Browsing by Author "Chowdhury, Jahedul Islam"
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Item Open Access Control of supercritical organic Rankine cycle based waste heat recovery system using conventional and fuzzy self-tuned PID controllers(Springer, 2019-08-19) Chowdhury, Jahedul Islam; Thornhill, David; Soulatiantork, Payam; Hu, Yukun; Balta-Ozkan, Nazmiye; Varga, Liz; Nguyen, Bao KhaThis research develops a supercritical organic Rankine cycle (ORC) based waste heat recovery (WHR) system for control system simulation. In supercritical ORC-WHR systems, the evaporator is a main contributor to the thermal inertia of the system, which is greatly affected by transient heat sources during operation. In order to capture the thermal inertia of the system and reduce the computation time in the simulation process, a fuzzy-based dynamic evaporator model was developed and integrated with other component models to provide a complete dynamic ORC-WHR model. This paper presents two control strategies for the ORC-WHR system: evaporator temperature control and expander output control, and two control algorithms: a conventional PID controller and a fuzzy-based self-tuning PID controller. The performances of the proposed controllers are tested for set point tracking and disturbance rejection ability in the presence of steady and transient thermal input conditions. The robustness of the proposed controllers is investigated with respect to various operating conditions. The results show that the fuzzy self-tuning PID controller outperformed the conventional PID controller in terms of set point tracking and disturbance rejection ability at all conditions encountered in the paper.Item Open Access Design optimization of supercritical carbon dioxide (s-CO2) cycles for waste heat recovery from marine engines(American Society of Mechanical Engineers, 2021-01-29) Hossain, Md. J.; Chowdhury, Jahedul Islam; Balta-Ozkan, Nazmiye; Asfand, Faisal; Saadon, Syamimi; Imran, MohammadThe global climate change challenge and the international commitment to reduce carbon emission can be addressed by improving energy conversion efficiency and adopting efficient waste heat recovery technologies. Supercritical carbon dioxide (s-CO2) cycles that offer a compact footprint and higher cycle efficiency are investigated in this study to utilize the waste heat of the exhaust gas from a marine diesel engine (Wärtsilä-18V50DF, 17.55 MW). Steady-state models of basic, recuperated and reheated s-CO2 Brayton cycles are developed and optimised for net work and thermal efficiency in Aspen Plus to simulate and compare their performances. Results show that the reheated cycle performs marginally better than the recuperated cycle accounting for the highest optimised net-work and thermal efficiency. For the reheated and recuperated cycle, the optimized net-work ranges from 648–2860 kW and 628–2852 kW respectively, while optimized thermal efficiency ranges are 15.2–36.3% and 14.8–35.6% respectively. Besides, an energy efficiency improvement of 6.3% is achievable when the engine is integrated with an s-CO2 waste heat recovery system which is operated by flue gas with a temperature of 373 °C and mass flow rate of 28.2 kg/s, compared to the engine without a heat recovery system.Item Open Access Feasibility study of biomass gasification integrated with reheating furnaces in steelmaking process(DEStech Publication Inc., 2019-11-04) Hu, Yukun; Chowdhury, Jahedul Islam; Katsaros, Giannis; Tan, C. K.; Balta-Ozkan, Nazmiye; Varga, Liz; Tassou, Savvas; Wang, ChunshengThis paper investigates the integration of biosyngas production, reheating furnace and heat recovery steam cycle, in order to use biosyngas directly as fuel in the furnace. A system model was developed to evaluate the feasibility of the proposed system from the perspective of heat and mass balance. To particularly study the impacts of fuel switching on the heating quality of the furnace, a three-dimensional furnace model considering detailed heat transfer processes was embedded into the system through an Aspen PlusTM user defined model. The simulation results show that biosyngas is suitable for direct use as fuel for reheating furnaces. Should CO capture be considered in the proposed system, it has a potential to achieve the capture without external energy input which results in so-called negative emissions of CO.Item Open Access Fuzzy nonlinear dynamic evaporator model in supercritical organic Rankine cycle waste heat recovery systems(MDPI, 2018-04-11) Chowdhury, Jahedul Islam; Nguyen, Bao Kha; Thornhill, David; Hu, Yukun; Soulatiantork, Payam; Balta-Ozkan, Nazmiye; Varga, LizThe organic Rankine cycle (ORC)-based waste heat recovery (WHR) system