Performance study on the evaporation and pressure drop of low‐temperature refrigerant blends in porous media

Abstract

An experimental investigation on the performance of different low‐temperature refrigerant blends is presented in this work. Five different low‐temperature refrigerant blends are put on display to replace the R22 refrigerant, which has a high ozone depletion potential. These five blends are R404A, R407C, R410A, R417A, and R422A. Different performance studies have been performed on these alternative refrigerants to replace R22. A comparative experimental performance study is performed during the evaporation of these refrigerant blends in porous media. A porous metallic heat transfer medium is used with different porosities (40%, 43%, and 45%) in the evaporator during the test experiments. The evaporator superheat and the condenser subcool are maintained constant throughout the experiments at 8°C (±0.5°C) and 6°C (±0.5°C), respectively. The condensing temperature is kept constant at 38.5°C, and the mean evaporating temperatures were selected to be from −33 to −18°C. The effect of the above‐mentioned given operating conditions on the compressor discharge temperature, evaporation pressure drop, evaporation capacity, and coefficient of performance of these five low‐temperature refrigerant blends has been analyzed for different porosities. This experimental study showed that the refrigerant R422A can give a similar or greater performance to R22 and R404A with a global warming effect and zero ozone depleting potential.

Numerical study of effective parameters on the drying process in a vertical porous channel

“…One of the most important limitations is the vapor pressure or viscous limit that occurs at the heat pipe start‐up when the heat pipe operates at low temperature . Due to the low vapor pressure of the liquid in the evaporator, the vapor pressure difference between evaporator and condenser of the heat pipe is insufficient to overcome viscous and gravitational forces.…”

Multiphase flow and boiling heat transfer modelling of nanofluids in horizontal tubes embedded in a metal foam

“…They showed that a smaller diameter of the tube results in a higher temperature variation over the entire metal foam tube. Tarawneh [39] studied experimentally the effect of different refrigerants on boiling heat transfer in a porous medium with different porosities. They showed that R422a shows a higher heat transfer performance compared with R22 and R404a helping global warming.…”