Efficiency Evaluation of the Ejector Cooling Cycle using a New Generation of HFO/HCFO Refrigerant as a R134a Replacement

Abstract

Theoretical investigations of the ejector refrigeration system using hydrofluoroolefins (HFOs) and hydrochlorofluoroolefin (HCFO) refrigerants are presented and discussed. A comparative study for eight olefins and R134a as the reference fluid was made on the basis of a one-dimensional model. To facilitate and extend the possibility of comparing our results, three different levels of evaporation and condensation temperature were adopted. The generator temperature for each refrigerant was changed in the range from 60 °C to the critical temperature for a given substance. The performed analysis shown that hydrofluoroolefins obtain a high efficiency of the ejector system at low primary vapor temperatures. For the three analyzed sets of evaporation and condensation temperatures (te and tc equal to 0 °C/25 °C, 6 °C/30 °C, and 9 °C/40 °C) the maximum Coefficient of Performance (COP) was 0.35, 0.365, and 0.22, respectively. The best performance was received for HFO-1243zf and HFO-1234ze(E). However, they do not allow operation in a wide range of generator temperatures, and, therefore, it is necessary to correctly select and control the operating parameters of the ejector.

Exergoeconomic Assessment of a Compact Electricity-Cooling Cogeneration Unit

“…The experimental results on the exergy behavior of R513A vs. R134a were discussed by Mota-Babiloni et al [94], with higher exergy efficiency verified for R513A with the advantage that the system does not require retrofitting. Employing a mixture of nanomaterials with pure conventional working fluids (such as refrigerants) presents significant benefits, such as lower global warming potentials, zero ozone depletion potential, higher energy efficiency, lower power consumption, non-flammability, non-toxicity, heat transfer enhancement, and better tribological and rheological behavior [95]. Most research is still primarily focused on the use of R141b and R134a as working fluids [95], but the possibilities of using non-standard refrigerants must be considered (such as hydrofluoroolefins, either pure or mixed).…”

Institutions and Governments Can Slow Climate Change by Regulating and Reducing Halocarbon Refrigerant Use

“…Several strategies, such as leak detection and drop-in retrofits, can halve the environmental impact of emissions while simultaneously reducing repair costs. While HFO units are generally less energy efficient than halocarbon systems, existing HFC drop-in replacements and natural refrigerants use up to 14% less energy than currently-used halocarbons to achieve the same cooling capacity [25,26]. This reduces operating costs and can offset the higher capital costs of new halocarbon-free systems over the equipment lifetime.…”

New HFC/HFO Blends as Refrigerants for the Vapor-Compression Refrigeration System (VCRS)

“…According to EN 378-1 [7], both HFO refrigerants have a very low level of GWP, at only 4 and 7, respectively. In addition to compressor cycles, HFOs are also considered for operation in other types of refrigeration equipment, such as ejector devices [8,9] or combined systems [10,11].…”