Featured Research

from universities, journals, and other organizations

How To Get Wind Turbines To Work Harder

Date:
June 17, 2009
Source:
Inderscience Publishers
Summary:
How much usable energy do wind turbines produce? It is a question that perplexes engineers and frustrates potential users, especially on windless days. A new study provides a formula for answering this vexing question.

How much usable energy do wind turbines produce? It is a question that perplexes engineers and frustrates potential users, especially on windless days. A study published this month in the International Journal of Exergy provides a formula for answering this vexing question.

Abolfazl Ahmadi and Mehdi Ali Ehyaei of the Department of Mechanical Engineering, at Iran University of Science and Technology-Arak Branch, in Arak, have investigated the "exergy" of wind power. Exergy is a term from thermodynamics that measures that the energy a system that is available to do work.

Wind is one of the oldest renewable energy resources. Fan blades atop a tall capture the wind's energy and convert it to useful power at ground level. Modern turbines, of course, take this notion of wind power one stage further and produce electricity to drive equipment elsewhere. A single wind turbine can vary in size from a few kilowatts for small residential applications to more than 5 megawatts for industrial scale electricity generation.

Ahmadi and Ehyaei point out that wind turbines have to compete with many other energy sources, primarily fossil fuels but also other renewable energy sources such as solar and biomass technology. As such, a wind turbine has to be cost effective in order to be environmentally effective.

Turbine design must meet load requirements and produce energy at a minimal per dollar cost. In order to address this cost issue, performance characteristics such as power output versus wind speed or versus rotor angular velocity must be optimized. Exergy analysis looks at the "quality" of the energy produced by a system. To be viable, there is little point in producing intermittent power at wildly varying levels, as this feeds only low-quality energy into the power supply system.

Usually, wind speeds of above 9 meters per second are considered irrelevant in exergy calculations of wind turbines and previous research has not taken all factors that are required for a holistic analysis into account, the Iranian team believes.

They have now developed an improved exergy analysis for wind turbines, which considers the kinetic exergy of the wind in much greater detail. Their approach gives them a model of how the turbine's potential for work can be lost. This then offers a way to optimize a wind turbine's three main parameters, cut-in, rated, and furling wind speeds, so that usable energy is maximized at any given wind speed from the gentlest breeze to a roaring gale; within the safe working parameters of the turbine.

They have carried out an exergy analysis of turbines sited in two cities in Iran, Tehran and Manjil, where wind speeds are very different. Tehran has low average wind, whereas Manjil is a windy city. Their formula offers optimized values for wind turbine rotation speed, which can be altered depending on wind speed. The results are a theoretical boost of 20% efficiency at both sites and a decrease in "wasted" energy of 80%.


Story Source:

The above story is based on materials provided by Inderscience Publishers. Note: Materials may be edited for content and length.


Journal Reference:

  1. Exergy analysis of a wind turbine. Int. J. Exergy, 2009, 6, 457-476

Cite This Page:

Inderscience Publishers. "How To Get Wind Turbines To Work Harder." ScienceDaily. ScienceDaily, 17 June 2009. <www.sciencedaily.com/releases/2009/06/090616103217.htm>.
Inderscience Publishers. (2009, June 17). How To Get Wind Turbines To Work Harder. ScienceDaily. Retrieved April 24, 2014 from www.sciencedaily.com/releases/2009/06/090616103217.htm
Inderscience Publishers. "How To Get Wind Turbines To Work Harder." ScienceDaily. www.sciencedaily.com/releases/2009/06/090616103217.htm (accessed April 24, 2014).

Share This



More Matter & Energy News

Thursday, April 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

UN Joint Mission Starts Removing Landmines in Cyprus

UN Joint Mission Starts Removing Landmines in Cyprus

AFP (Apr. 23, 2014) The UN mission in Cyprus (UNFICYP) led a mine clearance demonstration on Wednesday in the UN-controlled buffer zone where demining operations are being conducted near the Cypriot village of Mammari. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com
Air Force: $4.2B Saved from Grounding A-10s

Air Force: $4.2B Saved from Grounding A-10s

AP (Apr. 23, 2014) Speaking about the future of the United States Air Force, Chief of Staff Gen. Mark Welsh says the choice to divest the A-10 fleet was logical and least impactful. (April 23) Video provided by AP
Powered by NewsLook.com
Jets Fuel Jump in Boeing's Revenue

Jets Fuel Jump in Boeing's Revenue

Reuters - Business Video Online (Apr. 23, 2014) A sharp rise in revenue for commercial jets offset a decline in Boeing's defense business. And a big increase in deliveries lifted profitability. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Is North Korea Planning Nuclear Test #4?

Is North Korea Planning Nuclear Test #4?

Newsy (Apr. 22, 2014) South Korean officials say North Korea is preparing to conduct another nuclear test, but is Pyongyang just bluffing this time? Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins