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Abstract A simple transient analysis of the conventional mud chullah of single pot seat has been presented. The effects of various parameters, namely pressure and non-pressure pot, use of insulation in walls and basement of the chullah, heat capacity of pot-water, burning rate of wood, and heat losses from the combustion gas, have been incorporated in the analysis. Keeping in view the outcomes of this analysis, some interesting recommendations have been made to make the mud chullah more efficient.

Horizontal axis tidal turbines (HATT) are promising candidates for hydroelectric power extraction in coastal urban applications. Currently, concerns around the fluid–structure interaction (FSI) performance of turbines limit their industrial deployment while an efficient FSI prediction model can mitigate these concepts. In this paper, we present an innovative predictive model, TurbineNet, designed to accurately forecast the FSI characteristics of diverse composite tidal turbine blade structures, thereby facilitating its performance optimization. The TurbineNet model utilizes blade mesh information as input to predict HATT performance through a neural network framework. By integrating mesh convolution and fully connected layers, the model delineates the hydrodynamic behavior of deformed blades which then couples with the finite element method (FEM) for a comprehensive dynamic FSI analysis of composite material blades. Through the generation and training of a database of deformed blades, the new TurbineNet/FEM model is capable of precisely predicting the hydrodynamic performance under various structural parameters. This approach significantly streamlines the computational process associated with traditional FSI models, reducing prediction times by nearly 18 times compared to static FSI calculations using established platforms like Ansys Workbench, while maintaining high accuracy. Based on the innovative TurbineNet/FEM model, we analyzed the FSI characteristics of three different web structures. The incorporation of web structures can substantially reduce local stress and enhance the structural stability of the blades, thus preventing vibrations. Our high-efficiency predictive FSI tool and results can aid HATTs in increasing their much-needed contribution to stability optimization design. It has the potential to significantly optimize energy conversion in tidal turbines by refining blade designs to efficiently convert the kinetic energy of tidal currents into electrical energy.

Abstract Mixed NiSPbS and NiSCdS thin films deposited on commercial aluminium and galvanized iron substrates by spray pyrolysis have been extensively investigated for their solar-thermal performance over the complete composition range. Optical, thermal and structural properties of these films have been investigated to establish the optimized composition. NiSPbS (∼60% nickel) films and NiSCdS (∼67% nickel) films perform better than nickel sulphide films above 160°C due to their lower emissivity. The films are extremely adherent to the substrate and have stable operational characteristics under temperature cycling up to ∼250°C in dry environments.

Abstract Paraffins constitute a class of solid-liquid organic phase change materials (PCMs). However, low thermal conductivity limits their feasibility in thermal energy storage (TES) applications. Carbon nano tubes (CNTs) are one of the best materials to increase the thermal conductivity of paraffins. In this regard, the present study is focus on the preparation, characterization, and improvement of thermal conductivity using CNTs as well as determination of TES properties of expanded perlite (ExP)/ n -eicosane (C20) composite as a novel type of form-stable composite PCM (F-SCPCM). It was found that the ExP could retain C20 at weight fraction of 60% without leakage. The SEM and FTIR analyses were carried out to characterize the microstructure and chemical properties of the composite PCM. The TES properties of the prepared F-SCPCM were determined using DSC and TG analyses. The analysis results showed that the components of the composite are in good compatibleness and C20 used as PCM are well-infiltrated into the structure of ExP/CNTs matrix. The DSC analysis indicated that the ExP/C20/CNTs (1 wt%) composite has a melting point of 36.12 °C and latent heat of 157.43 J/g. The TG analysis indicated that the F-SCPCM has better thermal durability compared with pure C20 and also it has good long term-TES reliability. In addition, the effects of CNTs on the thermal conductivity of the composite PCM were investigated. Compared to ExP/C20 composite, the use of CNTs has apparent improving effect for the thermal conductivity without considerably affecting the compatibility of components, TES properties, and thermal stability.

This paper introduces an irradiance loss factor that quantifies the relationship between irradiance, tilt angle and power output of a soiled panel with the soil particle size composition. Artificial soiling experiments were performed using four soil samples at irradiance levels between 200 and 1200 W/m2 at 18 tilt angles. Biharmonic interpolation was used to develop power contours in terms of irradiance and tilt angle from experimentally obtained data. These contours were compared with ideal ones of a clean panel to observe deviation in the nature of contours for a soiled panel. A correction factor in terms of particle size composition (as a coefficient to tilt angle) was proposed to calculate power output of a tilted soiled panel. The angular loss on a panel with soil sample containing 150 μm particle size in abundance was observed to be 22% and for sample containing 75 μm particles in majority, the loss is 24%. Presence of 300 μm particle size in abundance causes a 23.7% loss, while 52% angular loss was observed for soil with highest composition of less than 75 μm particle size.

Abstract Performance and testing of an improved community size solar cooker have been carried out and compared with a hot box solar cooker with a single reflector. The cooker can meet the requirement of about 80 persons, therefore it is very suitable for hostels, temples, canteens, restaurants, etc. The economic analysis of the cooker has been carried out by considering the annual interest, maintenance cost and inflation in fuel prices and maintenance cost. The payback periods are in increasing order with respect to the fuels, firewood, coal, electricity, LPG and kerosene.

Abstract The development of commercial MHD (magnetohydrodynamic) power plants has come a long way, from the first MHD experiment by Michael Faraday at the River Thames in 1832 to the present day efforts towards early commercialization. Over these years, development of MHD technology has seen many ups and downs. Though technically substantial progress has been achieved, today financial constraints are impeding speedy commercialization. Nevertheless, it is hoped that the MHD development community will overcome the present setback and establish commercial MHD power plants in the near future. When we look back at the seminal stages of MHD technology development over these years, we can clearly identify certain bench-mark events which propelled its progress. These events not only gave a boost to the development of MHD technology proper but also, in some cases, triggered development of new spin-off concepts. This paper looks into the history of MHD technology development and discusses the bench-mark events with the hope that this historical knowledge will provide us with a bearing for the future. The material presented in this paper is based on the extensive literature study carried out by the author and private communications and discussions with many of the leading specialists in the field.