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, Cabal Alba RA and Chatzopoulou, M and Freeman, James JF and Markides, Christos CNM},
publisher = {ECOS},
title = {Optimisation of a high-efficiency solar-driven organic Rankine cycle for applications in the built environment},
url = {},
year = {2017}

RIS format (EndNote, RefMan)

AB - Recent years have seen a strong increase in the uptake of solar technologies in the built environment. Incombined heat and power (CHP) or cogeneration systems, the thermodynamic and economic ‘value’ of theelectrical output is usually considered to be greater than that of (an equivalent) thermal output, and thereforethe prioritisation of the electrical output in terms of system-level optimisation has been driving much of theresearch, innovation and technology development in this area. In this work, the potential of a solar CHPtechnology based on an organic Rankine cycle (ORC) engine is investigated. We present thermodynamicmodels developed for different collectors, including flat-plate collectors (FPC) and evacuated-tube collectors(ETC) coupled with a non-recuperative sub-critical ORC architecture to deliver power and hot water by usingthermal energy rejected from the engine. Results from dynamic 3-D simulations of the solar collectors togetherwith a thermal energy storage (TES) tank are presented. TES offers an important buffering capability duringperiods of intermittent solar radiation, as well as the potential for demand-side management (DSM). Resultsare presented of an optimisation analysis to identify the most suitable working fluids for the ORC unit, in whichthe configuration and operational constraints of the collector array are taken into account. The most suitableworking fluids (R245fa and R1233zd) are then chosen for a whole-system optimisation performed in a southernEuropean climate. The system configuration with an ETC array is found to be best-suited for electricityprioritisation, delivering an electrical output of 3,605 kWh/yr from a 60 m2 array. In addition, the system supplies13,175 kWh/yr in the form of domestic hot water, which is equivalent to more than 6 times the average annualhousehold demand. A brief cost analysis and comparison with photovoltaic (PV) systems are also performed.
AU - Ramos,Cabal Alba RA
AU - Chatzopoulou,M
AU - Freeman,James JF
AU - Markides,Christos CNM
PY - 2017///
TI - Optimisation of a high-efficiency solar-driven organic Rankine cycle for applications in the built environment
UR -
ER -