operating under a supercritical condition has a higher potential of thermal efficiency and work output than a traditional subcritical cycle. However, the operation of supercritical cycles is more challenging due to the high pressure in the system and transient behavior of waste heat sources from industrial and automotive engines that affect the performance of the system and the evaporator, which is the most crucial component of the ORC. To take the transient behavior into account, the dynamic model of the evaporator using renowned finite volume (FV) technique is developed in this paper. Although the FV model can capture the transient effects accurately, the model has a limitation for real-time control applications due to its time-intensive computation. To capture the transient effects and reduce the simulation time, a novel fuzzy-based nonlinear dynamic evaporator model is also developed and presented in this paper. The results show that the fuzzy-based model was able to capture the transient effects at a data fitness of over 90%, while it has potential to complete the simulation 700 times faster than the FV model. By integrating with other subcomponent models of the system, such as pump, expander, and condenser, the predicted system output and pressure have a mean average percentage error of 3.11% and 0.001%, respectively. These results suggest that the developed fuzzy-based evaporator and the overall ORC-WHR system can be used for transient simulations and to develop control strategies for real-time applications.Item Open Access A numerical thermal analysis of a battery pack in an electric motorbike application(MDPI, 2022-06-22) Shahjalal, Mohammad; Shams, Tamanna; Bin Hossain, Sadat; Kumar Roy, Probir; Alam Jion, Arafat; Ahsan, Mominul; Chowdhury, Jahedul Islam; Rishad Ahmed, Md; Bahauddin Alam, Syed; Haider, JulfikarToday, electric driven motorbikes (e-motorbikes) are facing multiple safety, functionality and operating challenges, particularly in hot climatic conditions. One of them is the increasing demand for efficient battery cooling to avoid the potential thermal stability concerns due to extreme temperatures and the conventional plastic enclosure of the battery pack. A reliable and efficient thermal design can be formulated by accommodating the battery within an appropriate battery housing supported by a cooling configuration. The proposed design includes a battery pack housing made of high conductive materials, such as copper (Cu) and aluminum (Al), with an adequate liquid cooling system. This study first proposes a potted cooling structure for the e-motorbike battery and numerical studies are carried out for a 72 V, 42 Ah battery pack for different ambient temperatures, casing materials, discharge rates, coolant types, and coolant temperatures. Results reveal that up to 53 °C is achievable with only the Cu battery housing material. Further temperature reduction is possible with the help of a liquid cooling system, and in this case, with the use of coolant temperature of 20 °C, the battery temperature can be maintained within 28 °C. The analysis also suggests that the proposed cooling system can keep a safe battery temperature up to a 5C rate. The design was also validated for different accelerated driving scenarios. The proposed conceptual design could be exploited in future e-motorbike battery cooling for optimum thermal stability.Item Open Access Optimising renewable energy integration in new housing developments with low carbon technologies(Elsevier, 2021-01-14) Gil, Gemma Oliver; Chowdhury, Jahedul Islam; Balta-Ozkan, Nazmiye; Hu, Yukun; Varga, Liz; Hart, PhilSince buildings account for more than one-third of final energy use, it is important to integrate renewable energy sources for new housing developments to reduce demand for grid energy and carbon emissions. This research investigates the potential of solar PV, energy storage, and electric vehicles in new housing developments and their associated grid impacts by taking the UK’s Cambridge, Milton Keynes, Oxford arc as a case study. Using published data on electrical loads for different types of dwellings, energy demands for new housing developments with and without renewable and low carbon technologies are analysed using techno-economic modelling frameworks. Technical analysis includes sizing and optimisation of PV and storage while economic analysis covers cost-benefit analyses, by considering a range of existing and future tariffs and subsidy schemes including Standard, Economy 7 (cheaper electricity for seven hours at night), Feed-in tariff, and the Smart Export Guarantee. Results show that installing PV panels and storage systems not only reduces the dwellings’ grid energy demand by 