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Whilst present buildings are still often energivorous systems, in the near future they will have to be converted to (or replaced by) zero energy buildings, also capable to export green energy (produced on-site by renewables) towards other buildings and/or users. Specifically, the paper focuses on the performance of naturally ventilated BIPV façade elements taking into account the total heat flow inside the building and the temperature of the building walls. 3 Building integrated photovoltaic collectors In the next few years, a further diffusion of PV collectors will be achieved by Building Integrated Photovoltaic (BIPV) devices, that will also overcome the unesthetic and functional issues of stand-alone and building-adjacent PV systems. 7 Building envelope technologies In order to reduce the heating and cooling energy demands of buildings and/or to improve the related comfort performance, different innovative envelope materials and/or design solutions for opaque and transparent building elements can be adopted. [Extracted from the article]

Highlights: [•] A new dynamic simulation code for building energy performance analysis is presented. [•] The thermal behavior of each building element is modeled by a thermal RC network. [•] The physical models implemented in the code are illustrated. [•] The code was validated by the BESTEST standard procedure. [•] We investigate residential buildings, offices and stores in different climates. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a detailed finite-volume model of a concentrating photovoltaic/thermal (PVT) solar collector. The PVT solar collector consists in a parabolic trough concentrator and a linear triangular receiver. The bottom surfaces of the triangular receiver are equipped with triple-junction cells whereas the top surface is covered by an absorbing surface. The cooling fluid (water) flows inside a channel along the longitudinal direction of the PVT collector. The system was discretized along its axis and, for each slice of the discretized computational domain, mass and energy balances were considered. The model allows one to evaluate both thermodynamic and electrical parameters along the axis of the PVT collector. Then, for each slice of the computational domain, exergy balances were also considered in order to evaluate the corresponding exergy destruction rate and exergetic efficiency. Therefore, the model also calculates the magnitude of the irreversibilities inside the collector and it allows one to detect where these irreversibilities occur. A sensitivity analysis is also performed with the scope to evaluate the effect of the variation of the main design/environmental parameters on the energetic and exergetic performance of the PVT collector. [Copyright &y& Elsevier]

Abstract: In this paper the integration of vegetable oil-fed reciprocating engines with solar thermal collector is investigated, seeking to design a novel polygeneration system producing: electricity, space heating and cooling and domestic hot water, for a university building located in Naples (Italy), assumed as case study. The polygeneration system is based on the following main components: concentrating parabolic trough solar collector, double-stage LiBr–H2O absorption chiller and a reciprocating engine fed by vegetable oil. The engine operates at full load producing electrical energy which is in part consumed by the building lights and equipments, in part used by the system passive loads and the rest is eventually sold to the grid. In fact, the engine is grid connected in order to perform a convenient net metering. The system was designed and then simulated by means of a zero-dimensional transient simulation model, developed using the TRNSYS software. The simulation tool developed by the authors allows one to analyze the results for different time basis (minutes, days, weeks, months and years), from both energetic and economic points of view. The economic results show that the system under investigation is profitable, especially if properly funded. [Copyright &y& Elsevier]

Seasonal storage of hydrogen is a valuable option today increasingly considered in order to optimize cogeneration plants under continuous operation in an incentive framework where electricity sale to the national grids is becoming less economically profitable than in the past. The paper concerns the numerical study and optimization of a cogeneration plant installed in an industrial site having an availability of hydrogen over a continuous time scale, to meet the energy needs and mitigating the environmental impact of the plant operation by reducing the energy withdrawal from traditional sources. Two alternatives are analyzed into detail: the former regards energy production through an internal combustion engine, this last properly controlled to be fueled with blends of natural gas and increasing percentages of hydrogen, the latter concerning the addition of fuel cells to the proposed layout to further reduce the electricity integration by the grid. The dynamic response of the cogeneration system under examination is dynamically evaluated to efficiently fulfill the industrial loads to be fulfilled. First, optimization is performed by implementing a PID controller to better track the industrial demand of electric energy. The main results of this solution reveal a −81% reduction of excess electricity, a −7% reduction of natural gas consumed but a 47% raise of CO 2 emissions due to the increase in thermal integration. Then, an additional energy generation from fuel cells is assumed. An economic analysis is carried out for each of the implemented configurations. The adoption of fuel cells, despite requiring a greater initial investment, allows obtaining a SPB of 1,4 years (− 16%), 1,17 Mln € of avoided costs (− 18,5%) and 1320 t/year of CO 2 emissions avoided (− 95%) with respect to the initial layout. • Seasonal storage of hydrogen is considered in an industrial cogeneration plant. • Electricity generation by hydrogen-NG blends powering an internal combustion engine or by fuel cells. • Design and optimization are conducted by dynamic modelling in TRNSYS. • The internal combustion engine is optimally calibrated under various fuel blends powering. • An economic and environmental analysis is carried out through an advanced engine model. [ABSTRACT FROM AUTHOR]

Abstract This paper presents a detailed exergetic and technoeconomic analysis of a Building Integrated PhotoVoltaic Thermal (BIPVT) system. BIPVT system, consisting of flat-plate PVT solar collectors, is integrated in the south facing façade of a non-residential high-rise building. BIPVT collectors produce: i) thermal energy for space heating purposes, by a radiant floor system; ii) Domestic Hot Water (DHW); iii) electricity. Electric air-to-water heat pumps/chillers and a condensing gas fired boiler are used as auxiliary systems for space heating/cooling and DHW, respectively. In addition, the system also includes an electricity storage system coupled to the BIPVTs in order to mitigate the effects of solar energy intermittency and to obtain a virtually grid-independent system. In order to compare the proposed BIPVT system to a conventional building, a reference building model, i.e. without BIPVTs, energy storage and radiant floor, is considered. Here, the space heating and cooling energy is supplied by air-to-water heat pumps (one for each floor), DHW is produced by a condensing boiler and electricity is supplied by the national grid. The comparison is performed for three thermal zones, well representative of the thermal behaviour of the whole building. In this paper, a detailed dynamic simulation model is developed by means of well-known tool TRNSYS 17, in order to predict the transient behaviour of BIPVT system. Energy and exergy balances are taken into account to determine, for the 1-year operation, the exergy destructions and exergetic efficiencies of each of the investigated components. The economic viability of the proposed system is also discussed and the resulted Simple Pay Back period is about 4 years. From the carried out exergy analysis, the average exergetic efficiency of electricity storage system is about 90%, whereas the condensing boiler one is close to 2% all year long. In addition, an exergy analysis on the proposed BIPVT system located in several European weather zones is also carried out, as well as a suitable exergy analysis is performed by varying the capacity of the electricity storage system. Such analyses aim to assess the weather condition and the size of electricity storage effects on the destroyed exergy and exergetic efficiency of BIPVT collectors and electricity storage, respectively. It resulted that, the highest destroyed exergy of BIPVT occurs in Larnaca (150 MWh/year) vs the lowest one in Belfast (87 MWh/year), whereas the BIPVT collectors exergetic efficiencies range from 8.4% for Larnaca to 8.8% for Belfast. Highlights • Exergy and thermoeconomic analysis of BIPVT - electricity storage system. • Assessment of exergy destruction and efficiencies of main system components. • Case study for a non-residential building in different European weather zones. • Analysis of heating, cooling, DHW and electricity production. • Assessment of exergetic, energy and economic enhancement vs. traditional systems. [ABSTRACT FROM AUTHOR]

