This paper illustrates a comparison between different solutions for waste heat recovery from a specific internal combustion engine using an Organic Rankine Cycle (ORC). The purpose of the present work is to find the cycle configuration and the fluid that can provide the maximum mechanical power for given conditions of waste heat recovery (WHR) from flue gas and motor cooling water of a Turbocharged Diesel Engine Electric Generator. The thermodynamic analysis is conducted for ten working fluids from different chemical classes: hydrofluorocarbons (HFC) and the new subclass hydrofluoroolefins (HFO), hydrocarbons (HC), siloxanes and alcohols applied on six ORC configurations, three conventional ones (basic ORC, regenerative ORC and preheater ORC), a regenerative dual-loop ORC (DORC), a mixture of two traditional ORC (one used for WHR from the motor cooling water and the other used for flue gas WHR) and a dual ORC but with a common condenser configuration. One of the working fluids investigated is a new HFO, named R1336mzz, which has very low GWP, zero ODP and good safety properties. This novel fluid also shows good results in our investigation. Future work and development perspectives are discussed

A modern computer generates a great amount of heat while working. In order to secure appropriate working conditions by extracting the heat, a specific mechanism should be used. This research paper presents the effect of nanofluids on the microchannel heat sink performance of computer cooling systems experimentally. CeO₂, Al₂O₃ and ZrO₂ nanoparticles suspended in 20% ethylene glycol and 80% distilled water are used as working fluids in the experiment. The concentration of the nanoparticles ranges from 0.5% to 2%, mass flow rate ranges from 0.028 kg/s to 0.084 kg/s, and the ambient temperature ranges from 25 °C to 40 °C. Regarding the thermal component, parameters such as thermophysical properties of the nanofluids and base fluids, central processing unit (CPU) temperature, heat transfer coefficient, pressure drop, and pumping power have been experimentally investigated. The results show that CeO₂-EG/DW, at a concentration of 2% and a mass flow rate of 0.084 kg/s, has with 8% a lower temperature than the other nanofluids and with 29% a higher heat transfer coefficient compared with the base fluid. The Al₂O₃-EG/DW shows the lowest pressure drop and pumping power, while the CeO₂-EG/DW and ZrO₂-EG/DW show the highest. However, a slight increase of pumping power and pressure drop can be accepted, considering the high improvement that the nanofluid brings in computer cooling performance compared to the base fluid.

According to the EU F-gas Regulation, the phase-out of the high global warming potential (GWP) refrigerants (with higher than 150 GWP value) had been established. The most currently existing household and commercial refrigerators and automobile air conditioners applications based on single-stage vapour compression systems operate with R134a as working fluid. The present paper aims, to review and evaluate the performance of a set of eco-friendly alternatives refrigerants to replace R134a, without change or with minor modifications in refrigeration equipment. The theoretical and experimental studies performed in this field of research were reviewed for this objective. These alternative refrigerants are some of HFCs, HFOs and HCs and their mixtures, which are expected to be an excellent candidates in many refrigeration applications. There are Many replacement possibilities had been proposed viz. drop-in replacement, retrofit refrigerant, and new systems. The results exhibited that the most suitable refrigerants as R134a drop-in substitutes are R1234yf, R152a, R450A, and R513A. The pure R1234ze and its mixtures are not suitable drop-in replacements of R134a but can be a good alternative to R134a only in new refrigeration systems. In terms of hydrocarbon refrigerants R290, R600, and R600a could replace R134a with some modifications to existing refrigeration systems to overcome the flammability issue. We should be using certain HFC and HC mixtures with the lowest TEWI index.

In the paper proposed here we focus on a possible solar engine. We study the influence of mass transfer coupled to pressure losses on the maximum available power of the system. Dans la publication proposée ci-après, nous étudions un éventuel moteur solaire. L'influence du transfert de matière couplé aux pertes de pression sur le maximum de puissance pouvant être obtenu par un tel système est analysée