31% in January but also helps the dwellings to become net exporters of green electricity to the grid in July and hence saves a substantial amount of money by taking advantage of Feed-in and Economy 7 tariffs.Item Open Access Potentials of load-shifting with renewable energy storage: An environmental and economic assessment for the UK(US Association for Energy Econimics, 2018-09-26) Chowdhury, Jahedul Islam; Balta-Ozkan, Nazmiye; Goglio, Pietro; Hu, Yukun; Varga, Liz; McCabe, LeahThe Paris Agreement set targets to limit global warming to less than 2°C above the pre-industrial level to significantly reduce the risks and impacts associated with climate change [1]. Globally, the energy supply sector is responsible for 25% of greenhouse gas (GHG) emissions [2]. In addition to ratifying Paris Agreement, the UK government has adopted legally binding 80% emissions reduction target from 1990 levels by 2050 as outlined in Climate Change Act. The decarbonisation of power supply, along with electrification of heat and transport, are highlighted as key elements of this transition by both policy and academic research [3]–[5]. Storage systems, via the multiple services they offer across the electricity supply chain [6] at different operational scales stand to create system-wide benefits, enhanced flexibility and reliability for effective management of the grid [7]. The potential contributions storage systems can make towards minimizing the carbon intensity of UK grid with high levels of renewables is recognised by the government as well [8]. This study aims i) to determine the amount of load shifting that can be achieved by the combination of current renewable energy mainly wind and solar and UK grid level storage, ii) analyse the amount of renewable energy generation and storage (RES) needed to phase out programmable gas power generation during the periods of peak demand and iii) assess their economic and environmental implications. The environmental impacts considered are the life cycle emissions associated with electricity generation from the UK mix and the production, installation and use of batteries. The analysis will be extended to cover the future energy scenarios.Item Open Access Reducing industrial energy demand in the UK: A review of energy efficiency technologies and energy saving potential in selected sectors(Elsevier, 2018-07-26) Chowdhury, Jahedul Islam; Hu, Yukun; Haltas, Ismail; Balta-Ozkan, Nazmiye; Matthew, George Jr.; Varga, LizCurrently UK industrial and manufacturing sectors are facing dual challenges of contributing to national 80% reduction targets in CO2 emissions by 2050 (compared to 1990 levels) and improving economic competitiveness in the face of low cost imports. Since energy consumption is the main source of CO2 emissions and directly related to products being manufactured, improving energy efficiency in energy intensive sectors is key to achieve CO2 targets. Energy consumption is unlikely to meet the targets unless energy efficiency opportunities and technologies are fully explored and timely changes are made to business models and policies This study explores potential energy efficiency improvements from three perspectives: system efficiency of steam networks, waste heat recovery technologies and bioenergy/waste utilisation. Two UK energy-intensive sectors, iron and steel, and food and drink, are selected for analysis and discussion. Potential business models for energy efficiency are also reviewed as there are now a variety of energy service companies who can support adoption of appropriate technologies. Furthermore, drivers and barriers to the adoption of energy efficiency technologies are considered in this paper revealing the factors affecting the diffusion of energy efficient and waste heat recovery technologies and their interactions and interdependencies to energy consumptions. Findings show that it is possible to achieve energy consumption reduction in excess of 15% from a technical point of view, however improving energy efficiency in UK industry has been hindered due to some inter-related technical, economic, regulatory and social barriers. The findings help to demonstrate the significant potential for energy efficiency improvement in two industrial sectors, as well as showing the specific types of technologies relevant for different sectoral processes. The range of business models show opportunities for implementation and for developing innovative business models, addressing barriers, and using enablers to accelerate the diffusion of energy efficiency technologies in UK industry.Item Open Access System integration study of oxy-biosyngas combustion based metal heating process using Aspen Plus(ICAE, 2020-12-10) Hu, Yukun; Chowdhury, Jahedul