Large Amounts Of Electric Power Research Articles

Performance Improvement of an Absorption-Compression Hybrid Heat Transformer by Utilizing the Absorber and Generator in Close-to-Equilibrium Operation.

A multiple-compartment absorber and generator in close-to-equilibrium operation is implemented in a single stage absorption-compression hybrid heat transformer. It is found that by utilization of a multiple-compartment absorber and generator in close-to-equilibrium operation, the high exergy efficiency and wide temperature range of heat source can be obtained. Further, a large amount of electric power can be saved.

Design of High Energy Density Thermoelectric Energy Conversion Unit by Using FGM Compliant Pads

In order to provide increasingly large amounts of electrical power to space and terrestrial systems with a sufficiently high level of reliability at a reasonable cost, thermoelectric (TE) energy conversion system by using Functionally Graded Material (FGM) compliant pads has been focused. To achieve high thermal energy density in TE power conversion systems, conductively coupling the TE units to the hot and cold heat exchangers is the most effective configuration. This is accomplished by two sets of FGM compliant pads. This design strategy provides (1) a high flux, direct conduction path to heat source and heat sink, (2) the structural flexibility to protect the cell from high stress due to thermal expansion, (3) an extended durability by a simple FGM structure, and (4) manufacturing cost reduction by spark plasma sintering. High thermal energy density of ten times as much as conventional radioisotope thermoelectric generator is expected. Manufacturing of Cu/Al 2 O 3 /Cu symmetrical FGM compliant pads by spark plasma sintering (SPS) and overall assembling of TE unit are also discussed.

Strategies for Carbon Reduction

Strategies for Carbon Reduction

高温超電導ケーブルシステムの開発

In order to supply large amounts of electric power to meet increasing demand, a high-Tc superconducting cable compact enough to be applied to ducts without construction of new underground tunnels is desired. There are, however, many key technologies which are necessary to develop long high-Tc cables capable of large capacity in compact size. For the purpose of studying these technologies, two systems were developed and tested. At the first step, a 7m long, 3-phase 1kA superconducting cable system was developed to study issues concerning large current loading. The measurements of AC losses and inductance show that total AC loss of this cable was 3.5W/m/cct at 1kA loading, that hysteretic loss was dominant, and that the magnetic shields were effective enough to reduce the eddy current losses in thermally insulated pipe. As the next step, a 30m long, 66kV-1kA high-Tc superconducting cable system prototype was developed to study issues for long-length cables. In this system, an AC current of 40kV-1kA was successfully applied in sub-cooled liquid nitrogen (72K, 1.2kg/cm2abs) regardless of mechanical history, such as handling in the factory, transportation, laying and the axial force due to contraction during cool down.

Experimental study of the performance characteristics of a steam-ejector refrigeration system

Conventional compression-refrigeration systems not only consume a large amount of electric power, but also cause serious environmental pollution. Among the various possible approaches in overcoming these two problems, a steam-ejector refrigeration system is believed to be most effective. This paper experimentally investigates the controlling parameters of a steam ejector, including operating conditions and the exit Mach number of the primary nozzle. Operation maps useful to the practical design are constructed from experimental results, and the empirical equations are correspondingly derived. Excessively increasing the exit Mach number of primary nozzle is unnecessary, and 4.35 should be a moderate value. With regard to the performance characteristics of the ejector itself, a steam ejector is better than an R114 ejector and is comparable to an R113 ejector. Moreover, with the use of a two-stage ejector, the required pressure to drive a steam ejector is reduced, and the low-grade heat source can be efficiently used. The results of primitive observation of the flow field are also discussed in this work.

France, Germany Drop Out of ITER Race

A surprise announcement last week that France and Germany will not be competing to host a multibillion-dollar fusion facility makes Japan the odds-on favorite as the site for the International Thermonuclear Experimental Reactor (ITER)—if it is built. Six nations were originally in the running as host for the reactor, a tokamak-shaped containment vessel that would demonstrate the feasibility of creating large amounts of electrical power. The catch is that the host country must pick up the biggest single share of the costs, which are expected to top $8 billion during a decade of construction. Japanese government and business leaders have said they are willing to put up as much of 70% of the cost, and that the time is long overdue for Asia to be the site of a major research facility.

Contactless Power Delivery System for Mining Applications

The ability to transfer large amounts of electrical power (up to 1 MW) to a moving load has traditionally used means that are unreliable, inefficient, and potentially unsafe. These include sliding or rolling metal contacts, sliding carbon brushes, and trailing cables. More recently, flat inductively coupled coils have been used to help mitigate these problems. Except for the inductively coupled coils, these techniques have not been developed with the capabilities of power electronics in mind. This paper presents the first conceptual description of a power delivery system design unifying power electronics and a coaxial-winding transformer for devices that require a contactless connection and/or relative motion while delivering large amounts of power. The transformer's unique characteristics and how they might be used to advantage in combination with power electronics are emphasized. Potential applications are flexible power distribution, material handling, electric vehicle boost, and battery opportunity recharge. Test results of a small scale prototype are presented and verify these initial concepts.

