Science Buddies: "Ask an Expert"

I am researching the ability of different models to generate
power from tidal waves. One model involves the compression/decompression
of air in a chamber. I am having problems finding something that is
sensitive to the pressure change to generate an electrical pulse that can
be measured. My dad suggested a piezo-electric diaphragm
or disc but we aren't sure they are viable options. We first tried a
small windmill/turbine but the pressure change wasn't sufficient to move
the blades. Any ideas on something that we could use that is sensitive to
air pressure change to generate an electric pulse?

Thank you,
Lauren Barber

Interesting problem. I know you would like to measure the pressure change to give an electrical signal, and I hope some other respondent will help you with that. I suggest that if you want to measure the pressure change of air as a wave passes over, that you consider a liquid column manometer. If you look up "manometer" on wiki, about 1/3 of the way down is a sketch of one. If you use water as the liquid, you ought to see the liquid moving up and down as the pressure changes. The manometer shown is the classic one made entirely of glass, but if you can get two glass tubes and some flexible tubing that fits them, the "U" portion can be that flexible tubing.

laurbar wrote:I am researching the ability of different models to generate
power from tidal waves.

laurbar,

Thank you for your question, and welcome to science buddies. I'm unclear what exactly it is you are trying to design. Are you looking to develop an alternative power source from wave action from the ocean? That's what it sounds like, but then you talk about differential air pressure and I get lost in your concept. If you could provide more detail, we may be able to provide better advice. Making the assumption about ocean tidal action, what about a bouy based system where the wave action causes a floating magnet to bob up and down inside a coil of wire, inducing a current to flow. The output signal would be AC and variable based on how fast and high this action happens as well as be, but could be rectified to a DC output and normalized to a specific voltage outside as well as combined in series with other similar devices in series for a combined increase in voltage output. There are devices like this in development, but each has strenghts and weeknesses, you could try to optimize some existing design or go for a unique one.

Thank you Borg. My full question didn't come through.
I am researching the ability of different models to generate
power from tidal waves. One model involves the compression/decompression
of air in a chamber. I am having problems finding something that is
sensitive to the pressure change to generate an electrical pulse that can
be measured. My dad suggested a piezo-electric diaphragm
or disc but we aren't sure they are viable options. We first tried a
small windmill/turbine but the pressure change wasn't sufficient to move
the blades. Any ideas on something that we could use that is sensitive to
air pressure change to generate an electric pulse?

Whoops, after reading your comment, I guess you did get the entire question. I have to go to bed, but will look at your response tomorrow. Thank you so much for your comments. Lauren

I know of no efficient piezo-electric effect materials so the won't generate a lot of power for the amount of energy input. There are various means of generating small amounts of power on a bouy for use on the bouy; however, trying to produce a lot of electricity this way for transmission to other consumers would be very expensive.