Optimization of government subsidization strategies for building stock energy refurbishment

The high initial investment required in existing building refurbishment can limit the initiative of the building owners and prevent the full exploitation of a huge energy saving potential. Public incentives can play an essential role in fostering the energy retrofitting of the existing buildings and in increasing the renovation rate of the building stock, effectively reducing the energy final uses, the dependence on the fossil fuels, and helping meet the national efficiency targets. Public subsidization are intended to enhance the economic performance in terms of global cost of the energy efficiency measures for the owner, in order to induce positive actions and move optimality from low to high energy efficient solution. In contrast, the overall economic efficiency is obtained with combinations of interventions, able to achieve a certain energy saving target for the entire building stock at the minimum initial Investment Costs (IC). This paper tries to identify the overall economic efficiency in reducing the energy consumption of the existing stock and compares it with the efficiency of solutions optimal from the owner’s perspective, in order to support more efficient subsidization strategies. Different mixes of three reference building archetypes, representative of the existing buildings, are considered to define different possible stocks, in order to analyse their impact on the efficiency of energy renovation solutions. Four groups of energy efficiency measures (EEMs) dealing with respectively the opaque envelope insulation, the windows substitution, the heat generating system replacement, and the mechanical ventilation introduction are defined and their combinations considered

Numerical and Experimental Analysis of a CPV/T Receiver Suitable for Low Solar Concentration Factors

AbstractSolar energy conversion is one promising technology to provide the building required energy. Generally, the main used technologies are the PV and thermal flat panels, but this situation provides separately electricity and thermal energy. Electrical and Thermal power combined production is available for the concentrating solar but, usually, this technology is applied to devices working at high concentration factor (over 100), which are large and, therefore, are not suitable for roof installations. At lower concentrating factors (less of 50 suns) small linear, mono-axial, roof integrated devices can be designed and built. The solar receiver plays a key role in the performance of energy generation because it houses the solar cells and itis used to recover the thermal solar power: actually, this is the device where solar energy is converted in electrical and thermal power. The radiation flux distribution on the receiver affects the efficiency of the linear solar concentrator system, because in a mono-axial sunrays are not perpendicular to the receiver. This paper describes the numerical and experimental investigation useful to evaluate the performance of a linear low (20 suns) CPV device and to understand the thermal working condition of the solar receiver. The experimental study focuses to a quantitative analysis of the energy transfer from sun to the water. The numerical activity is a CFD conjugate analysis where the solid volume and the fluids are investigated together; the scope is to individuate how the energy flux cross the device

Ruptured middle cerebral artery aneurysms. retrospective study and multivariate analysis of 105 patients treated by surgical clipping

Objective of the study: We analyze in this study only patients with surgically treated ruptured aneurysms in order to identify statistical significance of each predictive factor in terms of outcome of patients with ruptured MCAAs. Materials and methods: In this retrospective study, we analyzed 105 cases of ruptured MCAAs, admitted from January 2001 to December 2015 at Neurosurgical Department of Umberto I University Hospital of Rome, Italy. Predictive factors evaluated are: Patient’s features (age, sex, co-morbidities), aneurysmal location (proximal, bifurcation or distal) and size of aneurysmal dome (small, large or giant); surgical timing (ultra-early, early, delayed), and Intracerebral Hemorrhage (ICH) volume. For each parameter we calculated mean and standard deviation, covariance and relation coefficient (through the linear regression model). Results: The clinical evaluation of patients assessed through the World Federation of Neurological Surgeons (WFSN) grading scale, that is 5 for 37 patients (35.3%), 4 for 28 patients. In 40% of cases the maximum sac diameter was between 7 mm and 12 mm, while in 67% of the cases the aneurysms concerned the bifurcation of the middle cerebral artery. ICH was associated in 57 cases (54.3%). As far as outcome is concerned, at 3 months, 32 patients (30.47%) had a favourable outcome, while 73 (69.52%) patients had not favourable outcome. To one year, 46 patients (43.8%) had favourable outcomes, while 59 patients (56.19%) had not favourable outcome. The mean outcomes as mean mRS are significantly less favourable in patients with ICH. Conclusion: In MCAAs patients, the presence of ICH strongly affects the outcome with a marked increase in mortality and morbidity. Surgical timing significantly influences the outcomes and ultra-early surgery should always be taken into account

Analysis of Influencing Factors in the Implementation of Corporate Social Responsibility

In a world that must face epochal challenges, both from an environmental and social point of view, corporate social responsibility (CSR) is a topic that is becoming more salient. Companies, in fact, being one of the triggers of the crisis, must therefore also be part of the solution. Thus, implementing CSR within the organization has become a necessity. This thesis mainly contributes to the literature in analysing if the implementation of CSR is changing the organizational members' perception about the importance of this subject. Therefore, it analyses the factors that most influence the variation of this perception. Based on the CSR implementation literature, I deducted some possible influencing factors. These, then, have been tested empirically and consequently, I refined the list through the data collected. In the end, after a discussion of the different factors within the literature, I highlighted the beneficial potential in a collaboration between CSR and human resource functions

Impact of occupant behavior on performance optimized building retrofits

In the framework of the recent Directive 844/2018, practitioner often rely on Building Energy Simulation (BES) combined with Multi-Objective Optimization (MOO) to find optimal energy saving measures for building retrofits. However, occupant behaviour is usually oversimplified as a static schedule provided by technical standards mainly developed for energy certification. This can lead to a significant gap between the performance of the optimal designed solution and its actual performance. In this study, we investigate how detailed user-behaviour profiles - e.g. static, probabilistic, and adaptive models - for the operation of windows impact on the optimal retrofit strategy. While the standard and adaptive model use a base ventilation rate like a constraint for indoor air quality (IAQ), the probabilistic models rely solely on the occupant actions on windows. The results demonstrate that the behavioural models result in major differences in indoor comfort conditions. Optimal solutions defined through probabilistic models are likely to be not very robust to the ventilation rate showing the potential for performance gaps. The importance of realistic user behaviour representation is highlighted to raise awareness about its influence on the full potential of retrofitting a building, maybe excluding those solutions that could majorly improve comfort

Experimental and Numerical Evaluation of the NPSHR Curve of an Industrial Centrifugal Pump

Cavitation triggers harmful flow instabilities yielding both significant decrease of performance and reduced reliability. The aim of this paper is to investigate the accuracy of numerical methodologies for the correct prediction of cavitation inception in centrifugal pumps. Preliminary analyses are performed on the NACA 0009 hydrofoil using the ANSYS CFX V14.5 code. The available bubble dynamics model is calibrated using the experimental data in cavitation conditions. Then, the optimized parameters are used for the evaluation of the NPSHR curve of the R250 centrifugal pump industrial pump designed by WEIRGabbioneta srl. Reynolds-Averaged Navier-Stokes mono- and two-phase calculations are performed. The performance curve of the R250 centrifugal pump is evaluated at first, and then the NPSHR curve is obtained for the design flow rate. The control volume of the numerical analysis includes all the hydraulic features from flange to flange (except for the side chambers) and then a direct comparison with the available experimental data obtained during two experimental campaigns is possible. The numerical activity demonstrated that an adequately calibrated model is able to reproduce the shape of the cavitation curve of an industrial centrifugal pump, although the NPSHR value is underestimated