This paper aims at optimizing the energy performance of an innovative integrated collector-storage solar water heater (ICSSWH) prototype. The system incorporates a high-vacuum gap, which significantly reduces convective thermal losses, and a serpentine absorber system coated with a low-E layer to minimize radiative thermal losses. The methodology is based on a detailed dynamic simulation model, implemented in the MatLab environment, suitable conceived to accurately predict the energy performance and economic profitability of the ICSSWH under various weather conditions and energy market prices. This approach aims to initially identify the most influential geometrical, thermophysical and optical parameters that impact the energy performance of the system through the assessment of different objective functions. After identifying the most influential parameters, the range of existence with the interval step for each variable is defined, and the optimization procedure is conducted to determine the optimal set of variables that maximize/minimize the selected objective functions. To demonstrate the effectiveness of the proposed methodology, a proof of concept was conducted to optimize the energy performance of novel ICSSWH by considering nineteen parameters with the aim of maximizing/minimizing three different objective functions. The results of this analysis yielded various sets of optimised parameters for the ICSSWH. Therefore, by implementing the set of optimised parameters into the dynamic simulation model, the energy performance of the optimised and non-optimised ICSSWH collectors was evaluated in 42 different weather zones and compared to a reference case scenario. [ABSTRACT FROM AUTHOR]

Solar heating and cooling systems are a promising technology which may significantly contribute to the reduction of greenhouse gas emissions, the enhancement of energy efficiency, and the increase of renewables share in the building sector. The available literature show a high number of papers aiming at investigating solar heating and cooling systems based on heat driven and solar technologies, configurations, operating strategies, and financing issues. Nevertheless, none of the papers available in literature investigates the possibility to replace conventional solar thermal collectors by flat plat and concentrating photovoltaic/thermal systems, also producing renewable electricity. To cover this lack of knowledge, in this paper a dynamic simulation model of novel solar polygeneration heating and cooling systems is presented. Such dynamic simulation model is developed and implemented in a computer code, written in MatLab, and allows investigating the energy, economic and environmental performance of such novel solar polygeneration systems, based on both adsorption and absorption chiller technologies fed by dish-shaped concentrating and flat photovoltaic/thermal collectors. In order to show the potentiality of the presented tool, a comprehensive parametric case study is carried out to find out the optimal system configurations, as a function of crucial design and operating parameters and of weather conditions. The presented case study analysis refers to a small cluster of four buildings, including office and residential spaces, located in different European weather zones. The modelled solar polygeneration systems simultaneously produce electricity, space heating and cooling, and domestic hot water; electricity is self-consumed or delivered to the electrical grid. For comparative purposes, two different back-up system configurations, based on an electric chiller and a condensing gas-fired heater are also taken into account as conventional reference building-plant systems. By means of this systematic parametric analysis, comprehensive guidelines for system designers, practitioners and/or researchers focused on the development and use of solar heating and cooling systems are provided. [ABSTRACT FROM AUTHOR]

This work focuses on a dynamic simulation model for the energy, economic and environmental analysis of an innovative polygenerative system layout based on a building integrated photovoltaic thermal system coupled to an adsorption chiller and to an electricity storage system. The thermal energy of building integrated photovoltaic thermal collectors is exploited in order to produce solar space heating and cooling and domestic hot water. Auxiliary electric air-to-water heat pumps/chillers and a gas-fired condensation boiler are included in the system model in order to integrate the demands of heating, cooling and domestic hot water production. The electricity produced by building integrated photovoltaic thermal collectors is used to satisfy the building needs. The eventual extra-production is delivered to the grid or stored in lead-acid batteries. By means of the developed dynamic simulation model (implemented in TRNSYS environment) the energy system performance on the whole building can be analysed in terms of heating/cooling energy, electricity and domestic hot water demands. In particular, both the passive and active energy effects of the investigated collectors can be assessed. The model includes a suitable tool for the comparison of the innovative system layout vs. traditional reference building-plant systems. For energy, economic and environmental impact optimization purposes, sensitivity analyses can be performed by varying the main system design parameters with respect to the value of reference case ones. In order to show the potentiality of the developed simulation model, several new case studies are developed. They refer to a 3-floor office building located in four different Italian weather zones. Simulation results show that the obtained SPBs, the primary energy saving for electricity and domestic hot water production, and the equivalent carbon dioxide avoided emissions range between 10.6–11.3 years, 58.5–68.8% and 76.3–90.2%, respectively. [ABSTRACT FROM AUTHOR]

In this paper a new dynamic simulation model for the building energy performance analysis of multi-enclosed thermal zones, where rigid air temperature and humidity conditions must be kept, is presented. The model was implemented in a suitable computer code (DETECt 2.3.1) developed for research scopes. Such simulation model allows the hygrothermal analysis of buildings with multi-enclosed thermal zones surrounded by larger ones (e.g. display glass cases with valuable artefacts in museum halls, neonatal intensive care units for premature and full-term newborn babies in hospitals wards, etc.). For this purpose, a novel control algorithm, based on a model reference adaptive control scheme, enabling the online adaptation of the control gains, is implemented. Rigid air temperature and humidity conditions can be guaranteed also in case of sudden and rapid variations of hygrothermal loads. Through such new tool innovative techniques and operative strategies for obtaining energy efficiency and indoor comfort of special building spaces can be studied. In order to show the capabilities of the tool and the robustness of the adaptive algorithm, as well as the potentiality of the proposed multidisciplinary approach to the energy-related behaviour in buildings (based on building energy modelling and simulation and control theory), two meaningful case studies have been developed. In particular, they refer to the museums and hospital indoor spaces where enclosed thermal zones have to be kept under stringent hygrothermal conditions. [ABSTRACT FROM AUTHOR]

This paper analyses the energy and economic performance of roof and/or façades Building Integrated flat-plate PhotoVoltaic and Thermal (BIPVT) collectors for residential applications. Aim of the analysis is to assess the active and passive effects due to the building integration of solar technologies on the building energy consumptions. In particular, a comparison among innovative building-plant system configurations, based on BIPVT collectors for the simultaneous production of electricity, thermal energy, and domestic hot water, is carried out. The simulation models of the proposed system layouts are designed and implemented in TRNSYS simulation environment for the dynamic assessment of their energy and economic performance. By means of the developed simulation model, the occurring summer and winter building passive energy effects due to the PVT building integration are also analysed. Several case studies are developed by modelling a representative multi-storey residential building and by taking into account different European climates. For such case studies a suitable energy parametric analysis is performed by varying the thermal resistances and capacitances of the building envelope. By the simulation results interesting design and economic feasibility guidelines are obtained. In particular, by varying the weather location and the building-plant configuration, the adoption of BIPVT panels produces a decrease of the primary energy demands from 67% to 89%. The passive effects of the BIPVT system in both the winter and summer season are also assessed for all the investigated climate zones. The calculated economic profitability resulted slightly better for roof BIPVT panels than for roof and façade applications. For the investigated case studies, the pay back periods appear quite long, varying from 11 years for South European weather zones to 20 for North European ones. [ABSTRACT FROM AUTHOR]

