Working fluids for high-temperature organic Rankine cycles

Nonlinear Oscillations: Exact Solutions and their Approximations

Recent progress on flat plate solar collectors and photovoltaic systems in the presence of nanofluid: A review

Halogenated hydrocarbons with high ozone depletion potential (ODP) were banned under Montreal Protocol (1987) due to their detrimental effects on ozone layer that shields the planet against ultraviolet radiations. The greenhouse gases (GHG) used in modern refrigeration, air conditioning, and heat pumping systems, are under Kyoto Protocol (1997)’s time-barred permission period. In order to reduce the depletion of ozone and reverse the climate change effects, the European Union legislation (2014) and Paris Accord (2016) are strongly emphasizing the phasing out of the use of harmful synthetic refrigerants. Choice of natural refrigerants makes no net addition of the greenhouse gases (GHG) in the environment. To retrofit and modify existing cooling and heating systems using natural refrigerants, extensive investigations are in progress worldwide. This work reviews timeworn, current and the next-generation refrigerants using Refrigerant Qualitative Parametric (RQP) quantification model to assist the refrigerant choice decision process. It is based on the ratio of arithmetic sums of actual parametric values of refrigerants normalized to equivalent ideal values. This model can help in choosing alternative refrigerants to replace CFCs by HCFCs or HFCs provisionally and finally replacing HCFCs or HFC to low GWP and ODP synthetic and natural refrigerants. A set of 16 refrigerants, both natural and synthetic, as an example, is computed for the standard Vapour Compression Cycle (VCC) based on the proposed model using REFPROP (NIST- 23 standard). The techno-economic parametric values of chosen refrigerants are taken from cited literature, ASHREA safety standards and international environmental legislations, laws and protocols. This paper reports the environment benign natural (CO2, NH3, HCs) and a few synthetic (R-152a, R-1234yf) refrigerants to be the optimal options.

Natural and synthetic refrigerants, global warming: A review

A comprehensive review of ejector design, performance, and applications

Performance analysis and working fluid selection for ejector refrigeration cycle

Parametric and working fluid analysis of a combined organic Rankine-vapor compression refrigeration system activated by low-grade thermal energy.

Hydrofluorocarbons are now well established as refrigerants because of their zero ozone depletion potential Since they have a high global warming potential, other alternatives as, eg fluorinated ethers or cyclic hydrocarbons are considered as next-generation refrigerants Screening of alternative refrigerants is difficult because mostly no or only few data are available To evaluate, eg the cycle performance, the thermodynamic properties of the refrigerants must be known and described accurately by an equation of state Here, the physically based BACKONE equations are used to describe alternative refrigerants, such as natural refrigerants, hydrofluorocarbons, fluorinated cyclic hydrocarbons, and fluorinated ethers BACKONE needs only a few substance specific parameters to describe thermodynamic properties with high accuracy Thus, even alternative refrigerants, with very few available experimental data can be described Calculations with BACKONE of the performance of many refrigerants show that some hydrocarbons and fluorinated ethers are a good alternative

Screening of pure fluids as alternative refrigerants

Energy and exergy analysis of an integrated organic Rankine cycle-vapor compression refrigeration system

Entropy generation and exergy efficiency analysis of ethylene glycol-water based nanodiamond + Fe3O4 hybrid nanofluids in a circular tube

B. Saleh

Papers

Performance analysis and working fluid selection for ejector refrigeration cycle

Parametric and working fluid analysis of a combined organic Rankine-vapor compression refrigeration system activated by low-grade thermal energy.

Screening of pure fluids as alternative refrigerants

Energy and exergy analysis of an integrated organic Rankine cycle-vapor compression refrigeration system

Entropy generation and exergy efficiency analysis of ethylene glycol-water based nanodiamond + Fe3O4 hybrid nanofluids in a circular tube