Eco fan

[kustomkb]

Does anyone know what it would take to replicate these

 

[zeusrekning]

LOL, I was thinking the same thing. I came across one of these fans in a Northern Tool catalog today.
Tim

 

[mklotz]

You need a thermoelectric generator - something that operates on the Peltier-Seebeck effect to convert heat into electricity. Add a small electric motor and Bob's your uncle.

Now, a real model engineer would build a proper Stirling fan with integral pump to pump water to its own cold jacket and a small fountain to maintain the relative humidity in the room.

 

[Stan]

At one time, heat piles (multiple thermocouple junctions) were in common use on gas fired heating systems. They produced enough power to operate (not just hold open) the gas valve so should operate a small fan. I had one on a hot water boiler so that in case of utility power failure, the boiler still fired and the water circulated by convection.

 

[macona]

Those thermocouples are still used in almost every live pilot gas appliance.

Best bet thy are just using a generic peltier (Thermo Electric Cooler, TEC) in the junction between the base and the heat sink. TECs are getting pretty cheap.

 

[rickharris]

Does anyone know what it would take to replicate these

You need a solar motor (low current DC motor) - A fan blade and a Peltier unit - you may find a broken portable fridge that has them in it.

OR

A solar cell & drive with light.

BUT

on this site i guess you need to build a Stirling engine!!

 

[Brian Rupnow]

Many suppliers of wood stoves have a small heat operated fan that sets on top of the stove to run. Might be the same technology.---Brian

 

[Stan]

Macona: A thermocouple and a thermopile (heat pile) are not the same thing. I stole this paragraph from another site (http://hearth.com/econtent/index.php/articles/how_gas_works) which explains the difference.

"This valve is similar to the thermocouple only valve, however has a pilot which heats up BOTH a thermocouple and a thermopile. The thermocouple still acts to prove that the pilot flame is on and allows this flame to continue after startup. The thermopile is used to power a second circuit which is used to open the main valve. This second circuit is powerful enough (300-600 millivolts) to allow the use of a thermostat, wall switch or control switch to operate the main valve. Control of the valve is obtained simply by hooking a pair of wires to two terminals located on the valve."

A thermopile is capable of sourcing significant current whereas a thermocouple has to be measured with a high impedance or balanced bridge meter.

 

[likewho]

A standard TEC or peltier module will not last very long in this type of application. For power generation (Seebeck Effect) you really need to go with a TEG or thermoelectric generator module that's designed specifically for power generation applications. They are generally made with thermal material that is optimum for power generation and are constructed with a much higher melt point solder to enable extended operation at higher temperatures. You can find TEG modules for ECOFAN repair on eBay.

 

[MCRIPPPer]

just found this thread and wanted to comment because i used to have an ecofan. (i know the thread is old)

when the ecofan finally died(motor bushing wore out) i took it apart and got the thermo-electric cell out. i applied a voltage and was able to make ice on one side of it, while making the other side blazing hot. so it is a peltier effect device.

 

[gocy]

Or you can build one after watching this series
http://www.youtube.com/playlist?list=PLHUJDLlTM_9UC0NaVAD9ZOi04g0xuu_mo