In this paper a novel optimal Model Reference Adaptive Control approach, developed to tame the thermohygrometric behaviour of buildings as well as to guarantee the indoor comfort, is presented. The main advantages of the proposed method are: (i) no-need of a priori knowledge of the specific building dynamics due to climate, occupants’ behaviour, building use, envelope features and utility rates; (ii) robustness with respect to a large class of perturbations, external disturbances, nonlinear unmodelled dynamics or parameters uncertainty; (iii) ability to impose desired optimal dynamics; (iv) accurate regulation and fast tracking of indoor air temperature and humidity in the case of stringent requirements in special building spaces (e.g. hospitals, museums, laboratories, etc.). In order to investigate the effectiveness of the proposed method, the developed strategy has been implemented in the new release of a white-modelling building energy performance simulation code, called DETECt 2.3. The tool enables multi-zone building simulation analyses and is capable to dynamically predict: (i) spaces sensible and latent heating and cooling demands and loads; (ii) indoor air temperatures and humidity, as well as building envelope internal and external temperatures; (iii) the performance of phase change materials (PCM) embedded in building enclosures and for any layer configuration; (iv) the thermohygrometric comfort of occupants. In order to analyse the effectiveness and robustness of the proposed control strategy, several case studies have been carried out. They refer to some reference buildings with different geometry, use and construction materials (also including PCM integrated into the building envelope) simulated in different weather conditions. For each case study, both continuous and intermittent control system regimes have been considered. Results confirm the ability of the developed approach to achieve the selected indoor air temperature and humidity conditions in order to guarantee indoor comfort in uncertain conditions. The numerical analysis is complemented with the rigorous analytical proof of asymptotic stability. [ABSTRACT FROM AUTHOR]

In this paper a novel Concentrating Photovoltaic/Thermal Glazing system (CoPVTG), developed at the Centre for Sustainable Technologies of the University of Ulster (Belfast, UK), and exploiting concentration technology, is presented and investigated. The innovative device consists in two glazed panels of which the external one is moulded to form several lenses that concentrate the solar radiation onto photovoltaic cells lines. Thanks to the specific behaviour of these lenses, the solar radiation is capable to reach the indoor environment during the winter months (when it's more useful), while it ends onto the photovoltaic cells during the summer months (reducing the solar gains while also providing electricity to the building). To increase the electricity production, a forced air flux can be created inside the glazed cavity to reduce the PhotoVoltaic cells temperature, and the obtained hot air can be exploited for diverse purposes. Finally, such device is conceived to be integrated into existing windows framing to boost its adoption in new or refurbishment construction. With the intention of studying the device under a wide range of boundary and working conditions, a dynamic simulation tool was developed in MATLAB environment and validated trough experimentally gathered data. With this tool it is possible to investigate the performance of the novel device integrated into several buildings. Specifically, a case study analysis was performed by considering an office building located in five different localities. From the conducted analyses, interesting results and design criteria are obtained. Specifically, the CoPVTG adoption returns higher electricity yield vs. standard semi-transparent window, ranging between 54 and 84% in case of cold and hot weather zones, respectively. In term of overall economic performance, the adoption co CoPVTG allow for a HVAC system running cost reduction, for the investigated case study, ranging from 20 to almost 100% depending on the considered weather zone. • Novel building integrated concentrating photovoltaic thermal glazing system. • Modelling and dynamic simulation of smart building facades for energy efficiency. • Analysis of photovoltaic yield of concentrating and standard solar windows. • Analysis of passive effects of building integrated PV/T glazing systems. [ABSTRACT FROM AUTHOR]

This paper presents the design, simulation and optimisation of a small trigeneration plant supplied by geothermal and solar energies. Different technologies are implemented in a dynamic simulation model purposely developed for research scope: a 6 kW e micro Organic Rankine Cycle (ORC); a 30 kW f single stage H 2 O/LiBr absorption chiller; a geothermal well; a solar field obtained by new prototypal flat-plate evacuated solar collectors. The ORC is supplied by heat obtained by a geothermal well in which geothermal brine is about at 95 °C. In order to improve system performance, additional heat is provided by solar energy obtained through a 25 m 2 solar field. Diathermic oil (up to 130 °C) is adopted as working fluid in order to supply heat to the ORC evaporator. A suitable oil storage tank is modelled in order to mitigate the temperature fluctuations due to the variability of solar energy availability. The output power of the ORC depends on the availability of solar energy. The absorption chiller is switched-on in summer time and it is fed by geothermal energy only. This simulation model is implemented in TRNSYS environment. The ORC is modelled by zero-dimensional energy and mass balances implemented in Engineering Equation Solver (EES). A case study is developed in order to test the energy and economic performance of this innovative micro-trigeneration plant. In particular, the above mentioned model is applied to the Regina Isabella hotel in Ischia (Naples, South Italy), famous for its geothermal sources. Currently, such hotel is already equipped by a geothermal system (by several hot water wells) for thermal cares, domestic hot water production and space heating. By TRNSYS the optimisation of the system design parameters and the calculation of the thermo-economic conditions were performed. The system showed excellent energy performance indexes. In fact, the average yearly efficiency of the solar thermal collectors is close to 60%, whereas the average yearly ORC electric efficiency is about 6%, which is a good achievement considering the system driving temperature. Results also show that the system performance is more dependent on the availability of the geothermal energy than the solar one. From the economic point of view, good results are also obtained. In fact, in the worst operating conditions the Simple Pay Back Period is 7.6 years, decreasing to 2.5 years in the most convenient considered scenario (public funding and full utilisation of the produced thermal energy). [ABSTRACT FROM AUTHOR]

Abstract: The paper is focused on the dynamic simulation of a Photovoltaic/Thermal collector (PVT) integrated in a high-temperature Solar Heating and Cooling (SHC) system. The system is based on the following main components: concentrating parabolic PVT (photovoltaic thermal) collectors, a double-stage LiBr-H2O absorption chiller, storage tanks, auxiliary heaters, balance of plant devices. The PVT is made-up by a parabolic dish concentrator and a triple-junction receiver. The polygeneration system provides electricity, space heating and cooling and domestic hot water for a given building, whose simulation is also included in the model. In particular, PVT produces electric energy, which is in part consumed by the building loads (lights and equipments), in part by the system parasitic loads, whereas the eventual excess is sold to the public grid. Simultaneously, the PVT provides the heat required to drive the absorption chiller. The system was simulated by means of a zero-dimensional transient model, that allows the evaluation of temperature profiles and also heat/electrical energy flows for whatever period of the year. It is also possible to evaluate the overall energetic and economic performance on whatever time basis (day, week, month, year, etc.). The economic results show that the system under investigation can be profitable, if a proper funding policy is available. The paper also includes an extensive parametric analysis aiming at evaluating the set of design and operating parameters (solar field area, tank volumes, set point temperatures, etc.) that maximize the energetic and/or economic performance of the system. [Copyright &y& Elsevier]

Abstract: In this paper, a purposely designed code for the performance analysis of the Water Loop Heat Pump (WLHP) systems is presented. Hourly, daily and seasonal energy system consumptions, operating economic costs and environmental impact assessments are dealt with. For the scope of comparison, the performances of two reference HVAC system are investigated too. For the computation of the building heating and cooling requirements, a suitable dynamic performance simulation model is being developed. All the relevant algorithms are implemented in MATLAB®. A case study of an office building undergoing simulation in different European climatic areas is being presented. Here, different building thermal features are considered. In order to maximize the system performance an additional optimization procedure to the operating devices temperatures is carried out. Results show that primary energy savings and avoided CO2 emissions of the WLHP system vary in relation to the compared reference systems and can be obtained only in several European weather zones. The feasibility of the WLHP system strongly depends on electricity and natural gas national costs. [Copyright &y& Elsevier]

In this paper an accurate description of a combination water meter is provided. Therefore, the main results of calibration tests are presented. Final considerations about the reliability of a combination meter in very wide flow range applications are also reported. [Copyright &y& Elsevier]

