The invention relates to a method for providing a compressed air source according to the preamble of claim 1 and an arrangement according to the preamble of claim. 6
In pneumatic applications, the use of compressed air sources is required, with which, for example, drive units, such as a piston engine, are supplied with compressed air. Such compressed air sources may be exemplified pressure vessel or alternatively compressors. The compressed air sources may alternatively be part of a device for the recovery of fresh water, in which the compressed air under expansion cools a condensation surface at which water can precipitate out of the ambient air. The precipitated on the condensation surface water can be collected and supplied, for example, a fresh water supply.
In a generic method for providing a compressed air source, at least one pressure vessel located in a loading position is filled with compressed air in a charging step. The filling process is carried out under weight gain, in which the pressure vessel is filled from a reduced weight (that is, in its empty state) to a contrast greatly increased weight with compressed air. Subsequently, the pressure vessel filled with compressed air can be used in a position of use as a compressed air source, for example to supply a drive unit or the like.
In the above prior art, the pressure vessel may be filled with the compressed air by way of example by means of an electrically operated compressor under pressure energy build-up. The pressure energy stored in the pressure vessel is subsequently used for purposes of use, for example for supplying a drive unit. However, the conversion of the electrical energy required for the compression process into the pressure energy is associated with comparatively high energy losses in the prior art.
From the DE 10 2009 036 640 A1
is a mechanical lifting device with chain lift known. The lifting device thereby generates potential energy that heavier mass carriers are raised using electrical energy. The potential energy of the mass carriers is reduced in order to transform the losses of the lifting device by lowering the mass carriers back into electricity via generators. From the DE 10 2011 012 594 A1
a hydraulic energy storage is known, which has a first and a second fluid reservoir. The two fluid reservoirs are connected to one another via a turbine pump arrangement. In operation, a fluid is reciprocable between the first and second fluid reservoirs, thereby converting energy. From the DE 10 2005 015 169 A1
is a dynamic energy storage known, with the use of pressurized medium as an energy reservoir for a machine assembly is environmentally friendly and inexpensive.
The object of the invention is to provide a method and a device for providing a compressed air source, in which a more energy-efficient provision of the compressed air source is made possible in comparison to the prior art.
The object is solved by the features of the independent claims 1 and 6. Preferred embodiments of the invention are disclosed in the subclaims.
The invention is based on the problem that high energy losses occur in the conversion of the energy required for the compression process into the pressure energy stored in the pressure vessel. Against this background, the general idea of the invention is to use the energy associated with the filling of the pressure vessel with compressed air weight gain of the pressure vessel energetically, whereby the total energy efficiency can be increased to provide the filled with compressed air pressure vessel. Against this background, after the charging step has been carried out, a lowering step takes place in which the pressure vessel now having increased weight is moved downwards by a vertical displacement to the use position, using the kinetic energy obtained by the downward movement of the pressure vessel. Preferably, before carrying out the charging step (that is, the compressed air filling process), a lifting step take place in which the pressure vessel having the reduced weight force is moved upwards in the loading position by a height offset.
Preferably, the internal pressure of the pressure vessel, which still has a reduced weight, is essentially identical to the ambient pressure. In contrast, the pressure vessel having increased weight after the charging process can have an internal pressure which is many times greater than the ambient pressure. By way of example, internal pressures of the order of 900 bar can be achieved.
With the above invention can be achieved by way of example with an internal volume of the pressure vessel of 1 m 3 and a filling pressure of 900 bar, an increase in weight by about 1000 kg. In this case, by way of example, at a curb weight of the Container of 200 kg after the loading step of the container has a total weight of 1200 kg.
The up and down movements of the pressure vessel may preferably be carried out by means of a conveying device, in particular a freight elevator. The freight elevator may preferably have a brake unit, with which the downward movement of the pressure vessel is braked to the use position. To use the kinetic energy obtained during the downward movement, the brake unit can operate as a recuperation brake with which the kinetic energy gained is converted into electrical energy under braking deceleration. By way of example, the conveyor may comprise an electric machine which operates as a drive motor in a lifting movement up to the geodesically upper loading position, and works in a downward movement in the generator mode, in which the kinetic energy is recovered into the electrical energy while building up a braking force.
Accordingly, the relatively empty in the empty state pressure vessel can be promoted with reduced weight up to its loading position. In the loading position, the pressure vessel can be filled with the compressed air while building up the weight. Subsequently, using the added weight force of the pressure vessel, the downward movement is carried out, which is converted into electrical energy, for example, by means of the braking unit.
The charging station can in a technical realization have a compressor, with which the pressure vessel can be filled in common practice with the compressed air. The above-mentioned conveyor may, as mentioned, be a load elevator with which the pressure vessel is conveyable in a load cage between the upper loading position and the lower use position. In addition, the arrangement may have a lower unloading station, in which the pressure vessel is arranged in its use position. Both the unloading station and the loading station may have compressed air coupling points, with which a filling / emptying of the pressure vessel is made possible without removing the pressure vessel from the conveyor. This means that preferably the compressed air coupling points are positioned in the loading and / or unloading stations such that the filling and / or emptying process can be carried out at the pressure vessel remaining in the load cage of the load elevator.
To further increase energy efficiency, the compressor of the charging station can be assigned a water cooling with a heat exchanger. In compressor operation, the generated heat can be dissipated to heat exchangers. The heat exchanger may in particular be part of a heating system, for example for a building, in which the compressor waste heat can be used.
