The present work is a contribution towards the integration of building simulation tools in order to better represent the complexity of the real world. It attempts to overcome certain shortfalls of contemporary simulation applications with respect to indoor air flows. As a result, the evaluation of building energy consumption and indoor air quality is expected to be improved. Advanced fluid flow models (as employed within Building Thermal Simulation - BTS - and Computational Fluid Dynamics - CFD) with different degrees of detail were investigated and their modelling deficiencies identified. The CFD technique which defines the fluid flow on a micro scale was integrated into BTS in which fluid flow is described in a larger scale. The resulting combined approach strengthens the modelling potential of each methodology by overcoming their specific deficiencies. BTS's inability to predict air flow property gradients within a single space was surmounted and the difficult of estimating CFD boundary conditions are now supplied by BTS. The conflation approach is expected to be employed where gradients of indoor air flow properties can be considered crucial to the evaluation of thermal comfort and energy consumption. The BTS environment, ESP-r, was elected to perform the current work and a new CFD program, dfs, was specifically developed for the analysis of three-dimensional, turbulent, transient air flow. Finally, the two approaches were integrated. The integration work focuses on the CFD boundary conditions where the interactions of BTS and CFD take place; these occur at the inside zone surfaces and at the zone openings. Three conflation approaches were devised addressing different degrees of complexity and sophistication. The first one, involving the two types of zone boundaries, corresponds to a simple approach where the BTS and CFD systems exchange information without any direct interaction. The second approach consists of three other schemes to handle the thermal coupling at the internal zone surfaces. The third approach comprises coupling between the nodal network approach as employed by the BTS environment, and the continuity and momentum equations in the CFD technique. A validation methodology consisting of analytical validation, intermodel comparison and empirical validation is described and applied. The technique is shown to be adequate for modelling indoor air flows when compared to existing models. Three situations, covering the different types of air flows encountered within buildings are discussed to demonstrate the combined method's applicability when compared with the nodal network approach. Finally, general conclusions are presented and some possible future work is identified showing that the developed methodology is very promising.

This thesis investigates the modelling of drying processes for the promotion of market-led Demand Side Management (DSM) as applied to the UK Public Electricity Suppliers. A review of DSM in the electricity supply industry is provided, together with a discussion of the relevant drivers supporting market-led DSM and energy services (ES). The potential opportunities for ES in a fully deregulated energy market are outlined. It is suggested that targeted industrial sector energy efficiency schemes offer significant opportunity for long term customer and supplier benefit. On a process level, industrial drying is highlighted as offering significant scope for the application of energy services. Drying is an energy-intensive process used widely throughout industry. The results of an energy survey suggest that 17.7 per cent of total UK industrial energy use derives from drying processes. Comparison with published work indicates that energy use for drying shows an increasing trend against a background of reducing overall industrial energy use. Airless drying is highlighted as offering potential energy saving and production benefits to industry. To this end, a comprehensive review of the novel airless drying technology and its background theory is made. Advantages and disadvantages of airless operation are defined and the limited market penetration of airless drying is identified, as are the key opportunities for energy saving. Limited literature has been found which details the modelling of energy use for airless drying. A review of drying theory and previous modelling work is made in an attempt to model energy consumption for drying processes. The history of drying models is presented as well as a discussion of the different approaches taken and their relative merits. The viability of deriving energy use from empirical drying data is examined. Adaptive neuro fuzzy inference systems (ANFIS) are successfully applied to the modelling of drying rates for 3 drying technologies, namely convective air, heat pump and airless drying. The ANFIS systems are then integrated into a novel energy services model for the prediction of relative drying times, energy cost and atmospheric carbon dioxide emission levels. The author believes that this work constitutes the first to use fuzzy systems for the modelling of drying performance as an energy services approach to DSM. To gain an insight into the 'real world' use of energy for drying, this thesis presents a unique first-order energy audit of every ceramic sanitaryware manufacturing site in the UK. Previously unknown patterns of energy use are highlighted. Supplementary comments on the timing and use of drying systems are also made. The limitations of such large scope energy surveys are discussed.