Islam; Katsaros, Giannis; Balta-Ozkan, Nazmiye; Varga, Liz; Li, Kang; Tassou, Savvas; Wang, ChunshengGiven the increasing concerns on emissions, efficient and environmentally friendly combustion technologies are urgently needed to address energy trilemma. Metal heating is a large component of energy-intensive processes, as its energy consumption accounts for one third of the steel manufacturing process. Early attempts at using a new flameless oxy-fuel combustion burner give high performance, low NOx, and low-cost heating for the steel industry, while biosyngas is considered as an alternative fuel for reheating furnace with aiming at CO2 mitigation. Yet, all these technical solutions are developed in isolation. This paper investigates the system integration of biosyngas production, air separation unit (ASU), reheating furnace and heat recovery (HR) steam cycle, in order to enhance energy efficiency of steel industry and enable so-called negative emissions. An integrated system model was developed using Aspen Plus to evaluate the feasibility of the proposed integration from the perspective of heat and mass balance. In particular, to study the impacts of fuel switching on the heating quality of the furnace, a three-dimensional furnace model considering detailed heat transfer processes was embedded into the system. The simulation results show that the proposed system integration strategy is technically feasible. The electricity generation of the HR steam cycle used can compensate for about 90% of ASU’s energy consumption. The system is carbon capture-ready for being further integrated with CO2 conditioning and transportation processesItem Open Access Techno-economic assessment of waste heat recovery technologies for the food processing industry(MDPI, 2020-12-05) Mukherjee, Sanjay; Asthana, Abhishek; Howarth, Martin; Chowdhury, Jahedul IslamThe food manufacturing sector is one of the most dominant consumers of energy across the globe. Food processing methods such as drying, baking, frying, malting, roasting, etc. rely heavily on the heat released from burning fossil fuels, mainly natural gas or propane. Less than half of this heat contributes to the actual processing of the product and the remaining is released to the surroundings as waste heat, primarily through exhaust gases at 150 to 250 °C. Recovering this waste heat can deliver significant fuel, cost and CO2 savings. However, selecting an appropriate sink for this waste heat is challenging due to the relatively low source temperature. This study investigates a novel application of gas-to-air low temperature waste heat recovery technology for a confectionary manufacturing process, through a range of experiments. The recovered heat is used to preheat a baking oven’s combustion air at inlet before it enters the fuel-air mixture. The investigated technology is compared with other waste heat recovery schemes involving Regenerative Organic Rankine Cycles (RORC), Vapour Absorption Refrigeration (VAR) and hot water production. The findings indicate that utilising an oven’s exhaust gases to preheat combustion air can deliver up to 33% fuel savings, provided a sufficiently large heat sink in the form of oven combustion air is available. Due to a lower investment cost, the technology also offers a payback period of only 1.57 years, which makes it financially attractive when compared to others. The studied waste heat recovery technologies can deliver a CO2 savings of 28–356 tonnes per year from a single manufacturing site. The modelling and comparison methodology, observations and outcomes of this study can be extended to a variety of low temperature food manufacturing processes.Item Open Access Techno-economic optimisation of battery storage for grid-level energy services using curtailed energy from wind(Elsevier, 2021-05-15) Rayit, Narinderjeet Singh; Chowdhury, Jahedul Islam; Balta-Ozkan, NazmiyeThe increasing integration of renewable energy sources makes balancing an electricity grid challenging due to their intermittency. Renewable energy can be curtailed especially when production exceeds demand or when there are transmission and/or distribution network congestions within a grid. However, curtailment would become unnecessary with battery storage, provided the battery storage has enough available storage capacity, which can store energy during the time of excess generation and in turn discharge it to the grid once the demand is high during peak times. Hence, stored energy from batteries can potentially offset supply from expensive and environmentally harmful peak plants e.g. open/combined cycle gas turbine. We investigated the techno-economic prospects of the utilisation of curtailed energy