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A mathematical framework to model the heat transfer efficiency of cooking pots is proposed and exploited in this paper. The model consists of combining the experimental results and the statistical data of Residential Energy Consumption Survey (RECS) of Iran with a soft-computing concept such as neural network. Using neural network results, the variations of the efficiency with various parameters have...
Cooker-top burners are used extensively in Thailand because of the rapid combustion and high heating-rates created by an impinging flame, which is characteristic of these types of burners. High thermal efficiency with low level of CO emissions is the most important performance criteria for these burners. The wide variation in reported performances of the burners appears to be due to the ad hoc knowledge...
Recent study of the history of technological change has provided better understanding of the driving forces for technological innovation, as well as quantitative estimates of historical rates of technical change. Although such results are widely used in long-term energy models to estimate future costs over time periods of up to a century, most studies of technological learning for major energy technologies...
To increase the performance of Stirling engines and analyze their operations, a second-order Stirling model, which includes thermal losses, has been developed and used to optimize the performance and design parameters of the engine. This model has been tested using the experimental data obtained from the General Motor GPU-3 Stirling engine prototype. The model has also been used to investigate the...
This paper introduces a mathematical model of a boiler room to research its thermal efficiency. The model is regarded as an open thermodynamic system exchanging mass, energy, and heat with the atmosphere. On those grounds, the energy and energy balance were calculated. Here I show several possibilities concerning how this model may be applied. Test results of the coefficient of thermal efficiency...
We present a thermodynamic approach to simulation and modeling of nonlinear energy converters, in particular radiation engines. Novel results are obtained especially for dynamical engines when the temperature of the propelling medium decreases in time due to a continual decrease of the medium's internal energy caused by the power production. Basic thermodynamic principles determine the converter's...
This paper addresses the impact of excess air on turbine inlet temperature, power, and thermal efficiency at different pressure ratios. An explicit relationship is developed to determine the turbine inlet temperature as a function of excess air, pressure ratio and relative humidity. The effect of humidity on the calculation of excess air to achieve a pre-established power output is analyzed and presented...
This study was conducted to analyze the status of energy use for heating in rural areas and the energy demands required by rural households to maintain temperatures suitable for the residents to live comfortably. In addition, suggestions to improve the thermal comfort of such families are put forward. In this study, we obtained data regarding temperature changes and energy consumption in two villages...
The thermal performances of single and double pass solar air heaters with steel wire mesh layers are used instead of a flat absorber plate are investigated experimentally. The effects of mass flow rate of air on the outlet temperature and thermal efficiency were studied. The results indicate that the efficiency increases with increasing the mass flow rate for the range of the flow rate used in this...
Solar ponds provide the most convenient and least expensive option for heat storage for daily and seasonal cycles. This is particularly important for a desalination facility, if steady and constant water production is required. If, in addition to high storage capacity, other favorable conditions exist, the salt gradient solar ponds (SGSPs) are expected to be able to carry the entire load of a large-scale...
The thermal efficiency of a reheating furnace was predicted by considering radiative heat transfer to the slabs and the furnace wall. The entire furnace was divided into fourteen sub-zones, and each sub-zone was assumed to be homogeneous in temperature distribution with one medium temperature and wall temperature, which were computed on the basis of the overall heat balance for all of the sub-zones...
Two compact premixed LPG burners based on submerged and surface combustion modes in porous medium (abbreviated as MSB and SSB respectively) are developed and their combustion and emission characteristics are compared to those of the CB (conventional burner). The preheating and reaction zones of MSB are made from porcelain form and Alumina spheres of 30 mm size, respectively, and the corresponding...
The present work concerns the parametric study and optimization of regenerative Clausius and organic Rankine cycles (ORC) with two feedwater heaters. For the parametric optimization, thermal efficiency, exergy efficiency and specific work are selected as the objective functions, so the mentioned parameters are calculated for different values of the outlet pressures from the second and third pumps...
This study analyzes the system performance of a 50kW ORC system subject to influence of various working fluids. A dimensionless “figure of merit” combining the Jakob number, condensing temperature, and evaporation temperature is proposed for quantitatively screening working fluid as far as thermal efficiency is concerned. The thermal efficiency normally decreases with the rise of figure of merit,...
Minto engine is a kind of liquid piston heat engine that operates on a small temperature gradient. But there is no power formula for it yet. And its thermal efficiency is low and formula sometimes is misused. In this paper, deriving the power formula and simplifying the thermal efficiency formula of Minto engine based on energy distribution analysis will be discussed. To improve the original Minto...
In order to improve IC engine energy utilization efficiency, an open steam power cycle used for IC engine exhaust gas energy recovery is proposed. The bottom cycle concept is designed on a four-cylinder naturally aspirated IC engine: with three cylinders taken as ignition cylinder, the last one is used for steam expansion cylinder; IC engine exhaust pipe is coupled with a Rankine steam cycle system...
Waste heat recovery from the exhaust gases of gas turbines, geothermal resources, and from industrial plants offers a great opportunity for rational energy usage by productively converting the waste energy. In the present communication we report a systematic study starting with the hydrocarbons for the different temperature ranges at which the waste heat is available from high, medium, or low temperature...
Black liquor is a major by-product of pulp mills; it is one of the most important renewable energy resources, which can be used as a material to produce electrical power, hydrogen, methanol and dimethyl ether by the black liquor gasification technology. In this paper, experiments were carried out with an oxygen injected-gasifier with different oxygen mass ratios, and then the gas compositions were...
In this research, a boiler in a premixed combustion system used to achieve exhaust gas recirculation was investigated as a way to achieve high thermal efficiencies and low pollutant emissions. The effects of various exhaust gas recirculation (EGR) ratios, equivalence ratios and boiler capacities on thermal efficiency, NO x and CO emissions and the flame behavior on the burner surface were...
This paper investigates the application of porous medium burner (PMB) with micro cogeneration system. Thermoelectric (TE) cells coupled with the PMB constituted the cogeneration system developed in this study. The TE cells attached to the hexagonal walls absorbed the heat of combustion. Experiment was carried out for two different equivalence ratio of 1.3 and 1.6 and the values of maximum flame temperature,...
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