The advantageous embodiments and / or further developments of the invention explained above and / or reproduced in the dependent claims can be used individually or else in any desired combination with one another, for example, in cases of unambiguous dependencies or incompatible alternatives.
The invention and its advantageous embodiments and further developments and advantages thereof are explained in more detail below with reference to drawings.
1 in a rough schematic representation of an arrangement for providing a compressed air source;
2 to 4 each views according to the 1 illustrating the method of providing the compressed air source.
In the 1 is a freight elevator 1 indicated by way of example as a conveyor for carrying out the method according to the invention is usable. the load elevator can be arranged by way of example in a lift shaft of a high-rise building
The freight elevator 1 is shown and explained in terms of its construction and operation only insofar as it is necessary for understanding the invention. Consequently, the load elevator points 1 in the 1 vertically spaced cable drums 2 . 3 on. The two rope drums 1 . 3 are about a rope element 5 in operative connection with each other.
On the rope element 5 is in the 1 For example, only an indicated load basket 7 hinged, on which a pressure vessel 9 is positioned. The pressure vessel 9 has a pressure connection 11 with an indicated check valve on. About the pressure connection 11 can compressed air in the pressure vessel 9 initiated or alternatively from the pressure vessel 9 be led out.
The lower cable drum 3 is by means of an electric machine 13 drivable, which in turn can be controlled in common practice with a control unit, not shown. As will be described later, the electric machine 13 not only in the motor, but also in the generator mode, that is to say as a recuperation brake work, by means of a downward movement II ( 3 ) of the pressure vessel 9 is braked, under Transformation of kinetic energy from the downward movement II of the pressure vessel 9 in electrical energy, which in the figures by way of example in an accumulator 27 can be stored.
Like from the 1 further shows, the arrangement has approximately at the height of the upper cable drum 2 an upper charging station 15 as well as at the height of the lower cable drum 3 one under unloading station 21 which is offset by a height offset Δh ( 1 ) below the upper charging station 15 is arranged. The upper charging station 15 consists of a compressor 17 , which at its pressure side a compressed air coupling point 19 and whose suction side is connected to the ambient air.
In the lower unloading station 21 there is another compressed air coupling point 23 from which a supply line 25 to a compressed air consumer, not shown, for example, a piston engine, is guided. By means of the load elevator 1 can the pressure vessel 9 between the lower unloading station 21 and the upper charging station 15 be adjusted.
The following is based on the 1 and 4 the method of using the pressure vessel 9 described as compressed air source: So is located in the 1 the pressure vessel 9 still in its lower position, that is in the use position G at the level of the unloading station 21 , The still empty pressure vessel 9 has an internal pressure p i , which is here for example identical to the ambient pressure p u . Accordingly, the pressure vessel 9 only a reduced weight G empty . Subsequently, the pressure vessel 9 by means of the freight elevator 1 in an upward movement I by the height offset Δh ( 1 ) up to its loading position L at the level of the charging station 15 adjusted ( 2 ). In the loading position L is the still empty, to the compressor side coupling point 19 connected pressure vessels 9 by means of the compressor 17 filled with compressed air. The filling process takes place under weight gain, in which the weight G empty of the pressure vessel 9 increases to an increased weight G fully at the end of the filling process ( 3 ). In the 3 is the internal pressure p i of the pressure vessel 9 after the filling process, for example at 900 bar.
With an internal volume of 1 m 3 , the filling process results in a weight gain of about 1000 kg. That means that the pressure vessel 9 for example, at a curb weight of 200 kg after the filling of the pressure vessel 9 has a final weight of 1200 kg. According to the invention, this weight increase during the subsequent lowering step ( 3 ) used. During the lowering step, the pressure vessel, which has the increased weight G, becomes full 9 in a downward movement II by the height offset .DELTA.h down into its use position G (that is, in the lower unloading station 21 ), as it is in the 4 is shown.
The electric machine 13 of the freight elevator 1 works in the implementation of the lifting step as a drive motor to the still empty pressure vessel 9 in the charging station 15 to adjust. In contrast, the electric machine works 13 operate during the lowering step as a recuperation brake in regenerative operation. That means it is under braking deceleration of the pressure vessel 9 whose kinetic energy is converted into electrical energy. The thus obtained electrical energy is in the accumulator 27 cached. In his, in the 4 shown use position G has the pressure vessel 9 As before, an internal pressure p i of 900 bar and can thus be used as a compressed air source for any pneumatic applications. According to the 4 the pressure vessel remains 9 stationary in the load basket 7 and gets over its pressure connection 11 to the coupling point 23 the unloading station 21 connected, whereby over their supply line 25 a pressure supply to a compressed air end consumer, not shown, takes place. Alternatively, the filled pressure vessel 11 be transported by another funding to the site of use.
According to a further embodiment, the compressor 17 a water cooling 29 be assigned as it is only in the 3 is indicated. The water cooling 29 points in the 3 a heat exchanger 31 on, by means of which the heat generated in the compressor operation can be derived. The heat exchanger 31 may be an example of a building heating of a high-rise building, which in addition also the compressor waste heat is energy efficient usable.
LIST OF REFERENCE NUMBERS
- 2, 3
- cable drums
- cable element
- pressure vessel
- pressure connection
- electric machine
- charging station
- coupling point
- coupling point
- supply line
- water cooling
- heat exchangers
- height offset
- p i
- Pressure vessel internal pressure
- p u
- ambient pressure
- G empty , G full
- weight forces
- I, II
- Up and down movements