Cooling of air using heptadecane phase change material in shell and tube arrangement: Analytical and experimental study

A shell and tube latent heat storage (LHS) system using heptadecane with melting point 22.33 degrees C for active cooling of air has been analyzed analytically and experimentally in this paper. A theoretical model of laminar forced convection with varying wall temperature due to phase change material (PCM) outside a double wall circular tube and air as heat transfer fluid (HTF) inside a tube was employed to analyze active cooling of air. The analytical prediction in terms of outlet temperature was validated with experimental data. Furthermore, influences of some important design parameters (e.g. inner radius and thickness of the tube) on cooling effect were investigated. It was found that an optimum inner radius and thickness of the tube should be considered to design an LHS system. Better co-efficient of performance (COP) was observed for higher inlet air temperature while the outlet air temperature was almost identical. In this study, the COP of cooling was found 4.16 for 34.5 degrees C inlet air temperature using tube with 5.35 mm inner radius and 1 mm thickness. Some important thermophysical properties of heptadecane e.g. specific heat, thermal conductivity and density at liquid state were also examined and found 2.66 kJ kg(-1) K-1, 0.151 W m(-1) K-1 and 774 kg m(-3), respectively. (C) 2014 Elsevier B.V. All rights reserved

Curbing global warming with phase change materials for energy storage

The application of thermal energy storage (TES) system with phase change material (PCM) is an effective way for energy conservation and greenhouse gas (GHG) emission reduction. Global warming is increasing along with the energy consumption. Many researchers are concerned about this present global environmental problem for fossil-fuel burning. Thermal energy storage system with phase change material is observed as a potential candidate for mitigating this problem. This paper emphasizes the opportunities for energy savings and greenhouse-gas emissions reduction with the implementation of PCM in TES systems. For instance, about 3.43 of CO 2 emission by 2020 could be reduced through the application of PCM in building and solar thermal power systems. Similarly, energy conservation and GHGs emission reduction by other PCM applications for thermal comfort of vehicles, transport refrigeration, engine cold start, greenhouse and waste heat management are also presented. In addition, some present investigations on the performance improvement of the phase change materials are addressed

Liposomal prednisolone inhibits vascular inflammation and enhances venous outward remodeling in a murine arteriovenous fistula model

Arteriovenous fistulas (AVF) for hemodialysis access have a 1-year primary patency rate of only 60%, mainly as a result of maturation failure that is caused by insufficient outward remodeling and intimal hyperplasia. The exact pathophysiology remains unknown, but the inflammatory vascular response is thought to play an important role. In the present study we demonstrate that targeted liposomal delivery of prednisolone increases outward remodeling of the AVF in a murine model. Liposomes accumulate in the post-anastomotic area of the venous outflow tract in which the vascular pathology is most prominent in failed AVFs. On a histological level, we observed a reduction of lymphocytes and granulocytes in the vascular wall. In addition, a strong anti-inflammatory effect of liposomal prednisolone on macrophages was demonstrated in vitro. Therefore, treatment with liposomal prednisolone might be a valuable strategy to improve AVF maturatio