PhD Thesis - Energy Systems Research Unit - University of Strathclyde

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a system for the sustainable production of energy for India for the year 2020 by minimising the cost/efficiency ratio within the bounds of social acceptance, reliability, demand, and potential supply. This model, however, looks at the energy requirements for the year as a whole, and does not take into account the variable nature of the intermittent supply technologies. It can, therefore, not be used to aid decisions about the suitable type and sizing of storage devices or auxiliary plant that may be required. Another system, RETScreen [13], has been developed for the Canadian government. This is an Excel spreadsheet based model, which can be used worldwide to evaluate the energy production, life-cycle costs, and greenhouse gas emissions reductions for various single renewable energy technologies. These technologies include wind, PV, biomass heating, solar water and air heating, small-scale hydro, passive solar heating, and the use of ground source heat pumps. These models provide a good in-depth technical and economic assessment of these technologies used on their own, but do not consider the integration of these systems and, again, deal with annual energy requirements only. Ramakumar et al. [14,15] describe the use of the IRES-KB system to allow the technical analysis of potential renewable energy supply systems for remote areas. Demands for electricity, heat and mechanical power are considered, and these may be met by biogas from digested biomass, solar-thermal energy, hydropower, wind turbines, and PV panels. The year is split up into seasons, each of which is characterised by a set of daily demands and available resources. This information is input as energy needs per day for refrigeration, cooking, lighting etc, and as available wood and crop residues, volume of falling water, and a choice of pre-programmed cloud cover and wind regimes. These demands and supplies are split up throughout the day in hourly intervals, and some variability is added to the intermittent supplies through the cloud cover and wind regimes chosen, in order to analyse the required storage and reserve plant sizes. This system provides a good seasonal evaluation of the energy supplies and demands of an area, however, it lacks the more in-depth temporal analysis that would be necessary when considering more complex systems. 72
There are various models available which allow the analysis of different aspects of bioenergy system design [16]. For example, BEAM [17] is a spreadsheetbased decision support system that allows the easy technical and economic evaluation of integrated biomass to electricity systems. This is done by splitting the process into three different stages – the production of various feedstocks (biomass and waste), the conversion of these into a suitable energy carrier via gasification, pyrolysis, fermentation or combustion, and the generation of electricity via gas or steam turbines, internal combustion or diesel engines. BEAM allows the user to look at the overall planning issues related to the type, siting, number and sizing of biomass plant by permitting the comparison of the relative cost of different feedstock types, supply strategies, and generating methods. A similar analysis may be carried out with the BIOPOWER program [18], where the cost of power generation from a similar range of fuels and power technologies may be compared. These models, however, are complex, and require data that is not easily available. Another system, Biomass Toolkit [19] provides a group of programs that make up a diagnostic tool for the assessment of bioenergy projects at a local or regional level. This gives an assessment of biomass resource availability, a technical and economic evaluation allowing selection of the most appropriate conversion technologies, and an assessment of the environmental impact, acceptability and other non-technical factors for proposed projects. Some consideration is also given here to the time dependant output of crops and their by-products. These programs all look at the use of biomass and waste technologies on their own, and are useful when considering the comparative merits of different biomass and waste related energy systems, and the overall planning issues involved, when this is the only technology being considered. A similar program, MODEST [20] allows the optimisation of dynamic energy systems that have time dependant components and boundary conditions, in order to minimize life cycle costs. This program is capable of considering demands for electricity and heat, and divides the year into seasons, and each season into chosen time periods, in order to find the best operation profile to meet the heat 73
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Decision Support for New and Renewa
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Abstract The global requirement for
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CONTENTS 1 ENERGY SYSTEMS FOR SUSTA
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5.5 Steam Turbine Model 149 5.6 Fue
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FIGURES Figure 1.1 Final Energy Con
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Figure 7.30 Following Electricity a
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on the use of fossil fuels, energy
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The general increase in energy cons
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supply is reduced or eliminated, lo
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Figure 1.3 The Electricity Supply G
Page 21 and 22: on different generation mixes depen
Page 23 and 24: Various studies have been carried o
Page 25 and 26: provision for smaller areas, and he
Page 27 and 28: 1.7 References [1] The Internationa
Page 29 and 30: 2 Options for New and Renewable Ene
Page 31 and 32: the amount of usable heat that is g
Page 33 and 34: the conversion of petrol cars; howe
Page 35 and 36: set times, producing a constant ele
Page 37 and 38: partial load. Fast response and sta
Page 39 and 40: 2.3 The Production and Storage of H
Page 41 and 42: dedicated boiler, which runs contin
Page 43 and 44: Figure 2.3 A Typical Hydrogen Filli
Page 45 and 46: part of the natural carbon cycle (a
Page 47 and 48: Figure 2.4 Layout of a Gasification
Page 49 and 50: met by process integration and the
Page 51 and 52: Figure 2.5 The Inputs and Outputs o
Page 53 and 54: 1. Scale for measuring out lye and
Page 55 and 56: feedstock being used. Sugary feedst
Page 57 and 58: carbon dioxide via steam reforming.
