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F. Calise, et al. Energy Conversion and Management 220 (2020) 113043
load are also considered. Simulations of five different scenarios are environment, showed that the best pay-back value, equal to 6.75 years,
performed with and without electrical or water storages. The aim is to was achieved in case of evacuated tube collectors having gross area of
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optimize the unit cost of water obtaining the optimal values of the 216 m . The best performance in terms of daily production of mem-
water storage tank volume and PV and battery system capacity. The brane distillation and DHW production 92.8 kg/day and 301.67 kg/
better solution is obtained for the scenario including PV panels coupled day, respectively.
with water tank, batteries and variable load operation of RO desalina- In the framework of polygeneration systems for Islands, the con-
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tion units, with a cost of 3.75 €/m , which is obviously much lower version of fossil fuels or of renewable energy source, aiming at reducing
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than the cost of transported water, equal to 12.77 €/m . A further study the environmental pollution, mainly in the transportation sector, has
regarding a solar thermal polygeneration system integrating membrane recently attracted a significant interest. For example, Pfeifer et al. [21]
distillation was also investigated by Mohan et al. for United Arab analyse the use of zero emission ferry lines (hydrogen and fully elec-
Emirates locations [20]. Here, with respect to the previous solar poly- tricity fuelled ferries), for the interconnection and connection to the
generation system, the solar energy is directly provided to the desali- mainland for different Croatian islands (Mediterranean Sea). The
nation unit. A 35.2 kW single stage LiBr/H 2 O ACH is also included in availability of the solar and wind energy sources of the Croatian island
the system in order to meet the cooling load in a portacabins building, of Korčula exploited to supply both road transport but also ferry lines is
modelled in TRNBUILD and located in Rakric. The whole system, de- investigated in reference [22]. In particular, smart charging vehicles
signed for also producing DHW as coproduct, is modelled in TRNSYS and ferries are connected to the grid and allow charging and dischar-
environment and validated by the experimental data achieved from on- ging of the batteries. The development of 100% RES islands is ad-
site testing of polygeneration system. In this study, three different solar dressed for Croatian Islands of Vis, Korcula, Lastovo and Mljet in the
technologies were compared: flat plate, evacuated tube and compound work proposed in reference [23]. The interconnections of a group of
parabolic collectors. Dynamic simulations, developed in TRNSYS islands integrating the production from locally available RES is

Fig. 1. System layouts.

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