Thermoeconomic Analysis of Organic Rankine Cycle Using Zeotropic Mixtures

The selection of the working fluid is an important part of design and optimization of ORC system as it effects the systems efficiency, design of ORC components, stability, safety and environmental impact. Present study aims to investigate the performance of ORC system using pure working fluids and zeotropic mixtures for low temperature geothermal heat source on the basis of thermodynamic and economic parameters of ORC system. Evaporator, expander, condenser and feed pump models are developed in MATLAB. The control volume approach is adopted for evaporator and condenser model with appropriate database of heat transfer and pressure drop correlations. For comparison, pure working fluids are taken as the base case. The ORC system with pure working fluid and zeotropic mixture under same heat and sink source conditions are optimized using multi objective genetic algorithm for maximum exergy efficiency and minimum specific investment cost. The exergy efficiency of ORC system with zeotropic mixture is improved by 14.33% compared to pure working fluid. The exergy destruction in evaporator and condenser is reduced by 24~30%. The fraction of more volatile component in zeotropic mixture effected the thermal and economic performance of ORC system, for current study the mass fraction of 40% of R245fa corresponds to optimum exergy efficiency and specific investment cost. For same condensing pressure and expander power, area of evaporator for pure working fluids and zeotropic mixture is also calculated. The required heat transfer area for zeotropic mixture is approximately 13% less than required for pure working fluid

The feasibility analysis for the concept of low temperature district heating network with cascade utilization of heat between networks

Recently, low temperature district heating networks (LTDH) have received attention in district heating and cooling market due to their benefits in terms of efficiency, greenhouse gas reduction, flexibility to use renewable energy sources and economic benefits. In this work, physical and techno-economical aspects of the new concept of cascade types with high temperature district heating (HTDH) return is utilized to supply heat at low temperature networks. The HTDH return water temperature is around 45oC and supply of LTDH can be set around 60oC. The return water temperature of HTDH return line at 45oC can be raised to 60oC with the help of heat pump. A detailed study of major components, network design, pressure drop, heat loss and power consumption was performed to formulate an annual, hourly, based energy simulation to assess the techno-economic feasibility of the systems for different types of customers (residential & commercial) The economics were also analysed in terms of internal rate of return (IRR) and the results show that IRR for residential buildings varies from 14 ~ 17%. In order for the successful realization of the proposed system in the market new sustainable systems encouragement in government level is desired to be provided in the form of renewable energy target/certificates or CO2 reduction incentives especially at the initial stage of the commercialization of the model

High glucose induces MCP-1 expression partly via tyrosine kinase–AP-1 pathway in peritoneal mesothelial cells

High glucose induces MCP-1 expression partly via tyrosine kinase–AP-1 pathway in peritoneal mesothelial cells.BackgroundHigh glucose in peritoneal dialysis solutions has been implicated in the pathogenesis of peritoneal fibrosis in chronic ambulatory peritoneal dialysis (CAPD) patients. However, the mechanisms are not very clear. Peritoneal macrophages seem to participate in the process of peritoneal fibrosis and monocyte chemoattractant protein-1 (MCP-1) plays a key role in the recruitment of monocytes toward the peritoneal cavity. However, little is known about the effect of high glucose on MCP-1 expression and its signal transduction pathway in human peritoneal mesothelial cells.MethodsMesothelial cells were cultured with glucose (5 to 100 mmol/L) or mannitol chronically for up to seven days. MCP-1 expression of mRNA and protein was measured by Northern blot analysis and enzyme-linked immunosorbent assay (ELISA). Chemotactic activity of high-glucose–conditioned culture supernatant was measured by chemotactic assay. To examine the roles of the transcription factors activator protein-1 (AP-1) and nuclear factor-κB (NF-κB), electrophoretic mobility shift assay (EMSA) was performed.ResultsGlucose induced MCP-1 mRNA expression in a time- and dose-dependent manner. MCP-1 protein in cell culture supernant was also increased. Equivalent concentrations of mannitol had no significant effect. High-glucose–conditioned supernatant possessed an increased chemotactic activity for monocytes, which was neutralized by anti–MCP-1 antibody. EMSA revealed that glucose increased the AP-1 binding activity in a time- and dose-dependent manner, but not NF-κB. Curcumin, an inhibitor of AP-1, dose-dependently suppressed the induction of MCP-1 mRNA by high glucose. Tyrosine kinase inhibitors such as genistein (12.5 to 50 μmol/L) and herbimycin A (0.1 to 1 μmol/L) inhibited the high-glucose–induced MCP-1 mRNA expression in a dose-dependent manner, and also suppressed the high-glucose–induced AP-1 binding activity.ConclusionsHigh glucose induced mesothelial MCP-1 expression partly via the tyrosine kinase-AP-1 pathway

Improvement Characteristics of Ground Using C.G.S Through Field Case Study

Compaction Grouting System is widely used in densifying loose soils or fill voids caused by sinkholes, poorly compacted fills, and soft ground improvement. Also, it is used in preventing liquefaction, re-leveling settled structures, and using compaction bulbs as structural elements of minipiles or underpinning. But the effects of ground improvement depending on the type of soil must be studied in order to adopt in various soils. In this study, characteristics analysis of the ground improvement and the effectiveness of reinforcement were grasped by this study which shows applied ground by Compaction Grouting System in domestic 6 sites. After Compaction Grouting, strength characteristics of the ground are much better than before Compaction Grouting through the results of the standard penetration test, the dynamic cone penetration test, the vane test and laboratory test using performance Evaluation of Linear Regression. Especially improvement of strength was shown over 17% by Compaction Grouting through prediction formulas in sand

Comparison of postoperative changes in the distal and proximal segments between conventional and sliding mini-plate fixation following mandibular setback

The purpose of the present study was to evaluate the postoperative three-dimensional (3D) changes in the proximal segments after mandibular setback sagittal split ramus osteotomy and to compare the changes between the conventional mini-plate fixation and semi-rigid sliding plate fixation

Design of the VISTA-ITL Test Facility for an Integral Type Reactor of SMART and a Post-Test Simulation of a SBLOCA Test

To validate the performance and safety of an integral type reactor of SMART, a thermal-hydraulic integral effect test facility, VISTA-ITL, is introduced with a discussion of its scientific design characteristics. The VISTA-ITL was used extensively to assess the safety and performance of the SMART design, especially for its passive safety system such as a passive residual heat removal system, and to validate various thermal-hydraulic analysis codes. The VISTA-ITL program includes several tests on the SBLOCA, CLOF, and PRHRS performances to support a verification of the SMART design and contribute to the SMART design licensing by providing proper test data for validating the system analysis codes. A typical scenario of SBLOCA was analyzed using the MARS-KS code to assess the thermal-hydraulic similarity between the SMART design and the VISTA-ITL facility, and a posttest simulation on a SBLOCA test for the shutdown cooling system line break has been performed with the MARS-KS code to assess its simulation capability for the SBLOCA scenario of the SMART design. The SBLOCA scenario in the SMART design was well reproduced using the VISTA-ITL facility, and the measured thermal-hydraulic data were properly simulated with the MARS-KS code