Small Hydropower & Micro Hydropower

Tim,

Thanks for the words of encouragement about our “Small & Micro Hydropower Newsletter” work at DoradoVista, Inc. and now with our SmallHydro Blog and Small & Micro Hydro site at SmallHydro.com !

If there’s one thing I’ve learned in 30 years of engineering and management experience. There are no stupid questions. I am amazed how often the experts and novices alike assume a given field of knowledge is obvious.

One of the reasons we started the “Small & Micro Hydropower Newsletter” was the realization that people who are considering Renewable Energy Hydropower need a certain introductory level of Energy & Systems knowledge to get started. This is so individuals are comfortable asking what they need to ask about each unique project. This helps get the Hydropower projects evaluated accurately and allows them to make good decisions for project success.

Our plan is that part of this sequence of newsletters will become the basis for an on-line introductory to Small & Micro Hydro-power systems class. There are a few decent sites that start the ball rolling, but they often are talking only to experienced engineers in the hydro field. The two ESHA PDF links on the http://www.DoradoVista.com/DV_Hydro_Power.html pages have just such a course. Great stuff, but we’ll need to assist you in understanding what it means.

When we get to the various options and procedures, you should have enough knowledge to understand what to do, How to do it, who can help, and when. It’s a big goal, but worth doing. Once this base of understanding is established then we can begin the real fun with some Hydro-Pro-Amateur Blog-comments-forum type interactions to help one another.

By the way, feel free to ask questions. We’ll try to get you answers either via the newsletter or email.

Sincerely,
Jess

DoradoVista, Inc.
PS. Do you mind if we reprint your name (Tim), your question and this answer in a future newsletter update? It helps others to feel comfortable with the same issues you ask about. (You are not alone!)

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Q: Say you want to convert Psi & GPM to kW water power?

A: Good question – unfortunately there are a myriad of Unit conversions, like furlongs per fortnight.

Follow my round about conversions, I like to focus on the most common formula to start my thinking.
(unfortunately in English Units)

So I stick with the following formula and convert units to fit it. Metric converts too…
I usually think in CFS & Ft head:

I usually start with this formula –>  kW ideal = (CFS flow x Ft head)/11.8

But you have GPM & Psi for units

1 ft head = 0.433 Psi –> (1 ft/.433 psi) x Z Psi = ft head

There are 60 seconds to a minute –> 1 min = 60 sec

There are 7.48 Gal per Cubic Feet volume –> (1 CF /7.48 Gal) x (Gal /sec) = CFS

So say we have 78 Psi -> 78 psi /.433 psi/ft = 180.14 ft head

And now we’re given 1000 GPM = 1000 GPM x 1 Min/ 60 sec = 16.67 GPS

Now convert to CFS -> 16.67 gal/sec /7.48 Gal/CF = 2.23 CFS

Therefore our kW ideal is = (2.23 CFS x 180.14 ft)/11.8 = 34.02 kW Ideal –> Efficiency % not included

To factor efficiency in Multiply x ~72% for water to wire typical. (must use chosen Gen % x Turbine %).

So we get something like 34.02 kW x 72% = 24.49 kW Typical power as a more realistic measure of output potential.

I sure hope this helps,

Jess

DoradoVista, Inc.
PS:  Mileage will vary, there are a lot of issues not modeled here. It is a start though.

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Here is the result of the most recent feedback on the SmallHydro Logo ™. We think it looks better although there’s always room for improvement

SmallHydro Logo New

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