In this paper a novel dynamic simulation model for enhancing the sustainability of transportation systems equipped with diesel co-generators is presented. In each simulation time step of the carried out energy performance analyses, the best operation/combination of generators as well as their optimal part load ratio are determined with the aim to achieve the minimum fuel consumption. Input to the model are: size of each installed diesel generator; number of engines; required power profile; route scheduling and hourly weather data. The developed simulation model is implemented in TRNSYS environment. Here, a new in-house TRNSYS type written in Fortran is also included. With the presented approach - especially helpful for cruise ship designers, manufacturers and owners - new design criteria and useful technical results can be obtained. To show the capability of the tool a novel case study is presented. It concerns on an existing cruise ship to be refurbished from the energy point of view. Here, four diesel generators are installed on-board. The ship energy system includes five electric chillers, two auxiliary boilers, two reverse osmosis and two multi-stage flash desalination devices (driven by the diesel generators waste heat recoveries). Simulation results show remarkable energy savings obtained through the proposed optimization approach. Specifically, a maximum primary energy saving of about 15 GWh/y is obtained compared to the initial reference scenario. It corresponds to a fuel consumption reduction of 2.5 kt/y (-1.6 M$/y) and to an avoided CO 2 emission of 8.0 kt/y. • Proposed model improves sustainability of ships through unit commitment approach. • Optimization of the generators operating sequence increases a ship's energy efficiency. • The model dynamically adapts waste heat recovery to different operating conditions. • A novel algorithm identifies the best running sequence for on-board generators. • Primary energy saving of 1.92% and fuel consumption reduction of 1.73% are obtained. [ABSTRACT FROM AUTHOR]

This paper focuses on a novel energy management approach, namely Building to Vehicle to Building, in which electric vehicles act as vector devices for renewable energy exchanges among buildings. The main goal behind this concept is to benefit from the potentiality of electric vehicles toward the achievement of the zero-energy target extended to a buildings cluster level, by exploiting renewable generation on- and off-site. To this aim, a dynamic simulation tool is developed to assess the energy and economic performance of the proposed V2B2 scheme applied to a cluster of multiple users made of non-residential buildings and electric vehicles with bidirectional charging, used as a back-up power supply for increasing self-consumption of energy produced on-site by PV panels integrated in one of the buildings, to be also exploited off-site by other users. A case study analysis is conducted for a sample cluster of 3 building sand 3 electric vehicles, located in a Mediterranean city (Naples, Italy) with the aim at conducting the proof of concept. Simulation results show that the proposed V2B2 scheme enhances the match between the on-site renewable generation and the whole system demand, i.e. buildings and electric vehicles' needs, by reducing the grid operation and boosting the system economic convenience. The proposed energy management scheme represents an example of novel aggregator energy and business model which will play a crucial role in the next generation of smart cities and communities. • Building to Vehicle to Building concept for multiple users and electric vehicles. • Development of a dynamic simulation tool for the energy and economic analysis. • Increasing the share of self-consumed PV production at a virtual micro-grid level. • Electricity delivered from the grid reduced up to 11.4% and economic saving of 8.1%. [ABSTRACT FROM AUTHOR]

An advanced mathematical model capable of simulating the energy performance of an innovative Integrated Collector Storage Solar Water Heater (ICSSWHs) is presented. Usually, ICSSWH devices available in the market are typically simple and low-cost, combining solar heat collection and storage functions in one unified vessel. However, they exhibit higher heat loss characteristics when compared to standard solar collector systems, with a subsequent reduction in energy performance during night-time and non-collecting hours. An innovative ICSSWH prototype was developed at the Centre for Sustainable Technologies (CST) at Ulster University using a patented, innovative thermal diode feature, attained by incorporating a liquid-vapour phase change material (PCM) and very low pressures. In order to fully investigate the energy performance of the proposed prototype, a suitably dynamic simulation model has been developed and validated in MatLab environment. All modelled temperatures are ±1 °C from the respective experimental measurements. The developed model has been used to evaluate the ICSSWH energy performance by varying several pivotal parameters (physical features and materials) in order to produce an optimised device. • A novel thermal diode feature is achieved by incorporating a liquid-vapour PCM in a multi-vessel solar water heater. • Dynamic simulation analysis is used to characterise a thermal diode feature in a novel ICSSWH unit. • MatLab environment was used to develop to model the novel thermal diode operation, validated using experimental data. • All modelled temperatures show good agreement with the experimental measurements. • Thermal diode ICSSWHs can produce higher temperatures than simpler ICS units. [ABSTRACT FROM AUTHOR]

• Design evolution of novel thermal diode ICSSWH prototypes. • Daily collection efficiencies of >55%. • Diode heat transfer 35 W/m2K in forward mode and 2W/m2K in reverse mode. • Heat retention of (U sys A ab /V) 60 W/m3K (12 hr - 53%). • A planar reflector can increase collection efficiencies by up to 12%. Existing Integrated Collector Storage Solar Water Heaters (ICSSWHs) are typically simple and low-cost devices that combine heat collection and storage functions in one unified vessel. However, during non-collection periods they are affected by higher heat loss characteristics when compared to standard solar collector systems. This paper introduces the design evolution of new horizontal cylindrical ICSSWH prototypes developed at Ulster University that use novel, patented double vessel, thermal diode features (to enhance heat retention during non-collection periods) achieved by incorporating a liquid–vapour phase change material (PCM) with a very low pressure annular cavity. The energy performance evaluation and characterisation of different prototype designs under solar simulated experimental conditions has been conducted and the subsequent parametric analysis presented. A balance between performance and physical/operational considerations is necessary to ensure that new and practical design solutions (in materials, fabrication and assembly) can be formulated to improve the performance of the ICSSWHs within the limits of commercial reality. The importance of augmenting heat transfer across the annulus cavity has been demonstrated with improvement of the cold-start daily collection efficiency from around (η col) of 20% (no HTF), to > 55% when the annulus is evacuated to remove non-condensable gases and form a liquid–vapour phase change thermal diode. Annulus thermal diode heat transfer coefficients of around (U fr) 35 W/m2K in forward mode and 2 W/m2K in reverse mode have been demonstrated. Diurnal thermal efficiencies (η c o l 24) of 22% have been measured, but values of 39% have been identified as achievable in the longer-term development of presented ICSSWH. [ABSTRACT FROM AUTHOR]

This paper presents a novel dynamic simulation model for the analysis of a hybrid turboexpander system coupled with innovative high-vacuum solar thermal collectors. The model is developed in MatLab and it is able to dynamically calculate the energy, exergy, environmental, and economic performances of the investigated system, by taking into account the hourly fluctuation of thermodynamic and economic parameters (e.g. electricity cost, natural gas temperature, and flow rates, etc.). In addition, a computer-based Design of Experiment (DoE) approach was implemented for achieving the optimal design of the proposed system. A suitable case study is presented in order to show the capabilities of the developed simulation tool. Conventional and non-conventional decompression systems located in the weather zone of Messina (South-Italy) are investigated with the aim of assessing the optimal system configuration. By means of the computer-based DoE analysis, the optimal values of several design parameters (such as the number of solar thermal collectors, the volume of the hot water storage tank, and the size of the water loop pump) are calculated. Numerical results show significant primary energy savings (1.36 TWh/year) and avoided carbon dioxide emissions (348 t CO2 /year). From the economic point of view, a feasible simple pay-back period of 4.51 years is achieved. The destroyed exergy of the system components are calculated, obtaining the highest value for the turbo-expander, equal to 12.0 TWh/year. • Dynamic modelling and simulation of natural gas turbo-expander system. • Energy, exergy and economic analysis of the turbo-expander system coupled to solar thermal collector field. • DoE analysis for the optimization of the solar field. • Analysis of a case study of pressure reduction station. • Confirmed system feasibility by achieved energy, economic and environmental results. [ABSTRACT FROM AUTHOR]

