Performance and Emission Optimisation of an Ammonia/Hydrogen Fuelled Linear Joule Engine Generator

This paper presents a Linear Joule Engine Generator (LJEG) powered by ammonia and hydrogen co-combustion to tackle decarbonisation in the electrification of transport propulsion systems. A dynamic model of the LJEG, which integrates mechanics, thermodynamics, and electromagnetics sub-models, as well as detailed combustion chemistry analysis for emissions, is presented. The dynamic model is integrated and validated, and the LJEG performance is optimised for improved performance and reduced emissions. At optimal conditions, the engine could generate 1.96 kWe at a thermal efficiency of 34.3% and an electrical efficiency of 91%. It is found that the electromagnetic force of the linear alternator and heat addition from the external combustor and engine valve timing have the most significant influences on performance, whereas the piston stroke has a lesser impact. The impacts of hydrogen ratio, oxygen concentration, inlet pressure, and equivalence ratio of ammonia-air on nitric oxide (NO) formation and reduction are revealed using a detailed chemical kinetic analysis. Results indicated that rich combustion and elevated pressure are beneficial for NO reduction. The rate of production analysis indicates that the equivalence ratio significantly changes the relative contribution among the critical NO formation and reduction reaction pathways

Argon oxy-hydrogen combustion for power generation employing linear joule cycle engine generator

PhD ThesisThe global awareness of the unfavourable environmental effects due to fossil fuels' continuous use as the primary energy source has increased significantly. In order to tackle the adverse environmental consequences, innovative technologies will play a significant role. As a result, this thesis presents an investigation of the Linear Joule Engine Generator (LJEG) and its potential for zero-emissions power generation. It is believed that the results of the investigation will guide the further development of the LJEG. A background study on LJEG related technologies was conducted, focusing on the challenges and advantages of the reciprocating Joule Cycle engine and the free-piston engine generator. The semi-closed cycle argon-oxyhydrogen combustion LJEG was identified as the potential technology path towards LJEG development. This version of LJEG operated on dry friction principle, and an accurate friction model is required for a proper analysis of the engine. A novel friction model of the LJEG is proposed, and the proposed model validation was against test data from a lab-scale LJEG prototype. The dynamic and thermodynamic model of the LJEG was developed, and the numeric model validation was executed with the prototype's test data. The performance characteristics of the LJEG with different inputs and operating conditions were analysed. Results indicated that the friction model and the dynamic and thermodynamic model were reliable. The performance indicators of the LJEG depended on the input and operational parameters, and the most essential included the working fluid type, cycle pressure, valve timing, and electric load. The valve timing and electric load are optimised depending on preference between engine efficiency and power output. Operational parameter optimisation indicated that the efficiency decreased with extended expander intake duration but could improve with extended expander exhaust duration. Power output increased with longer expander intake duration; however, its relationship with compressor/expander diameter ratio (CER) depended on adopted expander exhaust duration. Substituting air with argon as the major working fluid resulted in over 60% improved indicated efficiency, and peak efficiencies of 40% and 60% are achieved with CER of 0.70 and 0.93, respectively. However, there could be a need for further fluid flow investigation; since the working volume of the expander and compressor is not fixed but could vary according to operation, and the fluid flow in the LJEG is pulsating

PARENTING STYLES OF IN-SCHOOL ADOLESCENTS IN SOUTH-EAST NIGERIA

The study investigated parenting styles of in-school adolescents in south-East, Nigeria. Three research questions were formulated to guide the study at .05 level of significance. The study adopted a survey research design. The population for the study consisted 137,095 in-school adolescents in secondary school in South East, Nigeria. The sample for the study was 1200 senior secondary school II adolescents. The instrument for data collection was a 53-item questionnaire. The instrument was validated by three experts, two from the department of educational foundations, and one from the department of science education, all from faculty of Education, University of Nigeria, Nsukka. Mean and standard deviation were used for data analysis. The study reveals, among others, that the parenting styles in-school adolescents were exposed to were authoritative, authoritarian and permissive. The study recommended, among others, that more school counselors should be employed and retained through in-service training programmes, capacity building workshops and refresher courses on adolescent value and moral upbringing.   Article visualizations

