Eco-Fan, doe's it work?

[carlt]

Geothermal energy is stellar, not solar energy.

[RLWP]

Geothermal energy is stellar, not solar energy.

 

And which star was the earth formed from?

 

Richard

[grahoom]

For instance why buy a Ferrari (not that I have one) when a Nissan Micra will do much the same thing.

 

Indeed, I had a 1989 nissan micra, was brilliant - excellent little car, ran like a dream - until some b*stard nicked it and crashed it writing it off. It was a sad loss.

[carlt]

And which star was the earth formed from?

 

Richard

It was not formed from a star it was formed at the same time as the sun, from essentially the same materials, but not from the sun directly.

 

The Sun and the Earth get their energy from the same source. The Earth's geothermal energy does not come from the Sun.

[Chris J W]

Just to briefly pull the subject back on topic ... I'm quite happy with my Eco-Fan, and it makes a big difference in my open-plan boat. One thing I've discovered is that it does require some minor maintenance now and then. Dusting! Mines been really sluggish until I ran a duster around the fins, and is now spinning like a good 'un (when I can convince the crappy wood I'm using at the moment to actually burn and not just sit there smouldering)

Edited December 19, 2008 by Chris J W

[RLWP]

It was not formed from a star it was formed at the same time as the sun, from essentially the same materials, but not from the sun directly.

 

The Sun and the Earth get their energy from the same source. The Earth's geothermal energy does not come from the Sun.

 

Being as you are so clever then...

 

Is the thing in the base unit of an eco-fan a thermocouple?

 

Richard

[carlt]

Being as you are so clever then...

 

Is the thing in the base unit of an eco-fan a thermocouple?

 

Richard

It's a thermoelectric generator which works using the seebeck effect, using two different types of semi-conductors.

 

If you want any more information about the electrical gubbins, going on, it's better if Gibbo, et al take over. Materials Science is my bag.

[churchward]

It was not formed from a star it was formed at the same time as the sun, from essentially the same materials, but not from the sun directly.

 

The Sun and the Earth get their energy from the same source. The Earth's geothermal energy does not come from the Sun.

 

We are stardust, we are golden,

We are billion year old carbon.

And we got to get ourselves back to the garden.....

 

Takes yer back man.

 

 

Just to briefly pull the subject back on topic ... I'm quite happy with my Eco-Fan, and it makes a big difference in my open-plan boat. One thing I've discovered is that it does require some minor maintenance now and then. Dusting! Mines been really sluggish until I ran a duster around the fins, and is now spinning like a good 'un (when I can convince the crappy wood I'm using at the moment to actually burn and not just sit there smouldering)

 

Yep I like mine too. I get a kick out of watching it warm up when the fire is lit and it starts turning. But in terms of eco credentials and saving money etc I guess it's a non-starter. It is just too expensive to begin with. I still wouldn't be without it though.

Edited December 19, 2008 by churchward

[RLWP]

It's a thermoelectric generator which works using the seebeck effect, using two different types of semi-conductors.

 

If you want any more information about the electrical gubbins, going on, it's better if Gibbo, et al take over. Materials Science is my bag.

 

So, having just done an extensive reading of a wikipedia page, the Seebeck-Peltier effect is how copper-constantan thermocouples work, but there are other material combinations as well.

 

Richard

 

As the Seebeck-Peltier effect is reversible, If you stand your eco-fan in a howling gale, will it cool your stove down or heat it up?

[carlt]

As the Seebeck-Peltier effect is reversible, If you stand your eco-fan in a howling gale, will it cool your stove down or heat it up?

I'm so glad I don't have an eco-fan because I'd now be trying to work out an experiment to find out.

 

The problem is measuring and removing the wind-chill factor or blowing a gale that is equal to the stove-top's temperature.

[RLWP]

I'm so glad I don't have an eco-fan because I'd now be trying to work out an experiment to find out.

 

The problem is measuring and removing the wind-chill factor or blowing a gale that is equal to the stove-top's temperature.

