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Abstract Breastshot water wheels are gravity hydraulic machines employed in low head sites. The scope of this work is to test the performance of a breastshot water wheel with two geometric inflow configurations: a sluice gate at different openings and two vertical overflow weirs. With the sluice gate, the maximum efficiency of the plant is 75%, constant over a wide range of flow rates, while the efficiency with the weir is increasing in the same flow rate range. Therefore, the wheel with the weir can exploit higher water volumes, and also it performs better at high power input. In practical applications, the inflow configuration can be effectively controlled to optimize the operative working conditions of breastshot water wheels, depending on the external hydraulic ones. The experimental results are also discussed in dimensionless terms, in order to support engineers in the design of similar breastshot water wheels.

Abstract This paper presents a theoretical and experimental investigation about the modelling of a 1:45 scale prototype Wave Energy Converter (WEC). An analytical model is implemented to describe its behaviour in a wave tank. The aim is to provide a contribution to modelling tools used for WEC characterisation and design. Hydrodynamic characterisation software is avoided in favour of a simpler and more versatile design tool destined to a wider range of users. Therefore, an alternative approach is presented, based on mechanical analogies and the use of Matlab/Simulink/SimMechanics environment. This analytical model was constructed using linear wave theory, coupled with a non-linear model for the device and its power take-off system (PTO). Assumptions on incident waves and geometric properties of the device were required and implemented on the basis of literature of naval architecture, ships stabilization and control issues. Simulation results were compared and validated with those obtained in the same range of experimental tests of the prototype in wave tank. Trends and values of both investigation techniques show a good agreement, indicating the validity of the methodology adopted and leaving space for future improvements of the same. Finally, as example of application, the model was applied in a show case in order to estimate the energy yield by the WEC if scaled to real size, using Froude scaling. Results are encouraging and show the viability of the proposed design.

This work presents a project of hi-tech and supergreen ‘nZEB casale’ in Italy. The ‘nZEB casale’ is located in Matera, in the south of Italy. The project concerns the renovation of a medieval ‘casale’, a group of rural houses for residential use. The shape of the new nZEB is in the style of old light-colored buildings, compact and with projections and shielding elements to reduce the summer thermal loads. The use of local and certified materials for the construction of buildings has resulted in a low environmental impact of buildings and an excellent winter and summer energy performance reaching the best energy class A4. Finally, this work presents an environmental protocol to be applied to nZEBs in order to take into account the other benefits of these constructions, as well as the energy benefits.

Abstract District Heating (DH) technology is considered to be a sustainable and quasi-renewable way of producing and distributing hot water along the city to heat buildings. However, the main obstacle to wider adoption of DH technology is represented by the thermal request peak in the morning hours of winter days, especially in Mediterranean countries. In this paper, this peak-shaving problem is tackled by combining three different approaches. A thermodynamic model is used to monitor the buildings’ thermal response to energy profile modifications. An agent-based model is adopted in order to represent the end-users and their adaptability to variations of temperatures in buildings. Finally, a Reinforcement Learning algorithm is used to optimally mediate between two needs: on the one hand, a set of anticipations and delays is applied to the energy profiles in order to reduce the thermal request peak. On the other hand, the algorithm learns by trial and error the individual agents’ sensitivity to thermal comfort, avoiding drastic modifications for the most sensitive users. The experiments carried out in the DH network in Torino (north-west of Italy) demonstrate that the proposed approach, compared with a literature solution chosen as a baseline, allows to achieve better results in terms of overall performances and speed of convergence.

