Should coal stay?

I would LOVE some global warming right now! This weather sucks! :(

Jo

Ensign/Jeff - I agree with you guys in that we should be following a shot gun approach to energy, i.e. go after any source that is viable. Cheap and plentiful energy will change this world in very significant ways.

I've been to Germany. I saw several large windmills in Bavaria, but they use solar on a distributive basis. That is, they don't use it for base load, but instead use it on their rooftops. I am a big fan of homegrown generation via photovoltaics (and the price/kwh is getting close to being competitive). I hope someday to fill my roof with them to run my house and generate hydrogen for my fuel cell car.

CP could use solar in this way (rooftops) to reduce dependence on other sources. I wonder what impact regenerative breaking would have if installed on their coasters? Use the recovered energy to charge batteries to run the lighting at night?

In any case, I still look fwd to smelling coal smoke next summer coming from Judy K.

Regenerative braking has its place, and as a matter of fact it is used on rides such as maXair. But in a safety critical system such as a coaster, it's not such a great idea. The idea behind regenerative braking is the same as magnetic braking, in fact the setup is almost exactly the same except that the electrical energy coming off the coil is run through a line reactor and/or an oscillator and dumped back into the power grid. Lots of big rides run that way. But for regenerative braking to work, you have to have someplace for the electric power to go (i.e. back to the grid).

The trouble is, if you blow the fuse on the regenerative braking circuit, you lose your electric brakes. This is unacceptable on a coaster, which is why magnetic brakes on coasters are non-regenerative and simply kick off their collected energy as waste heat.

It's a great idea in theory, and it works great on big flat rides where there really isn't a safety concern if something goes wrong, but in practice there are some conditions where it is just a little bit too risky. :)

Now, if we could figure out a way to collect that heat and somehow convert that into useful energy, that might be worthwhile...

--Dave Althoff, Jr.

If CP's coasters had regenerative breaking, they could get away with a smaller maintenance department . . .

bholcomb said:
As far as using a diesel generator as opposed to a Natural Gas generator, do they even make bigger sized Natural Gas generators?

Here is a 5200 kW commercial generator that comes in a natural gas/propane or diesel version. So they do exist in large sizes. This one looks huge compared to the truck carrying it. Generator Joe has a good selection of large, commercial natural gas generators.

Ensign: Good catch on the spelling. Perhaps coffee break = regenerative breaking.

RideMan: If the hybrid cars can use regenerative braking to stop cars, which is a critical function, I would expect coasters could do the same. Charge batteries to be used for night use or powering of non-critical functions.

This is an interesting thread, let's hope it doesn't get outta control too.......

RideMan said:
The trouble is, if you blow the fuse on the regenerative braking circuit, you lose your electric brakes. This is unacceptable on a coaster, which is why magnetic brakes on coasters are non-regenerative and simply kick off their collected energy as waste heat.

--Dave Althoff, Jr.

When the magnets on the coaster train move over the metal break fins on the track it creates a force in the opposite direction of the train, slowing it down. Doesn't it also generate some current or is all that energy just converted to heat?

Magnetic braking is a different animal than regenerative braking. The former uses the attractive forces of a magnetic field, either from an electromagnet or from a rare earth magnet, to retard the forward motion. The latter essentially turns a motor into a generator. When you do that you need someplace for the electricity to go to. It can be put back into the power grid, or converted into heat by routing through resistor banks. Both of these methods will create a braking effect. This is also known as dynamic braking, and has been used on electric and diesel-electric locomotives for over sixty years.

You're on the right track, Dutchman, except that magnetic braking is often done with a non-Ferrous braking fin (usually copper or aluminum).

Mechanically, you're doing basically the same thing either way. A motor converts electricity to mechanical force; a generator converts mechanical force to energy. The real difference is in what you do with that energy.

In a magnetic braking system, the brake fin isn't connected to a load, instead it behaves as an effective short-circuit. It allows for virtually unlimited current flow, which means the current does little more than to heat up the fin. It allows the brake fin to provide a theoretically infinite load which provides maximum mechanical resistance.

