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A concept for natural-gas (NG) fired power plants with CO 2 capture was investigated using exergy analysis. NG was reformed in an auto-thermal reformer (ATR), and the CO 2 was separated before the hydrogen-rich fuel was used in a conventional combined-cycle (CC) process. The main purpose of the study was to investigate the integration of the reforming process and the combined cycle...
This paper inquires into whether overall thermal transfer value (OTTV) is an appropriate building envelope energy performance index for use in regulatory control. First, a historical review of the use of OTTV in American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) Standard 90 is presented, followed by a review of more recent work on its further development and application...
This paper analyzes the change of aggregated CO 2 in China from 1957 to 2000 based on a complete decomposition approach-the logarithmic mean divisia index (LMDI) method. The study indicates that China has achieved a considerable decrease in its CO 2 emissions mainly due to improved energy intensity. In addition, fuel switching and renewable energy penetration also exhibit positive...
A phenomenological equation of exergy transfer, which indicates the relation between exergy flux, exergy resistance and exergy driving forces, is derived by applying non-equilibrium thermodynamics to second law analysis, and simultaneously the expressions of the coefficients of exergy transfer are obtained. The results show that exergy transfers in different forms interact on each other. This study...
Heating by radiation is widely used for materials processing. Electrical radiant heaters are the most commonly used heaters. Electricity is expensive and the combustion of fossils fuels for electricity production emits CO 2 . In order to convert the energy from the fuel to radiation energy directly and efficiently, our group has developed a compact, high efficiency, radiation converter using...
This study uses ultrasound in combination with tomography to obtain three-dimensional temperature measurements using projection data obtained from limited projection angle. The main feature of the new computerized tomography (CT) reconstruction algorithm is to employ extrapolation scheme to make up for the incomplete projection data, it is based on the conventional filtered back projection (FBP) method...
The authors have developed a shell-and-tube type thermal energy storage unit using carbon-fiber brushes as a thermal conductivity promoter. In this paper, experiments on heat transfer in the brush/n-octadecane composites are discussed, leading to further improvement of the unit. Experimental apparatuses imitate shell-and-tube type heat exchangers. Temperatures in the brush/n-octadecane composite are...
When we consider exergy analysis on combustion and thermodynamic processes, we introduce another concept against energy analysis, which is supported by an evaluation of its temperature level. When a higher temperature energy than that an ambient level is taken into consideration, it can be put for some domestic or industrial purpose. A medium temperature energy of 30-60 o C is used for domestic...
This paper begins from adsorption working pairs: water and ethanol were selected as refrigerants; 13x molecular sieve, silica gel, activated carbon, adsorbent NA and NB, proposed by authors, were selected as adsorbents, and the performance of adsorption working pairs in adsorption refrigeration cycle was studied. The adsorption isotherms of adsorbents (NA and NB) were obtained by high-vacuum gravimetric...
Six incremental but accumulative thermal schemes to improve the operation of a natural-gas-fired turbine in conjunction with a single steam turbine were analyzed in detail. Each of these was found to improve the efficiency and increase the electrical output, and to be justified economically on the basis of fixed and operating costs. The best overall scheme from a combined economic and thermodynamic...
The applicability of the hemispherical total emissivity measurement for metals those have a thin protective layer (passive scale) on its surface was investigated at high temperatures (above 1000 o C) using a modified hot-filament method. In this method, the Joule heat and the temperature of the specimen were measured by two sets of electrodes (two sets of thermocouples) spot-welded at the...
Practical flow problems with condensation due to phase change from water vapor to water liquid are numerically investigated. Fundamental equations solved in this study consist of conservation laws of mixed gas, water vapor, water liquid, and the number density of water droplets, coupled with the momentum equations and the energy equation. The classical condensation theory is employed for modeling...
To investigate the reaction chemistry of HCN oxidation, a modeling study was performed. The plug flow calculation code was used at atmospheric pressure in the temperature range from 1000 to 1400 K. The effect of initial H 2 O concentrations and that of other components were discussed. The oxidation of HCN is controlled primarily by the HCN+OH reaction in case of increasing H 2 O concentration...
A new system for converting combustion heat into electric power was proposed on the basis of reciprocating-flow super-adiabatic combustion in a catalytic and thermoelectric porous element. Self-sustaining combustion of an extremely low-calorific gas was successfully achieved in the element; because a reciprocating flow in the porous element recirculated energy, effectively regenerating combustion...
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