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The amount of pine needles (pinus roxburgii) potentially available for use as energy feedstock in the Central Himalayan state of Uttarakhand in India has been estimated. It involves estimating the gross annual amount of pine needle yield followed by a comprehensive identification and quantification of the factors that affect the net annual pine needle yield available as energy feedstock. These factors include considerations such as accessibility, alternative uses, forest fires, other losses, etc., that are influenced by aspects ranging from physical constraints to traditional societal traits. Tree canopy cover method has been used for estimating the gross annual pine needle yield. The information on canopy density is obtained from remote sensing data, that forms the basis for forest classification. The annual gross pine needle yield has been estimated at 1.9 million tonnes while the annual net pine needle yield at 1.33 million tonnes. The annual primary energy potential of pine needles available as energy feedstock has also been estimated. For annual net energy potential estimation, thermal and electrical routes are considered. Electrical energy generation from pine needles using thermochemical conversion has been examined and the corresponding potential for electricity generation been estimated. An installed capacity of 789 MW can be supported with pine needles feedstock for supplying electricity in rural areas for five hours a day. For round the clock generation, an installed capacity of 165 MW can be supported by the pine needle energy feedstock.

Purpose – The purpose of this paper is to develop a numerical model for estimating the unknown boundary heat flux in a parallel plate channel for the case of a hydrodynamically and thermally developing laminar flow. Design/methodology/approach – The conjugate gradient method (CGM) is used to solve the inverse problem. The momentum equations are solved using an in-house computational fluid dynamics (CFD) source code. The energy equations along with the adjoint and sensitivity equations are solved using the finite volume method. Findings – The effects of number of measurements, distribution of measurements and functional form of unknown flux on the accuracy of estimations are investigated in this work. The prediction of boundary flux by the present algorithm is found to be quite reasonable. Originality/value – It is noticed from the literature review that study of inverse problem with hydrodynamically developing flow has not received sufficient attention despite its practical importance. In the present work, a hydrodynamically and thermally developing flow between two parallel plates is considered and unknown transient boundary heat flux at the upper plate of a parallel plate channel is estimated using CGM.

Purpose>To better understand bioenergy's role in sustainable rural development and cleaner environment, it is necessary to place it in a local regional context. This paper aims to provide a conceptual approach for biomass-based energy self-sufficiency in rural areas of developing and underdeveloped countries having a strong agricultural sector. It further provides a framework for the estimation of surplus biomass and bioenergy potential and the biomass power emissions in a rural area.Design/methodology/approach>A detailed approach is laid out to attain energy self-sufficiency in rural areas encompassing identification of surplus biomass resources in a selected area, suitable conversion technologies, consideration of local end-use priorities, skill development and monitoring of the project.Findings>Following the novel approach proposed in this paper a case study analysis for Thanagazi block (Alwar District, India) is done, and it is observed that locally available biomass in the block can substitute more than 75% of the conventional energy demand and save 78% emissions vis-à-vis equivalent coal power. This indicates that creating local bioenergy production system as a means of substituting/complementing fossil energy can contribute to a cleaner self-sufficient ecosystem.Originality/value>Biomass is a spatio-temporal resource. Prior works have looked at bioenergy potential for national or state levels; however, granular data to reveal a more realistic outlook in a rural area is the novelty of this work. Furthermore, biomass assessment studies largely focus on crop residual biomass, whereas the present study also includes livestock manure assessment which is a major resource in rural areas. This paper highlights the need and the approach for exploring locally available biomass to meet the local energy demands for clean energy security while considering the involvement of the local population in bioenergy planning and implementation.

The present paper proposed a cycle to cycle prediction of in-cylinder pressure profile using double Wiebe function in a reactivity controlled compression ignition (RCCI) engine. RCCI engines lack direct control over combustion by means of any explicit hardware such as fuel injection or spark timing. Therefore, cylinder pressure sensor based control or model driven control is necessary for RCCI engines. In this work, an iterative algorithm to generate double Wiebe function parameters, were designed to model cycle average measured cylinder pressure. The model and measured data were in good agreement. However, when, this model was compared with measured cycles, the error and regression exhibited a near normal distribution. The quality of error and regression was found to deteriorate with premix energy share (ES) in RCCI mode due to higher cycle to cycle variations. To address this challenge, a range of double Wiebe parameters were generated to mimic the inner and outer most pressure cycle at three times the standard deviation from the cycle average cylinder pressure (99.7% confidence interval). This parameter range was randomized using Gaussian distribution and model cycles were generated stochastically. Leveraging this modelling approach for realistic sensing of selected combustion control parameters, indicated robustness and reliability. The stochastic approach was found to be an innovative strategy for RCCI engine model driven control.

Off-design operation of hydraulic turbines is contemporarily frequented for balance of variable energy intermittence in the electric grid. Being operationally highly flexible, these turbines allow a quick transition to off-design operation from the design point. However, such operational flexibility, and therefore the grid balancing capability is impeded by generation of flow instabilities like vortex breakdown during off-design operation. Vortex breakdown causes losses in efficiency and pressure recovery, pressure fluctuations and possibly mechanical vibrations in event of resonance between system natural and flow field fluctuation frequencies. While substantial experimental and numerical effort has already been made to study draft tube vortex breakdown, an accurate numerical flow characterization of the phenomenon is still a challenge. To this end, operation of a high head model Francis turbine under design and high load regimes using a bridged turbulence modelling approach is simulated. The approach allows a seamless transition between direct numerical simulation and Reynolds averaged Navier-Stokes equations. The highest attainable accuracy is limited by the mesh size. As such a satisfactory compromise between desired accuracy and invested computational effort is attained. The flow in the draft tube is free of anomalies under design specified operation. However, at high load an axial flow stagnation occurs centrally, and the flow is separated about the stagnated zone. The core of the vortex is enlarged with flow recirculation within it. Shear layers between the central stagnant zone and surrounding outflow kink and roll up transforming it into a spiral structure. In this work, a basic yet accurate numerical flow characterization of the aforementioned flow situations is achieved.

Abstract Effective utilization of low-grade steam in a Rankine cycle power plant is one of the challenging tasks for researchers. In a condensing turbine, last few stages of the turbine operate in two phase region leading to losses due to flow of wet steam, which results loss of work in low pressure turbine. Either wet or saturated steam normally called low grade is difficult to handle in a steam turbine due to its higher specific volume. Major portion of the heat in the cycle is rejected to cooling water, which results in thermal pollution of the environment and higher energy loss. Ammonia—water cycle or Kalina cycle is more efficient for the utilization of various low grade heat sources such as gas turbine exhaust gas, geothermal hot water, exhaust from steel plant etc. In this work, a new methodology was proposed for the utilization of low-grade steam in ammonia—water cycle to obtain a better power output and higher plant efficiency. The suggested ammonia—water cycle that utilizes low-grade steam produces higher-power output and it is more efficient than the Rankine steam cycle utilizing the low-grade steam and operates on a condensing mode.