Considering the current climatic and energy crisis, one of the simplest energy-saving practices most easily implemented during this winter is the reduction of operation hours of HVAC system and the reduction of set-point value of the room temperature. From an energy point of view the benefits are undoubted, but what does the occupants feel in terms of thermo-hygrometric comfort? Can other factors, such as lighting color or control affect it? In the literature discrepancies were found between the classic comfort assessment models (such as the Fanger static model) and the occupant’s sensations. This could, in fact, depend on other factors that influence the psychological and perceptive sphere of people. The present study aims to investigate in an experimental way these aspects that have not very been deep in the literature. The analysis is performed in a full-scale living-lab conceived as a nearly zero energy building, placed in Benevento, Southern Italy. It will be shown that the building occupant judges the environment warmer than the one described by a static thermal comfort model. If there are warm lights it is preferable to be controlled by the user while the cold lights are preferable to be controlled automatically.

The paper proposes the experimental characterization of a wall package made of geopolymer concrete and phase change materials (PCMs) in the climate of south Italy. Data collected from May to July 2021 were presented by elaborating surface temperatures and heat fluxes with the introduction of several new indices as the thermal stress reduction amplitude, the percentage of time in melting range and the extreme surface solicitations. The results indicate that the PCMs reduce the thermal solicitation and preserve the geopolymer blocks. The indoor surface temperature can be lowered also of 3 & DEG;C during the hours with maximum sol-air temperatures and this could contribute to reduce the local discomfort phenomenon. Globally, the heat flux monitored on the geopolymer layer behind the PCM is attenuated and its trend is more regular; this reduction implies a reduction of heat gains through the opaque building envelope and finally a reduction of the energy demand.

Because of the social importance of hospitals, characterized by energy-intensive users, large-scale refurbishment projects for these types of buildings are required. With the aim of helping researchers and designers, this paper proposes a multistage methodological approach for the optimization of retrofit designs based on energy, environmental, and economic indicators. Some guidelines are also highlighted thanks to the results obtained from a case study of a private hospital in Naples (Southern Italy, Mediterranean climate) located in a constrained landscape area. The first step consists of the calibration of a simulation energy model defined via in situ investigations, direct surveys and monitoring of energy loads and indoor quality. Then, the model is used to verify the effectiveness of several efficiency measures regarding the building envelope, the active energy systems, and the energy conversion from renewables in order to minimize the energy demand with acceptable economic profitability. This case study demonstrates that electricity demand can be reduced by up to 48% with an investment of around EUR 720,030.00; the payback time without national incentives is 10 years, but it can be halved with appropriate financial support.

The paper is focused on the evaluation of how windows design influences the energy performance of a nearly zero energy building, including the effects of the climate change. The case study is a single-story dwelling built in Benevento (South Italy, Mediterranean climate) with high performance. With five-years monitored meteorological data, the typical meteorological year is defined. This climatic condition represents the reference scenario for evaluating the performance with different types of windows and for the definition of future medium and long term climate projections, generated using the CCWorldWeatherGen tool. From these comparisons, the resilience of the nearly zero energy building is evaluated in terms of variation of heating and cooling energy demand and primary energy percentage difference (ΔPE). The results show that the selective, low-e clear double glazing may be able to better mitigate the summer overheating effect, with an increase of 23% in energy need for cooling at 2050.

The adoption of phase change materials (PCMs) is a promising solution for the improvement of building energy performances and indoor comfort, and the integration of geopolymer concrete (GPC) allows recycling materials and reducing the demand for raw materials in concrete production. Both materials contribute to reducing the carbon dioxide emission in the building lifecycle. In this frame, this paper proposes a complete numerical approach for selecting the optimal wall package made of GPC and PCMs in a Mediterranean climate. The first step of the method consists of a parametric analysis for evaluating the incidence on energy performance and thermal comfort of the main designing variables: insulation thickness, air cavity type and its thickness, and PCMs type. Then, assuming the discomfort hours as a limiting constraint, a multi-objective optimization is applied to a subset of solutions for determining the Pareto front solutions. The advantage of the proposed methodology is the combined evaluations of multiple variables with a simplicity in execution; for this reason, it is useful for other researchers aimed at studying innovative solutions. According to obtained results, the better exposure for the proposed wall package is the north or northeast one. The minimization of the cooling energy demand requires the adoption of two PCMs, on internal and external sides, with melting temperature of 26 °C. The optimization of yearly performance requires the adoption of the maximum insulation level on both sides and a not-ventilated air gap between the modules. The cooling and heating energy need can be reduced, respectively, by around −29% and −57%, compared to a reference configuration with vacuum insulation panels and thermal transmittance of 0.4 W/m2 K.