Certain features of dynamic models of energy demand based on the economic theory of production are examined. Attention is mainly confined to first and third generation dynamic models. First generation models are partial adjustment models where energy Is treated largely in isolation from other inputs. Third generation models are based explicitly on dynamic economic optimization, incorporating the notion of costs of adjustment for quasi-fixed inputs. The analysis focusses on three main issues. The first is the characteristics of first generation models and how these models can be extended to the industrial sector. The second is the nature and empirical significance of alternative definitions of third generation models according to whether adjustment costs are treated as a function of net or gross investment. The third issue is whether first and third generation models are generically related and, if so, how. The work on first generation models is mainly confined to the Balestra-Nerlove framework. This specification generally has been applied to individual fuels in the residential/commercial sector but is also applied to aggregate residentidal energy demand and to industrial fuel demand. In terms of third generation models, recognition that adjustment costs may reflect not only net but also gross investment leads to a more complex model, with significant differences in the theoretical specification between net and gross investment formulations. These differences remain significant empirically. Application of the net and gross investment model specifications to Canadian data show that estimation of the simpler net investment version may well entail erroneous estimates of certain parameters. The energy functions of the first and third generation models are found to be generically related. The simplicity of a first generation model can under certain conditions be consistent with the richer, more complex framework of third generation models. However, empirical testing did not support the notion of treating a first generation energy function as tantamount to a reduced form specification of a third generation model.

Since the end of the Second World war, United Kingdom energy policy has been highly influenced by beliefs about the adequacy of indigeneous resources, security of supply and macro-economic objectives. Over the same period we observe a growing sophistication in the official projections of energy requirements both in terms of content and technique. An analysis of the methods and models used in the calculation of recent official projections of UK energy demand identifies a number of problems. These mainly concern the size of the price elasticity of energy demand employed in the sectoral models and the modelling of interfuel substitution particularly in the Domestic Sector market for space and water heating. A review of econometric studies of UK demand indicates that the price elasticities of energy demand employed in the Department of Energy models of sectoral energy demand are generally lower than the estimates reported elsewhere. In contrast, official estimates of the own price and cross price elasticities for individual fuels in the Other Industry Sector are broadly consistent with other econometric studies. However the body of work carried out in this area is found to have a number of shortcomings: (i) in general, the problem of autocorrelation has been dealt with inadequately and inappropriately, (ii) it has not been possible to distinguish long run and short run effects satisfactorily, (iii) it has not been possible to distinguish the independent influences of income and price satisfactorily, (iv) models of interfuel substitution have generally performed poorly in the Domestic Sector and (v) the impact of biased disembodied technical change has not been considered in most studies of interfuel substitution. A new study of energy demand in the Industrial and Domestic Sectors of the UK economy attempts to address these problems. The results are mixed. Well established techniques are used to detect and adjust the results for first order autocorrelation. Biases of technical change are estimated and in particular the Domestic Sector interfuel substitution model performs well. However the problem of modelling the dynamic structure of energy demand remains unresolved. In the Industrial Sector, cross section and time series data is pooled in order to distinguish the independent influences of output and price. While the resulting price and output elasticities conform to the values that we would expect a priori, the explanatory power of the model is low. In the Domestic Sector it is possible to develop a model of energy demand with a good predictive performance, however simulation experiments with the model show that the high frequency variation of the dependent variable is mostly explained by the exogeneous temperature variable which itself is difficult to predict. In contrast it is found that relatively simple relationships between overall primary energy demand and key economic and demographic variables can have surprisingly good forecasting properties. This probably arises because of the inertia of systems at this level of aggregation. A severe test is constructed for a number of single equation forecasting models. The parameters of the models are estimated on UK time series data from 1954 to 1973 then the results are used to generate forecasts of the dependent variables over the highly unstable period between 1974 and 1980. Several of the models provide very accurate predictions. The main purpose of the thesis is to assess recent official forecasts of UK energy demand. The single equation model which performs best in the forecasting test is used as a basis for generating projections to the year 2000. The results are compared with the latest official projections. It is found that the official forecasts imply a lower price elasticity than used in the single equation model, a similar relationship between the structural composition of GDP and aggregate energy demand while the implicit income elasticity is higher than our estimate under high fossil fuel price assumptions but lower when fossil fuel prices are assumed to be lower. The simple model yields very similar forecasts to the official projections for 2000 with the exception of one case. With regard to projections of final energy consumption in the year 2000, there are some areas of contention between the bulk of econometric evidence and the implications of the official forecasts but they are small. Most aspects of the fuel mix forecasts are broadly supported by the econometric evidence given the relative fuel price assumptions. It is concluded that the latest official projections represent a fairly realistic appraisal of the likely outcome of an interplay of market forces in the energy market.

