Monday, December 28, 2015

The Science behind why there is no such thing as a greenhouse gas

I have pet peeves.

One is 'fossil' fuels, where the word fossil is horribly abused.
Go to a museum and ask to see their fossil collection and you will find a huge assortment of... rocks that couldn't be set on fire with a nuclear bomb, let alone a match.

Look up fossil in the dictionary and you'll find nothing that will ever lead to flammability or the use as a fuel. What you will find is a process that turns flammable flesh and plants into rocks. What we have is a pairing of words that have less to do with each other than 'military' and 'intelligence.'

But worse and more scientifically offensive than pairing fossil with fuels is greenhouse gas.

First, a gas can never give you a greenhouse effect, just as a fossil can never be burned as a fuel.

Let me explain. When I say greenhouse, most picture a building made of glass, but few know how it works and why.

A greenhouse 'traps heat'... but not really. Not scientifically. In reality, a greenhouse simply reduces the surface area of the boundary between two fluids, the one inside and the one outside the 'house'.

Greenhouse effect and ice cubes:

An IceCube is the perfect example of a greenhouse. If you drop an ice cube into hot soup it takes longer to melt than if you drop the same amount of snow into the same soup, or pour ice cold water into it. This is because snow (and ice water) has a billion times the surface area that a cube does, so the outside of the cube has to melt before the inside can get warm.

Another example is fill a water balloon with hot coffee and drop it in a bath tub of cold water. The balloon will stay warmer longer (trap the heat) than if you pour the same amount of coffee directly into the tub.

The balloon and the cube are examples of limiting thermal conduction by reducing boundary layer surface area (greenhouse effect)

A gas can never reduce surface area, hence there is no such thing as a greenhouse gas, it is a contradiction in terms.

Now, water vapor can form a boundary layer between two bodies of gas when in the form of a cloud, but what a cloud is is a gas turning into a liquid and a liquid reduces its surface area like an IceCube does. In other words, liquids are not gasses, by definition, and only in liquid state are clouds 'greenhouses'.

CO2, methane, etc do not gel or liquefy air molecules and hence can not be a barrier or reduce surface area. There is no layer or pockets of CO2 gas, and thus none of these 'greenhouse' gasses are producing a greenhouse anything.

Now, what they can do is add mass to the air and that added mass can 'trap heat' in the same way as 20 pounds of salt water can 'trap' or store more heat than 5 pounds of pure water at the same temperature. But this is not adding heat, but adding a resistance to changes in heat. In other words the only effect of adding/dissolving a gas into another gas is that you can change its mass and thereby change how fast or slow it warms or cools, but you can NOT change its average temperature.

In other words, the most these 'greenhouse' gasses can do is make mornings and nights warmer and days cooler, instead of dropping 20 degrees f every night and warming 20 degrees every day, the most adding a 'trapping' gas can do is change the 20 to a 15.

Pet peeve, I know, but there is no such thing as a fossil fuel or a greenhouse gas, both terms are as silly as military intelligence. :)

Friday, December 11, 2015

Safety idea

I watched a clip on how many people get killed every year trying to pass a tractor trailer, most of the time they tailgate it, then jump out into oncoming traffic blindly out of frustration or impatience. It's such a big problem (and opportunity) that some big time TV manufacturers are advocating 40" TVs be put on the back of trucks, wired to a camera in the cab so people stuck behind can see when its safe.

But there's an easier way. And much cheaper too.

Everyone that's ever seen a movie knows subs have periscopes, most kids have at one time or another used two mirrors and a cardboard box to 'spy' around a corner.

So the solution is rather simple, just build two more mirrors (one forward facing (wide angle dome style preferred), the other normal) into the driver side mirror, horizontal-periscope-style if that helps visualize it. That will let all drivers better see when its safe to pass anything too big to see around. It could easily be built as an after market clip on, likely for under $15.

Of course, since a lot of cars have backup cameras in them now, adding a second camera, forward facing and mounted on the driver's side mirror, would work just as well too.

Sunday, December 6, 2015

Last words on rechargeable batteries

My last two posts may have left the impression in some that I am anti rechargeables, which I am NOT.

But it is important to know when and where things belong, and what is the best use and misuse of resources.

