Importance of alkaline accumulators in the application of renewable resources

Importance of alkaline accumulators in the application of renewable resources

Renewab/eKnergy, Vol.5, Pm 1, pp. 295-297, 1994 Elsevier Science Ltd Printed in Great Britain 0960-1481/94 $7.00+0.00 Pergamon IMPORTANCE OF ALKALIN...

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Renewab/eKnergy, Vol.5, Pm 1, pp. 295-297, 1994 Elsevier Science Ltd Printed in Great Britain 0960-1481/94 $7.00+0.00

Pergamon

IMPORTANCE OF ALKALINE ACCUMULATORS IN THE APPLICATION OF RENEWABLE RESOURCES CENEK M. a, KAZELLE d. a, HAVEL j . b

BA~INKA R. a

aInstitute of Electrotechnology, Technical University of Brno Antonlnsk~ I, 662 09 Brno, Czech Republic bDepartment of Analytical Chemistry, Masaryk University of Brno K o t l ~ s k ~ 2, 602 00 Brno, Czech Republic

ABSTRACT The results are presented of Ni-Cd ~ud Ni-Fe accumulators,

resp.

application in the process of electric energy accumulation from wind power-stations and photovoltaic batteries. KEYWORDS Accumulation, regenerative sources, nickel-cadmium accumulators, nickel-iron accumulators, wind power-stations, photovoltaic batteries,

interval charging.

INTRODUCTION The optimization was made of the charging procedure of alkaline accumulators with regard to their service life and the actual efficiency of the charging process. Moreover, the optimum lenght of the supplied energy storage in these batteries was sought with regard to environmental protection, their lifetime and maintenance.For these reasons the interval mode of charging was adopted in these cases. The elimination of undesirable overcharging, optimization of electrolyte exchange intervals and a broader application of nickel-iron accumulators, are the factors which significantly contribute to the environmental protection. The application of nickel-iron accumulators in particular, increases the importance of renewable sources in the environmental protection issues.

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A special measuring instrument was used to check the degree of charging of accumulator batteries. The latter parameter can be controlled also by means of a disconnecting unit. Both instruments have been developed in the Institute of Electrotechnology, University of Brno.

Technical

Nickel-cadmium and nickel-iron accumulator batteries have been tested over the long run in combination with wind power-stations of the Czech origin. The batteries with capacity of 120 Ah ~ud 160 Ah, resp. and voltage 12 or 24 V, resp. were tested in this way. The output of the wind power-stations The long term tests

is 250, 300 and 500 W, respectively.

proceed on several places in Czech Republic,

Denmark and Antarctica.

The combination of these batteries with

a photovoltaic cell has also been tested. The combination of wind power-station, photovoltaic cell has also been tested. The combination of wind power-station, photovoltaic battery and Ni-Cd accumulator battery has been tested in five years experiment in which the accumulator was used for the diesel-aggregate starting in the cases of electric energy supply failures. RESULTS Long term field testing of Ni-Cd and Ni-Fe accumulators has been significantly extended during the last several years. Presently, there is a two years long term testing being carried out of a 12 V Ni-Cd battery, 160 Ah capacity, consisting of KPM 160 P cells. This battery is used to accumulate the electric energy from the wind power station made by AVECO Brno Ltd. This power station (model AVE 300 with the output of 300 W) has been installed on the polar station on Nelson Island in Antartica. The testing of a M~& Brno VICTOR 250 power station with output of 250 W has been carried out in Giant Mountains for two years. In this case a Ni-Cd battery with the capacity of 120 Ah is fed from this source. The Institute has been involved also in the project of Ministry of Economy of the Czech Republic called "Experimental ecological house with low electricity consumption" which has been ~1~ning for almost two years and is organised by V ~ shareholding company Brno.Within

297

the framework of this project the Institute ensures the running of the assembly consisting of a IkW photovoltaic collector as a main renewable electric source, wind power station 0,5 - IkW and an alkaline accumulator battery 24V with the capacity of 500 Ah. Moreover,

there have been proceeding long term experiments with a 12 V

Ni-Cd battery having capacity 120 Ah and consisting of KI~M 120P cells. The mentioned battery enables the electric energy accumulation from the wind power station AVE 500 (made by AVECO Brno Ltd.) whose output is 500 W. The tests are performed at Letovice near Brno. During two years of running with the mentioned wind power station the capacity decrease of the used Ni-Cd battery was noted to be as low as 9.9%. Besides the examination the performance of Ni-Cd batteries by combining them with wind power stations

, also the tests with a 25 W

photovoltaic battery made by Solarglas Prague were carried out in 1993. The photovoltaic panel was used to charge alkaline Ni-Cd batteries which were, in turn, used to supply electricity to a 12V TV set. The expertiments were carried out within Ist June and 20th September 1993. The photovoltaic panel exhibited the following characteristics: U o = 18 V, I s = 1,5 A. The employed nickel-cadmium battery exhibited the voltage 12V at the capacity 45 Ah and discharged by 1,5 A current. CONCLUSION The results presented in this paper have shown the possibility of using Ni-Cd as well as Ni-Fe accumulator batteries charged according to the interval mode from the wind power stations (250 W up to 20 kW) and from the photovoltaic cells. The results have been confirmed both in the Czech Republic and abroad, i.e. in Antartica and Ukraine.