
ISSN Online: 2688-7231
ISBN Online: 978-1-56700-524-0
Proceedings of the 26thNational and 4th International ISHMT-ASTFE Heat and Mass Transfer Conference December 17-20, 2021, IIT Madras, Chennai-600036, Tamil Nadu, India
A Real Gas Property-Based Thermodynamic Investigation of Ejector Based Refrigeration System for Automotive Applications
Abstract
Ejector refrigeration system (ERS) is a favourable
technology to recover the available exhaust heat of automobiles
for cooling purposes due to its uncomplicated structure, low
cost and easy maintenance compared to the other systems.
Despite these advantages, it suffers from poor performance
because of the irreversible fluid flow structures inside the
ejector. The refrigerant variant used, operating parameters and
design specifications influencing the ejector flow can affect the ERS performance significantly. As per the European
Parliament Directive 517/2014, the restrictions towards the
usage of high global warming potential (GWP) refrigerant
R134a reveals the necessity to find low-GWP alternates.
Accordingly, in the present study, a real gas property-based
theoretical model is developed to estimate the ERS behaviour
with six low-GWP substitutes for R134a: R1234yf, R1243zf
R1234ze(E), R152a, R513a and R440a. Within a wide variety
of evaporator and generator temperatures, the performance of
the proposed model is analyzed under the critical mode of
operation. Results indicate that for R1243zf and R1234yf
ejector cycles, the entrainment ratio is maximum and almost
equal. The coefficient of performance is observed as maximum
and nearly equal with R152a and R440a. Though the COP
values are higher for the refrigerants R152a and R440a because
of their higher GWP, it is suggested to use the next higher COP
refrigerants R1234yf and R1243zf in the ERS integrated with
automotive applications.