Imperial College London


Faculty of EngineeringDepartment of Chemical Engineering

Professor of Clean Energy Technologies



+44 (0)20 7594 1601c.markides Website




404ACE ExtensionSouth Kensington Campus






BibTex format

author = {Zhang, K and Chen, X and Markides, CN and Yang, Y and Shen, S},
doi = {10.1016/j.apenergy.2016.10.017},
journal = {Applied Energy},
pages = {404--412},
title = {Evaluation of ejector performance for an organic Rankine cycle combined power and cooling system},
url = {},
volume = {184},
year = {2016}

RIS format (EndNote, RefMan)

AB - Power-generation systems based on organic Rankine cycles (ORCs) are well suited and increasingly employed in the conversion of thermal energy from low temperature heat sources to power. These systems can be driven by waste heat, for example from various industrial processes, as well as solar or geothermal energy. A useful extension of such systems involves a combined ORC and ejector-refrigeration cycle (EORC) that is capable, at low cost and complexity, of producing useful power while having a simultaneous capacity for cooling that is highly desirable in many applications. A significant thermodynamic loss in such a combined energy system takes place in the ejector due to unavoidable losses caused by irreversible mixing in this component. This paper focuses on the flow and transport processes in an ejector, in order to understand and quantify the underlying reasons for these losses, as well as their sensitivity to important design parameters and operational variables. Specifically, the study considers, beyond variations to the geometric design of the ejector, also the role of changing the external conditions across this component and how these affect its performance; this is not only important in helping develop ejector designs in the first instance, but also in evaluating how the performance may shift (in fact, deteriorate) quantitatively when the device (and wider energy system within which it functions) are operated at part load, away from their design/operating points. An appreciation of the loss mechanisms and how these vary can be harnessed to propose new and improved designs leading to more efficient EROC systems, which would greatly enhance this technology’s economic and environmental potential. It is found that some operating conditions, such as a high pressure of the secondary and discharge fluid, lead to higher energy losses inside the ejector and limit the performance of the entire system. Based on the ejector model, an optimal design featuring a sm
AU - Zhang,K
AU - Chen,X
AU - Markides,CN
AU - Yang,Y
AU - Shen,S
DO - 10.1016/j.apenergy.2016.10.017
EP - 412
PY - 2016///
SN - 0306-2619
SP - 404
TI - Evaluation of ejector performance for an organic Rankine cycle combined power and cooling system
T2 - Applied Energy
UR -
UR -
UR -
VL - 184
ER -