A cafe in the Dutch town of Zeist has installed a revolving door which generates electricity as you pass through.
Holland has led the way in wind power for centuries. With a quarter of the country lying below sea level they have traditionally used windmills to pump out the water. They currently have the world’s largest offshore wind farm, generating enough power to supply more than 100,000 homes. They are also famous in harnessing human power for transport. Anyone who has been to Amsterdam has seen the millions of bicycles on the streets. So what are they up to now?
Well, it would seem that this forward thinking country is ahead of the game once again. A new restaurant situated at the train station in the town of Zeist has been working with the design company Rau in order to reduce their carbon footprint. They’ve come up with an innovative idea in the form of a power generation system fuelled by their own customers – They have installed a generator in their revolving door which converts the energy of people passing through into electricity. Each time you pass through the door you generate enough power to make a cup of coffee. The owners estimate that the door will generate approximately 4600 KWH per year. They are also investing in other ways to reduce their energy requirements such as a special low energy cooling system, a sun collector, and of course the obligatory Dutch windmill.
As a low lying country, the Netherlands is potentially one of the countries to be most affected by sea level rise. As usual they are leading the way in developing ingenious means to reduce their need for fossil fuels. Imagine how much power we could produce if every revolving door or turnstile was equipped with this kind of energy capture technology? One small cafe in Holland may not produce much of an impact on its own, but just think how much power could be generated by such a system in a busy subway station in London or New York?
Image credit: Frank Za’atar at Flickr under a Creative Commons license
And, they invented clogs too..
Wow, dude that is pretty cool aint it.
jess
http://www.privacy.de.tc
Ok, check my math here:
The owners estimate that the door will generate approximately 4600 KWH per year.
Let’s say they’re open 14 hours a day (say, 7am-9pm) for 360 days a year. That’s about 5000 hours.
Now, divide 4600 kilowatt hours per year by 5000 hours – that gives 920 watts.
920 watts – or 1.2 horsepower – from opening to closing, all year. I know Dutch people are (a) generally healthy and (b) like cafes, but somehow I doubt those figures.
That’s 920 watts – per hour. Not 920 watts continuously.
It would be easy to generate that.
I call bullshit on this – there is no way one person generates the energy to heat a cup of coffee.
Energy needed = mass * temp raise * specific heat capacity = ~0.25kg * ~70C * 4.187 kJ/kgK = ~73kj
If it takes you a generous 10s to walk though the door you would need to be producing 73kj/10secs = 7.3kWatts!!!
According to http://www.ncbi.nlm.nih.gov/pubmed/10090637
the maximum a normal person can produce is ~500W so they are way off.
No spin, just window dressing. Besides that the windpark is small and there is really nothing to be proud of.
http://www.stichtingmilieunet.nl/andersbekekenblog/?p=4235
And here more about the human powered door
http://www.stichtingmilieunet.nl/andersbekekenblog/?p=5610
I think someone should tell London: think of all those revolving doors and they have have their climate change bill to worry about now. On that scale it must be able to make some difference, and anything is better than nothing really! Although maybe if they turned off that gleaming, money wasting, carbon using mass of canary wharf and office building spread throughout the city – ever – it may help!
i really think this will be a better solution:
http://www.stichtingmilieunet.nl/andersbekekenblog/?p=5863
Congratulations UK.
Damon, you have no idea what you’re talking about, and you’re only making yourself look like an idiot. A Watt is already a unit of measurement over time. 1 Watt = 1 Joule per Second.
“920 watts per hour” is effectively a nonsense concept in the way you’ve used it. (it’s a useful measurement, but only for discussing a difference in wattage over time).
Put it this way, if this article was about running really fast, you would have essentially just said:
“That’s 50 kph – per hour. Not 50kph continuously.
It would be easy to run that fast.”
….. 50kph/h is not a measure of velocity, it’s a measure of acceleration. You can’t ‘run’ at 50kph/h, and you can’t generate power at 920watts/hour. You might as well measure weight in square feet.