In a regenerative braking system, the current generated in the braking coil is dumped into a load. It's the current flow through that load that provides the mechanical resistance, which means if that load should suddenly become an open circuit, the mechanical resistance will go away. It's great for a system where an operator can switch to friction braking in a pinch, as on a train, and it works beautifully for a motor-driven ride like a Pharoah's Fury or Top Spin or Fireball, where a loss of braking is little more than an inconvenience. But on a roller coaster, there is no tolerance for braking failure, so it makes more sense to waste the braking energy than to try and recover it.

Put another way: Lose the regenerative electric brakes on a Fireball, and it takes a long time for the ride to stop. Lose the magnetic brakes on Maverick, and you have a collision. For that reason, it makes more sense to use a system which is unlikely to suffer such a failure.

--Dave Althoff, Jr.

Rideman & Dutchman: I feel kindred engineering spirits in both of you, as I am a retired mechanical engineer.

I understand the safety issue of the regenerative braking, but, look, the Toyota Prius and other hybrids use this concept to increase battery charge and improve overall mileage. Clearly, they have found a way around the safety issue or reduced the chances of failue to acceptable levels (keeping in mind that not stopping a car going 70+ mph will probably kill you). Don't you think we can make it work for the coasters? But, as in most cases, it boils down to cost vs. reward. Still, those big, heavy coaster trains carry a lot of kinetic energy on every circuit of the track course. Surely the cheap way is to dump it as heat, as is currently done. It sure would be nice to see it recovered (of course not 100%) in some way.

But a Toyota Prius or other hybrids do not use regenerative braking as the primary source of braking. You still have hydraulic brakes when you press the foot pedal that will stop the car, which is the primary means of stopping the car. The regenerative braking simply serves as a way to increase battery life, loosing regenerative braking is not a safety issue.

As Dave said, a roller coaster with regenerative braking would have no such option. If the circuit opens - WHAM!

Right; that's the general problem. I'm not sure how the regenerative braking works on a Prius, but I do know that when you stomp on the brake pedal, that is still a conventional hydraulic system. I can understand perhaps building it so that the regeneration circuit kicks in with the brake lights, and perhaps through the first few degrees of pedal travel. But in a car, you've got a direct linkage to a hydraulic piston that will slam the friction brake closed as fast as you can punch the pedal.

The particularly great thing about it is that you, as a driver, can decide if you need to slam that friction brake closed. It's exactly the kind of 'fuzzy' decision making that computers quite frankly aren't very good at.

I still think that if you really want to recapture some of the energy from magnetic braking, the way to do it is to figure out a way to capture and use all that heat.

In fact, as long as you're capturing heat from the brakes, let's also capture heat from the motors, and heat radiating off the midway. We can make the whole park cooler and put that energy to use doing something useful. :)

--Dave Althoff, Jr.

Ever hear the scream of the resistors on the giant top spin at Kings Island? That's cool.

What they should really do is put 50 or so "human powered" generators all over the park. It could just be a big wheel or something that people can spin as they walk by and it would generate electricity.

^Genius! Turn every turnstile at the park entrance and ride entrances into generators. The one at Maverick could be used to power the broken tv in the queue!

Dvo: Why do I think I have actually heard about something along those lines before? I think it might have been a Disney headline or something. Not just spinning turnstiles, but also walkway pavers that generate a minute electrical current when you step on them. The idea is that while no system generates a useful amount of energy, distribute these itty bitty systems throughout a park and combine them with the tremendous number of people using them during the day, and you get something almost meaningful.

Then someone realized that the "meaningful" amount of power from all of this might be enough to light up a strand of LED Christmas lights and therefore wouldn't be worth the cost of implementation...

--Dave Althoff, Jr.

How bout we get the power from everybody screaming on the rides like Monsters Inc. :)

Your mom is to fat to ride TTD. said:
How bout we get the power from everybody screaming on the rides like Monsters Inc. :)

obviously because laughter produces more electricity.

I found a "wind map" that illustrates avg. wind speeds throughout the country; to no surprise the Sandusky and entire Lake Erie region is a perfect place for wind generators.

http://www.windpoweringamerica.gov/images/windmaps/oh_50m_800.jpg

I'm just curious if anyone has ever brought up the idea seriously at a meeting; I mean, imagine the money CP would save every year by being off the grid and self sufficient. Then again, is it legal for an entity like CP to go off the grid and generate its own energy? Im sure this is probably infintely more difficult than how it sounds.