Unlike conventional hydro and tidal barrage installations, water current turbines in open flow can generate power from flowing water with almost zero environmental impact, over a much wider range of sites than those available for conventional tidal power generation. Recent developments in current turbine design are reviewed and some potential advantages of ducted or “diffuser-augmented” current...

Utility system operators and engineers want a better understanding of the impacts of large wind farms on grid stability before they are interconnected to the grid. Utilities need wind electrical models and methods of analysis that will help them analyze potential problems of grid stability. Without the necessary tools and knowledge of the behavior of large wind farms, utilities are reluctant to...

Every year the number of installed wind power plants in the world increases. The horizontal axis wind turbine is the most common type of turbine but there exist other types. Here, three different wind turbines are considered; the horizontal axis wind turbine and two different concepts of vertical axis wind turbines; the Darrieus turbine and the H-rotor. This paper aims at making a comparative s...

An impulse bio turbine with circular inlet/outlet area which can be integrated into small devices, is presented. The system was designed using a scaled impulse macro turbine model, which was modified in size and shape to guarantee integration in implantable bio medical devices and physiological circulatory system. The simplicity in the design reduces cost and makes it very suitable for developi...

In order to harness the kinetic energy of marine currents, we propose a novel ocean-current turbine with a horizontal axis. The turbine can be moored to the seabed and function similarly to kites in a water flow. To operate such turbines in a marine current, the resulting rotor torque needs to be canceled. Therefore, the proposed turbine is designed with a float at its top and a counterweight a...

Wind turbines are known to produce shadow flicker by interruption of sunlight by the turbine blades. Known parameters of the seizure provoking effect of flicker, i.e., contrast, frequency, mark-space ratio, retinal area stimulated and percentage of visual cortex involved were applied to wind turbine features. The proportion of patients affected by viewing wind turbines expressed as distance in ...

Many challenges exist for the efficient and safe operation of wind turbines due to the difficulty in creating accurate models of their dynamic characteristics and the turbulent conditions in which they operate. A promising new area of wind turbine research is the application of adaptive control techniques, which are well suited to problems where the plant model is not well known and the plant o...

University of Cambridge J. Tudor, MB, BS, MRCS, LRCP, DMDR, FFR, Consultant Radiologist E. P. Wraight, PhD, DMRT, Consultant in Nuclear Medicine Addenbrooke’s Hospital, Hills Road, Cambridge CB2 2QQ, England. A. J. Coakley, MB, ChB, MRCP, MSc, Consultant in Nuclear Medicine St Thomas’ Hospital, Lambeth Palace Road, London SE1 7EH, England. Requests for reprints should be sent to Mr N. Rushton. ...

Typical wind turbine systems are sufficiently large so as to require extensive physical space for their installation and operation. These requirements preclude the use of turbines in crowded, urban environments. On the other hand, smaller turbine systems may find practical application as rooftop units, installed atop tall buildings. Such rooftop units must be much smaller than their ground-base...

application of cogeneration systems based gas turbine for heat and power production is increasing. because of finite natural energy resources and increasing energy demand the cost effective design of energy systems is essential. cgam problem as a cogeneration system is considered here for analyzing. two new approaches are considered, first in thermodynamic model of gas turbine and cogeneration ...