Proposed human cycle powered watermaker

[Adelie]

Originally Posted by StuM

or rather, Watts/litre (since Amps is dependent on actual system voltage).

Which Spectra give as 4.2 for their dual pump Spectra Cape Horn 330 (I can't find figures for Tellie's "one pump" version. (Most 12V watermakers seem to run around 6-8 W/l)

(And I won't say anything further about his 7-8amp/hr )

Shouldn't that be Watt-hours / Litre?

[Adelie]

Originally Posted by StuM

Darn it! Spectra sucked me in! Without thinking, I've just done what I complain about other people doing

All of my previous "W/l" units were quoted from Spectra's website without thinking. They should of course by Wh/l !

Nevermind Stu.

[swampbush]

Originally Posted by owly

Generating electricity from human power is absurd, H.W.

Using a person to generate power, irrespective of where the power goes seems more trouble than it is worth to me. You dont want to start and stop a watermaker, but you can with a generator. Why do you think a watermaker makes more sense than generating electricity?

[Adelie]

Originally Posted by owly

Generating electricity from human power is absurd, and I never suggested such a thing. Someone else may have. The only realistic application for that is a "cyclovision", where the kids have to pedal to watch TV ;-)

H.W.

Why is it absurd? A human puts out enough in one hour to run nav lights and an AIS receiver all night.

[FlyingScot]

The idea seems like a Rube Goldberg machine that turns food into water using your spare time. I'm in no way against it, as I believe anyone should do what they want (mostly).


I'm thinking a solar panel and a some fitness gear might be less hassle (although less rewarding?).

-Chris

[StuM]

Originally Posted by owly

As you can see, this pump is almost perfectly sized to the job of running a pedal power watermaker. .145 HP is well within the capacity of a healthy human for a reasonable period of time. .248 gallons per minute, means a bit less than 4 minutes of pedaling for a gallon of water.

But since about 10 gallons of seawater at high pressure are delivered to the RO membrane for each gallon of freshwater produced, you are talking about 40 minutes for a gallon of fresh water.

And you'd probably lose close to half of that gallon in sweat in your 40 minutes of pedalling in a hot climate.

[senormechanico]

Originally Posted by StuM

But since about 10 gallons of seawater at high pressure are delivered to the RO membrane for each gallon of freshwater produced, you are talking about 40 minutes for a gallon of fresh water.

And you'd probably lose close to half of that gallon in sweat in your 40 minutes of pedalling in a hot climate.

I was waiting for that post ever since the original one about a gallon in four minutes. Thanks.

[john61ct]

Originally Posted by Adelie

Why is it absurd? A human puts out enough in one hour to run nav lights and an AIS receiver all night.

Only in theory, inefficiency losses both ends are not negligible.

Certainly compared to the electricity required for making water, which is the topic at hand.

[seandepagnier]

Originally Posted by owly

Imagine the energy one could generate in a monohull on a trade wind run from the constant rolling, you could perhaps both dampen roll and generate electricity at the same time.

attach a weight at the end of an invertered pendulum like a metronome.

A microprocessor moves the weight up and down to tune frequency, and also sets the stops. It can also engauge a clutch to lock the movement and unlock it at the right times.

The algorithm on the microprocessor can be made to dampen the boat motion using minimal power. As for generating power, I'm afraid you will be disappointed. The output for typical boats is only a few dozen watts unless you are in severe conditions.