• Design and construction of a new low-cost air-based photovoltaic/thermal collector. • New simulation model for energy and economic performance assessments. • Description of the successful experimental validation of the simulation model. • Case studies for different weather zones by using the heated air in a heat pump. • Energy savings: 52–80%; avoided carbon dioxide: 4.6–10 t/y; pay-back: 3.2–4.8 years. This paper focuses on the design of an innovative low-cost air-based photovoltaic/thermal collector prototype, for which a novel dynamic simulation model is suitably developed in order to investigate its energy performance and economic feasibility under different operating conditions. The main novelty of this photovoltaic/thermal collector is the low-cost heat extraction system, implemented to reduce the photovoltaic cells temperature and to recover thermal energy. The prototype is tested under different operating conditions and the experimental data are used to validate the presented simulation model. The developed tool, implemented in a MatLab code, is used for analysing a suitable case study. The photovoltaic/thermal collectors are coupled to an air-to-air heat pump for space heating of a sample building. A novel performance map of such a coupled system is built with the aim of linking the heat pump coefficient of performance to both the outdoor air temperature and incident solar radiation. In addition, the system energy effectiveness and economic feasibility, compared to those of a traditional system, are assessed for the climate of 8 different European weather zones. Simulation results highlight the effectiveness of the proposed system, estimating primary energy savings (11.0–19.7 MWh/year corresponding to 52–80%), avoided carbon dioxide emissions (4.64–10.4 t CO2 /year), and simple pay-back periods (3.2–4.8 years). [ABSTRACT FROM AUTHOR]

The increasing energy demand in harbour areas, coupled with the need to reduce pollutant emissions, has led to the development of renewable energy-based polygeneration systems to face the carbon footprint of ports and ships at berth. In this way, in the coming years, ports can be converted into modern energy hubs. From this point of view, this paper presents a new dynamic simulation model for assessing and optimizing the energy and economic impact of ports. Here, energy systems and renewable sources can be designed to be connected to national electricity and natural gas grids and can include also alternative fuels (hydrogen, biomethane, etc.) and thermal energy networks, as well as different biomass fluxes (to be exploited for energy aims). Energy availability/demands of near towns and port buildings/infrastructures, as well as on-shore power supply are also included in the dynamic assessments. Hourly weather data and different prices for all the considered energy carriers are taken into account hour by hour. A multi-objective optimization approach is also implemented in the model considering energy and economic indexes to be optimized. The whole model is implemented in a computer tool written in MATLAB. For showing the capability of the developed model, a novel case study referred to the port of Naples (South-Italy) is presented. Here, several renewable energy sources are considered, including an anaerobic biodigester for producing biogas from the organic waste of docked cruise ships. A combined heat and power system (fed by biogas) is implemented in the port energy hub also for supplying absorption chillers. PV panels, and marine power generators are also included. In the conducted analysis, optimization targets are the maximization of system self-consumption and self-sufficiency as well as the minimum simple payback period. The proposed system can effectively contribute to the decarbonization of the port energy demand and reduce harmful pollutant emissions. Results showed that very high rate of renewable energy produced on-site can be exploited (up to 84%) by the considered port facilities, ensuring increasing independency from utility power grid (self-sufficiency index up to 40%). By the obtained results and through the developed simulation/optimization tool, novel design and operating criteria can be achieved for future port energy hubs featured by renewables and bi-directional energy exchange between ships and port. [ABSTRACT FROM AUTHOR]

Optimal design of building envelopes/HVAC systems and free cooling strategies are today necessary to reduce energy, economic and environmental impact of telecommunication, electricity distribution, or electric transportations infrastructures. To this aim, designers and operators require advanced techniques and tools. Target of this paper is to present the development of a simulation model for assessing and optimizing cooling performance of new/existing infrastructures to be designed/refurbished from the energy point of view. The model is implemented in a computer tool to assess the related potential benefits of different energy saving technologies/strategies and optimize different objective functions. By the presented approach new design and operating criteria are developed by varying all the occurring boundary conditions (weather, temperature limitations, electricity tariffs, etc.). To show the capability and suitability of the proposed approach, a case study concerning the equipment cooling of a railway substation is developed. The analysis is conducted for different Italian climates, obtaining remarkable energy savings. Specifically, by optimizing free cooling operation and thermal insulation the cooling energy consumption can be decreased up to 80% and 10%, respectively. By an energy refurbishment of all the Italian railway substations an annual electricity cost reduction due to equipment conditioning of about 0.5 M€ can be achieved, 47% lower. • Distributed building infrastructures have great potential of reducing cooling energy consumption. • Dynamic simulation is a paramount tool to design enhanced energy management strategies. • Free cooling contributes to 50% reduction of energy demand for equipment cooling. • Operational energy and use of material can be reduced with optimal envelope design. • The study proposes design criteria aimed at increasing energy efficiency at the infrastructure level. [ABSTRACT FROM AUTHOR]

This paper presents an innovative water photovoltaic thermal collector prototype. One of the main novelties of such system is its economic affordability, obtained through low-cost materials. The collector, constructed and experimentally tested at the University of Patras (Greece), is composed of a polycrystalline photovoltaic module coupled to eleven plastic pipes for water heating, located under the PV panel in an aluminium box. The prototype, suitable for building architectonical integration, can provide domestic hot water and electricity to the building. In order to assess the energy, economic and environmental performance of the system under different weather conditions and for diverse building uses, a suitable dynamic simulation model was developed and validated vs. experimental data. To investigate the convenience of the presented prototype and the potentiality of the developed software, a suitable case study is presented. In particular, the photovoltaic thermal collector is coupled to a stratified hot water storage tank for supplying domestic hot water to a single-family house located in three different European weather zones: Freiburg, Naples and Almeria. The system layout optimization was also performed through an energy and economic sensitivity analysis to some design and operating parameters. Useful design criteria and interesting energy and economic results were obtained. • Development of a novel low-cost photovoltaic/thermal collector prototype. • Development of a dynamic model for thermal and electrical performance assessment. • Experimental validation of the developed simulation model. • Comparative analysis between prototype and commercial collector performance. • Case study analysis for evaluating the prototype energy and economic feasibility. [ABSTRACT FROM AUTHOR]

Natural gas is typically transported for long distances through high pressure pipelines. Such pressure must be reduced before the gas distribution to users. The natural gas lamination process, traditionally adopted for this scope, may determine hydrate formation which may damagingly affect the system operation. Therefore, in order to avoid such circumstance, a suitable gas preheating is required. On the other hand, the available pressure drop can be recovered through a turbo-expansion system in order to provide mechanical energy to drive electricity generators. In this case a higher gas preheating is necessary. This paper presents a detailed simulation model capable to accurately analyse this process as well as the traditional decompression one. Such new model, implemented in a computer tool written in MATLAB, allows one to dynamically assess the energy, economic and environmental performance of these systems, by also taking into account hourly energy prices and weather conditions. Two turbo-expansion system layouts are modelled and simulated. In particular, the gas preheating is obtained by considering two different scenarios: gas-fired heater or solar thermal collectors. Another novelty of the presented dynamic simulation tool is the capability to take into account the time fluctuations of electricity feed-in and purchase tariffs. Finally, a suitable case study relative to a gas decompression station located in South Italy is also presented. Here, a remarkable primary energy savings and avoided CO2 emissions can be obtained through the examined turbo-expansion systems vs. traditional decompression ones. Results show that the economic profitability of the investigated novel technology depends on the available gas pressure drops and flow rates and on the produced electricity use. [ABSTRACT FROM AUTHOR]

