/sci/ - Science & Math

>while thermal energy reach 70-80's%

plus, storing heat is easy. Energy storage problem solved

Because it's like 3 times as expensive.

>>10706582

you got a good point there. even nuclear plants all they do is just boil water and I'm thinking if you use a closed system where you could use vacuum pumps to lower the preasure in that closed system the water would boil at lower temps for winter use , the power for the pump would come from the same plant, a closed low preassure "piping system" would allow low activity of the vacuum pump.

>>10706820
>lower the preasure in that closed system the water would boil at lower temps
That's not how steam power works.

>>10706582
what do you think 'efficiency' means you fucking first year engineer. i am so god damn sick of this shit

>>10706582
more expensive and complicated to produce and to maintain, and it is much less flexible. PV can be installed on every single roof, on an uneven field, and even in arctic climate. large scale energy storage is a meme and we will always need nuclear power.
imagine having to store energy to power the population of the greater Tokyo area. that is around 40 to 50 million people living at the highest standard of life on earth.

>>10707280
he means the efficiency of convertion from sun "rays", photovoltaic gets only to around 25% in the best materials.

>>10707923
i know he means that and i fucking know that.
Engineers in my experience can be some of the dumbest people when they lock into some buzz idea and can't ever see outside it.
>there's this number that we try to increase toward 100. it's the efficiency
>to me now, nothing else matters except this
Listen OP you dumb fuck, as if you were still here, there's enough sun coming in to power the whole world a million times. If you had a solar tech that was 1% efficient, but construction and maintenance cost is 50x less than solar PV, then the fucking efficiency doesn't mean shit, you go with this tech. Unless your criteria for some bizarre reason is not "wasting" sun rays which is so fucking dumb i want to kill you

>>10706582
I'm not sure where this high efficiency number even comes from. Photovoltaic is direct energy. Thermal goes to steam then has to use a generator. So I question the numbers.

>>10708221
stationary industrial and marine diesel engines can get up to around 50% 60% eff. (converting the theoretical maximum chemical energy of fuel into mechanical)

theres some compounded gas turbine that can get easy to 60% eff. (by extracting every last bit of heat and/or preassure from the exhaust)

https://www.ge.com/power/gas/gas-turbines/7ha

>>10706820
>>10706582
Does anybody else suspect samefagotry here?

>>10706582
Because solar photovoltaic is improving crazy fast, you can build it anywhere, maintenance costs for photovoltaic are basically nothing, and photovoltaics don't fry birds in mid air.
>>70-80%
not for electricity. Lying sack of shit. Perovskites are improving so fast it's not funny. Solar thermal could become obsolete before getting paid back. Perovskites could eventually reach 67% efficiency and thats straight to electricity. Perovskites could be crazy cheap.

>>10706582
Depending on the design and use type, you should be able to get about 81% (double glazing) - 90% (single glazing) efficiency at max no matter what system is invented and used simply due to glazing reflectivity and diffusion. All losses, due to glazing, beyond initial harvest can be recouped in other ways using hybrid systems for use and storage. The main problem is that a hybrid system may not be needed, where the thermal system is located, thus causing some waste eventually.

>>10706771
That's really only because it isn't proliferated much and there isn't much of a demand for it. PV was expensive as hell when it first came out. It took forever for the prices to drop, but once it got popular, better & cheaper manufacturing processes were developed to lower prices even more.

>>10706836
I'm pretty sure he's not talking about steam during that section. It is a typical energy storage method used for refrigeration in RVs.

>>10707352
Lower their standard of living and tell them to stop using so much power. That's easy to solve really.

>>10708411
yeah also this one is OP >>10707923

>>10708500
>> 90%
you're full of shit. The max allowed by Mr. Carnot is ~81%

>>10708527
90% is everything that can make it past the first glazing. Each glazing removes 10% (or more depending on the type of glazing). Once the energy is inside past that glazing it is up to your to devise a system to keep from losing the next 10% which will bring efficiency down to...81%. This is done fairly easily in things like solar box cookers that use aerogel insulation and Vantablack. The energy in that system must be used immediately. If it isn't then you won't get above the Carnot efficiency as you suggest. If you added a second glazing to prevent convection losses against the first glazing then that instantly brings it to 81% max before it can even be used for anything thus bringing total efficiency down even further. The only way to recoup these losses is to use a hybrid system that can carry waste heat that escapes to use for something else. Though, because it is a hybrid system the entirety of the Carnot efficiency is a moot point since it is no longer a completely thermal system anymore.

Bacially, it is like saying, "fuck you Carnot," when you start baking bread on top of your heat engine using its lost heat. Which doesn't count because it is now a hybrid system. Which is why a hybrid system may not work everywhere since the secondary or more forms of energy usage may not be needed in that location.

>>10708500
>I'm pretty sure he's not talking about steam during that section. It is a typical energy storage method used for refrigeration in RVs.

Then why is he comparing it to nuclear power.
>>10706820
>even nuclear plants all they do is just boil water

>>10708635
>Then why is he comparing it to nuclear power.

He isn't. He's talking about a new system. lrn2englsh

>>10706771
government subsidies drive market forces.
something about mining...

People play with efficiency numbers all the time.

What is the efficiency of sun to electrical energy, not the efficiency of solar power to heat energy in the pump.

>>10709549
or maybe it's because one is a fuckhuge tower of deathray mirrors boiling water and the other is a tiny panel you can put literally anywhere.

>>10708753
>He's talking about a new system.
>>10706820
>even nuclear plants all they do is just boil water

>muh efficiency