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(12) United States Patent (10) Patent No.: US 7,935,450 B2 Preidel Et Al

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(12) United States Patent (10) Patent No.: US 7,935,450 B2 Preidel Et Al US00793545OB2 (12) United States Patent (10) Patent No.: US 7,935,450 B2 Preidel et al. (45) Date of Patent: May 3, 2011 (54) METHOD FOR OPERATION OF AN ENERGY (56) References Cited SYSTEM, ASWELLAS AN ENERGY SYSTEM U.S. PATENT DOCUMENTS (75) Inventors: Walter Preidel, Erlangen (DE); Bernd Wacker, Herzogenaurach (DE); Peter 4,617,801 A 10/1986 Clark, Jr. Van Hasselt, Erlangen (DE) FOREIGN PATENT DOCUMENTS DE 36 34.936 C1 5, 1988 (73) Assignee: Siemens Aktiengesellschaft, Munich DE 39 08573 C2 3, 1992 (DE) WO WO O2, 14736 * 2/2OO2 WO WO O2, 1473.6 A1 2, 2002 (*) Notice: Subject to any disclaimer, the term of this WO WOO2,24523 A2 3, 2002 patent is extended or adjusted under 35 * cited by examiner U.S.C. 154(b) by 1079 days. Primary Examiner — Ula C. Ruddock (21) Appl. No.: 11/723,268 Assistant Examiner — Thomas H. Parsons (22) Filed: Mar 19, 2007 (74) Attorney, Agent, or Firm — Harness, Dickey & Pierce, P.L.C. (65) Prior Publication Data US 2007/O248849 A1 Oct. 25, 2007 (57) ABSTRACT An energy system, in at least one embodiment, includes an (30) Foreign Application Priority Data energy production device for production of energy for the Mar. 20, 2006 (DE) ......................... 10 2006 O12 679 energy system with the aid of an working medium, a Super conductor for low-loss conduction of electrical energy in the (51) Int. Cl. energy system, and a cooling device for cooling of the Super HOLM 8/04 (2006.01) conductor with the aid of a liquid phase of a cooling medium. HOLM 8/06 (2006.01) The liquid phase of the cooling medium is, according to at HOLM 8/00 (2006.01) least one embodiment of the invention, produced in the cool HOIF 6/06 (2006.01) ing device by condensation of a gaseous phase of the cooling HOB 12/00 (2006.01) medium, with the condensation of the gaseous phase of the (52) U.S. Cl. ........ 429/439; 429/408; 429/535; 505/163; cooling medium taking place by heat transfer from the gas 174f125.1 eous phase of the cooling medium to the working medium. (58) Field of Classification Search .................... 429/13, The overall efficiency of the energy system can improved by 429/26, 439,535, 408; 62/7: 505/163; 310/52–58: the heat transfer step. 174f125.1 See application file for complete search history. 20 Claims, 2 Drawing Sheets U.S. Patent May 3, 2011 Sheet 1 of 2 US 7,935,450 B2 FIG 1 1. 7 17 13 10- 32 14 N16 12 22 3 9- 21 4 N6 11 U.S. Patent May 3, 2011 Sheet 2 of 2 US 7,935,450 B2 FIG 2 53 54 US 7,935,450 B2 1. 2 METHOD FOR OPERATION OF AN ENERGY which projects into the cryostat, and nitrogen that has been SYSTEM, ASWELLAS AN ENERGY SYSTEM vaporized in the cryostatis liquefied again by recondensation. For this purpose, the cold head absorbs heat from the vapor PRIORITY STATEMENT ized nitrogen. In addition, the electrical power bushings which extend The present application hereby claims priority under 35 into the cryostat from the outside are cooled with the aid of a U.S.C. S 119 on German patent application No. DE 10 2006 second cooling device, in order to reduce the heat that is 012 679.3 filed Mar. 20, 2006, the entire contents of which is introduced into the cryostat. The second cooling device has a hereby incorporated herein by reference. cooling medium with a boiling point which is higher than the 10 condensation temperature of the liquid oxygen. The second FIELD cooling medium is, for example, liquid oxygen for operation of the fuel cell, which is stored in a liquid oxygen tank on Embodiments of the present application generally relate to board the submarine. The heat transfer from the electrical a method for operation of an energy system, and/or to an power Supplies to the liquid oxygen results in vaporization of energy System. 15 the liquid oxygen and, as a result of its vaporization enthalpy BACKGROUND in cooling of the electrical power Supplies. This on the one hand reduces the amount of heat introduced into the cryostat, An energy system is known, for example, from WO and thus the electrical power consumed by the compressor of 02/14736A1. the first cooling device, while on the other hand reducing the One or more working media Such as fuels, propellants or energy required for vaporization of the liquid oxygen, thus, cooling media, is or are required for operation of an energy overall, increasing the overall efficiency of the energy system. production device, depending on the nature of the energy produced (for example electrical energy, mechanical energy SUMMARY or thermal energy), the way in which the energy is produced 25 and the operating conditions. One example of this is a fuel Against this background, in at least