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 = {Ramos, A and Chatzopoulou, MA and Freeman, J and Markides, C},
doi = {10.1016/j.apenergy.2018.06.059},
journal = {Applied Energy},
pages = {755--765},
title = {Optimisation of a high-efficiency solar-driven organic Rankine cycle for applications in the built environment},
url = {},
volume = {228},
year = {2018}

RIS format (EndNote, RefMan)

AB - Energy security, pollution and sustainability are major challenges presently facing the international community, in response to which increasing quantities of renewable energy are to be generated in the urban environment. Consequently, recent years have seen a strong increase in the uptake of solar technologies in the building sector. In this work, the potential of a solar combined heat and power (CHP) system based on an organic Rankine cycle (ORC) engine is investigated in a domestic setting. Unlike previous studies that focus on the optimisation of the ORC subsystem, this study performs a complete system optimisation considering both the design parameters of the solar collector array and the ORC engine simultaneously. Firstly, we present thermodynamic models of different collectors, including flat-plate and evacuated-tube designs, coupled to a non-recuperative sub-critical ORC architecture that delivers power and hot water by using thermal energy rejected from the engine. Optimisation of the complete system is first conducted, aimed at identifying operating conditions for which the power output is maximised. Then, hourly dynamic simulations of the optimised system configurations are performed to complete the system sizing. Results are presented of: (i) dynamic 3-D simulations of the solar collectors together with a thermal energy storage tank, and (ii) of an optimisation analysis to identify the most suitable working fluids for the ORC engine, in which the configuration and operational constraints of the collector array are considered. The best performing working fluids (R245fa and R1233zd) are then chosen for a whole-system annual simulation in a southern European climate. The system configuration combining an evacuated-tube collector array and an ORC engine is found to be best-suited for electricity prioritisation, delivering an electrical output of 3,605kWh/year from a 60m2 collector array. In addition, the system supplies 13,175kWh/year in the form of domes
AU - Ramos,A
AU - Chatzopoulou,MA
AU - Freeman,J
AU - Markides,C
DO - 10.1016/j.apenergy.2018.06.059
EP - 765
PY - 2018///
SN - 0306-2619
SP - 755
TI - Optimisation of a high-efficiency solar-driven organic Rankine cycle for applications in the built environment
T2 - Applied Energy
UR -
UR -
VL - 228
ER -