DEVICE FOR COOLING AN ENERGY ACCUMULATOR

Description

PRIORITY STATEMENT

This application is the national phase under 35 U.S.C. §371 of PCT International Application No. PCT/EP2008/061557 which has an International filing date of Sep. 2, 2008, which designates the United States of America, and which claims priority on German patent application number DE 10 2007 046 369.5 filed Sep. 27, 2007, the entire contents of each of which are hereby incorporated herein by reference.

FIELD

At least one embodiment of the invention generally relates to a device for cooling an energy accumulator in a rail vehicle.

BACKGROUND

Energy accumulators may be provided in rail vehicles for different purposes. In particular, powerful energy accumulators are necessary in order to be able to operate a rail vehicle, for example a streetcar without an external supply of energy, at least in certain sections of a route. Sections of a route without an overhead line or power rail are desired if a streetcar is to be routed through a narrow street or through a pedestrian zone.

In an energy accumulator, particularly in a powerful energy accumulator such as is necessary for operating a streetcar, heating of the energy accumulator occurs due to internal power losses. This inputting of heat leads to a shortening of the service life of the energy accumulator.

It has already been proposed to provide air cooling or water cooling in order to cool an energy accumulator. Such cooling is not effective enough for energy accumulators which are subject to heavy electrical and thermal loading.

SUMMARY

At least one embodiment of the invention specifies a device for cooling an energy accumulator in a rail vehicle which permits more effective cooling than hitherto.

In least one embodiment of the invention, the energy accumulator has a direct thermal connection to an evaporator, and/or the evaporator and a condenser are components of a circuit of a refrigerator.

The refrigerator provides the advantage that the heat produced in the energy accumulator is quickly and reliably conducted away. The circulating process of the refrigerator means that sufficient coolant is always available. It is therefore possible to reliably cool even energy accumulators which are subject to heavy electrical and thermal loading. The advantage is also obtained that a plurality of energy accumulators can be installed with a significantly smaller distance between them than was possible hitherto and that nevertheless there is a good cooling facility. An additional advantage is that such a refrigerator operates with little noise so that fewer disruptive noises occur than is the case, for example, when there is a coolant blower.

For example, the evaporator is connected as a component of a compression refrigerator to the condenser via a compressor, and the condenser is connected to the evaporator via a throttle.

According to another example, the evaporator is connected as a component of an absorption refrigerator to the condenser via a compressor, and the condenser is connected to the evaporator via a thermal compressor.

Both a compression refrigerator and an absorption refrigerator provide the advantage that even energy accumulators which are subject to heavy electrical and thermal loading can be cooled reliably.

The compression refrigerator and the absorption refrigerator are known as such. While in the case of the compression refrigerator the condensed coolant is compressed only by a throttle and is then fed to the evaporator, the absorption refrigerator is provided with a thermal compressor which is a solution circuit. The coolant is firstly dissolved in a fluid there, with heat being emitted. The dissolved coolant is then expelled from the solution by supplying external heat. After this process, the coolant has a higher density than before.

In order to conduct thermal energy out of the thermal compressor, the latter has a thermal connection, for example, to a heating circuit for heating the passenger compartment of the rail vehicle. The heat which is generated is therefore advantageously utilized.

In order to feed thermal energy to the thermal compressor, the latter has a thermal connection, for example, to a waste heat line of the rail vehicle. In order to expel the coolant from the solution, it is in fact necessary to feed in thermal energy from the outside. Utilizing the waste heat line of the rail vehicle provides the advantage that this thermal energy does not have to be generated separately.

The energy accumulator is, for example, an electric energy accumulator such as, for example, an UltraCap or a double-layer condenser.

According to another example, the energy accumulator is an electrochemical energy accumulator such as, for example, a battery. Such a battery may be, for example, a nickel-cadmium battery.

For example, a plurality of energy accumulators are connected to just one evaporator. Since the power of just one refrigerator is sufficient to conduct the heat generated away from a plurality of energy accumulators, the cooling of a plurality of energy accumulators in a small space is advantageously made possible.

