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Abstract The solar thermoelectric generation（STEG）cogeneration system can provide heating and electric power simultaneously. Precedent studies on the STEG system were focused on getting higher electrical efficiency of the system and creating a new record. Optimization of thermal performance and evaluation of thermal efficiency are usually completed by calculation or numerical simulation. In this paper, a novel design of STEG cogeneration system was proposed. The system can work in three modes according to seasonal demand of hot water and electric power. A series of experiments were carried out in different working modes under variable conditions to evaluate the performance of the system. The results show that the system can generate 0.2 kW·h of electrical energy and about 100L of hot water at 41 °C in 1 day when solar irradiation is 1000 W/m2. The collector efficiency and electrical efficiency are calculated to be 42.2% and 2.1%, respectively. [ABSTRACT FROM AUTHOR]

Abstract Organic Rankine Cycle (ORC) is known as one of the best method amongst the other low-grade energy recovery methods. ORC can be applied for different applications such as geothermal, solar thermal and waste heat. However, the application of ORC in these applications requires the selection of suitable working fluid for better performance. So, this paper focuses on performance evaluation of ORCs for different working fluids. The modelling work was performed using MATLAB and, a thermo-physical database, REFPROP. The evaluation is performed based on the performance of the working fluid. The results reveal that MD2M & cyclopentane for temperature ranges 50 - 100 ⁰C, butane, neopentane & R245fa for 100 - 150 ⁰C, ethanol, methanol and propanone for 150-200 ⁰C and Water, m-Xylene and p-Xylene for 200 - 320 ⁰C are better working fluids for energy extraction. [ABSTRACT FROM AUTHOR]

Thermo Vapour Compressor TVC is the heart or prime mover of Multi-Effect Desalination MED system, it is also described as a steam ejector. Steam ejector is an economical device that utilizes high pressure steam to compress low pressure steam without any rotating parts or external power sources. The ejector performance is highly dependent on its geometry and operating conditions. The aim of the present work is to design and obtain steam ejector geometry, based on pre-specified operating conditions, and to investigate the flow behavior inside the ejector by using Computational Fluid Dynamics CFD through using “ANSYS FLUENT 14.5” software. In first section of this paper, 1-D mathematical model is carried out to predict the ejector geometry at designed operating conditions. The second part, describes the flow behavior inside the designed model of the ejector by CFD. CFD is a most reliable tool to reveal the phenomenon of the mixing process at different parts of the supersonic turbulent flow ejector and to study the effect of operating conditions on the effective ejector area. Obtaining such effects, using experimental work, is much costly and difficult. Finally, the results show the effect of the operating conditions on the entrainment ratio and the critical back pressure. [ABSTRACT FROM AUTHOR]

Thermo Vapour Compressor TVC is the heart or prime mover of Multi-Effect Desalination MED system, it is also described as a steam ejector. Steam ejector is an economical device that utilizes high pressure steam to compress low pressure steam without any rotating parts or external power sources. The ejector performance is highly dependent on its geometry and operating conditions. The aim of the present work is to design and obtain steam ejector geometry, based on pre-specified operating conditions, and to investigate the flow behavior inside the ejector by using Computational Fluid Dynamics CFD through using “ANSYS FLUENT 14.5” software. In first section of this paper, 1-D mathematical model is carried out to predict the ejector geometry at designed operating conditions. The second part, describes the flow behavior inside the designed model of the ejector by CFD. CFD is a most reliable tool to reveal the phenomenon of the mixing process at different parts of the supersonic turbulent flow ejector and to study the effect of operating conditions on the effective ejector area. Obtaining such effects, using experimental work, is much costly and difficult. Finally, the results show the effect of the operating conditions on the entrainment ratio and the critical back pressure. [ABSTRACT FROM AUTHOR]