Hands up! I have no idea what the calculation might be to verify how much electricity this might generate, but I doubt that it would be very much. However, this is an innovative idea (believe me, the Dutch are very innovative), and it suggests all sorts of ways that we could easily harness energy that is otherwise wasted. For example, some of us produce an awful lot of hot air on these forums
Seriously, we should be picking up on this idea and looking for other ways to replicate it and improve upon it.
Eric,
If I understand your point correctly, you feel that an initiative like this one is irrelevant and that what really matters is just mega wind turbine projects producing mega giga watts. I think that besides the fact that every little bit helps, more importantly it makes people aware. By dismissing small projects like this one you implicitly say to all individuals out there who are trying to make small changes in their lives: “Just don’t bother!”
The world is awash with energy, but much of it is wasted, and very little is harnessed. Clever initiatives like this help to demonstrate that everything is possible, and that by applying a little ingenuity we can slowly, step by step find smarter ways to power our world.
Those who dismiss such innovation are the same that said the world is flat, man will never walk on the moon, mobile phones will never take off etc etc. And those people look pretty silly now..
Umm the revolving door is a kids project. My sister did it for her 6th grade science fair some 18 years ago and in the meantime i made a unique type of windmill for that same fair and i was in 4th grade. its funny that 18 years on now they’re implementing this same simple system in a cafe and calling it the answer to global warming?! Its a drop in the ocean, but still something is better than nothing, its cute. Damn, we should’ve patented this thing ages back i suppose..
@Anna,
Yes, it creaties awarness. But i have to say that we have so many projects in our country to create awareness. That worked alraedy. Dutch people are very concerned about climate. Over 85 percent of the people want to do something.
And ther it stops. We are not realizing big projects. We are trying out all options, all possibilities and then? Nothing.
May be you didn’t know but renewable energy is only a fraction of our electricity use. The graphic shows it all:
http://www.stichtingmilieunet.nl/andersbekekenblog/?p=2546
@Mark
I don’t dismiss this initiative, but it is really ridiculous to think this is a way to go in the world.
@Sameer
Yes, the revolving door is a kids prokect, good education.
@all
I’m looking for some correct figures about the revolving door, but believe me, it will be genetrate less energy then you think.
May be you like those kind of awareness projects. We have a bunch of them. This one is also very educative, but doesn’t generate that much energy. So it isn’t an option to go dancing everywhere in the world on this energy generating dancefloor. Yep, human powerd again:
http://www.stichtingmilieunet.nl/andersbekekenblog/?p=3304
By the way: Amy Winehouse didn’t show up at the opening.
It takes about 20KCal to boil a cup of coffee (raise 250ml of water by 80 degrees Celsius from 20 to 100). I doubt if pushing a revolving door will generate 2KCal.
Uh, Ben…?
“Energy needed = mass * temp raise * specific heat capacity = ~0.25kg * ~70C * 4.187 kJ/kgK = ~73kj
If it takes you a generous 10s to walk though the door you would need to be producing 73kj/10secs = 7.3kWatts!!!”
I’m pretty sure that making 12 cups of coffee doesn’t require 87.6 kilowatts, when a Honda fuel cell produces only 80kW and an average US home only uses 0.9-2.0kW an hour. I think you might want to look into how electricity works.
Haha, millions of bicycles? I agree there are a lot, but with Amsterdam’s population being in the 750k range, I think you’re exaggerating.
Eric,
I don’t believe such a thing like too much awareness exists. Maybe this is the one project for a couple of thousand people that say: “hey we can make a change, it does not just take huge investments and grand projects”.
Moreover, the fact that we are discussing this initiative on a US based website with a large international audience, proves that even if you are of the opinion that it is not necesary to raise awareness in Holland anymore, the news travels far beyond its borders. Or is their no necessity for awareness anywhere in the world?
