A preliminary energy analysis of a commercial chp fueled with h2ng blends chemically supercharged by renewable hydrogen and oxygen

Currently, Power-to-Gas technologies are considered viable solutions to face the onset problems associated with renewable capacity firming. Indeed, carbon-free hydrogen production converting renewable electricity excess and its injection into natural gas pipelines is considered a short- to medium-term solution. In this way, the so-called H2NG blends can be fired within internal combustion engines and micro gas turbines operating in CHP mode, offering better environmental-energy performances in machines. As regards the distributed energy generation scenario, the local H2 production by means of electrolysis for methane enrichment will be more cost-effective if the oxygen is fruitfully used instead of venting it out like a by-product, as usually occurs. This study focuses on the usefulness of using that oxygen to enrich the air-fuel mixture of an internal combustion engine for micro-CHP applications, once it has been fuelled with H2NG blends. Thus, the main aim of this paper is to provide a set of values for benchmarking, in which H2NG blends, ranging in 0%-15% vol., burn within an ICE in partial oxy-fuel conditions. In particular, a preliminary energy analysis was carried out based on experimental data, reporting the engine operating parameters, gains and losses in both electrical and heat recovery efficiency. The oxygen content in the air varies up to 22% vol. A Volkswagen Blue Tender CHP commercial version (19.8 kWel. of rated electrical power output) was considered as the reference machine and its energy characterization was reported when it operated under those unconventional conditions

Energy use in residential buildings: Impact of building automation control systems on energy performance and flexibility

This work shows the results of a research activity aimed at characterizing the energy habits of Italian residential users. In detail, by the energy simulation of a buildings sample, the opportunity to implement a demand/response program (DR) has been investigated. Italian residential utilities are poorly electrified and flexible loads are low. The presence of an automation system is an essential requirement for participating in a DR program and, in addition, it can allow important reductions in energy consumption. In this work the characteristics of three control systems have been defined, based on the services incidence on energy consumptions along with a sensitivity analysis on some energy drivers. Using the procedure established by the European Standard EN 15232, the achievable energy and economic savings have been evaluated. Finally, a financial analysis of the investments has been carried out, considering also the incentives provided by the Italian regulations. The payback time is generally not very long: depending on the control system features it varies from 7 to 10 years; moreover, the automation system installation within dwellings is a relatively simple activity, which is characterized by a limited execution times and by an initial expenditure ranging in 1000 € to 4000 €, related to the three sample systems

An overview on safety issues related to hydrogen and methane blend applications in domestic and industrial use

The share of electrical energy hailing from renewable sources in the European electricity mix is increasing. The match between renewable power supply and demand has become the greatest challenge to cope with. Gas infrastructure can accommodate large volumes of electricity converted into gas whenever this supply of renewable power is larger than the grid capacity or than the electricity demand. The Power-to-Gas (P2G) process chain could play a significant role in the future energy system. Renewable electric energy can be transformed into storable hydrogen via electrolysis and subsequent methanation. The aim of this paper is to provide an overview of the required technical adaptations of the most common devices for end users such as heating plants, CHP systems, home gas furnaces and cooking surfaces, wherever these are fuelled with methane and hydrogen blends in variable percentages by volume. Special attention will be given to issues related to essential safety standards, firstly comparing existing Italian and European regulations in this regard, and secondly highlighting the potential need for legislation to regulate the suitability of hydrogen methane blends. Finally, a list of foreseeable technical solutions will be provided and discussed thoroughly

How climate change affects the building energy consumptions due to cooling, heating, and electricity demands of italian residential sector

Climate change affects the buildings’ performance, significantly influencing energy consumption, as well as the indoor thermal comfort. As a consequence, the growing outdoor environmental temperatures entail a slight reduction in heating consumption and an increase in cooling consumption, with different overall effects depending on the latitudes. This document focuses attention on the Italian residential sector, considering the current and reduced meteorological data, in anticipation of future climate scenarios. According to a sample of 419 buildings, referring to the climatic conditions of Milan, Florence, Rome, and Naples, the heating and cooling needs are calculated by a simplified dynamic model, in current and future conditions. The effects of the simplest climate adaptation measure, represented by the introduction of new air conditioners, have been also evaluated. The simulations results show an important reduction in complex energy consumption (Milan −6%, Florence −22%, Rome −25%, Naples −30%), due to the greater incidence of heating demand in the Italian context. However, the increase in air conditioning electrical consumption over the hot season (Milan +11%, Florence +20%, Rome +19%, Naples +16%) can play a critical role for the electrical system; for that reason, the introduction of photovoltaic arrays as a compensatory measure have been analysed

Single Cylinder Internal Combustion Engine Fuelled with H2NG Operating as Micro-CHP for Residential Use: Preliminary Experimental Analysis on Energy Performances and Numerical Simulations for LCOE Assessment

The paper presents data resulting by the preliminary experimental campaign performed on a micro CHP (combined heat and power) pre-commercial version (5 kWel) designed for dwellings. The engine employs the lubricant oil as the jacket coolant to simplify the heat recovery architecture and it was equipped by a condensing heat exchanger as well. The tests have been carried out at rated and partial load up to 2.9 kWel (59% of rated load) in condensing mode, fuelling the NG engine with hydrogen percentages equal to 0% vol. and 15% vol. In order to evaluate the CHP energy performance, the analysis was conducted for 160 h, using an alkaline electrolyser for hydrogen production, a static heat meter and two mass flow meters for both hydrogen and NG. The aim of this paper is to illustrate how the use of the hydrogen enrichment in a micro CHP plant, based on ICE technology, represents a foreseeable bridge solution to the forthcoming SOFC deployment

RES (Renewable Energy Sources) Availability Assessments for Eco-fuels Production at Local Scale: Carbon Avoidance Costs Associated to a Hybrid Biomass/H2NG-based Energy Scenario