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Before tidal stream energy is exploited, tidal power resource and environmental assessments must be undertaken. This thesis explores limits to power extraction for tidal sites defined by a strait between an island and landmass. Numerical simulations provided by Fluidity are used to analyse power extraction from locations in the strait and around the island for an idealised island-landmass domain and an actual coastal site. The numerical model is verified by comparing predictions with analytical solutions for inviscid flow past a circular cylinder located in the centre of a channel and in the vicinity of a wall. The model is then validated against laboratory measurements of flow patterns for impulsively-started flow past a submerged circular cylinder, and for flow past a surface-piercing circular cylinder in oscillatory laminar shallow flow. It is demonstrated that the numerical method captures satisfactorily the mechanisms of early wake formation, which indicates the model can be applied to assess tidal stream resource within the coastal geometries considered herein. Finally, the methodology to account for power extraction is satisfactorily verified for bounded and unbounded flows. Contrary to current practices, results from a parameter study for different idealised coastal sites reveal that the maximum power extracted in the strait is not well approximated by either the power extracted naturally at the seabed or the undisturbed kinetic power. Moreover, an analytical channel model underpredicts the maximum power extracted in the strait due to its inability to account for changes in the driving head resulting from power extraction and flow diversion offshore of the island. An exception is found for islands with large aspect ratios, with the larger dimension extending parallel to the landmass; i.e. the island-landmass geometry approaching that of a channel. In this case, the extracted power is satisfactorily approximated by the power naturally dissipated at the seabed and there is good agreement with the analytical model. The maximum power extracted in the strait is shown to decrease when water depths offshore are greater than in the strait, underlining the importance of fully understanding the wider bathymetry of a given site. A similar conclusion is reached when strait blockage is reduced. The power extraction in the strait is found to be sensitive to both viscosity and seabed friction, and these parameters need to be properly estimated during the setup and calibration of models in order to reduce uncertainty. Power extraction increases when turbines are sited simultaneously both in the strait and offshore. Tidal power assessment is performed for Rathlin Sound, off the coast of Northern Ireland. Again, no clear relationship is found between maximum power extracted in the strait and either the power dissipated naturally at the seabed or the undisturbed kinetic power. A similar ratio of power extracted to undisturbed kinetic power is obtained as for the equivalent idealised model. The analytical channel model underpredicts the maximum power extracted. The actual and idealised coastal site models indicate similar responses to changes in seabed friction, and similar reduction in power extraction with decreasing strait blockage.

Due to high regeneration energy demands for amine absorption processes for post-combustion CO2 capture, alternative technologies such as adsorption processes using solid adsorbents have been considered. Other practical issues such as corrosion of equipment and loss of solvent can be avoided with adsorption processes. Fixed bed adsorption processes, in which CO2 adsorption and adsorbent regeneration are performed successively in a vessel packed with adsorbent, are the most common adsorption processes. However, in fixed bed temperature swing adsorption (TSA) processes, large columns and long heating and cooling times would be needed. Fixed bed pressure swing adsorption (PSA) processes use electrical energy, which is more expensive than thermal energy in a power plant. Therefore, the feasibility of moving bed adsorption processes including fluidised-bed, co-current and counter-current systems is investigated. In these systems, the adsorbent continuously circulates from a CO2 adsorber to a regenerator. The adsorbents considered are a supported amine adsorbent, activated carbon and zeolite 13X. Numerical simulations of moving bed TSA cycles for CO2 capture have been carried out. The effects of influential parameters in the process have been assessed via sensitivity analyses. It was found that counter-current beds with supported amine adsorbent give the best overall performance. Compared to an amine absorption process, it was found that a moving bed TSA process without heat integration requires the same heat consumption per unit mass of CO2 captured. There is a potential for a lower heat consumption in moving bed TSA processes if, similarly to amine absorption processes, heat integration is carried out or if the CO2 working capacity of the adsorbent can be increased.

