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Heat Output (heat + output)
Selected AbstractsEfficiency analysis of a combined PEFC and bioethanol-solar-reforming system for individual housesINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 7 2010Shin'ya Obara Abstract In this research, the development of a bioethanol reforming system for fuel cells (FBSR: fuel cell with bioethanol steam reforming) using sunlight as a heat source was investigated. The system was investigated using the experimental result of catalyst performance, and numerical analysis. If ethanol purity is high, the production method of the bioethanol used for the proposal system will not be limited. The overall efficiency of the production of electricity and heat power of this system was determined by examining its thermal output characteristic. The FBSR was introduced into standard individual houses in Sapporo, Japan, for analysis. The amount of hydrogen production, the production-of-electricity characteristic, and the thermal output characteristic were examined using meteorological data on representative days in March and August. Compared with the representative day in March (28.0,MJ,day,1), the solar radiation of the representative day in August (37.0,MJ,day,1) is large. However, the amount of solar radiation fluctuation of the representative day in August in this analysis is large compared with the representative day in March. It depends for the overall efficiency of the system on the amount of solar radiation fluctuation rather than the amount of solar radiation. As a result, the overall efficiency of the system, defined as the rate of power and heat output compared with the amount of solar heat collected, was calculated to be 47.4 and 41.9% on the representative days in March and August, respectively. Copyright © 2009 John Wiley & Sons, Ltd. [source] Is the efficiency of mammalian (mouse) skeletal muscle temperature dependent?THE JOURNAL OF PHYSIOLOGY, Issue 19 2010C. J. Barclay Myosin crossbridges in muscle convert chemical energy into mechanical energy. Reported values for crossbridge efficiency in human muscles are high compared to values measured in vitro using muscles of other mammalian species. Most in vitro muscle experiments have been performed at temperatures lower than mammalian physiological temperature, raising the possibility that human efficiency values are higher than those of isolated preparations because efficiency is temperature dependent. The aim of this study was to determine the effect of temperature on the efficiency of isolated mammalian (mouse) muscle. Measurements were made of the power output and heat production of bundles of muscle fibres from the fast-twitch extensor digitorum longus (EDL) and slow-twitch soleus muscles during isovelocity shortening. Mechanical efficiency was defined as the ratio of power output to rate of enthalpy output, where rate of enthalpy output was the sum of the power output and rate of heat output. Experiments were performed at 20, 25 and 30°C. Maximum efficiency of EDL muscles was independent of temperature; the highest value was 0.31 ± 0.01 (n= 5) at 30°C. Maximum efficiency of soleus preparations was slightly but significantly higher at 25 and 30°C than at 20°C; the maximum mean value was 0.48 ± 0.02 (n= 7) at 25°C. It was concluded that maximum mechanical efficiency of isolated mouse muscle was little affected by temperature between 20 and 30°C and that it is unlikely that differences in temperature account for the relatively high efficiency of human muscle in vivo compared to isolated mammalian muscles. [source] Effects of fire intensity on plant species composition of sandstone communities in the Sydney regionAUSTRAL ECOLOGY, Issue 4 2002DAVID A. MORRISON Abstract Fire intensity measures the heat output of a fire, and variation in fire intensity has been shown to have many effects on the demography of plant species, although the consequent effects on the floristic composition of communities have rarely been quantified. The effects of variation in fire intensity on the floristic composition of dry sclerophyll vegetation with different fire histories near Sydney was estimated. In particular, differences in species abundance of woodland and shrubland communities subjected to four fire-intensity classes: unburnt, low intensity (<500 kW m -1), medium intensity (500-2500 kW m -1) and high intensity (>2500 kW m -1) were examined. The samples had a standardized previous fire frequency and season, thus minimizing the effects of other aspects of the fire regime. There was a clear effect of fire intensity on the relative abundances of the vascular plant species, with increasing intensity of the fire producing vegetation that was increasingly different from the unburnt vegetation. This pattern was repeated in both the woodland and shrubland vegetation types, suggesting that it was not an artefact of the experimental conditions. However, the effects of fire intensity on floristic composition were no greater than were the differences between these two similar vegetation types, with variation in fire intensity accounting for only approximately 10% of the floristic variation. Nevertheless, the effects of fire intensity on the abundance of individual species were consistent across taxonomic groups, with the monocotyledon and Fabaceae species being more abundant at higher than lower intensities, the Proteaceae and Rutaceae more abundant at intermediate intensities, and the Epacridaceae more abundant at lower rather than higher intensities. The number of fire-tolerant species increased with increasing fire intensity, and those fire-tolerant species present were most abundant in the areas burnt with medium intensity. The number of fire-sensitive species did not respond to fire intensity, and those species present were most abundant in the areas burnt with low intensity. This suggests that either fire-sensitive species respond poorly to higher fire intensities or fire-tolerant species respond poorly to lower fire intensities, perhaps because of differences in seed germination, seedling survival or competition among adults. [source] Development of a large-scale biocalorimeter to monitor and control bioprocessesBIOTECHNOLOGY & BIOENGINEERING, Issue 2 2002D. Voisard Abstract Calorimetry has shown real potential at bench-scale for chemical and biochemical processes. The aim of this work was therefore to scale-up the system by adaptation of a standard commercially available 300-L pilot-scale bioreactor. To achieve this, all heat flows entering or leaving the bioreactor were identified and the necessary instrumentation implemented to enable on-line monitoring and dynamic heat balance estimation. Providing that the signals are sufficiently precise, such a heat balance would enable calculation of the heat released or taken up during an operational (bio)process. Two electrical Wattmeters were developed, the first for determination of the power consumption by the stirrer motor and the second for determination of the power released by an internal calibration heater. Experiments were designed to optimize the temperature controller of the bioreactor such that it was sufficiently rapid so as to enable the heat accumulation terms to be neglected. Further calibration experiments were designed to correlate the measured stirring power to frictional heat losses of the stirrer into the reaction mass. This allows the quantitative measurement of all background heat flows and the on-line quantitative calculation of the (bio)process power. Three test fermentations were then performed with B. sphaericus 1593M, a spore-forming bacterium pathogenic to mosquitoes. A first batch culture was performed on a complex medium, to enable optimization of the calorimeter system. A second batch culture, on defined medium containing three carbon sources, was used to show the fast, accurate response of the heat signal and the ability to perfectly monitor the different growth phases associated with growth on mixed substrates, in particular when carbon sources became depleted. A maximum heat output of 1100 W was measured at the end of the log-phase. A fed-batch culture on the same defined medium was then carried out with the feed rate controlled as a function of the calorimeter signal. A maximum heat output of 2250 W was measured at the end of the first log-phase. This work demonstrates that real-time quantitative calorimetry is not only possible at pilot-scale, but could be readily applied at even larger scales. The technique requires simple, readily available devices for determination of the few necessary heat flows, making it a robust, cost-effective technique for process development and routine monitoring and control of production processes. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 125,138, 2002 [source] | ||||||||||