Estimation of monsoon wind characteristics in India

A detailed statistical analysis of monthly average wind speed data of monsoon period (June-September) for the year 1921-90 for 57 stations spread all over India have been reported. Probability densities, average wind speeds, standard deviations, kurtosis and skewness of wind speed frequency distribution for each station have been worked out. Histograms depicting relative frequency distribution of average wind speeds have also been prepared. It is observed that the different histograms do not exhibit any similarity among themselves indicating thereby that no single distribution is uniformly applicable for all the stations. It is also seen that the average wind speeds during monsoon period over major part of India varies from 7 to 14 kmph. Further, at most of the stations average monsoon wind speed is generally higher than average annual wind speeds. It is also noted that most of the time the wind speed exceeds 10 kmph in coastal regions of Gujarat and southern parts of the peninsular India. The information generated is of multi fold application such as (i) Identification of sites suitable for installation of Wind Energy Conversion Systems (ii) Development of Driving Rain Index and (iii) Design of buildings for creating comfortable environment indoors.

Energy, Conventional and Advanced Exergy Analysis of Low Temperature Geothermal Binary-flashing Cycle Using Zeotropic Mixtures

Due to deep utilization of geobrine and high net power output, binary flashing cycle (BFC) is deemed to be the future geothermal energy power generation technology. The BFC using R245/R600a zeotropic mixtures is presented in this paper. The thermodynamic model of the system is built, and energy, conventional and advanced exergy analysis are carried out, to reveal the real optimization potential. It is demonstrated that the optimal composition mass fraction of R245fa and dryness of working fluid at the evaporator outlet ranges are 0.30~0.50 and 0.40~0.60, considering the thermodynamic performance and the flammability of the mixtures, simultaneously. Conventional exergy analysis indicates that the maximum exergy destruction occurs in condenser, followed by expander, evaporator, flashing tank, preheater, high-pressure pump and low-pressure pump. While the advanced exergy analysis reveals that the expander should be given the first priority for optimization, followed by condenser and evaporator. The BFC has a large potential for improvement due to higher avoidable exergy destruction, about 48.6% of the total system exergy destruction can be reduced. And the interconnections among system components are not very strong, owing to small exogenous exergy destructions. It also demonstrates the effectiveness of advanced exergy analysis, and the approach can be extended to other energy conversion systems to maximize the energy and exergy savings for sustainable development.

In Situ Surface Reconstruction of a Ni-based Perovskite Hydroxide Catalyst for an Efficient Oxygen Evolution Reaction

One core reaction involved in many electrochemical energy conversion systems is the oxygen evolution reaction (OER), which usually dominates the overall polarization loss due to its sluggish kinetics. Activating O2...

Electrochemically activated Co-Prussian blue analogue derived amorphous CoB nanostructures: Efficient electrocatalyst for oxygen evolution reaction

The oxygen evolution reaction is a kinetically sluggish half-cell reaction plays an important role in tuning the efficiency of various electrochemical energy conversion systems. However, this process can be facilitated...

Electrothermal Model of Coupled Inductors with Nanocrystalline Cores

The paper proposes a new electrothermal model of a coupled inductor containing a nanocrystalline core dedicated to the analysis of electrical energy conversion systems. The formulated model has a form of a subcircuit for SPICE. The model takes into account the influence of direct current, frequency, skin effect, temperature, self-heating, and mutual thermal couplings on the parameters and characteristics of the coupled inductors. The form of the developed model and the method of model parameter estimation are presented. The applied measuring system is presented. The results of measurements and calculations made with the use of the proposed model are presented and commented on.