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Rainfuel


Marvin

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Rainfuel is a concept that has recently come to my attention. Like all inventor types into not wanting to buy power, the mind jumps to having the whole of the north facing roof covered and obtaining power when wet, day or night!

 

The principle seems to be (I am now opening myself to being corrected) that each rain drop falling form the sky has a small charge and collecting all those small charges could produce sensible power.  

 

The first things I want to know is will this work in a practical way!

 

In order to work this out my first questions are:

  1. How much power per square meter can be produced from what sort of amount of rain: Too little power and I will not bother.
  2. What are the limitations to production: rain to light or too heavy (a bit like the challenges with wind power.) Does it have to have the "right sort of rain"
  3. Based on local rain records what would be the annual typical output for my roof.

 

Like hydro power this has its problems: The rain usually falls far more during the winter months (well it used to) and so it does hardly anything during the summer months. This means that to manage all the power when at peak-supply the inverter required will have to be very high compared to the average load.  What I mean is the system could be doing nothing and then on full throttle.

 

The other thing is what you do with the power supplied. (Used, grid or stored).

 

Obviously there are videos showing this working. but has anyone seen any videos of technical information?

 

In one video the rainwater was taken from a beaker and dripped across a absorber. Can I fill my rain butt and use that water by making it drip? Can I use absorbers in my rainwater down pipe? 

 

There are going to be two outcomes to this blog:

 

  1. It will abruptly stop as the results are rubbish
  2. It will carry on and on as more information develops.

 

With your help we will have an answer.

 

Marvin.

 

 

 

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14 minutes ago, Marvin said:

 

Bottom of the Isle of Wight. 

Wave power would be better.

 

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16 minutes ago, SteamyTea said:

Wave power would be better.

 

I hope not to endure wave power, being 200ft above sea level.

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9 minutes ago, Marvin said:

I hope not to endure wave power, being 200ft above sea level.

What you do is drill a large diameter hole down to sea level.  Then, when the waves hit the bottom of the hole, the air in the tube is compressed, this then runs a turbine at the top of the hole.

The Wells turbine is the type to use as it spins the same way regardless of air direction.

8148

 

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7 minutes ago, SteamyTea said:

What you do is drill a large diameter hole down to sea level.  Then, when the waves hit the bottom of the hole, the air in the tube is compressed, this then runs a turbine at the top of the hole.

The Wells turbine is the type to use as it spins the same way regardless of air direction.

8148

 

Yes.. not practical at all for me.

 

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3 minutes ago, Marvin said:

Well its making up for it today!

It was alright till 10:30 AM.

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“that each rain drop falling form the sky has a small charge”

 

I guess that might explain why we sometimes get a static shock from our zinc cladding?

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26 minutes ago, Russdl said:

“that each rain drop falling form the sky has a small charge”

 

I guess that might explain why we sometimes get a static shock from our zinc cladding?

I don't know but it sounds reasonable. Also I understand that's also part of lightening. Searching for information I understand that this process can produce about 50w per square meter.

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I saw this discussed somewhere else and a figure of 50W per square metre when it is raining.

 

Solar panels will give more than that, and I am sure the sun shines more than it rains, even in Scotland.

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From 1926.

So a reality check is needed.

If a few drops of water could produce a usable amount of power, think of all the metal things, especially aluminium, that is insulated from the ground, say a boat on a trailer. Touching it would hurt.

As this is not a new concept, with the physics known about for over 100 years, if it was viable, we would be doing it.

rspa_1926.0108.pdf

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It's easy to a create a voltage, but without any current there is no power.  I suspect that there is more energy in storing rain water in a roof tank and using its potential energy to drive a water motor.   A typical roof will have ~70m3 of water. 70000 kg x 10 m/s² x 5 m (building height) = 3.5 Megajoules

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70 cube of water is either a big roof or someone living in a rain forest.

measured a new build house recently, less than 30 sqm in plan

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Where do you live, that a typical roof has 70 tonnes of water on the roof?  That's a lot of water, are sure your maths is correct?

 

A typical house may have a footprint of 70m2, so would need a 1m deep storage tank over the whole roof.  Not sure you would get planning permission.

 

Not sure what you would do with water when you finished driving the turbine, you could store it and pump it back up again, then it becomes a battery.

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Hi @Adrian WalkerYes! I have looked at energy from a rainwater turbine! No it's not practical for me to do.

Yes the bungalow is about 100m2 of roof and yearly we get about 450mm of rain, so about 450m3. However being a bungalow we have little height about 2.6m.

The problem would be the weight on the roof when any attempt was made to store the water up high and the fact that rain is even more of an on/off energy supplier than sun meaning the only way to produce the potential power is to have a very big turbine=£££££ as I have no storage capacity.

 

Even putting a turbine on the mains water supply to produce usable power that can be used or stored when the mains water is being used is tricky but we do use grey water.

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If a manufacturer combined the rainpower (but would need higher efficiency) into a PV panels, sun out power, wet day power, dull dry day not much power.

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2 hours ago, JohnMo said:

Where do you live, that a typical roof has 70 tonnes of water on the roof?  That's a lot of water, are sure your maths is correct?

 

A typical house may have a footprint of 70m2, so would need a 1m deep storage tank over the whole roof.  Not sure you would get planning permission.

 

Not sure what you would do with water when you finished driving the turbine, you could store it and pump it back up again, then it becomes a battery.

 

That is the rain fall for a whole year.  I don't think it's a goer, not much energy.  If you want to use water as a battery, pressure rather than volume is better - that's what the Victorian did.

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2 hours ago, Adrian Walker said:

3.5 Megajoules

Sod how large the roof is, or how wet.

It is less than a kWh.

My car does 1.5 miles to the kWh.  Be easier to park closer to 100 metres away from the house i.e. in the road I live in rather than the parking around the back.

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