Supercritical pressure power cycles working fluids

Supercritical pressure power cycles working fluids... 

Carbon dioxide is a good potential working fluid for the supercritical cycle for several good reasons. The critical pressure of carbon dioxide is one-third that of water. Carbon dioxide is known to be a stable and inert material through the temperature range of industrial power generation. It is also abundant, nontoxic, and relatively inexpensive. 

Carbon dioxide Stable in neutron flux Close to being an inert gas Average thermal conductivity Average specific heat Can be used inside reactor core Reactor coolant in OCRs and AGRs filling gas in CANDU reactors in gap between pressure mbe and calandria mbe working fluid in supercritical CO2 Brayton power cycle... 

A power plant operating on heat recovered from the exhaust gases of internal-combustion < uses isobutane as the working medium in a modified Rankine cycle in which the upper pressure I is above the critical pressure of isobutane. Thus the isobutane does not undergo a change of p" as it absorbs heat prior to its entry into the turbine. Isobutane vapor is heated at 4,800 kPa to 2 and enters the turbine as a supercritical fluid at these conditions. Isentropic expansion in the turh produces superheated vapor at 450 kPa, which is cooled and condensed at constant pressure, resulting saturated liquid enters the pump for return to the heater. If the power output of the modi Rankine cycle is 1,000 kW, what is the isobutane flow rate, the heat-transfer rates in the heater condenser, and the thermal efficiency of the cycle ... 

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