This paper analyses the integration of air open-loop photovoltaic thermal systems on the façade of high-rise buildings, with a special focus on their active and passive effects. The system energy performance and its impact on the building heating and cooling demands and electrical production are assessed through a new dynamic simulation model. The developed numerical model of the proposed system, based on a detailed transient finite difference thermal network, is verified by comparing its outcomes to experimental results. With the aim to carry out whole building energy performance analyses, the model is implemented in a dynamic simulation tool for the building energy performance assessment, called DETECt 2.3, and suitably modified to analyse the main building integration energy issues. To assess the potentiality of the numerical model and the feasibility of the investigated system, a comprehensive case study relative to a multi-floor high rise office building located in several European climate zones is developed. A comparative and parametric analysis is also carried out with the aim to evaluate the system active and passive effects as a function of the building height. Simulation results show that by using building integrated air open-loop photovoltaic thermal systems, an interesting percentage reduction of the heating demand can be obtained. Both passive and active effects contribute to the variation of the thermal and electrical efficiencies. For the investigated weather zones, the innovative system leads to a reduction of the final energy consumptions ranging from 56.8 to 104.4%, approaching the nearly or net positive zero energy building target in the southern climate. Finally, the proposed analysis also aims to show the main implications linked to the design of the system, to be carefully taken into consideration by designers and stakeholders in case of new buildings or renovations. [ABSTRACT FROM AUTHOR]

In the last years, the Covid-19 outbreak raised great awareness about ventilation system performance in confined spaces. Specifically, the heating, ventilation, and air conditioning system design and operating parameters, such as air change per hour, air recirculation ratio, filtration device performance, and vents location, play a crucial role in reducing the spread of viruses, moulds, bacteria, and general pollutants. Concerning the transport sector, due to the impracticability of social distancing, and the relatively loose requirements of ventilation standards, the SARS-COV-19 outbreak brought a reduction of payload (up to 50%) for different carriers. Specifically, this has been particularly severe for the railway sector, where train coaches are typically characterized by relatively elevated occupancy and high recirculation ratios. In this framework, to improve the Indoor Air Quality and reduce the Covid-19 contagion risk in railway carriages, the present paper investigates the energy, economic and environmental feasibility of diverse ventilation strategies. To do so, a novel dynamic simulation tool for the complete dynamic performance investigation of trains was developed in an OpenStudio environment. To assess the Covid-19 contagion risk connected to the investigated scenarios, the Wells-Riley model has been adopted. To prove the proposed approach's capabilities and show the Covid-19 infection risk reduction potentially achievable by varying the adopted ventilation strategies, a suitable case study related to an existing medium-distance train operating in South/Central Italy is presented. The conducted numerical simulations return interesting results providing also useful design criteria. [ABSTRACT FROM AUTHOR]

Several new technologies can be today implemented in buildings in order to achieve the NZEB goal. In this paper a novel computer model for predicting the energy demand of buildings integrating phase change materials, photovoltaic-thermal collectors, adjacent sunspaces and innovative daylighting control is presented. Through this tool, DETECt 2.2, written in MatLab and conceived for research purposes, the overall energy and economic performance of multi-zone NZEBs can be assessed. Both the active and passive effects on the energy demands of all the above mentioned technologies, even if simultaneously utilized, are taken into account by means of an integrated building modelling approach. In addition, parametric and sensitivity analyses, with a single simulation run, can be carried out for design purposes. A novel relevant case study referred to the energy design of a non-residential NZEB for Mediterranean climates is developed. For this building a suitable energy optimization analysis was also carried out. For each use of the indoor space, the optimal value of the pivotal design and operating parameters is calculated. Details about the optimal position of building PCMs and thermal insulation layers, also coupled to BIPV and/or BIPV/T systems, are provided. For the obtained best configuration very low heating and cooling demands are achieved (0.9 and 1.5 kWh/m 3 y, respectively). Results about a simplified economic analysis carried out on the investigated energy saving technologies are also reported. At last, new NZEB definition details and criteria are provided for non-residential buildings located in the southern European zones (Mediterranean climates). [ABSTRACT FROM AUTHOR]

This paper presents experimental and numerical analyses of a novel high-temperature solar cooling system based on innovative flat-plate evacuated solar thermal collectors (SC). This is the first solar cooling system, including a double-effect absorption chiller, which is based on non-concentrating solar thermal collectors. The aim of the paper is prove the technical and economic feasibility of the system, also presenting a comparison with a conventional technology, based on concentrating solar thermal collectors. To this scope, an experimental setup has been installed in Saudi Arabia. Here, several measurement devices are installed in order to monitor and control all the thermodynamic parameters of the system. The paper presents some of the main results of this experimental campaign, showing temperatures, powers, energies and efficiencies for a selected period. Experimental results showed that collector peak efficiency is higher than 60%, whereas daily average efficiency is around 40%. This prototypal solar cooling system has been numerically analysed, developing a dynamic simulation model aiming at predicting system performance. For a representative operating period, numerical data were compared with the experimental one, showing an excellent accuracy of the model. A similar system, equipped with Parabolic Trough solar thermal collectors (PTC) was also simulated in order to compare the novel solar collectors with such reference technology. For both systems a detailed thermo-economic model has been implemented in order to perform such comparison also from the economic point of view. Results showed that the rated energy performance of the prototypal solar cooling system featuring new collectors is better than that of the reference system. In particular, the difference between the novel and the reference solar cooling system becomes more and more significant, when considering the effects of dust and defocusing related to the tracking mechanism of concentrating collectors in harsh environments. Finally, from the economic point of view, results showed that the novel prototype was able to achieve a good profitability. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive review of the possible layout configurations of hybrid power plants based on the integration of solid oxide fuel cells (SOFC) and gas turbine (GT) technologies. SOFC/GT power plants have been investigated by using a plurality of approaches, such as: numerical simulations, experimental analyses, and thermo-economic optimizations. The majority of SOFC/GT hybrid systems are fed by methane, which is much cheaper and easier to manage than hydrogen. In fact, SOFC/GT systems use the capability of the fuel cell to internally perform the reforming process required to convert methane into hydrogen. The steam required to drive the reforming reaction can be supplied by the anode recirculated stream. Alternatively, such steam can be produced externally, by using the heat of the exhaust gases. In this case, steam can be used also for thermal purposes and/or for further system hybridization (e.g. Cheng cycle). The majority of the SOFC/GT power plants analyzed in literature are based on the pressurized arrangement, potentially able to ensure lower capital costs and higher efficiencies. Conversely, atmospheric plants are easier to manage, due to the possibility of operate the SOFC and the GT independently one of each other. The paper also investigates more complex SOFC/GT configurations, including: HAT turbines, IGCC SOFC/GT power plants, ORC cycles, etc. A detailed analysis of the SOFC/GT control strategies and part-load performance analyses is also presented, showing that such systems reach their best performance at nominal capacity, and are affected by significant reduction of the electrical efficiency in case of large variations of the load. Finally, the paper also presents a review of hybrid SOFC/GT power plants fed by alternative fuels, such as coal and biomass. [ABSTRACT FROM AUTHOR]