If you need to dig out a hole for a mailbox post, you use a shovel. When you need to dig out a basement for a new house, you use a backhoe.

The same is true of batteries.

Rechargeables are great for flashlights you use every day, they'll save you and the planet a fortune in disposable batteries. Same with cell phones, laptops, etc., these are heavily used, every day items. Rechargeables are ideal and the clear choice when they compete against disposable batteries. And yes, disposable batteries can power these everyday items, but it would be foolish to.

Take my flashlight example. Used 8hrs a day, 5 days a week by a security guard working nights, disposables would cost anywhere between $5 and $20 a week, where rechargeables would cost $30 for the next 3 years (including charging costs). An obvious savings.

But, if you only use the flashlight for emergencies, disposables are again ideal and rechargeables lose, and they lose for the following reasons. 1. The life of a rechargeable, used or not, is rarely over 6 years (think of it as rust, but on the inside), so even if it held a charge for that long (it won't) it's still a bad use of a very expensive battery. 2. Disposables keep their 'charge' much longer, and are generally more powerful. That's why we still use them in clocks, watches, smoke detectors and the likes.

Basic rule, rechargeables are perfect for replacing disposable batteries in items that are used every day.

So, you would think that this would extend to cars, except nobody ever would make cars that used disposable batteries.

Again, the boring math comes into play.

Rechargeables have a max life cycle of a thousand or so recharges. That effectively puts a 'replacement battery tax' on the electricity it stores of somewhere around 50%. This means for every dollar you spend charging a battery, it wears out 50 cents worth of the battery. That's trivial for an iPad or iPhone, but hundreds a year for a Prius and thousands a year for a Tesla... on top of the price for electricity itself. Even if the batteries lasted forever and cost nothing, electric cars generally don't break even unless gas prices are over $2.50/g.

Again, there are solutions to this math problem.

First, cheaper electricity would take a lot of the sting out of replacing batteries. People would happily pay $500 a year in batteries if it only cost them $100 in electricity, when in today's world it is more like $1,000. It's possible, but unlikely to happen any time soon.

The costs of rechargeables could drop by 90%, nobody would bat an eye at shelling out $50 a year and paying $1,000 in electricity for charging the car.

Third, my choice and achievable today. Compressed air. It can store a similar power to weight ratios as rechargeables, but it doesn't wear out. It is entirely possible, with today's tech, to build compressed air cars with 100 mile range that refill in 10 minutes, cost less than gasoline cars, and would have useful life spans of 20-40 years.

Now, one stumbling block is it loses/wastes a lot of stored power with a cryogenic effect (compressed air, when it decompresses, is cold, sometimes cold enough to form dry ice). This waste can be harnessed to nearly double the range/efficiency of compressed air by adding a stirling, but even without it, it is margineably competitive with rechargeables today and should not be overlooked, especially because it uses none of the exotic materials rechargeables do.

Compressed air would not work well with cellphones, laptops, drills, but like a lot of things, it has a scale where it does make sense.

And the department of energy, unfortunately, knows these thing but, sadly, is a place where math and good ideas go to get buried under political pet projects and connected corporate handouts.

Thursday, December 3, 2015

Elon Musks battery scam

In a previous post, I went over the math behind the electric car battery scam, but math loses most people, and the idea of rechargeable batteries also escapes most people. They don't know lithium ion batteries wear out because they've never kept a phone for more than five years. The only rechargeable battery most encounter is the $100 gasoline car battery we replace every 5 years or so.

The best way to think about rechargeable batteries (any of them) at the electric car scale is to think of them like car tires. Everybody knows tires wear out, somewhere between 20-60,000 miles and, in general, are very expensive to replace. Everyone remembers the sticker shock of buying their first set of four tires. Electric car batteries wear out at about the same pace, 20-80,000 miles, except they are nearly ten to thirty times as expensive as tires (by the way, you still need to buy tires too). Some 'after market' 'used' replacement batteries for the Prius start at $500, but typical is around $5,000, a tough purchase for a 5-10yr old car. Tesla, with a much bigger more expensive battery, can touch $20,000 to replace, again, a stiff repair bill for any car. But it's 'baked into the cake' and, in a way, may be where Musk plans to make his next fortune... replacement batteries.