[en] The method is based on the Bethe level density expression, where the parameters are used with constraints. It is applied to the level density of compound resonances observed at neutron separation energy. The change of the pairing energy compared to the ground state value determined by mass differences is discussed for different mass regions. (Auth.)

[en] In the late 1970-Years, Tracto-Technik developed a very effective radial-shaped percussion system for a geothermal heating, the ECOtherm-System, which was very well accepted by customers. Nowadays, a radial-shaped drilling system, operating some decameters below the surface, was developed by Tracto-Technik, which offers the chance of a very effective drilling for the use of geothermal energy. The main advantage of this development is the reduction of drilling costs by new constructions and new handling possibilities. Drilling processes like the rod connecting or the drill-hole enlargement were solved in other ways as usual, by very time-shortening and effective ways, which are presented in the paper. The new TT-Geothermal radial drilling methods need only a very small but highly effective drilling unit, which reduces the operational drilling cost in a enormous way. All operational drilling steps are reduced to less than a half time as usual. By these GRD-methods, the use of surface-close geothermal energy is simplified and less expansive. (authors)

[en] Photovoltaic lighting systems are proved as economically viable in many places around the world. In Sudan, it was widely introduced by Renewable Energy Development Project RSED In North Kordofan state. This paper summarizes this experience and discusses its economic and environmental aspects. A concept of kilo watt hour person (KWHP) is used to quantify the social benefits provided to each of beneficiaries by a KWH of energy. This concept is used to compare the economics of PV used as a social service in a rural area to the conventional energy within the urban context. (Author)

[en] The underground in the first approx. 100 m is well suited for supply and storage of thermal energy. The climatic temperature change over the seasons is reduced to a steady temperature at 10-20 m. With further depth, the temperatures increase according to the geothermal gradient (average 3 grad C for each 100 m of depth). Ground-source or geothermal heat pumps are a highly efficient, renewable energy technology for the space heating and cooling. This technology relies on the fact that, at a depth, the Earth has a relatively constant temperature, higher than that of air in winter and cooler than the air in summer. A geothermal heat pump (GHP) can transfer heat stored in the Earth into a building during the winter, and transfer heat out of the building during the summer. Special geologic conditions, such as hot springs, are not needed for a successful application of GHP. (authors)

[en] This energy balance of the Santa Catarina State presents the following main topics that can be outstanding: panorama of the energy matrix; supply and demand of energy by source 1983-1996; energy consumption by sector 1983/1996; socio-economic aspects; resources and reserves energy; and balance of the transformation centers 1984/1996

[en] In this paper solar global irradiation in R. Macedonia is estimated and some favorable fields for photovoltaic application are emphasized. By means of Angstrom's equation and using solar hour duration data for seven locations, mean daily horizontal surface solar energy is calculated. Obtained average value on whole territory is 4,2 kWh/m² day. On fixed tilt active surface (β=35⁰) solar flux would be increased approximately 15%. Possible fields for photovoltaic systems applications are: rural electrification, water pumping in mountain areas and supplying of Tv and radio relay station. In case of small village standard electrification, due to inevitable distribution network over sizing, the price of electricity is around 2,5 $/kWh. If photovoltaic system is used for the same purpose, the electricity would amount 35 c/kWh. (author). 7 refs., 4 tabs., 1 ill

[en] Highlights: • The desiccant wheels used honeycombed silica gel six-stage rotary desiccant cooling system was studied. • The mathematical model has been validated with the experimental data. • The optimal rotation speed increases with increasing the inlet temperature of the regeneration air. - Abstract: A mathematical model for predicting the performance of solar energy assisted hybrid air conditioning system (SEAHACS) is presented. The honeycombed silica gel desiccant wheel is used in this study. One-rotor six-stage rotary desiccant cooling system, (two-stage dehumidification process, two-stage pre-cooling process and two-stage regeneration process) are realized by only one wheel. Three air streams are involved in the present system. The mathematical model has been validated with the experimental data. The range of regeneration air inlet temperature changed from 65 to 140 °C, area ratio of process air to regeneration air change from 1 to 3.57, regeneration air inlet velocity from 1.5 to 5.5 m/s have been examined for a range of rotation speed from 6 to 20 rev/h. The optimization of these parameters is conducted based on the moisture removal capacity D, relative moisture removal capacity, dehumidification coefficient of performance and thermal coefficient of performance. At last, the influences of these main parameters on optimal rotation speed are discussed

[en] ENEL presents itself as a world leader in using renewable resources and thus, of course, in environmental protection. In Slovenske elektrarne, Enel is also engaged in several environment- oriented projects which are being implemented in Slovakia. Projects protection of Falcon Peregrinus and installation of photovoltaic battery on the Teryho circular (in High Tatras) are described. (author)

[en] The excitation energies of states belonging to the ground state bands of heavy even–even nuclei are analysed using recurrence relations. Excellent agreement with experimental data at the 10 keV level is obtained by taking into account strong correlations which emerge in the analysis. This implies that the excitation energies can be written as a polynomial of maximum degree 4 in the angular momentum. (paper)

[en] Highlights: • Laboratory tests on two commercially available pellet boilers. • Steady state and a dynamic load cycle tests. • Pellet boiler model calibration based on data registered in stationary operation. • Boiler model validation with reference to both stationary and dynamic operation. • Validated model suitable for coupled simulation of building and heating system. - Abstract: Nowadays dynamic building simulation is an essential tool for the design of heating systems for residential buildings. The simulation of buildings heated by biomass systems, first of all needs detailed boiler models, capable of simulating the boiler both as a stand-alone appliance and as a system component. This paper presents the calibration and validation of a boiler model by means of laboratory tests. The chosen model, i.e. TRNSYS “Type 869”, has been validated for two commercially available pellet boilers of 6 and 12 kW nominal capacities. Two test methods have been applied: the first is a steady state test at nominal load and the second is a load cycle test including stationary operation at different loads as well as transient operation. The load cycle test is representative of the boiler operation in the field and characterises the boiler’s stationary and dynamic behaviour. The model had been calibrated based on laboratory data registered during stationary operation at different loads and afterwards it was validated by simulating both the stationary and the dynamic tests. Selected parameters for the validation were the heat transfer rates to water and the water temperature profiles inside the boiler and at the boiler outlet. Modelling results showed better agreement with experimental data during stationary operation rather than during dynamic operation. Heat transfer rates to water were predicted with a maximum deviation of 10% during the stationary operation, and a maximum deviation of 30% during the dynamic load cycle. However, for both operational regimes the fuel consumption was predicted within a 10% deviation from the experimental values