Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

Register Log in
  • Congratulations KootK on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Electricity from trees?

Status
Not open for further replies.
0707

0707

Petroleum
Jun 25, 2001
3,338
Plugged in: Startup hopes to tap electricity from trees

“Lagadonis said tests have generated 0.8 volts to 1.2 volts by driving an aluminum roofing nail half an inch into a tree attached to a copper water pipe driven 7 inches into the ground. But the electricity is useless because it's unstable and fluctuates.”

e=2
 
Replies continue below

Recommended for you

Sort by date Sort by votes
Um, what's the electrical potential difference between aluminum and copper?



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
 
Upvote 0 Downvote
In Electropotential Series of Metals
Aluminium has 1.3 V
Copper is –0.345 V
The difference is 1.3-(-0.345)=1.645 V
 
Upvote 0 Downvote
Isn't journalism wonderful? Damn, what am I doing trying to develop real technology- there's got to be SO much more money in being a charlatan!
 
Upvote 0 Downvote
Um, I've never seen it with a living tree but isn't that the same as the old trick with a potatoe, or was it a citrus fruit?

I think I know people who got the little kit to make a potatoe powered clock as a kid, I certainly recall seeing it on TV or in some kids science book.

Anyway seems odd. In the unlikely event it leads anywhere cool but I'm extremely sceptical.
 
Upvote 0 Downvote
Image30.gif


This seems to me like an electrolytic cell where aluminium nail act as anode and copper water pipe, work as cathode the electrolyte would be the plant sap.

luis
 
Upvote 0 Downvote
Some very low current microprocessor companies have demo kits that operate a microprocessor off two electrodes stuck into a orange or lemon. Yet, I don't see Texas Instruments claiming that a fruit smoothie is the solution to the world's energy problems!

I used to have a long-wire antenna going from the house to a tree. The antenna would easily light several neon bulbs. Maybe I sould claim that I developed it first and get my own venture capital funding!
 
Upvote 0 Downvote
Long ago Popular Mechanics had plans for a model electric boat, The boat had 3 or 5 keels. alternating copper and zinc. The thing was supposed to run forever without batteries. In saltwater of course.
 
Upvote 0 Downvote
You know how to get more power from that tree?
Cut the damn thing down and throw it into my stove. Saves my electricity heating bill. Problem solved.

Frank "Grimey" Grimes
Rule 25. of Swanson's "Unwritten Rules of Management"
Have fun at what you do. It will reflect in your work. No one likes a grump except another grump.
 
Upvote 0 Downvote
BJC: not forever, just until the zinc runs out! Consider it a zinc-fueled boat, just as the tree idiot is fueling his process with aluminum nails. He's just choosing a lousy electrolyte in the form of a tree, and hence building a very poor battery.
 
Upvote 0 Downvote
I think Grimes may be making a good point.

Perhaps even better, cut down the tree & burn it for engergy. Then replace it with a more rapidly growing crop to repeat the cycle.

Obviously this doesn't take into account other environmental issues but...
 
Upvote 0 Downvote
electric_trees.jpg


As trees will have lots of led lights, during the night the photosynthesis will keep going on and the release of CO2 will be substantial lowered.

At Christmas times it will not be necessary to buy lots and tots of made in china Christmas lights because trees will be already lightened.

Luis marques
 
Upvote 0 Downvote
It's terrible that a journalist for 'Mass High Tech: The Journal of New England Technology' doesn't know basic science!

The correct method for drawing energy from trees requires a knowledge of Latin (Acer saccharum), climatology, machining/woodworking & gravitational flow:*
Tapping into source:
sugaring-pic2.jpg


Sophisticated collection network:

sugaring-pic3.jpg


Thermophysical concentration:
chaudron.jpg


Quality engineers:
sugaring-pic5.jpg


Energy content of product is 50 Kcal/tablespoon
(Note: A food Calorie = 1000 scientific calories)

*Fortunately, the Native Americans had developed the process eons ago, so no need to depend upon the idiots mentioned in the OP!
 