In this paper the results of an on-site experimental analysis carried out on a Molten Carbonate Fuel Cell (MCFC) fed by different fuels (hydrogen, landfill gas and different mixtures of them) are presented. The examined MCFC is one of the experimental devices of an innovative power plant located at the urban landfill of Giugliano in Campania (Naples, Italy). Here, electricity is produced through four cogenerative reciprocating engines and one cogenerative gas turbine fed by landfill gas, operating since 2003. At the same site, two different fuel cells are installed for scientific purposes. During the considered experimental campaign, the MCFC is initially supplied by hydrogen for testing the system at the best operating conditions. Afterward, the fuel cell is fed by mixtures of different ratios of hydrogen and reformed landfill gas. For this reason, the system is equipped with an external reformer and a suitable gas cleaning. In order to analyse the system energy performance under varying electricity loads (obtained through an electronic device), several tests were carried out. In addition, several stress tests were also performed aiming at analysing the system endurance when fed by landfill gas. The experimental results concerning the produced electric currents and voltages show satisfactory performance of the system, while the obtained operating temperatures and cell reliability still need to be improved. [ABSTRACT FROM AUTHOR]

This paper investigates several actions for the energy refurbishment of some buildings of the University Hospital Federico II of Naples. The analysis focuses on a specific lot of 4 buildings, representative of the whole district hospital. For those structures, sustainable energy savings actions are investigated. They regard the installation of: i) roofs thermal insulation; ii) a substation climatic 3-way valve; iii) radiators thermostatic valves; iv) AHU (air handling unit) time-programmable regulation. This paper aims at presenting an investigation methodology, useful for designers and other stakeholders involved in hospital energy refurbishments, based on an integrated approach which combines dynamic energy performance simulations and experimental campaigns. In order to measure all the simulations' missing input parameters, a suitable experimental analysis, including measurements of temperature, humidity, flow rate and density of construction materials, is performed. A thermographic investigation is also performed for investigating the building envelope performance. This analysis showed that significant savings can be achieved especially by adopting radiators thermostatic valves and AHU regulations. Coherently, the installation of a 3-way valve in the substation does not determine significant additional savings when radiators thermostatic valves are already installed. For high-rise buildings, roofs insulation returns only marginal reductions of space heating and cooling demands. [ABSTRACT FROM AUTHOR]

This paper explores the implementation of the Building To Vehicle To Building (V2B2) scheme in European Countries, by evaluating the influence of weather conditions and local energy market prices on its energy and economic performance. The use of electric vehicles as energy vectors among buildings belonging to a virtual cluster is the key aspect of the V2B2 scheme: by exploiting mobile electric storage devices, renewable electricity produced by building integrated PV panels is shared among diverse users and consumed off-site. This novel energy management scheme has a twofold aim: i) promoting energy flexibility and efficiency in multiple buildings by improving the share of self-consumed renewable electricity at a cluster level and ii) reducing the interaction with the power grid. The proposed cluster includes two buildings, a house and an office space, and an electric vehicle, and it can be considered as the basic nucleus of human linked energy users. The energy and economic performance of the proposed V2B2 scheme highly depends on weather conditions and purchasing/selling electricity price. Therefore, to assess the impact of weather and energy prices on the system energy and economic performance, a comprehensive parametric analysis is conducted by varying the main design and operating parameters of the capacity of the key components of the investigated energy cluster, such as of buildings integrating PV panels and electric storage devices. The modelled and simulated scenarios refer to two different layouts simulated in several European cities, selected to consider different weather conditions and national electricity market prices. To identify the optimal V2B2 configurations, several energy and economic indicators of each simulated scenario are compared to a conventional reference one in which the novel energy management scheme is not implemented. Through the proposed V2B2 scheme, encouraging energy savings, from a minimum of 13.6% to a maximum of 71.2%, and economic outcomes are achieved. • Energy and economic performance of the Building to Vehicle to Building scheme. • The proposed V2B2 layouts are simulated in 22 European cities. • Evaluation of the impact of the weather and of national energy market prices. • Grid interactions drop from a minimum of 13.6% to a maximum of 71.2%. • Net present values reach 18.0 k€, also thanks to favorable energy prices. [ABSTRACT FROM AUTHOR]

This paper presents an innovative Concentrating Glazing system to be adopted in smart building façades: The Concentrating Photovoltaic Glazing system (CoPVG). The device consists of a double-glazing panel integrating a series of concentrating lenses. A thin layer of PV cells is then placed at the lenses' focus. The peculiar lens design can produce, by using the Total Internal Reflection (TIR), a seasonal effect with more light entering the building at low incidence angles (i.e. in the winter months) and higher electricity production at high incidence angles (i.e. in the summer months). To investigate this device's performance, a suitable dynamic simulation tool has been developed in MATLAB environment. Furthermore, to investigate active (electric energy production) and passive (building insulation and solar gains variations) effects related to the building integrated devices, the developed CoPVG simulation tool is implemented in a building energy performance simulation one (DETECt). To show the potential of the innovative device, a case study relative to a multi-floor office building integrating the innovative CoPVG prototype is investigated. Conventional and semi-transparent PV windows are also investigated for comparative purposes. By using the novel façade system, interesting energy savings ranging from 30 to 60 % for the investigated weather zones can be obtained. • Novel building integrated concentrating photovoltaic glazing system. • Modelling and dynamic simulation of smart building facades. • Analysis of photovoltaic yield of concentrating and standard solar windows. • Analysis of passive effects of building integrated glazing systems. [ABSTRACT FROM AUTHOR]

Nowadays, due to the raising research interest in net and nearly zero-energy concepts at community level, great efforts are spent to investigate self-sustaining and energy-independent communities. Small and off-grid islands represent one of the best places to focus the attention on, and to suit pilot projects of self-sufficient energy communities. In this context, the dynamic simulation represents a useful tool for designing, analysing, and optimizing islands' energy system layouts, especially in case of renewable energy system adoption (due to the performance unpredictability of renewable energy sources). Therefore, powerful yet flexible dynamic simulation tools are increasingly in demand. In this framework, this paper presents a novel dynamic simulation model, developed in TRNSYS environment, purposely conceived to investigate innovative technologies, novel system layouts, and advanced control logics, in the case of small and off-grid islands, aiming at reaching the nearly/net-zero energy goal at a community level. To prove the potential of the novel dynamic simulation tool, a suitable case study referring to the existing island community of El Hierro (Canary Island) was considered and investigated. Specifically, to enhance the island energy independence, diverse scenarios and system layouts, including different renewable energy based technologies (e.g. wind turbines, hydroelectric power plants, solar thermal collectors, etc.) have been investigated by the novel developed simulation tool. Results demonstrate the potentiality of the adopted method as well as the feasibility of the proposed system layouts. Specifically, the investigated scenarios provide up to 85% of the annual electricity demand and about 79% of the annual thermal energy needs by renewable energy sources with substantial economic savings. [Display omitted] • Modelling and simulation of small islands hybrid multi-generation energy systems. • Using dynamic simulation to enhance off grid-islands energy independence. • Development of a design tool to boost renewable energy penetration of small islands. • Energy, economic and environmental optimization of islands' grid energy fluxes. • Exploitation of energy storage to mitigate fuel consumption in off-grid communities. [ABSTRACT FROM AUTHOR]

