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Solar Domestic Hot Water (SDHW) systems represent a constantly evolving technology in today's applications. With the new directives promoted by the European Union the renewable energy share produced in buildings will tend to increase further. Research on how to increase the efficiency of the thermal production from renewable energy are therefore of the foremost importance. This study aims to investigate the energy performance of an integral collector storage (ICS) prototype for DHW production. This ICS represents a new concept technology, integrating inside the same device a flat plate absorber and a storage section with phase change material (PCM) connected by heat pipes filled with methanol. An objective of this study was to investigate a possible alternative to conventional solar systems, with the aim of reducing investment costs and improving system reliability without compromising energy performance. The energy assessment was carried out using a numerical model in the Engineering Equation Solver (EES) environment, following an electrical analogy scheme. After a validation process by means of experimental data, a yearly simulation was launched in order to estimate the productivity and the solar fraction of the prototype. The results obtained allowed a global energy evaluation and a comparison with similar systems and to identify the pros and cons of this new technology.

In recent years, investigations on advanced technological solutions aiming to achieve high-energy performance in buildings have been carried out by research centers and universities, in accordance with the reduction in buildings’ energy consumption required by European Union. However, even if the research and design of new technological solutions makes it possible to achieve the regulatory objectives, a building’s performance during operation deviates from simulations. To deepen this topic, interesting studies have focused on testing these solutions on full-scale facilities used for real-life activities. In this context, a test facility will be built in the university campus of Politecnico di Torino (Italy). The facility has been designed to be an all-electric nearly Zero Energy Building (nZEB), where heating and cooling demand will be fulfilled by an air-source heat pump and photovoltaic generators will meet the energy demand. In this paper, the facility energy performance is evaluated through a dynamic simulation model. To improve energy self-sufficiency, the integration of lithium-ion batteries in a HVAC system is investigated and their storage size is optimized. Moreover, the facility has been divided into three units equipped with independent electric systems with the aim of estimating the benefits of local energy sharing. The simulation results clarify that the facility meets the expected energy performance, and that it is consistent with a typical European nZEB. The results also demonstrate that the local use of photovoltaic energy can be enhanced thanks to batteries and local energy sharing, achieving a greater independence from the external electrical grid. Furthermore, the analysis of the impact of the local energy sharing makes the case study of particular interest, as it represents a simplified approach to the energy community concept. Thus, the results clarify the academic potential for this facility, in terms of both research and didactic purposes.

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