For example, the condenser has a thermal connection to a heating circuit for heating the passenger compartment of the rail vehicle. Heat which is generated in the condenser of the refrigerator is therefore advantageously utilized.

In order to perform open-loop/closed-loop control of the cooling process, a control unit, for example, is provided in the rail vehicle. This provides the advantage that the cooling process can be adapted to the requirements.

For example, the control unit is composed of a plurality of units which can, if appropriate, be arranged distributed in the rail vehicle.

The energy accumulators which are to be cooled may be located in the vehicle head in the rail vehicle or at some other location within the vehicle, on the roof or under the floor. The rail vehicle can be a streetcar, an urban railway or a long distance train. The device for cooling the energy accumulator can, however, also be used in a locomotive, for example a shunting locomotive, or in a track-guided vehicle with rubber tires.

The device according to at least one embodiment of the invention provides in particular the advantage that even energy accumulators which are subject to heavy electrical and thermal loading, and correspondingly a series of energy accumulators arranged closely one next to the other, can be reliably cooled with little noise. As a result, the service life of the energy accumulators is significantly increased. The device is particularly suitable for arrangement in a streetcar which is intended to travel without an external energy supply at least in certain parts of its route.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments of a device for cooling an energy accumulator in a rail vehicle will be explained in more detail with reference to the drawing:

FIG. 1 shows a device with a compression refrigerator, and

FIG. 2 shows a device with an absorption refrigerator.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

According to FIG. 1, an energy accumulator 1 which is located in a rail vehicle and can be a battery or an electric condenser has a direct thermal connection to an evaporator 2 of a compression refrigerator 3. In the compression refrigerator 3, the evaporator 2 is connected via a compressor 4 to a condenser 5 which is connected again to the evaporator 2 via a throttle 6 so as to form a circuit. While the evaporator 2 absorbs heat from the energy accumulator 1, the condenser 5 outputs the heat to the surroundings. The coolant flows in the form of gas from the evaporator 2 to the condenser 5 and in the form of liquid from the condenser 5 to the evaporator 2.

According to FIG. 2, the energy accumulator 1 also has a direct thermal connection to the evaporator 2. The evaporator 2 is a component of an absorption refrigerator 7 in which, as in the case of the compression refrigerator 3 (FIG. 1) the evaporator 2 is connected to a condenser 5 via a compressor 4. However, in the absorption refrigerator 7 the condenser 5 is connected again to the evaporator 2 via a thermal compressor 8 so as to form a circuit. This thermal compressor 8 is a solution circuit. The coolant is dissolved there in a liquid within an absorber 9 and is then expelled again from the liquid within an expulsion device 10. As a result, the coolant is compressed. The expulsion device 10 has to have thermal energy fed to it, while the absorber 9 outputs thermal energy. In order to feed in heat, the expulsion device 10 has a thermal connection to a waste heat line 11 of the rail vehicle. In order to utilize the heat output by the absorber 9, the latter has a thermal connection to a heating circuit 12 which supplies, for example, the passenger compartment heating system of the rail vehicle. The solution passes through a first line 13, into which a solution pump 14 and the secondary side (cold side) of a heat exchanger 15 is connected, from the absorber 9 to the expulsion device 10. The liquid from which coolant has been removed passes from the expulsion device 10 back to the absorber 9 through a second line 16 into which the primary side (warm side) of the heat exchanger 15 has been connected.

Both in the embodiment according to FIG. 1 and in the embodiment according to FIG. 2, in order to utilize the heat output by the condenser 5 the latter has a thermal connection to the heating circuit 12 which supplies, for example, the passenger compartment heating system of the rail vehicle.

With the device for cooling the energy accumulator 1 it is possible to cool a large energy accumulator 1 or a plurality of energy accumulators simultaneously, with the result that a large storage capacity for electrical energy is possible in one rail vehicle. It is possible to operate high-power rail vehicles with such energy accumulators 1 over relatively large distances without an external energy supply.

Example embodiments being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.