Abstract Recent studies suggest that the supplementation of powdered Fe° generates a positive effect on anaerobic fermentation processes but the exact relationship between metals with biological systems has not been fully elucidated. Experimental tests on dark fermentation (DF) were carried out at different Fe° concentrations. The anaerobic corrosion (AC) of Fe° and the production of H2 through DF of Organic Waste Market (OWM) were tested separately, and subsequently DF tests with Fe° at 1 g/L and 2 g/L were carried out. A macroscopic dynamic study was conducted, using Roels approach based on relaxation times (τR) to establish whether interactions between AC and DF phenomena exist. Experimental bioH2 production and Fe° AC were fit by Gompertz and saturative models, respectively to estimate τR. The results of the macro-analysis suggest that both phenomena are concurrent, with τR of the same order of magnitude, generating a positive symbiotic effect. The experimental tests of hydrogen production via DF in presence of 2 g/L of Fe° showed an increase of 46% compared with the control tests, of amount of gas and a greater H2/CO2 ratio. The results suggest an enhancement of key enzymes activity due to the action of iron increasing bioH2 production.

Abstract Driven by urbanization growth, in recent years, the relationships among energy systems and underground space are becoming more and more intense for many reasons: the severe competition in the land use, the security of energy commodities management, the need of huge infrastructures for mass and energy transportation (e.g. pipelines), the safety requirements against seismic events and eventually, economic and environmental considerations. For such reasons, nowadays underground space is becoming an extremely important as an alternative for urban areas expansion, if properly planned. In fact, a correct underground space planning strategy, together with the progressive developments of suitable integrated connections between surface and subsurface can increase the livability of cities and improve public health. Population in urban areas is expected to grow, in particular in developing economies (such as China); this phenomenon leads to an increasing pressure on urban areas to supply the growing energy needs. In fact, several end-use services should be fulfilled to provide indoor comfort in buildings, for mobility of people and goods, etc. Anyway, only a very limited amount of energy can be generated inside urban areas (from municipal solid wastes, from thermal/solar PV and heat pumps installations); as a consequence, the majority of the energy commodities are produced, converted and stored in power plants located far from cities and require huge transport infrastructures. In this paper, the cost/benefit relationship between underground and energy use is explained by reviewing main application of existing underground space utilizations for energy processes (distribution, storage and generation), as well as other innovative opportunities. From the analysis of past experiences analysis, the main conclusion is that a rational approach in urban energy planning procedures, integrating both over- and below-ground space utilizations, could help to raise the quality of energy services and it is fundamental for reaching a smarter and more resilient society. In such a new Underground Urbanism approach, the need for long-term Integrated Master Plans that propose suitable Guidelines is highlighted.

This paper describes the modeling and validation procedure of a single spool Turbojet engine. This work was conducted during the collaboration between Politecnico di Torino and Alenia Aermacchi. The aim of such research is to investigate the performance in terms of propulsion and control of a thrust vectoring system applied to an Unmanned Aerial Vehicle (UAV). To do so there was the need to define in detail the working conditions of the turbojet engine (in particular of the turbine/nozzle stages). This target was achieved by developing and validating a steady state 1-D model of the UAV’s turbojet engine. The steady state model was used in turn to predict engine performance and to estimate components efficiencies in different flight conditions. Starting from the matching algorithm of the steady state 1-D model, by neglecting the work balance equation and introducing spool’s inertia, a transient 1-D model was developed and validated too. In order to provide more accurate engines dynamics estimation, a simplified Engine Control Unit was developed. Both models were verified and validated by using, synthetic data (original engine deck), engine test bench data, and flight data. A graphical user interface (GUI) was developed on both models in order to give a better and more effective experience to the user.

Abstract In the IEA-ECBCS Annex 23 `Multizone Air Flow Modelling,' a sensitivity analysis procedure, that included both the Monte Carlo and Fractional Factorial analyses, was defined to evaluate COMVEN, a multizone air flow code. This procedure is here applied to evaluate COMVEN, when the simulation of the ventilation of a detached house is performed for the case of ventilation driven mainly by stack effect. The simulated values are compared to the measured values using the uncertainty range for each value; the confidence interval for the simulated values are obtained using the Monte Carlo method while the fractional factorial analysis has been used to identify the relative effects of the input parameters on the output accuracy. It is an interesting case which makes it possible to demonstrate the application of both sensitivity techniques.