Eco-fuels are a sustainable solution to face increasing global energy consumptions and GHG emissions. This work was firstly focused on available renewables assessment linked to a local dimension. Furthermore, identifying the potential Eco-fuels capability, it was discussed how the capital expenditure for infrastructures is associated with carbon avoidance costs. A coastal municipality and an inland one, located in Central Italy, are selected as case studies. In order to assess PV and agro-forestry residues availability, a GIS-based analysis was performed. In this framework, a new energy scenario, based on H2NG blends use and ligneous biomass conversion, was presented. Specifically, the hydrogen for NG enrichment was produced by renewable electricity, while biomass energy content was evaluated considering gasification process. Finally, the governmental incentive schemes incidence (in force for bioenergy and hypothesized for hydrogen) on investments economic sustainability and on infrastructure deployment was compared in terms of carbon avoidance costs

Dynamic simulation model of trans-critical carbon dioxide heat pump application for boosting low temperature distribution networks in dwellings

This research investigates the role of new hybrid energy system applications for developing a new plant refurbishment strategy to deploy small scale smart energy systems. This work deals with a dynamic simulation of trans-critical carbon dioxide heat pump application for boosting low temperature distribution networks to share heat for dwellings. Heat pumps provide high temperature heat to use the traditional emission systems. The new plant layout consists of an air source heat pump, four trans-critical carbon dioxide heat pumps (CO2-HPs), photovoltaic arrays, and a combined heat and power (CHP) for both domestic hot water production and electricity to partially drive the heat pumps. Furthermore, electric storage devices adoption has been evaluated. That layout has been compared to the traditional one based on separated generation systems using several energy performance indicators. Additionally, a sensitivity analysis on the primary energy saving, primary fossil energy consumptions, renewable energy fraction and renewable heat, with changes in building power to heat ratios, has been carried out. Obtained results highlighted that using the hybrid system with storage device it is possible to get a saving of 50% approximately. Consequently, CO2-HPs and hybrid systems adoption could be a viable option to achieve Near Zero Energy Building (NZEB) qualification

Smart energy systems for renewable energy communities. A comparative analysis of power-to-X strategies for improving energy self-consumption

Renewable energy communities (RECs) represent the new scheme for promoting the distributed renewable generation, which must be managed to maximise the local energy self-consumption. The aim of this paper is to assess and discuss strengths and weaknesses of small-scale sector coupling strategies in residential RECs by means of a comparative analysis of their applications. Different power-to-X strategies have been applied to twenty-seven REC configurations. The systems have been separately simulated by means of the EnergyPLAN software. Power to-heat strategy turns out to be the most cost-effective solution to integrate the RES excess, however, its potential often is not enough to fully accommodate it. Power-to-vehicle has low infrastructure costs, but its limit depends on the electric vehicle penetration and citizens' participation. Exploiting the electric vehicle batteries is always more cost-effective than installing stationary batteries. The competitiveness of power-to-power is extremely linked to the REC electrification level. Power-to-gas is promising in high-RES excess conditions, but rarely represents the best solution due to current high electrolyser costs. The implementation of energy storage systems is crucial for improving the local self-consumption and the cross-sector integration is a better solution in energy, economic and environmental terms than focusing only on the electricity sector

How the italian residential sector could contribute to load flexibility in demand response activities: a methodology for residential clustering and developing a flexibility strategy

This work aims at exploring the potential contribution of the Italian residential sector in implementing load flexibility for Demand Response activities. In detail, by combining experimental and statistical approaches, a method to estimate the load profile of a dwelling cluster of 751 units has been presented. To do so, 14 dwelling archetypes have been defined and the algorithm to categorise the sample units has been built. Then, once the potential flexible loads for each archetype have been evaluated, a control strategy for applying load time shifting has been implemented. That strategy accounts for both the power demand profile and the hourly electricity price. Specifically, it has been assumed that end users access a pricing mechanism following the hourly trend of electricity economic value, which is traded day by day in the Italian spot market, instead of the current Time of Use (TOU) system. In such a way, it is possible to flatten the dwellings cluster profile, limiting undesired and unexpected results on the balancing market. In the end, monthly and yearly flexibility indexes have been defined along with the strategy effectiveness parameter. From calculations, it emerges that a dwelling cluster for the Italian residential sector is characterised by a flexibility index of 10.3% and by a strategy effectiveness equal to 34%. It is noteworthy that the highest values for flexibility purpose have been registered over the heating season (winter) for the weekends

Hydrogen to link heat and electricity in the transition towards future Smart Energy Systems

Nowadays, two fundamental issues are related to the Energy transition towards Future Smart Energy Systems: the design of new high efficiency technological appliances and the use of new Eco-fuels. The crucial challenge is to integrate the increasing share of intermittent RES (Renewable Energy Sources) in National energy mix. Above all, linking both heat and electricity production is the key strategy to face this challenge at urban, regional and national scale. Power-To-Gas application by means of Renewable Hydrogen (H2) production would be the viable solution due to H2 has a double application: as a fuel for combustion or chemical conversion as well as an energy storage medium for RES mismatch compensation. In this paper four different H2-technologies were considered: Hydrogen enriched Natural Gas (H2NG), MHHP (Metal Hydride Heat Pump), GHP (Gas-driven Heat Pump) and SCH4 (Synthetic Methane). An aggregated energy system model was built to assess H2 contribution in PES (primary energy saving). When RES share ranges from 25% to 50%, using H2 for heating purposes avoids the low round trip efficiency of its deferred electricity purpose. If transport excluded, there are no meaningful gains from H2Ts systems but, they allow to green NG end-uses and decarbonize heating, especially, where NG-Grid is widespread