Wind Electronic Generator NU-101 Driven by Axial-Flow Air-Turbine with Stator

"Generators driven by axial-flow air-turbine with stator are relatively small in size and can be adapted to withstand violent blizzards. They are suitable for antarctic use, especially as energy sources for unmanned observation units. An analysis is given of the performance of an axial-flow air-turbine comprising a stator having stationary blades and a rotor having moving blades. Changes in the velocity and thermodynamic properties of the air flow in passing through the turbine are discussed quantitatively, and the expression for the output power and efficiencies of the turbine are given. It is shown that the output attains its maximum when the axial velocity of the air flow in the turbine is 1/√ of the wind velocity. The method of evaluation of the maximum annual wind energy available is discussed. The design of turbine blades is described: the constant nozzle angle design is adopted for the stationary blades, and the axially leaving velocity design for the moving blades. The starting torque, the starting wind velocity, and the off- design performance of the wind air-turbine are also studied. The performance of an air-turbine with stator is compared theoretically to that of an ordinary wind air-turbine without stator, and it is verified the maximum output power allowable for the former will be about 140% of the latter at a lower rotational speed than the latter, which will be about 70% thereof. A wind electric generator designated NU-101 which has been designed on the basis of the discussion outlined above is described. This comprises an axial-flow air-turbine, 1.2m in diameter, whose maximum rotational velocityis 300 RPM, and a 2 kW, 100V, AC generator. In 1972, this generator wasshipped to Syowa Station, Antarctica, by the 14th Japanese Antarctic ResearchExpedition (JARE). The results of some test runs in Tokyo in 1972 and atSyowa Station in 1973 are given.

Axial Flow Wind Air -Turbine NU-102 with Electric Eddy-Current Brake

"A new axial-flow wind air-turbine NU-102 having an external diameter of 1.2 m was developed in 1977 by the authors for harnessing the energy of high speed winds in Antarctica. This multi-blade wind-turbine is featured by the presence of a stator before the rotor, which enables the turbine to give a higher power, a higher torque at a lower rotational speed than an ordinary wind air-turbine. A 3-kW AC-DC generator is driven by the air-turbine through a planetary speed-up gear of speed ratio 6. The rotational speed of this generator can automatically be kept at a desired value even in violent blizzards by means of an electric eddy-current brake newly developed by the authors. The brake also affords a new means for converting the wind energy directly into heat through the liquid heated in the jacket of the brake-stator. The present report describes the design of the whole system, the general perormance of the air-turbine, and the combined performance of the wind-turbine and generator evaluated in wind-tunnel tests and field tests at Syowa Station. The field tests have proved that a generator output of 2.4 kW can be obtained at a wind velocity of 30 m/s, and that the rotational speed of the generator can be kept at a desired value for variable loads and wind velocities exceeding 30 m/s.

Energy saving at Syowa and Mizuho Stations

"At Syowa Station, which was opened in 1957, two diesel electric generators were installed, one of which was always operated as the main energy source. The electric capacity of each generator has been increased from 20 kVA to 110 kVA in accordance with the expansion of the station. In order to save fuel consumption, the authors have developed some waste heat recovery systems of the diesel engines. By fully utilizing the waste heat of diesel engines, i.e., their exhaust-gas energy and coolant energy, cold and hot water was made from ice or snow even in winter. The hot and cold water was supplied to the living quarters through insulated water pipes. The hot water was also supplied for bathing and heating of apartments of the buildings. At Mizuho Station, which was opened in 1970, a system for recovering coolant heat of a diesel electric generator was installed. The cold and hot water is made by the similar system. The hot water is supplied to a bathtub and to a fan-coil unit in a trench living room. The heating by utilizing the waste coolant can ensure the safety of the personnel living in the trench room against fire, contamination by CO, CO_2 and lack of oxygen. In this report, the technical problems and experiences on waste heat recovering, especially on exhaust-gas heat exchangers are described.