from the wind with bulk battery storage to replace open and combined cycle gas turbine power plants, by taking the UK as a case study. A techno-economic model to size and optimise a Li-ion type battery was developed. The optimisation aimed to determine at what cost and size the storage can be commercially viable for grid-level energy applications. Results show that under base case assumptions of a 15% day to day curtailment from wind and £200/kWh battery cost, an optimised battery size of 1.25 GWh could supply 285 GWh peak demand per annum and its corresponding net present value of £22.4m, internal rate of return of 1.7% and a payback period of 14 years could be achieved. However, to achieve the internal rate of return of 8%, a minimum hurdle rate for investment, the cost of battery would need to be below £150/kWh. Sensitivity analysis with parameters such as curtailed wind, depth of discharge, battery efficiency, and cost and income of battery shows that all techno-economic parameters considered in this research have a significant impact on the commercial viability of battery storage for grid applications.Item Open Access Techno-environmental analysis of battery storage for grid level energy services(Elsevier, 2020-06-10) Chowdhury, Jahedul Islam; Balta-Ozkan, Nazmiye; Goglio, Pietro; Hu, Yukun; Varga, Liz; McCabe, LeahWith more and more renewable energy sources (RES) going into power grids, the balancing of supply and demand during peak times will be a growing challenge due to the inherent intermittency and unpredictable nature of RES. Grid level batteries can store energy when there is excess generation from wind and solar and discharge it to meet variable peak demand that is currently supplied by combined cycle gas turbine (CCGT) plants in the UK. This paper assesses the potential of battery storage to replace CCGT in responding to variable peak demand for current and future energy scenarios (FES) in the UK from technical and environmental perspectives. Results from technical analysis show that batteries, assuming size is optimised for different supply and demand scenarios proposed by the National Grid, are able to supply 6.04%, 13.5% and 29.1% of the total variable peak demand in 2016, 2020 and 2035, respectively while CCGT plants supply the rest of the demand. Particularly, to phase out CCGT variable generation from the UK grid in 2035, electricity supply from wind and solar needs to increase by 1.33 times their predicted supply in National Grid’s FES. The environmental implications of replacing CCGT by batteries are studied and compared through a simplified life cycle assessment (LCA). Results from LCA studies show that if batteries are used in place of CCGT, it can reduce up to 87% of greenhouse gas emissions and that is an estimated 1.98 MtCO2 eq. for an optimal supply, 29.1%, of variable peak demand in 2035Item Open Access Waste heat recovery integration options for commercial bakeries in a thermo-economic-environmental perspective(Elsevier, 2023-11-11) Chowdhury, Jahedul Islam; Asfand, Faisal; Ja’fari, Mohammad; Mukherjee, Sanjay; Balta-Ozkan, NazmiyeIn commercial bakeries, a substantial amount of heat is exhausted which is not only a waste of useful resource, but also contributes to higher fuel consumption and carbon emissions, if not recovered. In this study, waste heat from a single oven is considered and five potential heat recovery options are investigated in a techno-economic-environmental perspective to provide essential results for integrating an appropriate technology for waste heat recovery in the commercial bakeries sector. Waste heat recovery options were selected considering the temperature profile, the waste heat source, quality and quantity of heat and the heat energy demand for the various processes in commercial bakeries. Thermodynamic, economic, and environmental models are developed to assess the heat recovery performance, cost savings and emission reduction at both design and off-design conditions. Results show that up to 286 kW of waste heat can be recovered and reused in the case of air pre-heater, which can save up to 161.93 t/year of natural gas and an equivalent cost and emission savings of $ 93,594/year and 412.5 tCO2e/year, respectively. Moreover, the earliest payback period of 0.77 years was estimated for the air pre-heater option with an estimated capital investment cost of $71,631, whereas a maximum payback period of 4.59 years was estimated for the electricity generation by the organic Rankine cycle having an estimated capital investment cost of $304,040. These results reveal that air preheating is the most energy-efficient and cost-effective option to recover the waste heat from the ovens in the bakery industry.