T he thermodynamic and economic performance of a solar combined heat and power (S - CHP) system based on an array of hybrid photovoltaic - thermal (PVT) collectors and an organic Rankine cycle (ORC) engine is considered for the provision of heating and power to swimming pool facilities . Priority is given to meet ing the thermal demand of the swimming pool , in order to ensure a comfortable condition for swimmers in cold er weather conditions, while excess thermal output from the collector s at high er temperatures is converted to electricity by the ORC engine in warm er weather conditions. The thermodynamic performance of this system and its dynamic characteristics are analysed on the basis of a transient thermodynamic model. Various heat losses and gains are considered in accordance to environmental and user - rela ted factors for both indoor and outdoor swimming pools. A case study is then performed for the swimming pool at the University Sport Centre (USC) of Bari, Italy. The r esults show that employing a zeotropic mixture of R245fa/ R227ea (30/70%) as the ORC working fluid allows such an ORC system to generate ~50% more power than when using pure R236ea due to the better temperature match of the cycle to the low - temperature hot - water heat source from the output of the PVT collectors . Apart from generating electricity, the ORC engine also alleviates PVT collector overheating , and reduc es the required size of the hot - water storage tank. With an installation of 2000 m 2 of PVT collectors, e nergetic analyses indicate that the proposed S - CHP system can cover 84 - 9 6 % of the thermal demand of the swimming pool during the warm summer months and 61 % of its annual ly integrated total thermal demand. In addition, the system produces a combined (from the collectors and ORC engine) of 328 MWh of electricity per year, corresponding to 36% of the total electricity demand of the USC , with ~4% coming from the ORC engine . The analysis suggests a minimum payback time of 12. 7 years with a n optimized tank volume of 125 m
