More on monitoring

Over a year ago, I was contacted by a Meter & Monitoring Services company who were keen to add a hydro installation to the range of sites they were already monitoring.  At the time, I couldn't see that the data they collected, or the way they collected it, would add to what I was doing before.  But one year on I'm rather impressed by their system.

Their set up involved installing a second energy meter in series with my existing kWh meter;  the new meter collects and stores generation data and once per 24 hrs transfers it over a mobile phone link to my 'account' held on a central server; by logging into this 'account' I can view all the data and down-load both the raw data and the graphs which the data make possible.

'Smart' meter and circuit diagram in the required G83 format

This is the record of generation since 1st Oct 2015 to today 31st Jan 2017 as logged by the system:

...the vertical scale shows kWh generated per day; a point of note in this record is how little generation there has been in Dec / Jan 2016/17 compared with 2015 /16; the present daily yield is just 8 kWh per day whilst last year at this time it was 18 kWh, - testament to how dry this year has been.

The advantages of this system compared with what I was, and am still, doing are that it is automated, more accurate and more secure.  My old system takes data from the inverter (which is less accurate than this 'industry standard' energy meter); requires me to take it manually each month (whereas this needs no human input); and requires me to keep it on my computer (whilst this system uses 'cloud storage').

All in all, I think it's quite a useful addition to the way I monitor my Powerspout... especially since for me it's free, - though that might change. But take note - it does require mobile phone reception.

After waiting...

After waiting a month for rain, I've given up waiting any longer, - yesterday I got on with measuring values for the discharge co-efficient of my nozzles.  This was the job left hanging at the end of the last diary entry and is part of my aim to refine the accuracy of knowing what flow the jets deliver.

At this time of year I had hoped that rain would have been increasing the flow and that I could have done the measurements at each increase in nozzle size with little inconvenience; there being no rain, no increase in flow and no call to increase nozzles, all I could do was measure the smaller nozzles one after the other in a single blitz of measurement.

It made for a lot of exercise up and down the hill between turbine and header tank, - and for an interesting record in the on-line power trace:

The results of the experiment are presented in the following graph; on it I have also indicated the flow each nozzle delivered, as determined by measurement:

I was only able to measure the seven smallest nozzles, identified by Roman numerals I to VII; apart from one outlier in the measurement of nozzle IV (which I am at a loss to explain**), the others came in with discharge coefficients scattered around the 0.85 value; there was no obvious trend for Cd to increase or decrease with change in orifice size; I conclude from this that Cd is determined only by the design of the nozzle, - design that includes such features as its angle of taper, its length and the smoothness of the inner surface over which water is flowing. Whether Cd changes with head was something I couldn't determine with this experiment conducted as it was at one site.

Thus far so good: - from now on I will take 0.85 to be the discharge coefficient.  In time there will be opportunity to take measurements for the larger nozzles VIII to XII and when available these will add weight to the picture so far obtained.

Does all this cause the earth to shift on its axis of rotation ? - no but it's still worth investigating !

**later I discovered this nozzle was badly cut explaining why it was different.

Addendum dated 2 Feb 2017
Today copious rain has made it possible to measure the Cd and flow of the remaining 5 nozzles; the results are shown in the revised chart below; overall the Cd of EcoInnovation nozzles on my site seems to be 0.85 ± 0.01.