Within the “Solar Jails” programme, two solar thermal plants have been installed yet. They are operating respectively into the Jail of Rebibbia (Rome) since 2002, and into the Jail of Terni (about 120 km north of Rome) since summer 2008.

In the framework of the first “Solar Jail” project, 96 flat — plate solar thermal collectors have been installed with a total useful area of 250 m2 (175 kWth) in order to contribute to the preparation of 18,000 l/day of DHW at 45 °C, for 400 prisoners. The plant, designed to perform a solar fraction of about 60% of the DHW annual demand, was installed with the support of 10 prisoners previously trained on solar thermal. Currently, prisoners are also involved in maintenance and in data acquisition.

Thanks to this first pilot experience, many of the problems faced during either the system operation or the implementation of the general procedures have been already solved, and several improvements carried out in the second phase of the programme.

Concerning the new plant in Terni, 60 flat — plate solar thermal collectors have been installed with a total useful area of 156 m2 (109 kWth).

The average daily consumption of 350 users is around 13,500 l/day, at 40 °C. The solar thermal system is expected to supply the 70% of the estimated total annual energy request, that is 208 MWh per year. Therefore, the annual solar output foreseen is about 146 MWh.

The plant is endowed of a monitoring system for gathering all the parameters needed to control the energy performances of the plant, the operating temperatures and the achievement of the solar results. Furthermore, in the next future, it might be possible to store the data collected (in different sites) in a central database.

A second plant is now under construction in Rebibbia Jail, where 180 m2 (126 kWth) flat — plate thermal collectors are expected to deliver 110 MWh per year to 396 prisoners. Five more systems are foreseen to be carried out within the 2009 in Florence, Turin, Laureana di Borrello (Reggio Calabria), Viterbo and Velletri (Rome).

3. Conclusions

Jails, not only in Italy, are usually located in buildings with large surfaces suitable for installation and without strict aesthetical requirements for the architectonic integration. Those characteristics, coupled with the very high and continuous annual DHW energy demand, show clearly the huge potential for the repeatability of this initiative.

The main outputs expected by the completion of this phase of the “Solar Jails” programme are:

• empowerment and new reemployment opportunities for about 250 prisoners trained as solar thermal

installers;

• 15 new large scale solar thermal plants, i. e. up to 3,750 m2 (2.6 MWth) of solar thermal collectors

installed;

• energy costs savings for jails to be reinvested in activities and infrastructures;

• staff of public technical departments skilled in solar thermal to secure the project durability and to act

as multiplier in other public buildings;

• improvement of knowledge on the behaviour of solar thermal plants.

References

[1] A. Corrado, R. Battisti, A. Micangeli, (2002), Large Scale Solar Thermal Plant For Domestic Hot Water In The Italian Rebibbia Jail, Proceedings of the EuroSun 2002 Conference, 23 — 26 June 2002, Bologna, Italy