Palacus project is a solar assisted heat pump pilot plant in Genoa, Italy. The heat pump combined with solar hybrid photovoltaic thermal panels provides both electrical energy from the solar irradiation and hot water sent into the heat pump circuit. The photovoltaic field covers the energy need of the heat pump and it is even capable of producing extra electrical energy, stored in the national grid through a net-metering, looking for an energetically independent installation. The benefits coming from the net-metering, considered during the design stage, reduced dramatically due to a change in Italian laws concerning feed-in-premium. A brief report on the global facility performance during the past two years is proposed, proving the difficulties of the plant to reach its maximum design potential due to its complexity and problems related to the end users’ “acceptance”. Possible strategies to restore or increase the economic balance of the facility are discussed according to the new feed-in-premium criteria. Supervision and detection of any failure of the plant are performed by means of a large data acquisition system. New related regulation criteria, presented in this work, are compulsory to optimise the plant.

A solar assisted heat pump integrated with fossil burners provides the space heating and Domestic Hot Water (DHW) demand of the sport palace Palacus, Genoa. The plant complexity requires a Data Acquisition System (DAS) to perform diagnoses for problem troubleshooting. A DAS with a set of sensors able to measure every key parameter of the plant loses economic feasibility as the installation complexity increases. This compulsory lack of information can be handled with numerical modelling calibrated on the collected data. In the case study, a net variation in the thermal losses during night (where all the plant is off and the facility is closed) within the DHW storage tanks has been measured. Without any apparent reason, the temperatures reached within the tank at 8.00 a.m. can be either 33 °C or 50 °C. According to the approach of inverse heat transfer problems, a numerical simulation in TRNSYS17 is used to enquire the most likely causes of failure and to establish new regulation criteria. Thermal stratification and its destruction are studied to better understand the temperature trend in the DHW tanks.

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Acceptance, meant as a social issue, plays a fundamental role on different levels in the effective integration of technological innovations into building heating systems. Many efforts have been made in previous studies to understand the key indices and indicators of acceptance, used to improve the agreement of people towards the considered innovation and widen its use. In Italy many laws have come into force with the target of increasing the level of acceptance of renewable plants in terms of affordability and economic benefits. The paper reports the Authors' experience in a specific application of solar assisted heat pump designed and built to provide up to the 70 % of the heating energy needs of Palacus sports center in Genoa, Italy. A voluntary passage from the heat pump heating mode to the classical burner has been noticed most of times when a technical action on the plant was required, despite of the well-known pollution and environmental impact. These difficulties can be overcome easily, working not on how people could better manage the innovative, not user-friendly plants, but on how the plant automation could satisfy the end-users' needs minimizing their intervention at affordable costs.

High-performance thermal insulators allow a dramatic reduction in the thickness of coatings, thanks to their low thermal conductivity. This study provides an overview about thermal insulation materials, with regards to heat reflective insulators in particular. Then, the numerical investigation method adopted to compute the thermal resistance associated with reflective insulators is introduced. This method has been used in turn to check the accuracy of the declared, measured performance of different, heat-reflective materials on the market. Many manufacturers of reflective insulators were available to provide information and a good agreement between the declared and expected thermal resistance has been found. The choice of a non-experimental approach is meant to check the validity of an already performed test on a reflective insulator using a predictive approach instead of standard, additional testing. Then, the insulation of five typical walls at three different sites in Italy has been simulated, showing that most of heat-reflective materials cannot achieve the maximum required transmittance. Interstitial condensation is likely to occur in specific cases, also because of the aluminum layers inside. The economic analyses showed comparable costs for both heat reflective and traditional insulators, and their cost effectiveness needs to be evaluated case by case.