Data science to investigate temperature profiles of large networks of food refrigeration systems

The electrical generation and transmission infrastructures of many countries are under increased pressure. This partially reflects the move towards low carbon economies and the increased reliance on renewable power generation systems. There has been a reduction in the use of traditional fossil fuel generation systems, which provide a stable base load, and this has been replaced with more unpredictable renewable generation. As a consequence, the available load on the grid is becoming more unstable. To cope with this variability, the UK National Grid has placed emphasis on the investigation of various technical mechanisms (e.g. implementation of smart grids, energy storage technologies, auxiliary power sources, Demand Side Response (DSR)), which may be able to prevent critical situations, when the grid may become sometimes unstable. The successful implementation of these mechanisms may require large numbers of electrical consumers (e.g. HVAC systems, food refrigeration systems) for example to make additional investments in energy storage technologies (i.e. food refrigeration systems) or to integrate their electrical demand from industrial processes into the National Grid (i.e. HVAC systems). However, for food refrigeration systems, during these critical situations, even if the thermal inertia within refrigeration systems may maintain effective performance of the device for a short period of time (e.g. under 1 minute) when the electrical input load into the system is reduced, this still carries the paramount risk of food safety even for very short periods of time (e.g. 1 under minute). Therefore before considering any future actions (e.g. investing in energy storage technologies) to prevent the critical situations when grid becomes unstable, it is also needed to understand during the normal use how the temperature profiles evolve along the time inside these massive networks of food refrigeration systems during either shorter (i.e. minutes) or longer periods of time (i.e. days, months) and this paper presents this.

Data Analysis and Symbolic Regression Models for Predicting CO and NOx Emissions from Gas Turbines

Predictive emission monitoring systems (PEMS) are software solutions for the validation and supplementation of costly continuous emission monitoring systems for natural gas electrical generation turbines. The basis of PEMS is that of predictive models trained on past data to estimate emission components. The gas turbine process dataset from the University of California at Irvine open data repository has initiated a challenge of sorts to investigate the quality of models of various machine learning methods to build a model for predicting CO and NOx emissions depending on ambient variables and the parameters of the technological process. The novelty and features of this paper are: (i) a contribution to the study of the features of the open dataset on CO and NOx emissions for gas turbines, which will enable one to more objectively compare different machine learning methods for further research; (ii) for the first time for the CO and NOx emissions, a model based on symbolic regression and a genetic algorithm is presented—the advantage of this being the transparency of the influence of factors and the interpretability of the model; (iii) a new classification model based on the symbolic regression model and fuzzy inference system is proposed. The coefficients of determination of the developed models are: R2=0.83 for NOx emissions, R2=0.89 for CO emissions.

Combined Cycle Powerplant Cost Sensitivity Analysis

In Gas turbine-based combined cycle power plant market, the customer conducts an economic evaluation of competitive products to decide their buying option. There are different methods to calculate the economics of a power plant like Levelized cost of electricity (LCOE), Net present value (NPV) and payback period. LCOE methodology is commonly used for lifecycle cost analyses for combine cycle power plant that covers cost details of the plant and plant performance over the complete lifetime of a power plant from construction to retiring. Typically, it includes a combine cycle power plant ownership costs (Total plant cost and operating & maintenance cost) and combine cycle power output and efficiency. This LCOE method is helpful to compare power generation system that use similar technologies. This paper encompasses the LCOE calculation method, assumptions & approach to analyze the impact of key parameters of the electrical generation cost. They key parameters includes combine cycle output, combine cycle efficiency, fuel cost, annual operating hours, capital charge factor, annual operating hours, power plant life, discount rate, nominal escalation rate, operating & maintenance cost. This paper analyses result will provide insights to the customer & Gas turbine-based OEM (Own Equipment Manufacturing) companies to focus on different area/parameters to reduce the unit cost of generating electricity.

