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This paper explores the use of molten alkali-carbonate salts as a reaction and heat transfer medium for steam gasification of plant biomass with the objectives of enhanced heat transfer, faster kinetics, and increased thermal capacitance compared to gasification in an inert gas. The intended application is a solar process in which concentrated solar radiation is the sole source of heat to drive the...
A theoretical model for predicting thermodynamic behavior of thermal-lag Stirling engine is presented in this study. Without a displacer and its link, the thermal-lag engine contains only a moving part (piston) and a static part (regenerative heater) in engine's cylinder and hence, is regarded as a unique type of Stirling engines that featuring rather simple mechanical structure. In this study, a...
By using phase-Doppler anemometry (PDA) measurements within a cold small-scale model for a down-fired 600-MW e supercritical utility boiler, gas/particle flow characteristics were acquired at various staged-air declination angle settings (i.e., 0°, 15°, 30°, and 45°) so as to assess the availability of a staged-air declination method in improving the strong asymmetric gas/particle flow field...
In this paper, we propose a simplified method and build a model accordingly for estimating the energy-saving potentials of building construction and demolition with the consideration of China's rapid growth of building construction and its short actual lifespan of buildings. To demonstrate the practicability of the proposed method and model, we further develop an illustrative case study to estimate...
The particle swarm paradigm is employed to optimize single mixed refrigerant natural gas liquefaction process. Liquefaction design involves multivariable problem solving and non-optimal execution of these variables can waste energy and contribute to process irreversibilities. Design optimization requires these variables to be optimized simultaneously; minimizing the compression energy requirement...
India has recently witnessed the production of coalbed methane (CBM) on a commercial scale. The analysis of Garg and Shukla (2009) summarizes that initial carbon dioxide storage opportunities should be ventured in CBM sector where the effective cost of the process is partly lowered due to enhanced recovery of methane. This research work was carried out to understand and establish the technical feasibility...
Recent work has proposed that hybridization of residential-scale cogeneration with roof-mounted solar PV (photovoltaic) arrays can increase the PV penetration level in ideal situations by a factor of five. In regions where there is a significant cooling load PV-cogen hybrid systems could be coupled to an absorption chiller to utilize waste heat from the cogen unit. In order to investigate realistic...
Aalborg Municipality, Denmark is investigating ways of switching to 100% renewable energy supply over the next 40 years. Analyses so far have demonstrated a potential for such a transition through energy savings, district heating (DH) and the use of locally available biomass, wind power and low-temperature geothermal resources. The analyses have also demonstrated that the municipality will still rely...
The first experiment on a pumpless Rankine-type cycle (PRC) with a practical expander was performed to verify the feasibility of the PRC in power generation from low-grade heat sources. The PRC is an alternative to a Rankine cycle (RC) for lower output power and lower- and/or unstable temperature heat sources, where the conventional RC is rarely economically efficient owing to the low efficiency of...
Starting on the 24th of April, 2011, the Romanian government offered to subsidize all potential buyers of electric vehicles, both private and corporate, offering 25% off of the retail price up to 5000 euros with no pollution tax. The Romanian government encourages all governmental institutions to consider buying electric vehicles when deciding to change their existing vehicles stock. This decision...
The micro combined heat and electrical power systems (micro-CHP) with hot air engines are well adapted for solid biomass upgrading, in particular, the Ericsson engines working with an open cycle and an external combustion. This paper presents a model of an Ericsson engine with a compression and an expansion cylinder which allows a thermodynamic optimization of the engine performances in a global approach...
The method to improve the heat sink utilization of fuel is the primary issue for thermal management of advanced aeroengines. In order to study the methods to control the fuel heat sink utilization, a one dimensional model of flow and heat transfer process in a single cooling channel of endothermic hydrocarbon fuel cooled scramjet in terms of endothermic reaction is developed, which is validated by...
An ANN (artificial neural network) approach was used to model the fuel consumption of wheat production. This study was conducted over 35,300 ha of irrigated and dry land wheat fields in Canterbury in the 2007–2008 harvest year. From an extensive data collection involving 40 farms, the total fuel consumption in wheat production was estimated at 65.3 l/ha. On average, fuel consumption in tillage and...
The majority of thermal power plants of more than 300 MW use river water for cooling purposes. Increasing water and air temperatures due to climate change can significantly impact the efficiency and the power production of these power plants. In this paper we analyse these impacts by modelling selected German thermal power plant units and their respective cooling systems through dynamic simulation...
Recently, TEES (thermo-electric energy storage) systems have been proposed as a new method for large-scale energy storage wherein electric power is stored as thermal energy by using a heat pump and retrieved from the TES (thermal energy storage) by using a heat engine. The advantages of TEES systems are their higher energy density and independence from geological formations in comparison with pumped...
This article illustrates an innovative approach for the characterization and comparison of the performance of power-supply systems. The concept of ‘grammar’ forces to declare the pre-analytical decisions about: (i) semantic and formal categories used for the accounting – primary energy sources (PES), energy carriers (EC), and production factors; (ii) the set of functional and structural elements of...
The paper evaluates sustainability of maize cultivation in Bangladesh in terms of energy use while taking into account factors affecting choice of the growing season and farmers' production environment using a sample selection framework applied to stochastic frontier models. Results reveal that the probability of growing winter maize is influenced positively by gross return, irrigation, subsistence...
An optimization method, which considers the Combined Heat and Power (CHP) model under uncertainty, has been developed to determine the optimal capacities for the CHP and boiler such that thermal and electrical energy demands can be satisfied with high cost efficiency. The proposed method offers an energy management system (EMS) strategy which employs the fuzzy set theory to account for the uncertainties...
Micro Grids (MGs) are clusters of the DER (Distributed Energy Resource) units and loads which can operate in both grid-connected and island modes. This paper addresses a probabilistic cost optimization scheme under uncertain environment for the MGs with several multiple Distributed Generation (DG) units. The purpose of the proposed approach is to make decisions regarding to optimizing the production...
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