Matt Coston

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since Nov 07, 2017
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Recent posts by Matt Coston

Link - Interview with Paul Stamets on the Tim Ferriss Podcast. You can stream it direct from the page - no need to download first.

It's similar to the interview he did on The Joe Rogan Podcast.
3 weeks ago
Don't worry about how to scale it right now. Concentrate on demonstrating that your idea actually works and is beneficial.
4 weeks ago

Travis Johnson wrote:The ideal place for this would be in an old quarry.


If the crane is economically viable, thousands of them would need to be built around the world. The crane makes sense because it can be built anywhere, and also built adjacent to the power plant, saving on high voltage cabling.
4 weeks ago
@Austin Shackles

I believe we can both agree that GPE is economically viable at large scale (I said it twice in my first post).

I also agree that batteries are made from very finite resources, which is a major drawback.

But I am convinced that GPE is not economically viable at the scale you're proposing in your OP. Let me know when you've figured out what your idea will cost you and how long it will take to pay for itself.

Another interesting calculation to think about - the Tesla battery cost $66 million and stores 129MWh. That means it costs approx $500 per kilowatt-hour. The "Energy Vault" crane in the video is projecting $150 per kilowatt-hour. If true, that would seem extremely good.
4 weeks ago

Austin Shackles wrote:but 5000kg and 5m height would give you  25x the energy, say, and wouldn't be hard to build.  Obviously, you can't carry it around like a drill, but many things don't need so much power as a drill.  Take lighting, for example, if you use LEDs 10W will light a room.


5000kg at 5m = 245,000 J
10W LED light for 6 hours = 216,000 J
So you can basically illuminate 1 room for 1 evening. It's not even remotely economically viable - if it was, we would already be doing it everywhere.

Have you done an estimation on what your idea would cost? What $-per-kilowatt-hour do you expect?

Austin Shackles wrote:It might be that for small scale, batteries are still the way to go - but town-sized, they are still way too expensive.


I assume you're aware of Tesla’s 100MW/129MWh Powerpack project in South Australia? The reported figures show that it will pay for itself in less that 2 years.
4 weeks ago
A simple calculation will show that gravitational potential energy (GPE) is a poor store of power unless you have access to enormous amounts of storage - i.e. a lake.

Austin Shackles wrote:Gravitational potential energy though is given by mgh:  so a 1 tonne weight (1000kg) lifted by only 1m has a potential energy of somewhere around 9.8KJ


Take a look at this cordless drill battery.

It's 18v 9ah. This converts to 162 Watt-hours, which converts to approx 0.58 megajoules.

So that hand-held battery has approx 60x more energy than a 1 tonne weight raised to 1 metre.

Storing energy as GPE just isn't practical unless you can do it on a massive scale.
4 weeks ago

Daniel Burnam wrote:His boat has a 425hp diesel caterpillar motor and he says he burns about 35 gallons of fuel/day on average. Just a quick search on the internet and some simple math says that he's using about 1 megawatt electrical equivalent in diesel fuel


I think the units you're using to analyse the problem are wrong.

Watts are a unit of power, not energy. Power is the instantaneous flow of energy. The base unit of power is Watts. The base unit of energy is Joules, which can be converted into Watt-hours.

The 425hp engine is equal to approx 317 kilowatts - this is the max instantaneous output of the engine.
The 35 U.S. gallons of diesel is approx 5128 megajoules or 1424 kilowatt-hours. See diesel-to-Joules conversion calculator here - https://www.convertunits.com/from/gallon+[U.S.]+of+diesel+oil/to/joule

So for equal performance, the boat will need a 317 kilowatt motor and a 1424 kilowatt-hour battery.

The top-of-the-line Tesla model S has a 100 kilowatt-hour battery, so they will need the equivalent of 15 Tesla model S battery packs in their boat. The estimated weight of the 85 kWh battery pack in a Tesla is 540 kg (there's no official figure that I can find in a brief search), so this boat will need about 10,000 kg (22,000 lbs) of batteries.

Here is an example 300 kilowatt electric motor. It weights 3050 kg (4500 lbs).

I'm not a scientist or an engineer so all this could be complete rubbish!

EDIT 1: link formatting

EDIT 2: I forgot to think about efficiencies!!! Internal Combustion Engine is typically 20% efficient.
Electric motor is typically (I believe) 90% efficient. Lithium Ion battery is also about 85% efficient. I guess you could get away with only 700 kilowatt-hours of batteries or approx 5,000 kg.

EDIT 3: I think you should ignore that link I gave to the 300 kilowatt motor. My instinct is now telling me you wouldn't need something as big as that. I don't know enough to give any further info.
1 month ago

josh ober wrote:I guess what I’m having trouble with is understanding how cob would stay cool in the heat, considering the fact that it seems it would be absorbing heat from the sun.


It does indeed absorb heat, but different materials can absorb more energy before they actually start to feel warm.

I appreciate that could be a bit hard to wrap your head around. The fundamental reason for this property is highly technical and beyond my understanding, but is explained on Wikipedia:

https://en.wikipedia.org/wiki/Heat_capacity
https://en.wikipedia.org/wiki/Thermal_mass

An example given on Wikipeida (see this table) is that water requires about 4.5x more energy (measured in Joules) to raise its temperature by 1°C compared to an equivalent mass of concrete. So in layman's terms, concrete starts to feel warm four to five times faster than water does. This means water is the better material to use as thermal mass. Of course, water has a habit of leaking out of containers and destroying stuff. On the other hand, water can also be pumped through heat exchangers which allow you to push the heat around much faster. So there are a number of factors to consider.

Here's another useful table showing heat capacity. Sandy clay requires about 1.6x more energy than concrete to raise the temperature.

An interesting (and counter-intuitive) detail to note is that air has a higher heat capacity than concrete. But of course, 1 tonne of air occupies a much larger volume than 1 tonne of concrete.

Finally I just want to point out that I am not a scientist or engineer, so I would love somebody who is to confirm what I have written above.
1 month ago
cob
Hi Jay,

Jay Angler wrote:...if the goldenrod was grown in dirt with fertilizer, it might well show some of the changes for reasons other than the presence of higher levels of CO2.



There were two separate trials conducted (link to study at bottom)
    1) Comparing present-day goldenrod to historic goldenrod (which does not directly address your above concern)
    2) Conducting an isolated trial where the goldenrod was grown in polytunnels where atmospheric CO2 was the only variable (which does directly address your concern)

The report explains that the confidence in their conclusions from both tests is high: "...the current data do indicate a clear and unequivocal link, both historically and experimentally, between rising [atmospheric carbon dioxide] and a qualitative decline in pollen protein".

Jay Angler wrote:Who was that guy anyway?



He is a professional science communicator. He has a degree in physics engineering and a PhD in science education research.

Finally, I do also dislike how quickly he dismisses (in the video) the idea that soil health does not contribute. However I am comfortable believing the results of the study.

The study - http://rspb.royalsocietypublishing.org/content/283/1828/20160414
2 months ago