Conceptual Process Design, Energy and Economic Analysis of Solid Waste to Hydrocarbon Fuels via Thermochemical Processes

Thermochemical processes use heat and series of endothermic chemical reactions that achieve thermal cracking and convert a wide range of solid waste deposits via four thermochemical processes to hydrocarbon gaseous and liquid products such as syngas, gasoline, and diesel. The four thermochemical reactions investigated in this research article are: incineration, pyrolysis, gasification, and integrated gasification combined cycle (IGCC). The mentioned thermochemical processes are evaluated for energy recovery pathways and environmental footprint based on conceptual design and Aspen HYSYS energy simulation. This paper also provides conceptual process design for four thermochemical processes as well as process evaluation and techno-economic analysis (TEA) including energy consumption, process optimization, product yield calculations, electricity generation and expected net revenue per tonne of feedstock. The techno-economic analysis provides results for large scale thermochemical process technologies at an industrial level and key performance indicators (KPIs) including greenhouse gaseous emissions, capital and operational costs per tonne, electrical generation per tonne for the four mentioned thermochemical processes.

Palm Oil Fuel Ash-Based Eco-Friendly Concrete Composite: A Critical Review of the Long-Term Properties

Rapid global infrastructural developments and advanced material science, amongst other factors, have escalated the demand for concrete. Cement, which is an integral part of concrete, binds the various individual solid materials to form a cohesive mass. Its production to a large extent emits many tons of greenhouse gases, with nearly 10% of global carbon (IV) oxide (CO2) emanating from cement production. This, coupled with an increase in the advocacy for environmental sustainability, has led to the development of various innovative solutions and supplementary cementitious materials. These aims to substantially reduce the overall volume of cement required in concrete and to meet the consistently increasing demand for concrete, which is projected to increase as a result of rapid construction and infrastructural development trends. Palm oil fuel ash (POFA), an industrial byproduct that is a result of the incineration of palm oil wastes due to electrical generation in power plants has unique properties, as it is a very reactive materials with robust pozzolanic tendencies, and which exhibits adequate micro-filling capabilities. In this study, a review on the material sources, affecting factors, and durability characteristics of POFA are carefully appraised. Moreover, in this study, a review of correlated literature with a broad spectrum of insights into the likely utilization of POFA-based eco-friendly concrete composites as a green material for the present construction of modern buildings is presented.

Experimental investigations of a new concept of wave energy converter hybridizing piezoelectric and dielectric elastomer generators

A novel concept of a surge wave energy converter for nearshore applications is investigated experimentally. The centimetre-sized prototype developed in this work represents a proof of concept of a submerged system, which entails a hybrid transduction solution for the electrical conversion of wave energy, that uses piezoelectric elements (PZEs) and dielectric elastomer generators (DEG). The idea is to exploit the horizontal pressure gradient and horizontal water velocity underneath the waves to compress the PZE and inflate each half wave period a soft variable capacitance, which composes the DEG. The electrical charges created by the PZE are used to polarize the DEG, which is able to multiply the input energy. This hybridization is conceived to allow the system to generate electrical energy from waves without conventional high voltage supplies, thus reducing production costs and allowing standalone clean electrical generation. The article provides the preliminary fluid-mechanical measurements performed in a wave flume with a first version of the prototype and supported by a model comprising the fluid/structure interaction, the materials response, and the electrical operations. An estimation of the output energy of a small-sized prototype in constant charge mode is computed, and perspectives for optimizing the system are presented.