Σκοπός της παρούσας εργασίας είναι η πειραματική μελέτη διατάξεων μετατροπής αιολικής και ηλιακής ενέργειας σε ηλεκτρική. Αρχικά, στην εργασία αναλύονται οι κυριότερες ανανεώσιμες πηγές ενέργειας (Α.Π.Ε.), με μικρές αναφορές στο κάθε σύστημα ξεχωριστά. Στη συνέχεια της εργασία, εξηγείται το φαινόμενο της δημιουργίας ανέμων στην ατμόσφαιρα, τονίζεται ο σημαντικός ρόλος που έπαιζε ο άνεμος από τα αρχαία χρόνια, παρατίθεται μια σύντομη ιστορική αναδρομή, αναλύονται τα μέρη της ανεμογεννήτριας, επισημαίνονται τα πλεονεκτήματα και τα μειονεκτήματα της ενέργειας που παράγεται από τον άνεμο. Τέλος αναφέρονται κάποιες αποθηκευτικές διατάξεις και στη συνέχεια αναλύονται περιληπτικά οι συσσωρευτές, αφού στο σύστημα μας υπάρχει χρήση συσσωρευτών. Επιπλέον, αναφέρουμε τα βασικά στοιχειά για ένα μετεωρολογικό σταθμό, τον οποίο και δημιουργήσαμε για το σκοπό της παρούσας διπλωματικής εργασίας. Στη συνέχεια έχουμε την επεξήγηση του τρόπου εγκατάστασης της ανεμογεννήτριας την οποία απέκτησε το εργαστήριο για σκοπούς μελέτης. Επιπλέον επεξηγείται η κατασκευή ορισμένων κυκλωματικών διατάξεων, μέσω των οποίων γίνεται δυνατός ο έλεγχος της ανεμογεννήτριας όπως επίσης και η μέτρηση, καταγραφή, αποθήκευση τεσσάρων βασικών στοιχειών (ταχύτητα ανέμου, διεύθυνση ανέμου, τάση και ρεύμα στο φορτίο) τα οποία θα μας βοηθήσουν στη συνέχεια της διπλωματικής ώστε να δημιουργήσουμε ανεμολογικά δεδομένα για την περιοχή του Πανεπιστημίου Πατρών, όπως επίσης και για την κατασκευή της καμπύλης φόρτισης της ανεμογεννήτριας του Εργαστηρίου Η.Μ.Ε. Ταυτοχρόνως με τις ίδιες κυκλωματικές διατάξεις έχουμε τη δυνατότητα να λαμβάνουμε δεδομένα από τα οποία μετά από επεξεργασία μπορούμε να λάβουμε την παραγόμενη ενέργεια από το κάθε σύστημα, ενώ παρουσιάζονται οι πειραματικές καμπύλες οι οποίες έχουν εξαχθεί από τα πειραματικά δεδομένα της διπλωματικής. Το επόμενο μέρος της διπλωματικής μου εργασίας αναφέρετε στα ηλιακά ΦΒ-συστήματα, αναφέροντας τα βασικότερα μεγέθη τα οποία επηρεάζουν την απόδοση τους. Επίσης αναφέρονται οι βασικότεροι τύποι υλικών κατασκευές ΦΒ-στοιχειών για τα οποία αναφέρουμε τις βασικότερες παραμέτρους τους. Αναφέρουμε επίσης κάποια πειραματικά συστήματα τα οποία προσπαθούν να αυξήσουν την παραγωγή ενέργειας από τα ΦΒ. Μετά ακολουθούν οι γραφικές παραστάσεις των πειραματικών αποτελεσμάτων τα οποία έχουμε πάρει από τις πειραματικές μας διατάξεις. Τέλος, γίνεται μια προσπάθεια να αναπτύξουμε ένα μαθηματικό μοντέλο με τα οποίο προσπαθούμε να δώσουν απάντηση στο ερώτημα, αν συμφέρει η όχι από οικονομικής άποψης, το θέμα της επένδυσης χρημάτων σε ΦΒ-σταθμούς. / -

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