A review of key performance indicators for building flexibility quantification to support the clean energy transition

The transition to a sustainable society and a carbon-neutral economy by 2050 requires extensive deployment of renewable energy sources that, due to the aleatority and non-programmability of most of them, may seriously affect the stability of existing power grids. In this context, buildings are increasingly being seen as a potential source of energy flexibility for the power grid. In literature, key performance indicators, allowing different aspects of the load management, are used to investi-gate buildings’ energy flexibility. The paper reviews existing indicators developed in the context of theoretical, experimental and numerical studies on flexible buildings, outlining the current status and the potential future perspective. Moreover, the paper briefly reviews the range of grid services that flexible buildings can provide to support the reliability of the electric power system which is potentially challenged by the increasing interconnection of distributed variable renewable generation

Experimental and Computational Fluid Dynamic study of an active ventilated façade integrating battery and distributed MPPT

Ventilated Façades integrating photovoltaic panels are a promising way to improve efficiency and the thermal-physical performances of buildings. Due the inherent intermittence of the non-programmable renewable energy sources, their increasing usage implies the use of energy storage systems to mitigate the mismatch between power generation and the buildings’ load demand. The main purpose of this paper is to investigate the thermo-fluid dynamic performances of a prototype integrating a photovoltaic cell and a battery as a module of an active ventilated façade. Based on an experimental setup, a numerical study in steady state conditions of flow through the air cavity of the module has been carried out and implemented in a fluid-dynamics Finite Volume code. In order to assess the viability of the prototype, the calibrated model was lastly used to predict thermal performance of the prototype on different climate conditions supporting its further improvement

The risk stratification of adverse neonatal outcomes in women with gestational diabetes (STRONG) study

Aims: To assess the risk of adverse neonatal outcomes in women with gestational diabetes (GDM) by identifying subgroups of women at higher risk to recognize the characteristics most associated with an excess of risk. Methods: Observational, retrospective, multicenter study involving consecutive women with GDM. To identify distinct and homogeneous subgroups of women at a higher risk, the RECursive Partitioning and AMalgamation (RECPAM) method was used. Overall, 2736 pregnancies complicated by GDM were analyzed. The main outcome measure was the occurrence of adverse neonatal outcomes in pregnancies complicated by GDM. Results: Among study participants (median age 36.8 years, pre-gestational BMI 24.8 kg/m2), six miscarriages, one neonatal death, but no maternal death was recorded. The occurrence of the cumulative adverse outcome (OR 2.48, 95% CI 1.59–3.87), large for gestational age (OR 3.99, 95% CI 2.40–6.63), fetal malformation (OR 2.66, 95% CI 1.00–7.18), and respiratory distress (OR 4.33, 95% CI 1.33–14.12) was associated with previous macrosomia. Large for gestational age was also associated with obesity (OR 1.46, 95% CI 1.00–2.15). Small for gestational age was associated with first trimester glucose levels (OR 1.96, 95% CI 1.04–3.69). Neonatal hypoglycemia was associated with overweight (OR 1.52, 95% CI 1.02–2.27) and obesity (OR 1.62, 95% CI 1.04–2.51). The RECPAM analysis identified high-risk subgroups mainly characterized by high pre-pregnancy BMI (OR 1.68, 95% CI 1.21–2.33 for obese; OR 1.38 95% CI 1.03–1.87 for overweight). Conclusions: A deep investigation on the factors associated with adverse neonatal outcomes requires a risk stratification. In particular, great attention must be paid to the prevention and treatment of obesity

Typhoid fever as a cause of opportunistic infection: case report

BACKGROUND: Typhoid fever is a systemic infection caused by the bacterium Salmonella enterica subspecies enterica serotype typhi, which is acquired by ingestion of contaminated food and water. Each year the disease affects at least 16 million persons world-wide, most of whom reside in the developing countries of Southeast Asia and Africa. In Italy the disease is uncommon with a greater number of cases in Southern regions than in Northern ones. CASE PRESENTATION: We report on a 57-year-old Sri-Lankan male affected by typhoid fever, the onset of which was accompanied by oropharyngeal candidiasis. This clinical sign was due to a transient cell-mediated immunity depression (CD4+ cell count was 130 cells/mm(3)) probably caused by Salmonella typhi infection. Human immunodeficiency virus infection was ruled out. Diagnosis of typhoid fever was made by the isolation of Salmonella typhi from two consecutive blood cultures. The patient recovered after a ten days therapy with ciprofloxacin and his CD4+ cell count improved gradually until normalization within 3 weeks. CONCLUSION: Our patient is the first reported case of typhoid fever associated with oropharyngeal candidiasis. This finding suggests a close correlation between Salmonella typhi infection and transitory immunodepression

An integrated building energy simulation early—Design tool for future heating and cooling demand assessment

