Washing Machine Micro HEP

[TeeDee]

I have an old washing machine and access to a decent fast running stream that falls parallel to the property - for educational purposes only I would quite like to install a micro HEP and see what electricity I could produce.

Anyone done anything along these lines before and can offer any tips / hints or suggestions.

TIA.

 

[Broch]

To be honest, it's quite hard to use a 'flowing steam' to generate meaningful electricity. What you need is a 'head' i.e. a water column from a height that gives you a good pressure to drive a turbine. The energy in a flowing stream is much lower than the energy from water coming down a pipe from 100m up. That's why old fashioned mills had to have huge wheels and large 'buckets' to create enough torque to turn the mill.

We did some automated turbine control systems that maintained the header tank level so the electrical power generated was controlled to make sure the water supply wasn't depleted. In one case the tank was some 500m above the turbine.

 

[TeeDee]

To be honest, it's quite hard to use a 'flowing steam' to generate meaningful electricity. What you need is a 'head' i.e. a water column from a height that gives you a good pressure to drive a turbine. The energy in a flowing stream is much lower than the energy from water coming down a pipe from 100m up. That's why old fashioned mills had to have huge wheels and large 'buckets' to create enough torque to turn the mill.

We did some automated turbine control systems that maintained the header tank level so the electrical power generated was controlled to make sure the water supply wasn't depleted. In one case the tank was some 500m above the turbine.

Thanks Broch - Not wishing to call you or your experience "out" but a while back I was randomly chatting to some on the FB pages who had experience of doing this before - He requested I send him some video footage of the flow rate and he assured me its 'enough' volume to get a positive and effective charge from.

What this all means , i'm unsure - I'm familiar with the need for Head and although this stream doesn't have much it seems to manage a very constant and positive flow rate from the very large catchment area upstream.

 

[Broch]

Oh, it's possible to generate from any flow of water, I'm not denying that - just very difficult to get worthwhile power from a flowing stream.

If you measure the speed of flow (over a period of time to get the average) and the dimensions i.e. how deep (again, average) you can put some form of turbine or paddle to calculate the surface area being 'pushed', and the width of the stream you will be able to reasonably use (in case a paddle is the only option) I can tell you exactly how much power (on average) you should be able to generate.

We only did the control systems (and automated source - wind, solar, hydro, mains, switching), but I was involved in long meetings and deep conversations about the feasibility of a few installations; some were abandoned mainly for consistency of flow reasons.

 

[TeeDee]

Oh, it's possible to generate from any flow of water, I'm not denying that - just very difficult to get worthwhile power from a flowing stream.

If you measure the speed of flow (over a period of time to get the average) and the dimensions i.e. how deep (again, average) you can put some form of turbine or paddle to calculate the surface area being 'pushed', and the width of the stream you will be able to reasonably use (in case a paddle is the only option) I can tell you exactly how much power (on average) you should be able to generate.

We only did the control systems (and automated source - wind, solar, hydro, mains, switching), but I was involved in long meetings and deep conversations about the feasibility of a few installations; some were abandoned mainly for consistency of flow reasons.

Speed of Flow - So how quickly something passes through point A to B on a measured set distance?

Not sure if I can measure the depth - I could tell you how quickly it fills an empty bucket up? Is that of any use?

 

[Broch]

For the sake of discussion, but I know you know this, a river/stream has a flow profile - slower at the bottom and along the banks, fastest in mid-stream (crudely, it's not quite as simple as that). But for approximation purposes, the surface speed (how fast something goes from a to b) will do. However, without depth and width we can't work out the maximum volume flow rate. But, we could work out the pressure and hence the force generated against a turbine blade or a paddle blade of area X m sq - but, of course, you need to be sure you have the depth to get that area into the flow.

Sorry, I just remembered, you have an engineering background so all that is teaching my Grandmother to suck eggs!!!

Are you looking to generate DC 12/24v or AC mains? If the latter, what are you planning on using as your generator?

