Sunday, May 24, 2015

Air-powered cars? Not energy efficient enough

Three years after this post was published, I published an update here.

The most recent version of an air-powered car, first introduced by Guy Nègre in 1991, was featured on Shark Tank recently. Robert Herjavec is willing to invest $5 million into Zero Pollution Motors provided that they negotiate a North American license from Guy's company, Motor Development International. Currently, ZPM only has a license for Hawaii. Autoweek covered the story here.

Don't expect to see these cars on the road any time soon. Guy has been flogging this idea for over 20 years now with only prototypes to show for it. In 2007, he announced that Tata Motors had licensed the technology and would manufacture cars in India but a visit to Tata Motors' Web site shows no mention of air-powered cars. To my knowledge, Tata has not sold a single air-powered car.

Most people see the appeal of the concept. Where is the problem? It's in compressing the air for the car. Compressing air produces heat, which is typically lost, reducing efficiency. On the flip side, in the car, expanding the air absorbs heat which means the air needs to be heated, reducing efficiency. One way around this is to capture the heat and store it in a battery, using that energy to heat the air when it is used in the car. The end result is that an air-powered car is not sufficiently energy efficient to be practical.

I could see using air power in situations where energy efficiency is not a factor but convenience or access to compressed air is. For example, in an electrical power plant, the waste heat from the boilers could be used to compress the air, reducing the overall energy cost.

Part of the Shark Tank pitch was the concept of using "turnkey micro-production factories" to build the cars locally. With the car already being impractical, saddling it with an unrealistic manufacturing model will surely doom it. Just as Tesla has one manufacturing plant, only one manufacturing plant is needed to serve North America.

One final point: Neither Ethan Tucker or Pat Boone, the presenters on Shark Tank, appear to have any experience building or selling cars. Ethan, at least, is listed on the management page of ZPM.

I wish Mr. Nègre the best, but the physics are against him.

Sunday, May 17, 2015

Amtrak crash in Philadelphia: A possible scenario

Thanks to reporting by the New York Times in this story, I have put together a possible scenario of the events leading up to the crash of Train 188:

1. The train leaves the North Philadelphia station and accelerates at maximum power to a planned 80 mph.

2. A rock strikes the train, damaging the windshield.

3. At some point, the engineer is supposed to take the throttle to idle and then apply the brakes to reduce the speed to 50 mph for the curve.

4. However, the engineer is distracted by the rock striking the windshield and doesn't start braking at the correct time.

5. Still accelerating at maximum power, the train continues past 80 mph to 106 mph.

6. The engineer regains concentration, realizes the train is going too fast, and applies the emergency brake.

7. But it's too late. The train tries to go around the curve at 104 mph, derails and crashes.

A Septa and an Acela train were also hit by rocks about the same time. Note that the engineer in the Septa train that was hit was shaken up enough by the incident that he couldn't continue driving the train.

The rock throwing has continued for many years. It's one of those things that the authorities don't worry about until someone dies. With this accident, eight people have died. The problem will now be fixed.

Friday, May 1, 2015

Computer camps for third graders

Recently, I got a call from a mother whose son wants to learn about computer programming. His school offers classes but they don't start until the fifth grade and they won't make an exception for her son who will be a third grader in the fall (seven years old). I found two summer day camps in the Cincinnati, Ohio area that have camps for third graders. (Note: The summer camp folks look at the grade your child will be in in the fall.)

I don't know much about these camps and this is not a specific recommendation. The main reason I'm posting this is to reassure parents that seven years old is not too early to begin learning about computers, whether it's developing games or writing programs.

One set of camps are offered by Classroom Antics. The camps range from Junior Video Game Design (ages 7 to 9) to Stop Motion Animation (ages 9 to 13).

Another place for a variety of scientific camps, including programming camps, is CINSAM at Northern Kentucky University.

Drake Planetarium also has camps that involve concepts related to programming. Once you display the page, click on "2015 Summer Camps" for more information.

There may be more camps that I'm not aware of. If you are connected with a summer computer camp, drop me a line and I will update this post.

Please provide feedback in the comments. You may comment anonymously if you wish.

Updated May 17: Added Drake Planetarium.