ECLIPSE uses standard generic chemical engineering equations and formulae and includes a high accuracy program for steam/water cycle analysis. It is designed to perform rapid and reliable technical and economic evaluations of energy conversion and allied processes, including mass and energy balances, utilities usages, capital costing and economic analysis. To ensure that these comparisons were performed on a consistent and reliable basis, all of the technologies and processes were simulated using the ECLIPSE process simulator.ĮCLIPSE is a PC-based process simulation package which was developed within the Energy Research Centre of the University of Ulster ( 2). In this study both commercially established and conceptual technologies were included and the effect of modifying these technologies to include processes for the sequestration of CO 2 was also evaluated. The objective of this study, which was carried out under the European Community JOULE R&D Programme ( 1), was to evaluate and compare the technical, environmental and economic performance of a number of fossil fuel based power generation technologies with particular reference to the emission of greenhouse gases. Campbell, in The Institute of Energy's Second International Conference on Combustion & Emissions Control, 1995 INTRODUCTION The ratio of specific heats may be taken as κ = 1.4. If these approaches have not increased the efficiency, propose another method by which the gas turbine performance might be improved (between the same temperature limits), without reducing the work output evaluate the thermal efficiency of the proposed plant. Introducing reheat to the turbine by splitting the turbine pressure ratio such that the pressure ratio of each stage is the square root of the compressor pressure ratio.Įvaluate the basic cycle efficiency, and then evaluate separately the effects of the heat exchanger and reheat. The customer then feels that the efficiency of the turbine could be improved by 1. The first specification requires that the turbine produces the maximum work output possible between the peak temperature (1200 K) and the inlet temperature (300 K). It is required to specify an ideal closed cycle gas turbine to produce electricity for a process plant. Show that the thermal efficiency at maximum power output of an endoreversible engine executing an Otto cycle is Discuss why external irreversibility reduces the effective temperature ratio of an endoreversible engine. P6.4Įxplain why the Carnot cycle overestimates the thermal efficiency achievable from an engine producing power output. What are the mean temperatures of energy addition and rejection in the Joule cycle? What would be the thermal efficiency of a Carnot cycle based on these mean temperatures? 3.Ĭalculate the external irreversibilities and describe how these may be reduced to enable the Joule efficiency to be achieved. This ratio is less than the Joule efficiency – explain why in terms of unavailable energy. 2.Ĭalculate the ratio of the gas turbine cycle work to the energy delivered from the high-temperature reservoir ( Q H for the Carnot cycle). 1.Įvaluate the Carnot efficiency and compare this with the Joule efficiency explain why the Joule efficiency is the lower. Temperature-entropy diagram for Joule cyle. What is the maximum work output from the engine as the reservoir temperatures equalise? Is the equalisation temperature for maximum work a higher or lower limit of the equalisation temperature?Ĭlosed cycle gas turbines operate on the internally reversible Joule cycle with an efficiency ofįigure P6.3. The temperature of the hot reservoir falls by 1 K for each 1 kJ extracted from it, while the temperature of the cold reservoir rises by 1 K for each 1 kJ added. The maximum and minimum temperatures of the working fluid at maximum power output.ĭerive all the necessary equations, but assume the Carnot efficiency, η = 1− T C/ T H.Ī heat engine operates between two finite reservoirs, initially at 800 and 200 K, respectively. The maximum power output, W ˙ / C H and 5. The engine efficiency at maximum power output 4. If the heat transfer conductance from the reservoirs to the engine are in the ratio ( UA) H/( UA) C = C H/ C C = 2, evaluate the following: 1. Introducing the concept of external irreversibility, evaluate the efficiency of an endoreversible engine at maximum power output.Ĭonsider a heat engine connected to high-temperature reservoir at T H = 1200 K and a low temperature one at T C = 300 K. Explain why the Carnot cycle efficiency is unrealistically high for a real engine.
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