The rated flow is not necessarily the maximum flow available. Yes, you can compute it as i have shown below but it depends on the stream characteristics and what you want to do with the stream or river. 1:
You have a stream or river that is gauged. By this i mean that flow data is available. These could be records of daily flows or monthly flows for a time period. 2:From these flows you can develop a flow duration curve. This is defined as follows: A cumulative frequency curve that shows the percentage of time that specified discharges are equaled or exceeded.. www.crh.noaa.gov/hsd/hydeff.html A graphical representation of the number of times given stream flow volumes are equaled or exceeded during a certain period of record. fwie.fw.vt.edu/rhgiles/appendices/glossf.htm A curve which plots a list of ordered data (greatest to least) against the percent of time each value is exceeded. Used to analyze stream flows. (Chow (1964)) cdss.state.co.us/glossary.asp A graphic representation of the number of times given quantities of flow are equaled or exceeded during a certain period of record. www.conservation.state.mo.us/fish/watershed/big/glossary/20gltxt.htm >From these curves you are able to tell the probability or frequency of >exceeding a certain flow in a year. So say you have a demand for which a flow >of 3cubic metres/s is required. Then you check and see how often this flow is >exceeded in a year. Then you may find that this flow is exceeded 90%. If you >feel that 90% availability suits you well, then you go ahead and design for >that. However, in some cases you are not looking at the stream from a demand point of view but from a "what can i optimally get out of the stream" point of view.So you try to design it normally so that your system does not have idle capacity for most of the year. Then you could take for instance the flow that is exceeded at least 90%. Some people will decide what percenatge to take after a comprehensive technical-economic analysis. This percentage will correspond to a certain flow which is the rquired flow rate for the hydrostation. Some people call it the rated flow. So you see, the rated flow is not necessarily the maximumflow available. Yes, you can compute it as i have shown but it depends on the stream characteristics. I hope that i have got it right for you. I hope that i have got it right for you. Emmanuel Jjunju Your question was: > What do we understand by rated flow for microhydro. If > we have available flow for the year, Can we compute > the rated flow for micro hydro plant. Or Is it the > maximum flow available in the year? > > sandeep chittora > > > > [Non-text portions of this message have been removed] ------------------------ Yahoo! Groups Sponsor --------------------~--> Has someone you know been affected by illness or disease? Network for Good is THE place to support health awareness efforts! http://us.click.yahoo.com/RzSHvD/UOnJAA/79vVAA/FGYolB/TM --------------------------------------------------------------------~-> Does your company feature in the microhydro business directory at http://microhydropower.net/directory ? If not, please register free of charge and be exposed to the microhydro community world wide! NOTE: The advertisements in this email are added by Yahoogroups who provides us with free email group services. The microhydro-group does not endorse products or support the advertisements in any way. More information on micro hydropower at http://microhydropower.net To unsubscribe: send empty message to [EMAIL PROTECTED] Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/microhydro/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