Upvote 0 Downvote
GrimesFrank said:
You know how to get more power from that tree?
Click to expand...

Rather than directly heating your home, use the wood to boil water, run a heat engine by steam, run a heat pump by heat engine and use the discharged heat from both heat engine and heat pump into your house. You will have more heat energy now.(Courtesy : Lord Kelvin)

I will never know whether this is a technical calculation or entrepreneurial[bugeyed]




 
Upvote 0 Downvote
Quark, more energy?

Or do you mean more useful energy/able to make use of more of the energy?

 
Upvote 0 Downvote
Suppose, you get 1kW heat by direct combustion, then it is possible to get about 5kW by above arrangement, theoretically. You will straight away get 1kw from the fuel as usual + you have heat energy extracted by heat pump from atmosphere.

 
Upvote 0 Downvote
Hmm, I'm wishing I had my thermodynamics notes handy right now as I have a feeling I'm being an idiot but something doesn't sound right to me.

I was never any good at thermodynamics (not too bad at propulsion though strangely) so I may well be wrong.

Perhaps I was harsh in my previous post about engineering journalism and am no better myself.
 
Upvote 0 Downvote
KENAT: I think quark's figures are not quite right. You burn the tree to produce heat to run a heat engine (say 30% efficient tops) but the balance of the heat goes to beneficial use to heat your house (consider it a "co-generation" scheme if you will- the heat engine uses your home as its "cold reservoir". The work you generate from the first heat engine is used to drive another heat engine (the heat pump), which depending on the temperatures of your house and its surroundings could be as much as 400% "efficient" in terms of useful watts of heat into your living space per watt of work into the heat pump. So at best, your 1 kW of heat energy from the tree is giving you about 0.70 +4*(0.3)= 1.9 kW of useful heat into your home.
 
Upvote 0 Downvote
Yes, my figures are not quite right, in the sense that I was a bit conservative. The original calculation by Kelvin, considering Carnot efficiencies for heat engine(steam based, at 200C) and heat pump, gives 6kW for every 1kW of direct combustion. The detailed calculation may be out of the scope of this forum.



 
Upvote 0 Downvote
oddly enough I was looking at coefficients of performance for heat engines. They typically run at around 3-7 (that is heat out/mech work in), which seems like money for old rope.

But a steam engine running at 200 C, even into 20C heat sink, cannot exceed

1-293/473 =38% efficiency

So for every kW of fuel in you might get .38*7 =3 kW of heat out

Admittedly you might manage better than a CP of 7, as a lot of your reject heat will be available, and at more than 20 deg C, but this cuts into your steam engine efficiency. Interesting tradeoff actually - given a required output heating temperature Tout, and a given upper temperature TH, and a given environmental temperature Tin, what is the optimum cold side temperature TC of the Carnot cycle that is providing the mechanical energy? I suspect it depends on how much plant complexity you are prepared to buy.





Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
 
Upvote 0 Downvote
Status
Not open for further replies.

Similar threads

OLD_STUDENT
  • Locked
  • Question
Update from an OLD post on 40 year old engineering student thread730-439198 6
Replies
9
Views
95
DM61850
DM61850
GKXFQ
  • Locked
  • Question
I come from China ,nice to meet you
Replies
10
Views
53
Scrip
Scrip
BSVBD
  • Locked
  • Question
Transition from ASD to LRFD 1
Replies
3
Views
98
BUGGAR
BUGGAR
drawoh
  • Locked
  • Question
How to Prevent Free Student Simulation Software from Becoming “Shelfware” 1
2
Replies
33
Views
190
SwinnyGG
SwinnyGG
zdas04
  • Locked
  • Article
Orkney generates 103% of Electric needs from Renewables
Replies
11
Views
36
moltenmetal
moltenmetal

Part and Inventory Search

Sponsor

Back
Top Bottom