High Voltage/High Power for Airborne Applications

The Air Force has requirements for large amounts of electrical power at high voltage (up to hundreds of kilovolts) for certain airborne applications. Because of the severe weight and volume constraints, these systems cannot be realized using conventional technology. The Air Force, therefore, has been heavily involved in the development of lightweight power generation and conditioning equipment. Programs have been undertaken to reduce the weight of rotating machines, transformers, switches, inverters, and capacitors. The advances made in these areas are described, and some aspects of the use of these components in the design of lightweight systems are discussed.

Impact of Multiple-Purpose Reservoir System on Regional Environment

In 1933 the Tennessee Valley needed the resource tools with which to improve itself economically. In addition to the tools to rehabilitate agriculture, the TVA provided the developed river. Flood control has made the level land on the shoreline safe from floods and, therefore, safe for industrial use. The waterway provides low-cost barge transportation. The impoundment of water provides abundant supplies for cities and industries. It provides a great source for water-based recreation, vital to the welfare of all in today’s world. And, of course, TVA dams and steam plants provide large amounts of electric power at low cost. Capitalizing on opportunities in the Tennessee Valley in the future will require bold new programs to upgrade the quality of life in the region, particularly in the rural areas. It will require imaginative planning to guide the development of rapidly growing small towns and comprehensive approaches to revitalize existing cities and even create new ones. In some instances, it will require carefully coordinated development.

Wet vs Dry Gas Cleaning In the Steel Industry

Deciding whether the gas should be cleaned by a “dry” system or a “wet” system requires a full consideration of all factors of which the capital cost is only one. Anticipating the various problems which might be expected and designing adequate measures for each calls for major engineering effort,but onlythen can a best choice be made. The principles which govern the above are illustrated by a typical selection of gas cleaning equipment to be used as part of a BOF steel making installation. Two entirely different gas cleaning systems are presently in BOF service in North America. Both will do an excellent job if properly designed. Either system will cost in excess of $2,000,000 and will require careful control and large amounts of electrical power. One system, the dry electrostatic precipitator, requires humidification of the gas; protection against explosions; elaborate electrical controls, insulators, etc.; and a rugged handling system for the bone dry dust collected. The other system, wet washing with water, Is easier to control but uses large quantities of water and electric power. As in the case of the “dry” system, handling the dirt collected is a difficult problem requiring careful study and choice of equipment. In either case the dust may be discarded or reused, but it must be handled with care lest it become an air or stream pollution problem all over again.

Superconducting lines for the transmission of large amounts of electrical power over great distances

As an application of high-field, high-current superconductors we sketch the design of a power transmission line to carry 100 GW (10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sup> watts) of direct current over a distance of 1000 km. (It is interesting to note that the present peak power generating capacity of the United States is approximately 200 GW, or just twice the capacity of the proposed line.) Such a line, in contrast to one made of ordinary metal, would dissipate none of the power transmitted through it, although it is necessary to tap power from the line for refrigeration. The consequences of negligible transmission loss are substantial: power transmission would be more economical than the present practice of shipping coal to the region in which electricity is generated and consumed; generating-plant site selection could be made almost entirely on economic considerations; at the same time, thermal and air-pollution problems could be minimized; novel power sources could be considered. The power line would be made of Nb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Sn and would be refrigerated to 4°K. The power must be transmitted as direct current, rather than as alternating current, because the very large (comparatively) alternating-current losses would require excessive refrigeration capacity. Specifically, we shall discuss a line at 200 kV carrying 0.5 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> A. The investment in the line will be approximately $806 million, or $8.06/kW. Of this, some $6.06/kW is line cost, the remainder being converter cost, which, of course, is the same for an ordinary dc line. In comparison with the shipping of coal, the investment cost would be repaid in ten months. We have investigated in some detail the problems of refrigeration along the line, including those of heat leak through the wires which deliver power to customers at room temperature. The efficiency of the line is greater than 99.9 percent (power transmitted less the power drawn off to run refrigeration equipment, all divided by transmitted power). While the technical discussion is probably correct, the cost figures do not include engineering expeditures and do not consider in detail the costs involved in providing the redundancy and safety factors for, say, a failure rate of one per ten years with a time of a few seconds to restore power. This is not an engineering study but rather a preliminary exploration of feasibility. Provided satisfactory superconducting cable of the nature described can be developed, the use of superconducting lines for power transmission appears feasible. Whether it is necessary or desirable is another matter entirely.