Performance evaluation of linear variable valve actuation for a linear engine generator

The Joule cycle Linear Engine Generator (LEG) is a promising power generation technology with the potential to achieve zero carbon emissions. However, the LEG expander valve actuation system presents unique challenges due to its lack of a traditional crankshaft, the need for swift valve lift and reversal, and variable lift. This paper presents a Linear Variable Valve Actuation (LVVA) system for a LEG prototype. The LVVA system is powered by voice coil motors. Rigorous experimental investigations were conducted to analyze crucial performance factors, including energy consumption, force balance, energy flow distribution, and the relationship between valve lift duration and energy consumption. The results show that the LVVA system can achieve the desired valve lift and timing, as well as very small variations in LEG performance compared to the model using an ideal lift curve. The LVVA accounts for approximately 3.59 % of the LEG power output. The energy consumption of 1.607 J per valve stroke provides a slight advantage over traditional actuation systems. The obtained optimal lift curves were used to refine the LEG model. The influence of valve lift curves on LEG performance was evaluated which reveals rapid valve openings and relatively short duration contributing to improved LEG performance

Industrial cluster energy systems integration and management tool

Critical for achieving the United Kingdom's net-zero targets, decarbonising industrial clusters would require robust tools to assess the feasibility of decarbonisation technologies and investment solutions. This paper presents an integrated energy system planning tool for decarbonising industrial clusters. The adoption of the transfer functions method enables the development of individual component models for technologies, networks, and loads, facilitating the control and simulation of complex dynamics in multi-energy system operation, as demonstrated in a case study investigating heat and power demands of a dynamic hybrid cluster, with evaluation of decarbonisation implications including heat electrification, renewables, and fuel switching in both grid-connected and island modes to establish potential pathways for decarbonisation. With the implementation of these decarbonisation measures in the case study cluster, primary energy demand, costs, emissions, and energy losses were reduced by 42%, 71%, 53%, and 72% in grid mode and by 40%, 70%, 53%, and 63% in island mode, and higher losses in island mode is due to excess heat production by electric boilers intended to consume all available power. While outcomes might differ among various clusters due to their specific features, the study cluster, characterised by substantial heat demand compared to electricity and significant electricity exports, achieves significant emission reduction via heat electrification compared to other individual decarbonisation technology. Moreover, this tool will be instrumental in helping industrial clusters formulate comprehensive decarbonisation roadmaps based on informed decisions

Principi di funzionamento di alcuni dispositivi per il monitoraggio domiciliare

La gestione e la continuità dell'assistenza si avvalgono fortemente del contributo delle tecnologie innovative come la Telemedicina per garantire l'attuazione di una modalità operativa a rete che integri i vari attori del percorso assistenziale(medici, paramedici, infermieri, tecnici) per la presa in carico globale dell' anziano o di una persona con patologie croniche come le malattie cardiovascolari, il diabete, le malattie respiratorie croniche

Evaluation of decarbonisation options for heritage church buildings

Heritage church buildings are significant energy consumers and carbon emitters, but hard to decarbonise due to construction materials and designs, which presents an imperative challenge for churches that have a mission to achieve net-zero targets by 2030. The study aims to provide a clear pathway for decarbonising heritage church buildings to support net-zero planning and evidence-based decisions. The methodology involved producing a virtual replica for each building to generate valuable insight into retrofit possibilities; exploring the potential of various decarbonisation interventions using dynamic modelling simulated with site data; comparing the interventions to the baselines in terms of energy, cost, and emissions; and tailoring decarbonisation solutions according to specific conditions. The results show that for small churches, replacing the gas boiler with another technology and using existing hydronic heating could be effective for low usage, whereas replacing the current heating system with heat pumps with PV offset would be more economical for high usage; on the other hand, for large churches, heat pumps or biomass could significantly reduce emissions. It is concluded that due to the unique characteristics of heritage church buildings, there is no one-size-fits-all solution but the uniform methodology proposed in this study could be applied to support evidence-based decisions for net-zero heritage buildings. The case studies contribute towards current knowledge and understanding. The work is original as it quantifies the benefits of various decarbonisation measures in 4 case studies of different ages, sizes, and usage patterns, representing a significant portion of heritage church buildings in England