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Green hydrogen technologies are crucial for decarbonization purposes, while cogeneration offers efficient heat and power generation. Integrating green hydrogen and cogeneration brings numerous benefits, optimizing energy utilization, reducing emissions, and supporting the transition to a sustainable future. While there are numerous studies examining the integration of combined heat and power with Power to Gas, certain aspects still requires a more detailed analysis, especially for internal combustion engines fuelled by natural gas, due to their widespread adoption as one of the primary technologies in use. Therefore, this paper presents a comprehensive numerical 0-D dynamic simulation model, implemented within the TRNSYS environment, considering internal combustion engines fuelled by natural gas. Specifically, the study focuses on capturing CO2 from exhaust gases and producing green hydrogen from electrolysis. Based on these considerations, two configurations are proposed: the first involves the methanation reaction, while the second entails the production of a hydromethane mixture. The aim is to evaluate the technical and economic feasibility of these configurations and compare their performance within the Power to Gas framework. Self-sufficiency from the national electricity grid has been almost achieved for the two configurations, considering an industrial case. The production of hydromethane allows smaller photovoltaic plant (81 kWp) compared to the production of synthetic methane (670 kWp) where a high quantity of hydrogen is required, especially if all the carbon dioxide captured is used in the methanation process. Encouraging economic results with payback times below ten years have been obtained with the use of hydromethane. Moreover, hydromethane shows potential residential applications, with small required photovoltaic sizes.

In this paper the implementation and application of a novel methodology for the estimation of the energy demand of the railway building stock is presented. To this aim, a bottom-up modelling approach implemented in a simulation tool is developed to assess the energy footprint and potential savings of railway buildings. The tool is intended to support operators and decision-makers in the planning of systematic energy retrofit necessary to up to date the railway infrastructure.The developed methodology is applied to the Italian railway building stock with a bottom-up approach, identifying several groups of similar stations (archetypes) that are clustered according to real data collected. Afterwards, a data-driven model is derived from the detailed dynamic simulations of physic-based models representing the whole building heritage. As a demonstration of the validity of the proposed methodology and its capability to be exploited in real applications, some energy-saving strategies are simulated, and a comprehensive analysis is conducted on the considered stations.The surrogate data-driven model shows R2 coefficients always above 0.93 compared to physic-based model in predicting heating, cooling and electricity demand. Depending on the size of the stations, the mean relative error is in the range 5.9–15.0%. Furthermore, the surrogate model turns out to be an easy-to-use tool to analyse retrofit scenarios and take informed decisions, while the methodology is easily extensible and scalable to other contexts.As demonstrated, the most impactful measure among the ones investigated is the adoption of high-performance lighting systems which entail an overall primary energy saving up to 26%, with very low pay back periods (∼1 year).

The Canary Islands have great potential for the implementation of sustainable energy systems due to its availability of natural resources. The archipelago is not connected to the mainland electricity grid and the current generation system is mainly based on traditional fossil fuel. Therefore, the islands strongly dependent on fuel importations, with high costs due to logistics. Furthermore, due to the inadequate coverage of residential heating and cooling needs, the per capita energy consumption is far below the Spanish national average. This occurrence has inspired an intense debate on the current development model of the Canary Archipelago, which has led to the implementation of actions and measures aimed at achieving greater energy sustainability in the archipelago. Furthermore, at a local scale, an important investment plan has been carried out by the Spanish grid operator to ensure energy supply, to improve the system security and reliability, and to optimize the integration of renewable energies. Future measures and investments will be crucial to ensure a sustainable growth, both from the economic and the environment point of views. In this framework, this paper aims to discuss and compare the energy solutions, based on renewable energy technologies, identified to boost the sustainable transition of the islands. To this aim, multiple configurations of a wind power plant coupled with reversible hydro power/storage system for the distributed and on-site energy production in the island of Gran Canaria were modeled, simulated, and optimized by a TRNSYS/Matlab algorithm suitably developed. Specifically, along with the proposed system layouts, different scenarios related to diverse annual costs growth rate of fuel were investigated. The proposed analysis covers a time horizon of 20 years, up to 2040, and aims at assessing the impact of the investigated solution on energy demand, energy supply, and population incomes. Depending on the considered fuel cost growth rate, the best system configurations allow a primary energy saving in the range of 58.1–68.1%. Based on the system choice, the enterprise will generate significant revenues to the island population. The net present values are estimated in the range 1.50 × 103 ÷ 1.84 × 103 and 0.85 × 103 ÷ 1.27 × 103 M€, respectively for the two considered scenarios (annual costs growth rate of fuel 2 and −2%). The analysis demonstrates the importance of investments targeted at the implementation of renewables. The proposed scenarios indicate that the current energy model has the potential to radical change and to tackle climate change and energy issues while producing substantial economic savings and better life conditions for the population in the next years.

Phase change materials are considered a very promising technology to reduce energy consumption for space heating and cooling purposes in buildings. In this framework, this paper presents a comprehensive energy performance analysis of building envelopes integrating phase change materials to provide suitable selection and design criteria of such technology. To this aim, an in-house dynamic simulation model implemented in a computer code, and validated by means of experimental data, has been used. The performance of phase change materials embedded in building enclosures and their optimal configuration (i.e., positions with respect to the construction layers) are evaluated. The results obtained by applying the code to suitable case studies (several climate zones and buildings are investigated) return that the energy saving percentage potentials per cubic meter of phase change materials range from 1.9%/m3 to 18.8%/m3. Finally, interesting design criteria for their adoption in buildings are provided.

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.

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.

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.

In this paper the economic analysis of the energy recovery in all-outdoor-air HVAC systems for the Italian climate is performed. The energy recovery device considered here is the same for both heating and cooling periods. During the summer season, the energy saving is achieved by evaporative cooling. The performances of the hybrid innovative HVAC system and the traditional system are calculated hour by hour by following the test reference year (TRY) profile. Such analysis is carried out taking into account simultaneously, the trend of some climatic indexes computed in order to (i) better understand the influence of climate on the HVAC system behaviour, (ii) obtain a swift feasibility analysis of the energy recovery system and (iii) perform a rough operating cost estimate of the traditional HVAC system. Copyright © 2001 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The economic analysis for running two kinds of hybrid air conditioning systems: all-air and air-and-water, both with add-on evaporative cooling stages, is studied in this paper. Single-duct, single-zone, constant volume systems are dealt with. Processing the climatic data of the European ‘test reference year—TRY’ for Italy, a comparison of such systems' performance versus the relative traditional one is performed. Energy consumption and operating costs are evaluated by an appropriate computer code written with the aim of: (i) making plain the input/output of data; and (ii) displaying very friendly software masks as well as useful graphical elaboration. On the basis of outdoor air state, calculations are performed according to two different procedures: (a) hourly, following the TRY profile; and (b) for each bin, 1°C wide, in which the simultaneous dry- and wet-bulb temperatures fall. Copyright © 2000 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper deals with European TRY weather data processing for climatic indexes generation, useful for HVAC energy and cost simplified evaluation. For nine Italian locations are presented: 99 and 2·5% dry bulb temperatures, 2·5% wet bulb temperatures, heating and cooling degree days, latent enthalpy days, unitary sensible and latent loads. TRY psychrometric data were processed according to a bin method that preserves the correlation between dry bulb temperature and moisture content, and then reduced by an averaging technique. An example is worked out in order to present an engineering shorthand for energy and cost evaluation of HVAC system. © 1998 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]