Gas turbine cycle technologies will play a major role in future power generation, and several well-justified concepts have been developed or are the subject of major feasibility studies. In the present work, gas turbine cycles are modified with steam injection between the combustion chamber exit and the gas turbine inlet. Heat recovery steam generators, utilizing the exhaust gases, provide these cycles with the injected steam at saturated vapor. The thermodynamic characteristics of the various cycles are considered in order to establish their relative importance to future power generation markets. The irreversibility of the different composing units of the cycles and the variation of gas properties due to steam injection as well as changes in the interrelation of component performance parameters are taken into account. The isentropic temperature ratio and maximum to minimum cycle temperature ratio are varied over some ranges that slightly exceed their practically acceptable bounds in order to comprehensively investigate their effects on cycle characteristics. The performance characteristics for various modified and regeneration cycles are presented at the same values of the operating parameters. The present modified cycles with steam injected cycles achieve an additional power output and higher efficiencies, resulting in a lower specific cost. At the chosen values of the operating parameters, the enhancement achieved in the overall efficiency for the simple, reheat (with steam injection at high and low pressures) and partial oxidation (with steam injection at high and low pressures) gas turbine cycles are of about 20–30%, 120–200%, 10–12%, 120–260% and 20%, respectively. The present modified cycles technique can be considered among the possible ways to improve the performance of gas turbine cycles-based power plants at feasible costs. This concept can be used for similar core engines. Copyright © 2011 John Wiley & Sons, Ltd.

In this paper, a new online capacitance estimation method for dc-link capacitors in a three-phase ac/dc/ac pulsewidth-modulation converter is proposed. A controlled ac voltage with a lower frequency than the line frequency is injected into the dc-link voltage, which then causes ac power ripples at the dc output side. By extracting the ac power component on the dc output side using digital filters, the capacitance can then be calculated using a support vector regression method. A function that defines the relation between a given capacitor power and its corresponding capacitance is determined using a set of training data. This function is then used to predict the output for the given input which is not included in the training set. The proposed method can be simply implemented with only software and no additional hardware. Experimental results confirm that the estimation error is less than 0.15%.

Intelligent Building technologies have a potential significant impact on sustainability issues (energy efficiency, due diligence, health and safety and indoor environment).It is widely recognized that intelligent building can improve the environmental and economic performance of buildings. Consequently, the promotion of intelligent buildings is regarded as means of fostering sustainability. Intelligent building technology encompasses sophisticated systems targeting various facets of building automation. Developing such an integration system of intelligent buildings technologies can significantly increase the energy efficiency of the building while also providing enhanced occupant comfort and cost effectiveness. Given the developments in information and communication technology and the increasing level of complexity of intelligent building systems, this paper introduces an integration system that facilitates improving the utilization of intelligent building technologies. The proposed system in this paper provides three indispensable sets of criteria by which successful integration of intelligent building technologies can be achieved. These measures are integration criteria for sub-system operation, best practices of sub-system business considerations,and interoperability criteria. Detailed and articulated measures for each set of these criteria are introduced. The paper explores the potential benefits of integrating intelligent building technologies as a useful means for fostering sustainability in buildings.