one embodiment a cell, whose working media are hydrogen and oxygen. method is specificed for operation of an energy system, by Particularly for energy systems in mobile applications, which the overall efficiency of the energy system can be there is a requirement for the working media to be stored with improved even further. a high energy density in as Small a space as possible. For this 30 The method according to at least one embodiment of the purpose, the working media can be stored in liquid form at invention provides for the liquid phase of the cooling medium high pressure. In submarines, for example, hydrogen and to be produced in the cooling device by condensation of a oxygen for fuel cells are thus stored in special pressurized gaseous phase of the cooling medium, with the condensation tanks in liquid form at 5-6 bar. However, storage of a working of the gaseous phase of the cooling medium taking place by medium in liquid form has the disadvantage that it must be 35 heat transfer from the gaseous phase of the cooling medium to vaporized again, with energy being added, for use in the fuel the working medium. cell. The liquefaction of the cooling medium and thus the cool Superconductors, and in this case in particular high-tem ing of the Superconductor thus take place by way of the perature superconductors from the family of YBCO conduc working medium which is required for energy production, for tors or bismuth cuprates, are already being used as low-loss 40 example of a fuel. This allows the energy required by the conductors of electrical energy for initial applications in a cooling device to cool the Superconductor to be reduced, thus large number of different electrical devices. These include increasing the overall efficiency of the energy system. In the rotating electrical machines, which operate as motors and/or best case, there is no need whatsoever for a refrigerator sys generators, and whose stators and/or rotors are equipped with tem with a cold head and a compressor or a similar conven windings composed of a Superconductor material, or static 45 tional device for liquefaction of the cooling medium, and this electrical devices such as current limiters or transformers. is associated with low investment costs as well as lower One disadvantage of the use of a Superconductor is the energy maintenance costs (life cycle costs), and higher reliability which must be added for a cooling device, with the aid of owing to the absence of the moving parts that are normally which the Superconductor is cooled to the temperature, nor used in the refrigerator system. mally of 20-100 K, which is required to maintain supercon 50 In this case, an energy production device includes any type ductivity. of device for production of energy in a technically usable The use of fuel cells to produce electrical energy, and of form, for example electrical energy, mechanical energy or electrical devices with Superconductors in a joint system is thermal energy. This includes, for example fuel cells, internal currently being investigated for widely varying energy sys combustion engines as well as gas turbines and steam tur tems. These include energy generators, distributors and load 55 bines. installations on marine vessels (see for example WO02/ According to one advantageous refinement of the method 24523A1), large-machine installations and electrical traction according to at least one embodiment of the invention, the systems for heavy-goods transports and locomotives. How energy production device is operated with a gaseous phase of ever, the energy that is required to liquefy the fuel and to cool the working medium, with the gaseous phase of the working the Superconductor reduces the overall efficiency of energy 60 medium being produced by vaporization of a liquid phase of systems such as these. the working medium, and with the heat transfer taking place WO 02/14736A1 discloses an energy system for a subma from the gaseous phase of the cooling medium to the liquid rine having a fuel cell, and having a current limiter with a phase of the working medium. The enthalpy of vaporization high-temperature Superconductor. In this case, the Supercon or the latent heat of vaporization of the working medium is ductor is cooled in a cryostatusing liquid nitrogen. The liquid 65 thus used to cool the Superconductor. At the same time, this nitrogen is in turn cooled by a first cooling device in the form reduces the energy required by the cooling device to cool the of a so-called refrigerator. The refrigerator has a cold head Superconductor, and the energy required to vaporize the US 7,935,450 B2 3 4 working medium, thus making it possible to improve the An energy system according to at least one embodiment of overall efficiency of the energy system particularly well.
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