Douglas Probert

Energy consumption in UK households: Impact of domestic electrical appliances

The social-psychological aspects of energy use in UK households have been reviewed. A major survey, which focused on identifying environmental attitudes and beliefs, energy-use behaviour, ownership levels for certain appliances and their utilisation patterns, was undertaken among householders resident in the south-east of England. The results indicate that members of the general public are (i) interested in receiving information concerning household energy use and the associated environmental impact, and (ii) willing to modify their behaviour in order to reduce household energy consumption and environmental damage. Therefore, there is an urgent need to provide end-users with accurate energy-consumption and environmental-impact information, persuasively presented, to stimulate energy-rational and environmentally sustainable behaviour. For each major domestic electrical appliance, the survey data permit estimates of the variations in energy consumption per household and of the aggregate annual consumption nationally.

Exergy-method analysis of a two-stage vapour-compression refrigeration-plants performance

The behaviour of two-stage compound compression-cycle, with flash intercooling, using refrigerant R22, has been investigated by the exergy method. The condensers saturation-temperature was varied from 298 to 308 K and the evaporators saturation-temperature from 238 to 228 K. The effects of temperature changes in the condenser and evaporator on the plants irreversibility rate were determined. The greater the temperature difference between either (i) the condenser and the environment, or (ii) the evaporator and the cold room, the higher the irreversibility rate. Any reduction in the irreversibility rate of the condenser gives approximately 2.40 times greater reduction in the irreversibility rate for the whole plant, and any reduction in the evaporators irreversibility rate gives a 2.87 times greater mean reduction in the irreversibility rate of the whole plant. Because the changes in the temperatures in the condenser and the evaporator contribute so significantly to the plants overall irreversibility, there is considerable scope for optimising the conditions imposed upon the condenser and evaporator.

Novel approach for improving power-plant availability using advanced engine diagnostics

Technological advances and high cost of ownership have resulted in considerable interest in advanced maintenance techniques. Quantifying fault and consequently availability requires the use of gas-turbine and combined-cycle models able to undertake appropriate diagnostics and life-cycle costing. These are complex processes as they include the simulation of such issues as performance and assessment of degraded gas-turbines, life usage and risk analysis. This report describes how the recent developments in engine diagnostics using advanced techniques like Artificial Neural Network (ANN) and Genetic Algorithm (GA) based techniques have provided new opportunities in the field of engine-fault diagnostics. It also discusses the potential of advanced engine-diagnostics, employing such features as ANN and GA for contributing to the management of availability of industrial gas-turbines.

Implications of engine deterioration for a high-pressure turbine-blade's low-cycle fatigue (LCF) life-consumption

Abstract As a result of experiencing a deterioration of efficiency and/or mass flow, an aero-engine will automatically adjust to a different set of operating characteristics; frequently resulting in changes of rpm and/or turbine entry-temperature in order to provide the same thrust. As such, the stresses that the engine is subjected to will change (and thereby alter the blades low-cycle fatigue-life consumption) relative to that for an engine suffering no deterioration (i.e. in the jargon—a ‘clean’ engine). Rises in the turbines entry-temperatures and the high-pressure turbines rotational-speed result in greater rates of creep and fatigue damage being incurred by the hot-end components and thereby higher engines life-cycle costs. Possessing a better knowledge of the effects of engine deterioration upon the aircrafts performance, as well as fuel and life usages, helps the users to take wiser management decisions and hence achieve improved engine utilization. For a military aircraft, by employing a bespoke computer simulation, the consequences of engine deterioration on a high-pressure turbine blades low-cycle fatigue-life consumption are predicted.

Designs, thermal performances and other factors concerning cooking equipment and associated facilities

Cooking appliances are notoriously wasteful of energy. The present survey and investigations outline the history and behaviours of the main forms of cooking equipment available and indicate the energy efficiencies of the various designs. Improvements regarding equipment design, cooking techiques and consumer education are suggested from an energy-thrift perspective.

Harnessing hydropower: A practical guide

Macro and micro hydropower systems are described, along with a consideration of the technical and environmental problems involved. A case study, with Bargoed in the Rhymney Valley, South Wales as the proposed site is then presented, with some of the issues involved when choosing a specific hydropower-harnessing scheme discussed. In conclusion, a set of associated proposals, which would improve the Rhymney Valley in an environmentally- and socially-beneficial way, are described.

Engine-fault diagnostics:an optimisation procedure

A diagnostic process capable of providing an early warning of a fault in a gas turbine is of tremendous value to the user and can result in substantial financial savings. The approach in the Genetic Algorithm based technique adopted is to treat the problem of engine diagnostics as an optimisation exercise using sensor-based and mathematical behavioural model based information. The engine performance model would simulate a range of possible combinations of potential faults (i.e the effects of model-based information) and a comparison would be made with values of the actual (sensor-based) parameters obtained from an engine. The difference between the actual and simulated values of would be converted into a suitable objective-function and the aim of the optimisation technique such as the genetic algorithm would be to minimise the objective function. The technique has given promising results for simple cycle engines.

Implications of engine's deterioration upon an aero-engine HP turbine blade's thermal fatigue life

Possessing a better knowledge of the impacts of engine deterioration upon an aircrafts performance as well as its fuel and component life usage, helps the users make wiser management decisions and hence achieve improved engine utilization. For a military aircraft, using a computer performance simulation, the consequences of engine deterioration on a high pressure turbine blades thermal fatigue life are predicted.

Role of constructed wetlands in environmentally-sustainable developments

Whilst discounting the likely, frequent widespread use of natural wetlands for liquid-effluent treatment within the UK, a brief history of the global development of constructed wetlands is given. The designs and types of flora and fauna used within UK-based constructed wetlands, are discussed. Then, a case study of the constructed wetlands used at the Wildfowl and Wetlands Trust, Gloucestershire, UK, highlights how constructed wetlands can be used successfully for decontaminating liquid effluent within the UK.

Implications of engine deterioration for creep life

World developments have led the armed forces of many countries to become more aware of how their increasingly-stringent financial budgets are spent. One major expenditure for military authorities is upon aero-engines. Deterioration of an engine generally results in a lower specific thrust and higher specific fuel-consumption for the same spool speeds and turbine-entry temperatures. In order to meet the thrust requirement for the same aircrafts performance, the engines are run at higher spool speeds and/or turbine-entry temperatures. This results in greater rates of fuel consumption, and a shorter life (due to the greater creep damage and low-cycle fatigue incurred). Possessing a better knowledge, of the impacts of engine deterioration on an aircrafts operational performance as well as its fuel and residual life-expectancy, helps the users to improve engine utilization.