Evaluating Eco-Friendly Refrigerant Alternatives for Cascade Refrigeration Systems: A Thermoeconomic Analysis

A simple vapor-compression refrigeration system becomes ineffective and inefficient as it consumes a huge energy supply when operating between large temperature differences. Moreover, the recent Kigali amendment has raised a concern about phasing out some hydrofluorocarbon refrigerants due to their impact on the environment. In this paper, a numerical investigation is carried out to compare the performance of a cascade refrigeration system with two environmentally friendly refrigerant combinations, namely, R170–R404A and R41–R404A. Refrigerant R170, from the hydrocarbon category, and refrigerant R41, from the hydrofluorocarbon category, are separately chosen for the low-temperature circuit due to their similar thermophysical properties. On the other hand, refrigerant R404A is selected for the high-temperature circuit. An attempt is made to replace refrigerant R41 with refrigerant R170 as a possible alternative. The condenser temperature is kept constant at 40 °C, and the evaporator temperature is varied from −60 °C to −30 °C. The mathematical model developed for the cascade refrigeration system is solved using Engineering Equation Solver (EES). The effect of evaporator temperature on different performance parameters such as the COP, exergetic efficiency, and total plant cost rate is evaluated. The predicted results show that the thermoeconomic performance of the R170–R404A-based system is marginally lower compared to that of the R41–R404A-based system. The system using refrigerant pair R170–R404A has achieved only a 2.4% lower exergetic efficiency compared to the system using R41–R404A, with an increase in the annual plant cost rate of only USD 200. As the global warming potential (GWP) of R170 is less than that of R41, and R170 belongs to the hydrocarbon category, the use of the R170–R404A combination in a cascade refrigeration system can be recommended as an alternative to R41–R404A

Optimization of Coated Friction Drilling Tool for a FML Composite

10.1080/10426914.2020.1832684Materials and Manufacturing Processes363351-36

Increasing the waste heat absorption performance in the refrigeration system using electromagnetic effect

This paper enables a simulation model for analyzing and predicting magnetic field patterns and their magnetic flux density on the pipe. Different types of arrangements of magnets like series, parallel, and Halbach arrays are utilized and their magnetic flux density and magnetic field intensity are compared on the respective pipes. Electromagnetic field simulation software calculates different magnetic fields and circuit parameters. Using this software, accurate results can be obtained such as the perfect arrangement of magnets and so on. For this experimentation, Neodymium-35 type magnets are used which have appropriate and stable magnetic strength as compared to other magnets. Diffusion absorption refrigeration systems can also be used alternatively in domestic refrigeration, thus replacing conventional vapor compression refrigeration systems. Thus, results obtained by using different magnetic arrangements will be highly beneficial to choose the proper magnetic arrangement in diffusion absorption refrigeration system for various cooling applications

Influence of deposition time on titanium nitride (TiN) thin film coating synthesis using chemical vapour deposition

Titanium nitride (TiN) thin film coatings were grown over silicon (p-type) substrate using the atmospheric pressure chemical vapour deposition (APCVD) technique. The synthesis process was carried out to evaluate the effect of deposition time on the physical and mechanical characteristics of TiN coating. Thin films grown over Si substrate were further characterised to evaluate the morphological properties, surface roughness and mechanical properties using a scanning electrode microscope (SEM), atomic force microscopy (AFM) and nanoindentation, respectively. EDS equipped with SEM showed the presence of Ti and N elements in considerable amounts. TiN morphology obtained from the SEM test showed small-sized particles on the surface along with cracks and pores. AFM results revealed that by increasing the deposition time, the surface roughness of the coating also increased. The nanomechanical properties such as nanohardness (H) and Young’s modulus (E), etc., evaluated using the nanoindentation technique showed that higher deposition time led to an increase in H and E. Overall, it was observed that deposition time plays a vital role in the TiN coating deposition using the CVD technique.Web of Science1613art. no. 461