Hydro Power Calculator

[LowGear]

I've been at a couple of hydro calculator sites and I just don't get it.  Is there a simple place to find out if there's much potential in a 20 foot drop through a 4 inch line?

Casey

[mobile_bob]

around here, a 4" column of water falling 20 feet would be referred to as "huge" potential!

have you checked "sailawayrob"s list of online calculators? i was thinking he had a hydro calculator on there?


bob g

[Thob]

Thread on calculators here:

http://www.microcogen.info/index.php?topic=2781.0

Which points to website with calculators here:

http://www.borstengineeringconstruction.com/Calculators.html

There's a hydroelectric capacity calculator there.  I just don't know what are reasonable numbers for GPM and turbine efficiency.  Anybody know good starting numbers?

I put in 100 GPM, 20' head, 35% turbine efficiency, 85% generator efficiency, and got 50KW, HOLY COW!

How much water do you have behind that 4" pipe?

[LowGear]

Hi Thob,

It's the GPM on this calculator that throws me.  How much water comes through a 4" line with a 20' drop?  How would you calculate in the 200 meter line run for resistance.  I'm simply in over my head.

I'll Google a couple turbine sales organizations.

Casey

[AdeV]

Hmm....

According to  my calculations:

A 4" pipe at low pressure will move 240 US gal/hr = 15 litres/second
A 20' head is about 6 metres.

At 100% system efficiency, you have 883watts continuous power; at 60% efficiency, 530watts.

Pipe capacity: http://flexpvc.com/WaterFlowBasedOnPipeSize.shtml
Calculator (in metric) here: http://www.reuk.co.uk/Calculation-of-Hydro-Power.htm
Comprehensive conversion calculator here: http://www.convert-me.com/en

530 watts * 24 hours * 365 days = 4.6MW per year, if you can keep that 4" pipe full for the full year.

It's possible that the 20' fall will actually cause the pipe to transport more than 240gal/min; if you could bank on the medium pressure volume (480gal/min) then you get twice as much power  

[AdeV]

http://www.borstengineeringconstruction.com/Calculators.html

There's a hydroelectric capacity calculator there.  I just don't know what are reasonable numbers for GPM and turbine efficiency.  Anybody know good starting numbers?

I put in 100 GPM, 20' head, 35% turbine efficiency, 85% generator efficiency, and got 50KW, HOLY COW!

Their calculator is broken.... it doesn't convert GPM to cubic feet/second before doing the sums...

If you convert 240gals/min to cubic feet/second you get 0.5347 - put that in as your flow rate and you get 0.91KW theoretical, 0.54KW actual (based on 60% system efficiency - I put a 60% efficient turbine, 100% efficient generator). From their numbers, it looks like an 80% efficient turbine and 95% efficient generator should be well within a DIY'ers reach, so 75%+ system efficiency should return about 675watts continuous power.

[LowGear]

I did the marketeer thing.  I inquired at a place that sells small hydro systems.  So far, at Wild Natural Solutions, I got:

3" line 20 ft of head + approx 250-350 watts.
4" line 20 ft of head approx 300-400 watts.

Worse case is 6 KWH per day or about 60 cents.  Boy am I unexcited.

I'll try another store just for drill.

Casey