The set up

The set up
5.46mm jet delivering 0.68 l/s to the pelton which is rotating at 900 rpm and generating 135 watts into the grid.

Thursday, 6 August 2015

Little but worthwhile.

I'm happy !  

Last year I had to stop generating in the first week of July but this year I've been able to keep going all through the month.  It's not that there has been more water this year, in fact there has been less.  No, the reason is because of the changes made to the turbine which mean it can keep generating when flows are low.  The reduced core stator is the foremost of those changes but other changes have included using reduced friction bearings and learning that operating on the bottom jet alone gives better efficiency.

Here is what the output has been through July this year:

The step in the middle of this graph was when I changed nozzles: from a nozzle delivering 0.96 lps to one giving 0.83 lps, followed on the same day by another change to one delivering 0.68 lps. 

At 0.68 lps, the daily yield has been 3.02 kWh per day, - not very much admittedly but if one works out what the cash value of that daily level of production is over a full month, it comes out at £37.

£37 is about what it costs to fill our car with petrol, so put that way, if we get a free full tank each month on the back of what the Powerspout is generating, even this low level of output is worthwhile.

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