Hope or hype: A critical assessment of Jatropha curcas for domestic biofuel production in Senegal

<p>This thesis was designed to critically test the suitability of Jatropha curcas as a plant feedstock for liquid biofuel production in Senegal. Many countries around the globe have attempted to incorporate bioenergy into their broader energy supply mix, and liquid biofuels are a key component of a low-carbon economy to replace fossil fuels for transport and electrical generation. The Senegalese government instituted a national biofuel plan between 2007 and 2012 to achieve energy independence through biofuels with an annual production target of more than a billion liters of oil. The plan was intended to reduce problems with energy scarcity and price fluctuations, contribute to local economic growth, and expand agricultural production to degraded or otherwise fallow land. The project was largely unsuccessful, and to date there has been no significant oil production from Jatropha curcas for the national energy supply. This research study was developed to understand the key barriers to the success of this program and mitigate the mistakes of future project developers and policymakers. Preliminary literature reviews and examples from similar endeavors in other countries suggested three main barriers that would be primary determinants of success or failure: the agronomic suitability, and therefore production and yield capacity, of Jatropha curcas to the Senegalese climate; the socio-economic challenges of integrating a broad national plan with smallholder farmers and assuring that the economics are fair for both growers and buyers; and the policy framework developed by government agencies, development organizations, and commercial interests to support an emergent biofuel industry. A mixed-method research design including document reviews, interviews and surveys, and case studies was employed to answer the key questions of why and how the Senegalese biofuel program has failed to achieve its intended goals. Results from this study indicate that Jatropha curcas is unsuitable as a plant feedstock for liquid biofuels in Senegal at this time, due to significant shortcomings in all three key categories examined. The plant is vastly underproductive and requires considerable investment in scientific improvement of yield, pest tolerance and seed oil content; the economic gain is neither adequate to justify smallholder farmers to adopt it as an alternative to existing crops nor for project developers to generate income from fuel on the open market; and supporting policy has not been consistent or favorable enough to carry this emergent industry from nascence to maturity. There are, however, encouraging signs of resilience in two particular case studies that provide insight into how future programs could be structured, most notably in the Sine-Saloum Delta region. Further research should be devoted to specific economic schemes and innovative financing options for community focused biofuel programs.</p>

Hope or hype: A critical assessment of Jatropha curcas for domestic biofuel production in Senegal

<p>This thesis was designed to critically test the suitability of Jatropha curcas as a plant feedstock for liquid biofuel production in Senegal. Many countries around the globe have attempted to incorporate bioenergy into their broader energy supply mix, and liquid biofuels are a key component of a low-carbon economy to replace fossil fuels for transport and electrical generation. The Senegalese government instituted a national biofuel plan between 2007 and 2012 to achieve energy independence through biofuels with an annual production target of more than a billion liters of oil. The plan was intended to reduce problems with energy scarcity and price fluctuations, contribute to local economic growth, and expand agricultural production to degraded or otherwise fallow land. The project was largely unsuccessful, and to date there has been no significant oil production from Jatropha curcas for the national energy supply. This research study was developed to understand the key barriers to the success of this program and mitigate the mistakes of future project developers and policymakers. Preliminary literature reviews and examples from similar endeavors in other countries suggested three main barriers that would be primary determinants of success or failure: the agronomic suitability, and therefore production and yield capacity, of Jatropha curcas to the Senegalese climate; the socio-economic challenges of integrating a broad national plan with smallholder farmers and assuring that the economics are fair for both growers and buyers; and the policy framework developed by government agencies, development organizations, and commercial interests to support an emergent biofuel industry. A mixed-method research design including document reviews, interviews and surveys, and case studies was employed to answer the key questions of why and how the Senegalese biofuel program has failed to achieve its intended goals. Results from this study indicate that Jatropha curcas is unsuitable as a plant feedstock for liquid biofuels in Senegal at this time, due to significant shortcomings in all three key categories examined. The plant is vastly underproductive and requires considerable investment in scientific improvement of yield, pest tolerance and seed oil content; the economic gain is neither adequate to justify smallholder farmers to adopt it as an alternative to existing crops nor for project developers to generate income from fuel on the open market; and supporting policy has not been consistent or favorable enough to carry this emergent industry from nascence to maturity. There are, however, encouraging signs of resilience in two particular case studies that provide insight into how future programs could be structured, most notably in the Sine-Saloum Delta region. Further research should be devoted to specific economic schemes and innovative financing options for community focused biofuel programs.</p>