Super Soaker Inventor Hopes to Double Solar Efficiency

mattnyc99 writes "With top geeks saying photovoltaic cells are still four years away from costing as much as the grid, and the first U.S. thermal power plant just getting into production, there's plenty of solar hype without any practical solution that's efficient enough. Until Lonnie Johnson came along. The man who invented the Super Soaker water gun turns out to be a nuclear engineer who's developed a solid-state heat engine that converts the sun's heat to electricity at 60-percent efficiency—double the rate of the next most successful solar process. And his innovation, called the Johnson Thermoelectric Energy Conversion (JTEC) system, is getting funding from the National Science Foundation, so this is no toy. From the article: 'If it proves feasible, drastically reducing the cost of solar power would only be a start. JTEC could potentially harvest waste heat from internal combustion engines and combustion turbines, perhaps even the human body. And no moving parts means no friction and fewer mechanical failures.'"

Re:Hmmm....

[ScrewMaster]

On the other hand, there aren't many solar processes that really qualify as "efficient" so he doesn't have to work all that hard to double them.

Re:And...

[moderatorrater]

I can guarantee that the water wasted from super soakers is nowhere near the amount wasted by poorly aimed sprinklers watering cement.

Re:Hmmm....

[Anonymous Coward]

As long as you don't count plants....

Re:Second Law of Thermodynamics

[tsm_sf]

By that logic geothermal power plants wouldn't exist.

Re:Hmmm....

[kesuki]

well your bs detector was good to be at high alert.

Currently he has a working prototype that operates at 200 degrees centigrade. the theory implies that at 600 degrees it would achieve 60% efficiencies, existing solar (parabolic mirror based solar electric plants) operate at 800 degrees. since he has a system that works at 200 centigrade, it is not a massive power plant sized unit, that would need to be stable and still work in the 600-800 degree range. if his invention only works at 200 degrees centigrade, then it will never replace convention solar power models. but there are still many potential uses for a 200 degree centigrade model, such as using 'waste heat' from existing power plants to create 'more electricity' with less fuel.

so yeah, i wouldn't hold my breath on this 'still working' at 600 degrees when the guy who invented it hasn't gotten to those temperatures yet.

This will be of bigger uses elsewhere

[WindBourne]

In particular, with nuclear power plants AND geo-thermal. Our power plants dump loads of energy to the environment. This may possibly help with using more of that energy.

Perhaps more important would be geo-thermal. It does not say what the temp differences need to be, but if it can work on ~ 100 degree difference, then this is the answer for the large number of dried up oil wells that have loads of heat down there. The big problem for USA is that we have a large number of wells where the max temp is ~170F. We could hook up a solar heater to carry it up in temp, but if this works, then it will enable these old wells to be re-used and new ones to be drilled.

Re:Anyone spot the danger?

[Anonymous Coward]

Possible? Sure. Practical? Hardly. This invention is a heat engine, so it is limited by the Carnot efficiency (1-Tc/Th) where Tc is the cold reservoir (in absolute temperature) and Th is the hot reservoir (in absolute temperature). For a 60F cold reservoir(519.7 degrees Rankine), and a 98.6F body temperature(558.3 degrees Rankine), that works out to a Carnot efficiency of (1-519.7/558.3)= 7%

You'd be much better off concentrating the sunlight (used to grow the algae), and harnassing the energy directly from that.

Re:And...

[MishgoDog]

What a naive comment.

I live in Melbourne, the 2nd largest city in Australia. Australia has incredibly low population density, yet where the number one issue on everyone - including the everyday mums and dads - is water.
For the last 3-4+ years we've been on water restrictions such as:

• Can only water garden between 6 and 8am, only on 2 days a week (depending on street number). Must use a trigger nozzled hose. Cannot water grass. With the exception of One in every FOUR sporting grounds.
• Cars cannot be washed at home, only at a commercial venue where they recycle water. Bucket can be used to remove spot corrosion.
• Cannot fill new or existing pools or spas. Topping up can be done with a bucket or watering can only.

So you see, when you say you cannot 'waste' water, I wonder what in the world we're doing all this for, because clearly your knowledge is greater than our own.

Yes, the total water amount on this planet may be constant - but only 0.3% of this is accessible fresh water (not counting glaciers, ice caps and ground water). And this isn't where we want it.
Hmm... maybe you're right. Maybe I should leave Australia, and move to some other place, just because our climate patterns have been changing over the last 10 years (gee, I wonder how that happened) such that we now have no water...

Re:Not sure about this...

[mprinkey]

He claims that this is equivalent to the Carnot cycle...specifically it is an Ericsson cycle. It still has the same (low) fundamental efficiency for small temperature differences. This is unlike a fuel cell which is not a heat engine and the Carnot limit doesn't apply. His target application is solar concentrators so the temperature difference would be much higher.

Re:Hmmm....

[Firethorn]

The larger the temperature difference, the more efficient a theoretically 'perfect' plant can be. This is also true for real world plants, though engineering limits often restrict how high of a temperature they can sustain and use.

Different technologies are differently capable at different temperature ranges - If this process is cheap enough and can get good results from a 'mere' 100 degree or so temperature difference, it can indeed increase the efficiency of many heat plants.

Re:Are you serious?

[cryfreedomlove]

I'm not talking about the US. Have you ever traveled to a country with a low standard of living?

Re:You cycle it

[Waffle Iron]

Given that prototype vehicles are currently in use which are fueled by hydrogen gas pressurized in tanks at hundreds of atmospheres, I doubt that the leakage problem is as severe as you make it out to be. What's more, if hydrogen is cheap enough to burn like gasoline, then replacing a little leaked working fluid that will get cycled hundreds of times in the engine wouldn't be any big deal.

Re:Carnot Efficiency is for Carnot Engine!

[f97tosc]

Carnot Efficiency is only a limit on a Carnot Cycle Engine!

Carnot Efficiency is a limit to any mechanism that converts heat to energy. Thus it applies to for example steam engines, internal combustion engines, and solar thermal power. Carnot Efficiency does not apply to for example solar cells (PV), although currently these typically have efficiencies of 20% of less so this new thermal method could still be a big improvement.

Re:Hmmm....

[smaddox]

It says it is more efficient than Stirling engines, but I wonder if it is more efficient than a full blown solar steam plant.

However, I suppose it doesn't have to be if it can be used in confined areas.

Re:Hmmm....

[thejuggler]

The Stirling engine was the first thing I thought of when I read the description. The Stirling engine is very inefficient in practice and lacks any real world power, but considering when it was first invented it was a brilliant idea. It's about time someone went back to look at old ideas that were discarded to see if modern day technology can make the unfeasible feasible.

This is probably better classified as a Solid State Stirling Engine (err, electrical generator).

Cool stuff either way.