• Energy Research

Abstract The paper investigates the energy performances of several configurations of solar-assisted heat pumps equipped with photovoltaic (PV) and photovoltaic-thermal (PVT) panels as well as solar thermal collectors for domestic hot water production. The systems are sized to serve small aggregates of users assumed as micro energy communities in low housing density context in the South of Italy. Electricity storages are also considered to smooth the interaction with the electric grid. Several indices are defined and calculated to guide toward a correct sizing, to check users’ satisfaction and to assess primary energy savings. The results show how the energy consumption from the analysed systems is mainly influenced by the amount and structure of domestic hot water demand per day. Also, according to the chosen plant layouts, it is shown that thermal contribution of PVT slightly influences the system performances. Better results in terms of less non-renewable primary energy consumption are recorded for the PV-based plant. Solar thermal collectors, even if sized for high solar fractions, do not properly support the daily heat pump operation, especially in winter, and present a certain electricity consumption for auxiliaries which results to be penalizing. Additional calculations were performed for the case of energy communities in a context with higher uses of non-renewable energy for electricity generation. Finally, opportunities to support demand-response actions for grid electricity management were investigated.

The study reported in this paper aimed to investigate the response of a GAFChromic? HD-V2 film dosimeter in the dose range between 10 and 300 Gy, normally used to perform irradiation tests on electronic devices with a 60Co gamma-ray irradiator. The well-defined linearity of response in terms of absorbance as a function of absorbed dose, easiness of handling and data analysis of irradiated dosimeters, reproducibility, stability, and insensitivity to visible light and most of the environmental parameters, make HD-V2 film a flexible, inexpensive and reliable dose measurement device. The study has shown a fogging effect of the dosimeter response since its value changes over time. Strategies and adequate precautions to take into account changes on HD-V2 film physical properties for calibration and routine use in industrial applications, with a specific reference to radiation testing of electronic devices, have been discussed.

The achievement of United Nations Sustainable Development Goals, related to energy and resource use, is a critical issue for small and insulated communities. In many minor islands, solar energy is not correctly exploited, and electrical heaters are connected to weak grids with very a high share of generation by fossil fuels. As a consequence, there is the necessity to assess the potential and the suitability of diffusion of alternative systems to avoid dependency on the electrical grid and reduce carbon emissions. This paper aims to evaluate the technical and economic performances of some alternative systems exploiting renewable energy for domestic hot water production. Four different systems were simulated and studied: a heat pump connected to the grid, a heat pump coupled with a photovoltaic plant, a heat pump combined with a solar thermal collector, and a solar thermal plant. Moreover, heat and electricity storages were studied for reducing impacts on the distribution network. The work presents data gathered for a study on energy-retrofit strategies on Lampedusa Island (Italy, 35°30′56″ north (N), 568 degree-days). Finally, to select the most cost-effective plant, an economic analysis of the chosen systems was carried out. This analysis shows that the best net present values are associated with the heat pump (HP) coupled with a stand-alone PV system and a small battery and solar thermal-assisted HP. The shortest payback time was calculated for the solar thermal system.