Recent years have seen a strong increase in the uptake of solar technologies in the built environment. In
combined heat and power (CHP) or cogeneration systems, the thermodynamic and economic ‘value’ of the
electrical output is usually considered to be greater than that of (an equivalent) thermal output, and therefore
the prioritisation of the electrical output in terms of system-level optimisation has been driving much of the
research, innovation and technology development in this area. In this work, the potential of a solar CHP
technology based on an organic Rankine cycle (ORC) engine is investigated. We present thermodynamic
models 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 using
thermal energy rejected from the engine. Results from dynamic 3-D simulations of the solar collectors together
with a thermal energy storage (TES) tank are presented. TES offers an important buffering capability during
periods of intermittent solar radiation, as well as the potential for demand-side management (DSM). Results
are presented of an optimisation analysis to identify the most suitable working fluids for the ORC unit, in which
the configuration and operational constraints of the collector array are taken into account. The most suitable
working fluids (R245fa and R1233zd) are then chosen for a whole-system optimisation performed in a southern
European climate. The system configuration with an ETC array is found to be best-suited for electricity
prioritisation, delivering an electrical output of 3,605 kWh/yr from a 60 m2 array. In addition, the system supplies
13,175 kWh/yr in the form of domestic hot water, which is equivalent to more than 6 times the average annual
household demand. A brief cost analysis and comparison with photovoltaic (PV) systems are also performed.