Page 59 and 60: • Where CHP is used, the balance
Page 61 and 62: [22] Vehicle Certification Agency (
Page 63 and 64: [55] M. A. Paisley, J. M. Irving, R
Page 65 and 66: 3 Approaches to Renewable Energy Sy
Page 67 and 68: Because of the intermittent nature
Page 69 and 70: A renewable energy supply evaluatio
Page 71: the system are kept. The output of
Page 75 and 76: When the use of climate dependant i
Page 77 and 78: 3.5 References [1] M. Muselli, G. N
Page 79 and 80: 4 A Procedure for Demand and Supply
Page 81 and 82: pumped storage and flywheels), a ba
Page 83 and 84: for the agricultural vehicle use re
Page 85 and 86: Figure 4.4 Combining Demands to Tak
Page 87 and 88: ates for vehicles, engines and othe
Page 89 and 90: Figure 4.5 Derived Fuel Production
Page 91 and 92: together if desired, and taken forw
Page 93 and 94: profiles are output from this part
Page 95 and 96: dividing the production rate at eac
Page 97 and 98: As it would be too confusing to sho
Page 99 and 100: Figure 4.12 Output of the Matching
Page 101 and 102: However, when more than one transpo
Page 103 and 104: considered, this amount is added to
Page 105 and 106: users are alerted if there is not e
Page 107 and 108: at the matching stage, along with t
Page 109 and 110: vehicles if they are increased by 1
Page 111 and 112: If biogas is being considered, the
Page 113 and 114: The number of timesteps per hour wi
Page 115 and 116: After the algorithm has been follow
Page 117 and 118: • Float Charge - once the battery
Page 119 and 120: Discharge No tank = tank fuel used
Page 121 and 122: equired (kW) = maxkWh x bulk% (5.16
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An example of the output graph prod
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5.2.1 Required Power Specifically d
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5.2.3 Engine Performance in the Con
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used for gas powered ICEs, but the
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and five times, depending on the nu
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Is PL < Min ? No Is PL = 0 ? No Is
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where Max = maximum energy availabl
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where Ratiopart = heat to electrici
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(including following heat demand wh
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where SFC = specific fuel consumpti
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engines running respectively). If t
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(continued) Is Fuel Available > (4
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of the definition window for a Stir
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and continuous operation. Again, mu
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The performance of a fuel cell is n
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percentage loading, rather than usi
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Is Min = 0 ? No Is Min = PC1 ? No I
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5.6.4 If Fuel Availability is Less
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5.7 Electrolyser Model An electroly
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original calculation of the amount
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5.8 Regenerative Fuel Cell Model A
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following the heat demand. To follo
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C:\ My Documents\ Nic\ Thesis\ Old\
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As 1 kWh = 3610.3 kJ, and using lit
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Add Heat to Water Storage Tank Usin
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Use Stored Hot Water to Supply Heat
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information is given about the over
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[23] K. Foger, B. Godfrey, “Syste
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the gasification and pyrolysis defi
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eing used each day for a continuous
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Where Biogas = Biogas production ra
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6.1.3 Use of Biogas Various options
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The amount of hydrogen that can be
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direct proportion, and the weight o
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produce in total (Nm 3 per tonne fe
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Electricity (kW) = Elec x Feed (6.1
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3. Make hydrogen via steam reformin
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Where Methane = Methane Production
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(continued) Keep as medium heating
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Yes Feed1 = Yield1 x Land1 / No. of
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production and energy use profiles
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If it is the last timestep of the p
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For each process, the process chara
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At the end of the simulation, graph
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As the time required for one batch
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Ethanol = Factor1 x Eth x Timesteps
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6.5 Electrolysis As it is sometimes
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6.7 Landfill Gas Processing As the
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Demand Profile Design & Profile Dat
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Figure 7.2 Degree-Days Versus Month
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Stage 1 - Sustainable Fuel Supply S
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The different profile of use graphs
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Figure 7.3 Fermentation System Inpu
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Figure 7.7 Fermentation System Info
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Figure 7.10 Fermentation System Out
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The output obtained when a second h
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Figure 7.16 Anaerobic Digestion Par
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Figure 7.19 Fermentation System Inp
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clarity. A constant supply rate of
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Figure 7.25 Heat Demand Profile Fig
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Figure 7.28 Effect of Minimum Load
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esidual heat demand as this would r
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Figure 7.35 Second Engine: Followin
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This chapter described how the over
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heat and electricity during the tou
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Figure 8.2: Overall Yearly Heat Dem
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to allow for efficient operation du
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would be incurred, and the scale of
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Figure 8.5: Electricity Supply and
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heat demand or both, or run at cons
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ut with 30% less land being require
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9 Conclusions and Recommendations T
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through these, technically viable p
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considered. The introduction of coo
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When considering larger geographica
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Appendix 1: Program Windows Figure
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Figure A1.5 CreateClimate.exe Figur
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Figure A1.9: Demand Profile Designe
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Figure A1.13: Derived Fuel Supply W
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Figure A1.17: Fermentation System D
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Figure A1.21: PV Electrolysis Syste
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Figure A1.25: Fuel Supply Profile D
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Figure A1.29: Auxilliary Supply Def
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Figure A1.33: Stirling Engine Syste
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Figure A1.37: Fuel Cell System Defi
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Figure A1.41: Electric Vehicle Syst
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Figure A1.45: Vehicle Conversion Fa
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Figure A1.49: Heating System Defini
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Figure A1.53: Pumped Hydro System D
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Figure A1.57: Auto Search Evaluatio
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PhD Thesis - Energy Systems Research Unit - University of Strathclyde

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