 

Actually, I think it depends which way round it turns the fan. If it is the direction that the fan usually runs it will cool the stove (like it does when it is working), if it is in the other direction it will heat it.

 

Richard

[John Orentas]

Those damn fans must hold some form of record for the number of posts they have generated and is there some form of relationship to value for money.. I have never understood why people don't simply make something utilising a computer fan, my mate made a very crude arrangement along these lines to test the principle, it worked a treat.

 

Bother! now I have done the same thing.

[chris w]

So, having just done an extensive reading of a wikipedia page, the Seebeck-Peltier effect is how copper-constantan thermocouples work, but there are other material combinations as well.

 

Richard

 

As the Seebeck-Peltier effect is reversible, If you stand your eco-fan in a howling gale, will it cool your stove down or heat it up?

These Peltier junctions are the same things that are used in your warm/cool insulated picnic box. When you apply a voltage across the Peltier junction, one side cools and the other heats up so, depending which way you insert the 12v dc plug into the picnic box, the inside metal plate of the box will either get warmer or cooler, thus warming or cooling the food therein.

 

Most of these electronic effects in physics are reversible. ie; if you apply a voltage to the junction you get one hot side and one cold side. So if you instead do it the opposite way round and manually heat one side and cool the other, then you get a voltage out, which is what is used to drive the Eco-Fan's motor.

 

I measured the temperature difference on mine, needed to make the fan start to revolve, and its only 20degC.

 

Chris

Edited December 19, 2008 by chris w

[RLWP]

These Peltier junctions are the same things that are used in your warm/cool insulated picnic box. When you apply a voltage across the Peltier junction, one side cools and the other heats up so, depending which way you insert the 12v dc plug into the picnic box, the inside metal plate of the box will either get warmer or cooler, thus warming or cooling the food therein.

 

Most of these electronic effects in physics are reversible. ie; if you apply a voltage to the junction you get one hot side and one cold side. So if you instead do it the opposite way round and manually heat one side and cool the other, then you get a voltage out, which is what is used to drive the Eco-Fan's motor.

 

I measured the temperature difference on mine, needed to make the fan start to revolve, and its only 30degC.

 

Chris

 

Hi Chris,

 

Any idea of the material combination/number of junctions in the peltier cell in one of these fans?

 

Richard

[chris w]

Hi Chris,

 

Any idea of the material combination/number of junctions in the peltier cell in one of these fans?

 

Richard

I would imagine it's just one junction but I don't know the material used in the Eco-fan.

 

Chris

[Pretty Funked Up]

If people are looking to build/make their own it might be prudent to just buy the Peltier module ready made.

I found this one for £18.95...

peltier module

 

Be interesting what people come up with and I'm sure theyll be cheaper modules out their.

 

I'd of also thought more junctions along with more heat would increase the power output enabling higher speeds or larger fans to improve air circulation

Edited December 19, 2008 by Pretty Funked Up

[Keeping Up]

Any idea what is the actual power generation of the Peltier units (or consumption of the fan) in the Eco units?

[Gibbo]

Any idea what is the actual power generation of the Peltier units (or consumption of the fan) in the Eco units?

 

As an educated guess I'd say somewhere between 100mW and 200mW

 

Gibbo

 

Hi Chris,

 

Any idea of the material combination/number of junctions in the peltier cell in one of these fans?

 

Richard

 

Almost certainly P-N type silicon junctions. Probably (but this is just a guess) 3 or 4 groups in series (thus giving a voltage of around 2.6 volts unloaded (0.65 volts per junction), each group consisting of several hundred, or possibly thousand, parallel junctions (big junctions can be made but they are less efficient so parallel small junctions are usually used).

 

Edited to add: The power per unit area is limited by the state of the art. The voltage can be chosen to be whatever is required. I suspect they will choose the voltage to match whatever reasonably efficient motors they can find at a sensible price.

