Operation analysis of a photovoltaic plant integrated with a compressed air energy storage system and a city gate station

Thermoeconomic and environmental feasibility of waste heat recovery of a data center using air source heat pump

A new design for natural gas pressure reduction points by employing a turbo expander and a solar heating set

Thermo-economic analysis and sizing of a PV plant equipped with a compressed air energy storage system

Energy consumption minimization in an innovative hybrid power production station by employing PV and evacuated tube collector solar thermal systems

Defining a technical criterion for economic justification of employing CHP technology in city gate stations

Original scientific paper DOI: 10.2298/TSCI110505082F Vortex tube is a simple device without a moving part which is capable of separating hot and cold gas streams from a higher pressure inlet gas stream. The mechanism of energy separation has been investigated by several scientists and second law approach has emerged as an important tool for optimizing the vortex tube performance. Here, a thermodynamic model has been used to investigate vortex tube energy separation. Further, a method has been proposed for optimizing the vortex tube based on the rate of entropy generation obtained from experiments. Also, an experimental study has been carried out to investigate the effects of the hot tube length and cold orifice diameter on entropy generation within a vortex tube with natural gas as working fluid. A comparison has been made between air and natural gas as working fluids. The results show that the longest tube generates lowest entropy for natural gas. For air, it is middle tube which generates lowest entropy. Integration of entropy generation for all available cold mass fractions unveiled that an optimized value for hot tube length and cold orifice diameter is exist.

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The second law analysis of natural gas behaviour within a vortex tube

Photovoltaic-thermal (PV-T) panels are one of the major solar energy sources used to convert solar radiation into electrical power directly. This type of panel is considered a viable solution to guarantee energy security and reduce greenhouse gases. On the other hand, the efficiency of PV-T modules diminishes when the temperature of the nodule rises, leading to a degradation in the conversion efficiency along with the life span of a photovoltaic cell. Applying cooling techniques will lead to the decrease of the excess heat that is generated and will make the life span longer simultaneously. Higher efficiency can be achieved by incorporating oscillating heat pipe (OHP) into energy systems. PV-T module thermal and electrical efficiency can be improved by using an oscillating heat pipe. This review encourages the selection of an oscillating heat pipe and the heat transfer enhancement approach to increase energy conversion rate and the productivity corresponding to the PV-T system, as well as identifies the research gaps, future vision, and development that can be done. Firstly, the OHP-PV-T system and its performance in detail are illustrated. Then, the structure and working principles of the system are discussed, followed by a review of the work conducted in this case. The advantages of using an oscillating heat pipe as a solar panel cooling approach are then highlighted. Understanding the advanced cooling technologies mentioned above is vital for further modifications of current PV-T panels. Moreover, using nanofluid as coolant can make a significant contribution to enhancing the total system efficiency. 

An extensive review on the latest developments of using oscillating heat pipe on cooling of photovoltaic thermal system

Investigation of natural gas thermal separation through a vortex tube

Vortex tube is a simple device which separate an inlet gas with a proper pressure into hot and cold flows .This device is well-suited for generating cooling load gas because it provides the cold gas without using any refrigerants . Many research works has been carried out in order to identify the factors which contribute to Vortex tube performance. Here, an experimental study has been made to determine the effect of geometrical (length of vortex tube) and thermo-physical (pressure) parameters on vortex tube performance and air also used as a working fluid.

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Mahyar Kargaran

Papers

Defining a technical criterion for economic justification of employing CHP technology in city gate stations

The second law analysis of natural gas behaviour within a vortex tube

An extensive review on the latest developments of using oscillating heat pipe on cooling of photovoltaic thermal system

Investigation of natural gas thermal separation through a vortex tube

An experimental study of the effect of pressure inlet gas on a counter-flow vortex tube