodiment of Fig. 1, whereby the same reference numerals have been used
for the corresponding parts, and are therefore not discussed in detail in connection
with this embodiment.
In this embodiment, however, the fuel cell module 2 is
provided with two auxiliary nozzles 21. One auxiliary nozzle 21 is located just
above the fuel cell stack 6 and is in fluid communication with the fire extinguishing
medium supply 12 through a branch line 22 connecting to the pipe 11. The other auxiliary
nozzle 21 is located just above the power conditioning apparatus 8 and is in fluid
communication with a fire extinguishing medium supply 12, in this case shown as
a dedicated container or bottle, through an auxiliary pipe 23. The basic idea of
this set up is to have a fire fighting system directly focused on one or more separate
The control and function of such auxiliary arrangements
can generally be the same as discussed above. Furthermore, if desired, these arrangements
could include dedicated fire detection sensors (not shown). The fuel cell module
could also be provided only with such directly focused nozzles depending on its
In addition to the above, the fire extinguishing system
according to the invention could have water mist as a supplementary fire extinguishing
medium. In practice this could include water mist sprinklers (not shown) located
at desired points, such as outside the sidewalls 4 and roof 5 of the container structure
3 for cooling purposes. Water mist sprinklers could also be located in connection
with specific components. These supplementary arrangements should of course be designed
so that the water would not cause thereto related damages, such as electric short
In the description above, the present invention has been
described only in relation to one fuel cell module. It is to be understood that
engine rooms may comprise more than one, or even multiple fuel cell modules.
The drawings and the description related thereto are only
intended for clarification of the basic idea of the invention. The invention may
vary in detail within the scope of the ensuing claims.