Help!! Renewable Energy Project Simple Electronics Problem

[MightyJayJay]

Hi, I'm making a model of a solar updraft tower. Basically the way it works is air gets heated by the sun (in my case a 500w lamp) and rises through a pipe. In the pipe there is a "turbine" connected to a generator that extracts energy from the rising air and thus generating electricity. For my project, I have to use this electricity to power 1 or more LED's. I also want to add solar panels to the design to increase power generated in the same amount of space.

The problems I have are: #1 not knowing much of electronic circuit design (which I'm working on) and #2 how to hook up the DC generator and the solar panels to turn on the LED's. I think that if the generator does not produce much power, the solar panels might turn it on and make it work as a motor, which is something I don't want!!

My generator is a DC motor taken from a printer I had lying around, although I have a couple smaller ones too. The LED specs are 1.7v and 20mA. The solar panels produce about .5v @ 30mA. Any other things I would need just let me know.

ANY help will be GREATLY appreciated. Thanx!

Jay

 

[WimRFP]

Hello,

I assume your motor is a real DC motor, not a stepper motor (as that will not work). Use a motor that required relative high supply voltage, otherwise you need too much RPM to get sufficient voltage to overcome the threshold voltage for the LED. I hope your turbine has sufficient torque to overcome the friction in the motor.

To avoid current flowing back into the motor, you need a diode (rectifier), think of 1N400X series. As you are dealing with low voltage a so-called schottky diode (1N581x series) has less drop when it conducts, so you don't lose significant voltage. LED's are current driven devices. Applying some too high voltage will destroy them.

I would recommend you to find somebody locally with some knowledge on electronics; it will save you lots of time.

¡Mucha suerte con su proyecto de energía renovable!

 

[MightyJayJay]

Re: Help!! Renewable Energy Project Simple Electronics Probl

Thanks for your help, I'm still looking for someone with knowledge here but it's hard 'cause the university is on strike! At last I have basic knowledge so I'm doing alright.

Thanks!

 

[WimRFP]

Hello,

Did you already have something in mind for the turbine (torque, RPM) and an idea about the power you can extract from the updraft?

 

[karesz]

HI,
Because are the assumable Updraft-generator`s & PV`s (Photo Voltaic) output power changing_I think a storage element (some Farad capacitance, Super or Gold Capacitors, or small battery) is to use that you do charge over the two low input voltage DC/DC converters (from generator & PV)...
K.

 

[MightyJayJay]

Re: Help!! Renewable Energy Project Simple Electronics Probl

Hi:

Well I really have no idea of the power that may be extracted from the updraft because it is completely dependent on the design of the actual tower (which is in process). Actually the power (current & voltage) output is what I will be using to determine which design is better. About the torque that I can generate, I think is going to be pretty low which is why I think I'll need an external power input to start the generator because of the high starting torque required for the DC motor I'm using as generator.

- I don't think I'll use any storage devices because I'm only showing the tech works by lighting up a LED. Also, I think the PV's output will be pretty constant because it's not for long and the light source is a 500w lamp and not the sun itself. (Please correct me if I'm wrong)

Thank's for your replies!!!

 

[FvM]

Re: Help!! Renewable Energy Project Simple Electronics Probl

Before you come to specific electronic problems, you have to solve a simple, basic problem: Make your "turbine", or windmill,
or whatever you designed turn the motor. You didn't tell about the height of your tower, but I doubt if the generated torque will be
sufficient to overcome the stand still friction of a brushed DC motor. I would rather use a (brushless) AC generator with
a suitable rectifier.