 

[Mesquite]

Check out Marty T on youtube, he runs his house off of power generated from a washing machine turbine

 

[Broch]

Yep, 800w from a 45 m head (not a flowing stream) - kinda proves my point. So, you need a large battery bank for when you are drawing several Kw at peak time (a kettle needing 1kw+) and something like a 5 or 8kw inverter (which I have going spare by the way ). Now, the maths all comes down to how many batteries you're prepared to use and maintain and whether your average consumption exceeds the average generation. Remember that you will achieve about 80 to 85% efficiency in the inverter so the more equipment you can run directly off the battery DC voltage the better (except that there's larger losses running low voltage DC over distance than AC mains).

 

[Tengu]

If you are looking at making a stream do work for you, would you have any use for a Hydraulic ram?

 

[TeeDee]

 

[TeeDee]

If you are looking at making a stream do work for you, would you have any use for a Hydraulic ram?

I will give a try.

 

[MrEd]

If you are looking at making a stream do work for you, would you have any use for a Hydraulic ram

could use the hydraulic ram to fill a large header tank or something so that you can have the head required for the power generation? Good thing is a hydraulic ram pump requires no power put into it other than water

 

[TeeDee]

could use the hydraulic ram to fill a large header tank or something so that you can have the head required for the power generation? Good thing is a hydraulic ram pump requires no power put into it other than water

@Broch - Thoughts on this suggestion?

 

[MrEd]

My only thought is the ram pump won’t feed enough in to keep up with the output of a header tank,

 

[slowworm]

could use the hydraulic ram to fill a large header tank or something so that you can have the head required for the power generation? Good thing is a hydraulic ram pump requires no power put into it other than water

They're very expensive though, even parts are £100s to get an old one running again. (A new one is just under £3k).

I note there's a new Blake's Hydram site that has details about working out heads and flows that my be helpful to TeeDee

Installation - Blake's Hydram water pump installation

Here you will find information on how to install the Blake Hydram pump including measuring drive water and working fall.

blakeshydram.co.uk

One thing I've wondered about my pump is whether I could use the excess flow to generate a small amount of power.

I'd like a basic kit to play with, like some of the basic solar kits, but couldn't find anything sensible when I last looked.

 

[MrEd]

There are a few videos on YouTube showing diy ram pump builds that seem simple.
I have been fascinated With ram pumps ever since I came across one quietly sitting doing its thing to supply water troughs for cows almost 1/2 a mile away, I was astounded how simple it was!

 

[slowworm]

The fascination wears off a tad when it stops working on a freezing winters day, or you need a new clack and someone wants over £100 for a rubber washer.

But they are great when you get used to them and I've now found out how to make the washers for pennies.

I might have to look into making a replacement one day but the cheaper pumps seem to come and go, so I'm not sure how easy it would be to make a pump that runs day in day out.

 

[Broch]

@Broch - Thoughts on this suggestion?

OK, I'm away for the week, so access to the internet may not be continuous

Remember O-level (or GCSE for the younger ones) physics - 'energy can neither be created nor destroyed, it merely changes form'

So, if you increase head, you lose flow rate (that's actually how hydro rams work).

Power generated (or available) from a fluid flow can be expressed in two ways:

P = mass flow rate x g x head
P is in watts
mass flow is in kg/s
g = 9.81m/s
head is in metres

or

P = pressure x flow speed
pressure is in pascals
speed is in m/s

You cannot gain any additional power from these fundamentals no matter how complex your contraption.

If you are into 'dimensional analysis' you will see that both these equations are dimensionally the same (unless I've made a mistake )

Both these equations, in practice, need to be tempered by an efficiency factor of around 75%

 

[Silverclaws2]

I have an old washing machine and access to a decent fast running stream that falls parallel to the property - for educational purposes only I would quite like to install a micro HEP and see what electricity I could produce.

Anyone done anything along these lines before and can offer any tips / hints or suggestions.

TIA.

For educational purposes as even failure is educational, I say go for it, as was when I was a kid I made small inefficient short lived turbines for both wind and water to light no more than an incandescent torch bulb, just to see it working.

As to hints and tips there's loads out there on the web re converting washing machines into useful HEP generators.

 

[Broch]

Define 'useful'

Without either a good 'head' or high mass flow you will not generate 'useful' energy.