Power System Operation at the Cambridge Electron Accelerator

The laboratory requires a large amount of electric power to produce the high energy particles and perform the physics research. This makes it important to operate the power system with maximum efficiency and economy. This paper discusses the problems and actions taken to accomplish these objectives.

Permanent Electrodes for Magnetohydrodynamic Power Generation

THE principles of magnetohydrodynamic generation have been experimentally verified1, and quite large amounts of electrical power have been produced experimentally using plasmas at temperatures around 2,500° C. obtained from the products of combustion of hydrocarbons with oxygen by seeding with potassium. Brogan et al.2 have generated more than 200 kW. for 9 sec., and Way et al.3 have generated 10 kW. for many minutes; but the electrode surfaces were considerably eroded during the course of both these experiments. One of the major problems is, therefore, to find an electrode which is stable and which will emit electrons (to maintain electronic conductivity in the plasma) into a fast-moving partially ionized gas stream containing carbon monoxide, water vapour and impurities such as sulphur which normally poison low-temperature cathodes, at a pressure of about one atmosphere and a temperature in excess of 2,000° C.

Testing aircraft generators

The modern fighting airplane requires a large amount of electric power for its successful operation. The aircraft generator provides a reliable source of power at the lowest possible weight. The development of these generators has required close co ordination of design, testing, and interpretation of test results. The tests include raw material, parts, laboratory, life, mechanical, and flight tests. This paper describes tests which have been made and the interpretations which have led to improvements in d-c aircraft generators.

Testing Aircraft Generators

The modern fighting airplane requires a large amount of electric power for its successful operation. The aircraft generator provides a reliable source of power at the lowest possible weight. The development of these generators has required close co-ordination of design, testing, and interpretation of test results. The tests include raw material, parts, laboratory, life, mechanical, and flight tests. This paper describes tests which have been made and the interpretations which have led to improvements in d-c aircraft generators.

The measurement of the energy of cosmic rays I—The electro-magnet and cloud chamber

1—The Construction and Performance of the Electro-Magnet The energy of the cosmic ray particles has been determined from the curvature of their tracks in a strong magnetic field by Kunze, and by Anderson. Kunze used a power of 500 kw in a copper solenoid weighing 1100 kg to give a magnetic field of 18,400 gauss over a chamber 16⋅4 cm in diameter. Anderson used an electro-magnet with heavy water-cooled copper coils and a relatively light iron yoke. A power of 440 kw gave a field of 15,000 gauss over a chamber 16⋅5 cm in diameter, the actual length of the tracks photographed being about 12 cm. In order to obtain a similar performance without the use of such a very large amount of electric power, an electro-magnet has been constructed of a more conventional design, that is with an iron yoke which is heavy compared with the weight of the copper coils. The iron yoke weighs about 8000 kg and the copper coils 3000 kg. Figs. 1 a and 1 b show the detail of the design, and fig. 2 shows a photograph of the magnet in use with the cloud chamber and subsidiary apparatus. The diameter of the pole face is 25 cm, and the gap can be varied from 5 to 20 cm by sliding one pole piece along the baseplate by means of a screw.

Insulators for Switchgear and Busbars

AT present there is a great demand for insulators for high voltage outdoor isolating switchgear. With a pressure of 132,000 volts and a high mechanical stress, the greatest care has to be used in thei»design, as any breakdown in the continuity of supply of a large amount of electric power may disorganise many factories. In the usual design of high pressure insulators, cement is used inside the porcelain to join the shells and the metal parts together. Any expansion of the cement imposes bursting stresses on the porcelain, which often cracks. Some manufacturers, with this danger in view, sacrifice some of the mechanical strength of the joint by inserting elastic layers of bitumastic paint and, in addition, dilute the cement with sand to reduce the percentage expansion. Continental engineers have recently been using insulators in which internal cement layers have been entirely eliminated. They consist of porcelain cylinders carrying suitable projections called rain-sheds and containing no cement layers. The elasticity of the flanges takes up the expansion of the cement. This cylindrical construction has been developed in Great Britain by Messrs. Steatite and Porcelain Products, Ltd., who export them abroad. They now supply 132 kv. cylindrical type switchgear insulators for the substations of the latest section of the British grid. The disadvantage of the wide base customary with this type of insulator has been overcome by the introduction of ah ingenious series of flanged castings, so made that all the standard methods of fixing now in use can be applied to the cylindrical insulators. They are so designed that the greatest possible amount of surface is exposed to natural cleaning. The use of these new insulators on the grid will, during the next few years, give an opportunity of comparing them with the older type under working conditions. Then1 increasing use on lower voltages should help towards the electrician's ideal of complete continuity of service.

Societies and Academies

Societies and Academies