 

Gibbo

Edited December 19, 2008 by Gibbo

[RLWP]

As an educated guess I'd say somewhere between 100mW and 200mW

 

Gibbo

 

 

 

Almost certainly P-N type silicon junctions. Probably (but this is just a guess) 3 or 4 groups in series (thus giving a voltage of around 2.6 volts unloaded (0.65 volts per junction), each group consisting of several hundred, or possibly thousand, parallel junctions (big junctions can be made but they are less efficient so parallel small junctions are usually used).

 

Gibbo

 

Thanks Gibbo, that makes sense.

 

Richard

 

(I'm wondering how long it will be before Chris or Gibbo get a mulitmeter onto one of them)

[Gibbo]

If people are looking to build/make their own it might be prudent to just buy the Peltier module ready made.

I found this one for £18.95...

peltier module

 

Be interesting what people come up with and I'm sure theyll be cheaper modules out their.

 

I'd of also thought more junctions along with more heat would increase the power output enabling higher speeds or larger fans to improve air circulation

 

Ok...... So...... a small electric motor (50 pence ebay) and a propellor, model shop, ebay, 50 pence. Aluminium heatsink for the top and aluminium base plate, painted black, ebay a few quid. Could be quite easy and cheap this.

 

Gibbo

[RLWP]

This one is 320W for £12.95 : Clicky

 

and here's the datasheet: another clicky

 

Richard

Edited December 19, 2008 by RLWP

[churchward]

Ok...... So...... a small electric motor (50 pence ebay) and a propellor, model shop, ebay, 50 pence. Aluminium heatsink for the top and aluminium base plate, painted black, ebay a few quid. Could be quite easy and cheap this.

 

Gibbo

 

It's a good idea isn't it. I quite fancy having a go at building my own. It'll make for a fun project.

 

 

This one is 320W for £12.95 : Clicky

 

and here's the datasheet: another clicky

 

Richard

 

Would that be OK though? The spec says a max temp of 138 deg which wouldn't be enough for the top of the fire I would have thought.

[Gibbo]

This one is 320W for £12.95 : Clicky

 

and here's the datasheet: another clicky

 

Richard

 

I'm trying to work out a way to type "bullshit" interspersed with a cough.

 

If they could produce peltier elements at that rating for that money it would be the end of the world's energy crisis.

 

A quick fag packet calculation from the size of that unit and a typical boat multi fuel stove shows 100Kw of electrical power output from 1Kw of coal burning.

 

I think they have the decimal point in the wrong place, by about 6 positions. Or perhaps that is the maximum electrical input when running as a cooler?

 

Gibbo

 

This one is 320W for £12.95 : Clicky

 

and here's the datasheet: another clicky

 

Richard

 

Right I just checked the data sheet for that unit.

 

That's the mean between the heat transfer and the electrical input. Which is a slightly od way of rating one.

 

I reckon on top of a fire it might produce about 300mW

 

The problem is, how does one rate these things when they have so may uses?

 

Gibbo

 

It's a good idea isn't it. I quite fancy having a go at building my own. It'll make for a fun project.

 

I'm pretty sure you can make one for next to nothing (apart from the peltier element itself).

 

Gibbo

[RLWP]

I'm trying to work out a way to type "bullshit" interspersed with a cough.

 

 

 

Right I just checked the data sheet for that unit.

 

That's the mean between the heat transfer and the electrical input. Which is a slightly od way of rating one.

 

I reckon on top of a fire it might produce about 300mW

 

The problem is, how does one rate these things when they have so may uses?

 

 

 

I'm pretty sure you can make one for next to nothing (apart from the peltier element itself).

 

Gibbo

 

The brief research I have done on these suggests you put them between the processor and heat sink in a PC, so the 320 Watts could mean anything. No way is it the electrical output if you hot it up.

 

Richard

[Keeping Up]

Personally I feel tempted by the opposite approach using a similarly small, quiet, very low power motor running from 12v, driving a fan from behihnd the flue-pipe where the dog's tail won't keep knocking it over. After all, another 100mW or so won't drain the battery overnight.

 

Edited for tryping errrors again!

Edited December 19, 2008 by Keeping Up