Exergoeconomic analysis of solar organic rankine cycle for geothermal air conditioned net zero energy buildings

This study is an attempt at achieving Net Zero Energy Building (NZEB) using a solar Organic Rankine Cycle (ORC) based on exergetic and economic measures. The working fluid, working conditions of the cycle, cycle configuration, and solar collector type are considered the optimization parameters for the solar ORC system. In the first section, a procedure is developed to compare ORC working fluids based on their molecular components, temperature-entropy diagram and fluid effects on the thermal efficiency, net power generated, vapor expansion ratio, and exergy efficiency of the Rankine cycle. Fluids with the best cycle performance are recognized in two different temperature levels within two different categories of fluids: refrigerants and non-refrigerants. Important factors that could lead to irreversibility reduction of the solar ORC are also investigated in this study. In the next section, the system requirements needed to maintain the electricity demand of a geothermal air-conditioned commercial building located in Pensacola of Florida is considered as the criteria to select the optimal components and optimal working condition of the system. The solar collector loop, building, and geothermal air conditioning system are modeled using TRNSYS. Available electricity bills of the building and the 3-week monitoring data on the performance of the geothermal system are employed to calibrate the simulation. The simulation is repeated for Miami and Houston in order to evaluate the effect of the different solar radiations on the system requirements. The final section discusses the exergoeconomic analysis of the ORC system with the optimum performance. Exergoeconomics rests on the philosophy that exergy is the only rational basis for assigning monetary costs to a system’s interactions with its surroundings and to the sources of thermodynamic inefficiencies within it. Exergoeconomic analysis of the optimal ORC system shows that the ratio Rex of the annual exergy loss to the capital cost can be considered a key parameter in optimizing a solar ORC system from the thermodynamic and economic point of view. It also shows that there is a systematic correlation between the exergy loss and capital cost for the investigated solar ORC system.

The moderate voice of John Sherman and the Republican agenda 1855-1898

Republican John Sherman, United States Congressman, Senator, Treasury Secretary, and Secretary of State had a political career of major importance from 1855 to 1898, yet there have been only casual references by historians and only two biographies of him, with the most recent published in 1902. From a strong Whig Party background, he was first elected to the United States House of Representatives in 1854; switching to the Republicans that same year. Then elevated to the Senate in 1861, he served in that body throughout the Civil War and Reconstruction when he was the most important voice of party unity and moderation. In 1877, the new President Rutherford Hayes appointed Sherman Secretary of the Treasury. He returned to the Senate after the Hayes administration where he sat for the following 15 years. In this particularly notable period, he not only led the upper house, but he engineered more bills in Congress which bore his name than any other member of either house. These included the critically important Sherman Silver Purchase Act, the Sherman Anti-Trust Act and Sherman Inter-State Commerce Act. In 1897 he left the Senate finally when William McKinley appointed him Secretary of State. ^ Through this long, distinguished career, Sherman was involved in all the important legislation that brought the country through the Civil War and Reconstruction and into the post-war world of the Gilded Age of rapid industrialization, and urban growth, Politically, he never strayed far from the nationalistic and economic principles of the Whig Party, and brought both these values to bear in the Republican Party that dominated American political life from 1860 to 1900. Similarly, party loyalty and loyalty to the President always characterized his service. He was indeed, an exemplar of political and statesmanship. ^ While research for this dissertation included review of both journal and monographic literature, its basis lies more critically in primary research in unpublished archival material in repositories from Maine to Ohio, in particular the Library of Congress. ^