Climate change and its effects are becoming clear on a global scale either from the perspective of global warming and the increase in the rate of occurrence of weather events of extreme magnitude. This has impacts also for sure on the standard building performance analysis approach, since the buildings designed today are supposed to withstand for the following decades climate impacts that may be different than those they were designed for. The paper proposes a simple, easy to use and freely available building simulation utility which performs morphing of existing weather data files and, by connecting to the Energy Plus simulation routine, allows to perform future climate building simulation analyses. Users are required to select one of the ASHRAE buildings models or provide one of their own choosing and to input the original weather data file. The tool will generate a future weather data file with the preferred assumptions (e.g. RCP scenarios, time frame) and elaborate results in terms of heating and cooling required for air conditioning. The paper proposes also an implementation of the tool to a case study aimed at showing the potential of the application proposed. A typical office building model from the ASHRAE library was simulated in two different locations under different climate change assumptions up to the year 2090. The analysis of the results in the two locations of Palermo (Italy) and Copenhagen (Denmark) highlight relevant increases in the current century of up to +20% of cooling requirements and similar reductions for heating in both case studies, if compared to current levels. The research targets a specific limit in the investigation of climate resilience of buildings and follows the principles described by SDSN in the definition of SDGs and the interest at the EU level towards climate neutral and innovative cities. In this context, the paper may contribute to the limited availability of easy to use and free tools available for practitioners to investigate the design of climate resilience buildings

Maximum likelihood identification of cavitation instabilities in axial inducers

The article illustrates the application of maximum likelihood estimation to the identification of cavitation instabilities in axial inducers from the unsteady pressure readings measured on the impeller casing. The typical triangular pressure distribution in the blade channels of the impeller is parametrized and modulated in time and space in order to theoretically reproduce the expected pressure generated by known forms of cavitation instabilities (cavitation auto-oscillations, n-lobed sub/super-synchronous rotating cavitation, higher-order surge/rotating cavitation modes). The Fourier spectra of the theoretical pressure so obtained in the rotating frame are transformed in the stationary frame and fitted by maximum likelihood estimation to the auto-correlation of the pressure measurements on the inducer casing. Each form of instability generates a characteristic spectral distribution of side bands in addition to its fundamental frequency. The identification makes use of this information for effective discrimination of simultaneous flow oscillations with significantly different intensities and partially overlapping frequencies. The method returns the estimates of the model parameters and their standard errors, allowing for both recognition of the forms of instabilities occurring in the inducer and assessment of the statistical significance of the results

Grid interaction and environmental impact of a net zero energy building

The concept of Net Zero Energy Building (NZEB), as a grid-connected building that generates as much energy as it uses over a given period, has been developing through policies and research agendas during the last decade as a contribution towards the decarbonization of the building sector. However, since the most applicable and widely used renewable energy supply options are non-programmable, the large-scale NZEBs diffusion into the existing power grids can seriously affect their stability having a relapse on operation costs and environmental impacts. In this context, the study aims at performing the design of the energy systems to be used in the case-study through a wide numbers of point of views, including the grid interaction, global warming potential, and different design alternatives such as using fuel cells and renewable energy generation systems and drawing lessons learned to be saved for similar buildings. A novel approach for developing for NZEBs, combining load match and grid interaction indicators with an environmental impact indicator, is proposed. The proposed design approach allows for the quantification of the power grid interaction and environmental impact (in terms of Global Warming Potential) aiming to find trade-offs between the opposing tendencies of building energy performances and the need to limit the embodied carbon within building envelope and systems. The design approach has been used to investigate the performances of a NZEB prototype with the aim to explore the effectiveness of the solution sets used in the current design (only Photovoltaic system) and plan different solutions (batteries and fuel cells system) for the future ones. For the base case, even though the overall PV energy generation (8069\u202fkWhe) in a year surpasses the electricity consumption (5290\u202fkWhe), on a yearly base only the 29% of the PV generation is used on-site. Hence, the assessed indicators show clearly how installing a PV system merely able to cover the energy uses on a yearly net base (or even slightly oversized) will have stress implications on the power grid. On the other hand, the use of batteries at the building scale largely decreases the reliance on power grid when not programmable renewable sources are present. Moreover, if coupled to the right size of the on-site generation systems, the storage system could increases the environmental benefits arising from the renewable energy technologies (the GHG emission reaches its minimum value of 0.92\ub7103\u202fkg CO2eq/year, with a reduction of the 50.4% if compared to the base case) for a storage capacity of 20\u202fkWh and a PV system nominal power of 4.56\u202fkW). Fuel cells guarantee a good load match at high energy efficiency, furthermore, a high installed power of fuel cells is not required to obtain high load cover factor values. On the other hand, since the specific CO2eq emission per unit of energy of the fuel cells are high, the CO2eq emissions are always greater than those of the base case if the system is equipped with a fuel cell system. Therefore, future research will have to focus on the eco-design of fuel cells with to reduce environmental impacts of these systems in a life cycle perspective