Worldwide, the design, renovation, and sustainable management of port buildings play a crucial role for sustainability. In this framework, a computer simulation of a building's thermal behaviour is an almost mandatory tool for making informed decisions. However, the development of a building energy model is a challenging task that could discourage its adoption. A possible solution would be to exploit an existing Building Information Modeling (BIM) model to automatically generate an accurate and flexible Building Energy Modeling (BEM) one. Such a method, which can substantially improve decision-making processes, still presents some issues and needs to be further investigated, as also detectable from the literature on the topic. In this framework, a novel workflow to extrapolate BIM data for energy simulation is proposed and analysed in this paper. Here, the BIM to BEM approach was tested as a useful tool for the maritime industry to improve the implementation of effective energy-saving measures. Specifically, in order to prove the capabilities of the proposed method, a maritime passenger station in Naples was chosen as case study and investigated by comparing different strategies to reduce the annual primary energy consumption. The optimal level of modelling detail required by a trustable building energy assessment was also investigated. By the proposed method, interesting primary energy savings (ranging from 24 to 41%) are achieved and CO2 emissions avoided (ranging from 16 to 34 tons CO2/year) for the investigated building, proving the potential of this approach. Definitely, this paper proves the validity of the proposed methodology and emphasizes its numerous benefits towards the achievements of the most modern sustainability standards. [ABSTRACT FROM AUTHOR]

The new standards on energy saving for new and existing buildings have animated both researchers and technicians in recent years, aiming at reducing the dependence on fossil fuels, improving indoor comfort, and systems efficiency. In this scenario, special attention must be paid to historical buildings that need to preserve their key testimonial heritage within the society. This paper describes the design and realization stages of a pilot system based on a ground-coupled heat pump, operating both in heating and cooling modes, installed in the monumental site of Saints Marcellino and Festo (SM&F), in Naples, Southern Italy. This study aims to demonstrate that low-enthalpy geothermal systems can be employed as energy retrofit applications in buildings of historical, artistic, and cultural interest and, at the same time, to prove that the use of this technology allows achieving the objectives, set at global level by the current regulations, and requiring a reduction of carbon dioxide emissions (tCO2) of 53% compared to technology using fossil fuels. [ABSTRACT FROM AUTHOR]

Solar systems represent a viable way to reduce in a sustainable manner building energy consumptions. Nevertheless, two issues can be underlined: insufficient building surface areas for hosting typical stand-alone solar devices and related high initial costs. Consequently, growing research and industrial interest in cost-effective building-integrated solar systems is today observed. In this framework, this paper presents a comprehensive analysis of two low-cost building-integrated hybrid photovoltaic/thermal collector prototypes (water- and air-cooled, respectively). Both active and passive effects are investigated employing a purposely developed dynamic simulation tool, able to carry out complete system performance analyses. The capability of such the proposed innovative devices as well as of the presented in-house code is shown by a novel case study regarding a dwelling unit located into a multi-story residential building for three diverse European weather zones. Here, the investigated prototypes are modelled as integrated into the building South façade. For comparison purposes, a building integrated photovoltaic panel is also modelled as a reference case. Both active and passive effects are assessed. Relevant energy savings (up to 4236 kWh e /y), comfort outcomes (related hours variation range from −190 to +121), and economic results (paybacks are between 3 and 6 years) are achieved. • Novel low-cost building integrated photovoltaic thermal collectors are presented. • A dynamic simulation tool for the prototypes analysis is developed and validated. • Thermal energy and electricity production are estimated by using the developed tool. • Analyses of the prototypes building integration passive effects are performed. • Energy, economic and indoor thermal comfort analyses have been conducted. [ABSTRACT FROM AUTHOR]

• New design approach of cruise ships based on dynamic energy simulations. • New customised hourly weather data files for moving systems energy assessments. • Waste heat recovery optimization of cruise ships equipped by LNG engines. • Novel energy saving technologies and strategies for cruise ships. • Fuel savings (1.9 kt/y), avoided CO 2 (4.51 kt/y), and paybacks (lower than 5 years). Modern cruise ships are energivorous systems and their design is challenging due to stringent restrictions on the environmental impact recently imposed by the International Maritime Organization. Nowadays, energy saving technologies and strategies for ships can be selected and analysed by means of system dynamic simulations. In this paper this innovative goal is obtained through TRNSYS where the ship-envelope and the related energy system are modelled and simulated by means of new customized weather data with the aim to optimize the system energy performance by considering different objective function (maximum energy saving, minimum payback, etc.). To show the effectiveness of the proposed approach, a novel case study is presented. It refers to a modern cruise ship fuelled by liquefied natural gas cruising in Mediterranean and Caribbean seas. Novel hourly weather files are developed for accounting actual locations and orientations of the moving ship. Low-, medium- and high-temperature engines waste heat recoveries are exploited for supplying different thermally activated energy saving devices. Results of the conducted optimization procedure show significant reductions of fuel consumption (between 0.1 and 1.9 kt/y), operating costs (up to 615 k€/y), and pollutant emissions with respect to traditional systems. Short paybacks are obtained (lower than 5 years), depending on the considered innovative system layouts. Finally, useful design and operating criteria for ship manufacturers and users are provided. [ABSTRACT FROM AUTHOR]

Nowadays, due also to high hygrothermal comfort requirements, the energy consumption for heating/cooling of modern trains can reach 30% of the related overall electricity demand. Energy-saving of train Heating, Ventilation and Air Conditioning systems can be suitably assessed through dynamic simulation approaches. Specifically, the weather solicitation has to be dynamically accounted for by considering the actual moving train location and orientation. Through such methodology different innovative actions for energy efficiency, environmental impact reduction and comfort enhancement can be analysed by also assessing their economic feasibility. In this paper, a novel simulation tool for the complete performance analysis of trains was developed in TRNSYS environment. To show the capabilities of the considered approach, a novel case study referred to an existing medium-distance train operating in South Italy is presented. Heating/cooling loads and demands, and the related electricity requirements, are dynamically assessed for the standard and revamped train. Several energy saving actions are considered for the coupling between the envelope and the Heating, Ventilation and Air Conditioning systems enhancement. The obtained results return significant benefits in terms of energy saving, avoided CO 2 emissions and comfort. Paybacks depend on operating conditions. Useful design and operating criteria for trains manufacturers and users are provided. • Dynamic simulation for train HVAC system energy performance analyses using TRNSYS. • Customized weather data files for accounting real train locations and orientations. • Innovative energy efficiency solutions for trains with saving up to 6.0 MWh e /y. • Economic feasibility of energy efficiency solutions for trains. • Reduction up to 50% of the train environmental impact. [ABSTRACT FROM AUTHOR]

This paper focuses on the experimental validation of a building energy performance simulation tool by means of a comparative analysis between numerical results and measurements obtained on a real test room. The empirical tests were carried out for several months under variable weather conditions and in free-floating indoor temperature regime (switched off HVAC system). Measurements were exploited for validating an in-house simulation tool, implemented in MatLab and called DETECt, developed for dynamically assessing the energy performance of buildings. Results show that simulated indoor air and surface room temperatures resulted in very good agreement with the corresponding experimental data; the detected differences were often lower than 0.5 °C and almost always lower than 1 °C. Very low mean absolute and percentage errors were always achieved. In order to show the capabilities of the developed simulation tool, a suitable case study focused on innovative solar radiation high-reflective coatings, and infrared low-emissivity materials is also presented. The performance of these coatings and materials was investigated through a comparative analysis conducted to evaluate their heating and cooling energy saving potentials. Simulation results, obtained for the real test cell considered as equipped with such innovative coatings and material, show that for the weather zone of Naples a 5% saving is obtained both in summer and in winter by simultaneously adopting a high-reflectance coating and a low- emissivity plaster for roof/external walls and interior walls, respectively. [ABSTRACT FROM AUTHOR]