And her is a nice human powered floor:
JR East will begin its experiment on December 10 and continue it until February 2009. The power-generating floor will cover an area of 25m squared and will be installed at 7 ticket gates and 7 staircase steps inside the gate.
The company expects the floors to produce 1,400 kW/sec each day. If the piezoelectric experiment is successful, the train station floors will ultimately be used to power ticket gates and electronic display systems.
http://cleantechnica.com/2008/12/04/tokyo-train-station-testing-power-generating-floor/
@Anna,
No, that is not what i mean. We need more awareness. That is never enough. Lots of work to do in the world. So we shouldn’t stop writing about good examples.
What i mean is that revolving doors are not the solution. But i agree: all little things to save energy will help on our way to a sustainable society.
See these energy saving tips:
http://www.stichtingmilieunet.nl/energysavingtips.php
Well apparently there are many more bicycles than people in Amsterdam…..
@M – yeah they all have several bikes each. I’ve never seen anything like it.
The ‘obligatory Dutch windmill’ was never meant to gain energy, but to keep the Dutch from getting wet feet ..
I thought that it required energy in order to pump water. Therefore the Dutch use windmills to gain energy and keep their feet dry.
It’s “The Netherlands”, not ‘Holland’. Small but significant difference.
Well what a good debate, if nothing else it has got people to do a bit of mathematics! The good thing is to give consideration to anything at all that will save or produce energy ecologically. It does not have to be a lot each small bit adds up to a bigger bit (I think thats mathematically correct!)
Ryan, I think you’re the one not getting it here. Ben’s calculation is correct (even if 2.5 dl is a rather large cup of coffee)
The energy it takes to make a cup of coffe, per Ben’s math, is 73kJ.
Ben then showed that if you want to generate that amount of energy by walking through a door, assuming generously as he did that it takes 10 seconds, then your power (energy per unit of time) would have to be 7.3kW. Which is unreasonable.
These numbers cannot be correct.
Regardless of all the calculations, this idea is firmly copyrighted by Andre Franquin, when he had his cartoon hero Gaston Lagaffe (or Guust Flater in Dutch) invent a machine that, when someone would push open the door to his office, would do a variety of things, amongst which feed his fish, get the juice from an orange, grind some coffee. Needless to say, the effort to open the door was very high…:-)
BTW, the company that built the door is Boon Edam. http://www.boonedam.us.
I should have mentioned that the article got the energy calculation part wrong: the door *saves* 4600kWh per year. Regarding the energy that is generated from the door:
“The revolving door is equipped with a special generator that is driven by the human energy applied to the door whilst the generator controls the rotating speed of the door and makes it safer. The ceiling of the revolving door is made of safety class and gives a clear view of the technology. A set of super capacitors stores the generated energy as a buffer and provides a consistent supply for the low energy LED lights in the ceiling. In case the LED lights have used-up all the stored energy, the highly efficient control unit will switch to the alternative mains supply of the building. This ensures that the door is illuminated at all times, even when the passenger flow is minimal.”
You can see the entire press release about the door by going here: http://www.boonedam.us/inc/press/pressdetail.asp?PressId=182.
They didn’t read the press release right ( http://www.boonedam.us/inc/press/pressdetail.asp?PressId=182 )
The door gives a *saving* of 4600kWH/year compared to sliding doors. The saving comes from keeping the heat in! Not from the generator, which almost works up enough power to light some LEDs.
Interesting idea and presumably it is not so hard to get through that old people and disabled people have trouble operating it (though it can hardly be accessible for wheelchairs).
I just wonder how much heat energy is lost by having a revolving door?
This article says more about this website than about the article. The figures mentioned in this article are away from plausibility by several orders of magnitude. Even a first-grader who is able to operate a calculator will notice this nonsense.
Of course, it is possible *some* energy this way. But the generator built into the door has a CO2 footprint that the door will never make up.
You guys at ‘ecoworldly’: that’s exactly the way of environmental activities we *don’t* need. Better go and hug a tree, leave the writing to people who think
ADD kids revolving door energy crisis solved