Zafer Gemici

Thermal Comfort Analysis of Novel Low Exergy Radiant Heating Cooling System and Energy Saving Potential Comparing to Conventional Systems

In this study characteristics of a model room with dimensions 6 m × 4 m × 3 m has been investigated using Computational Fluid Dynamics method with regard to thermal comfort, in case of that the room is heated and cooled by the means of radiant panels. Both general thermal comfort parameters [PMV (percentage mean vote), PPD (predicted percentage of dissatisfied)] and local thermal comfort parameters (radiant temperature asymmetry, draught, vertical air temperature difference, warm and cool floors) which are described by the standards ISO 7730 and ASHRAE 55 have been taken into consideration. Radiant panels have been placed to exterior walls for heating system, and they have been put on both exte\rior walls and ceiling for cooling system. According to the TS 2164 standards, different regions are identified with regard to outdoor climate conditions for heating and cooling seasons in Turkey, and analysis of heating/cooling is done for each region. Heat fluxes from radiant panels and corresponding values of room mean temperature required in order for the conditions of thermal comfort described by the standards ISO 7730 to be met have been determined for these regions and heating/cooling system configurations. Energy saving potential of radiant system has been evaluated for these regions and heating/cooling mode.

Predicting the Numerical and Experimental Open-Channel Flow Resistance of Corrugated Steep Circular Drainage Pipes

AbstractThis paper studies flow resistance characteristics of corrugated circular drainage pipes through experimental measurements and numerical calculations under turbulent uniform open-channel fl...

Aramid-HDPE Composites: Influence of Interface Adhesion Measured by T-peel Test on Tensile Properties

Abstract In this study, the influence of using compatibilizer as tie-layer between fiber matrix interfaces in continuous aramid fiber reinforced high density polyethylene (HDPE) composites was investigated. Maleic anhydride (MAH) grafted polyethylene and ethylene-methyl acrylate-glycidyl methacrylate (EMA-GMA) terpolymer were used as compatibilizers at varying layer numbers. Adhesion strength was determined by T-peel test, and tensile test was carried out. It was found that higher MFR (Melt Flow Rate) valued matrix and compatibilizer application increased the mechanical performance. The maximum strength values were obtained with EMA-GMA applications. In observations of peeled parts and cross-sectional slices, interface adhesion was investigated and failure patterns were determined. It was seen that the samples with compatibilizer had more wetted portions especially the EMA-GMA tie-layered ones.

Experimental Analysis of Viscoelastic Properties of High Density Polyethylene (PE100)

A High-density polyethylene has been used for buried plastic pipe production for over a decade. The structural performance of these pipes mainly depends on the viscoelastic properties of using materials. The aim of this study is to determine the creep behavior of PE100 material under constant tensile and flexural stress within 24 hours. In both tests, large deformation occurs within the first 1000 seconds and then very little or no deformation is observed. Primary and secondary creep stages have also been observed. At highest stress level, maximum strain is 5%, approximately.At the flexural creep experiments, modulus of the material has been obtained from total deflection value at the end of 24 hours by using three point bending experiment under constant load. Large deflection occurs within in first 1000 seconds, after that, continues to increase slowly. Maximum strain is about 2%. The material exhibits linear viscoelastic response to 8 MPa stress level.Copyright

Experimental Analysis of Ring Stiffnesses of Pipes, Made of High Density Polyethylene, due to DIN 16961-2:2010-03 Standard

The parallel plate load test is used to measure “pipe stiffness” for HDPE pipe. Pipe stiffness is employed as a measure of pipe resistance to bending deformation as well as a quality control index for the manufacturing process. This work presents the results of a series of parallel plate tests conducted on profiled HDPE plastic pipes to determine ring stiffness values. During the study, all pipe samples were tested according to the DIN 16961 2:2010-03 standard. The nominal inside diameters of the test pipes were selected 500 and 600mm. These pipes compressed radially a constant load during 24 hours and deflection were measured by a comparator. Then experimental ring stiffness values were calculated by using these data.Copyright