4 ms·

So it would seem, but we could also air condition the world and beam the energy into deep space instead.

by K0balt 1y ago

WillAdams 1y ago
Why beam it anywhere? Why not capture and make use of it? Isn't that the whole point of heat pumps? Grab energy from one locale, move it another to do useful work?
- ithkuil 1y ago
  You need a temperature differential.
- JumpCrisscross 1y ago
  “Energy” is a colloquially ambiguous term. The better terms are available energy (exergy) and entropy. The Earth radiates away almost exactly as much energy as it receives. It has to. Otherwise it would boil. Our biosphere, however, extracts a lot of available energy from that system. That results in the Sun shining low-entropy energy on the Earth, and the Earth radiating high-entropy radiation away. Put another way, a universe that is homogenous at 10 million degrees has plenty of energy. But it has zero useful energy because you have no entropy gradient.
grues-dinner 1y ago
Could that actually work? You'd have to expend energy to concentrate the heat into your power generation system to power the (I assume) a laser or similar emitter to beam the energy away. Would you be able to make sure that the extra energy used to move the heat around, plus inefficiencies in the laser power generation gets included in the outgoing photons? This seems, perhaps naively, like the entropy is going the "wrong" way. You could presumably radiate it to space by moving the heat to something that can "see" a clear sky, but you can have this happen naturally on a far huger scale by reducing GHG content in the atmosphere and increasing the radiative efficiency of the entire planet surface, as well as various passive systems like cool roofs, albedo manipulation and special materials that radiate specific wavelengths.
- K0balt 1y ago
  Yes, it would require radiative surfaces with sky view. Such systems are already in use, including surfaces that get much cooler than air temperature, in the sun on a warm sunny day. When you cool a building or a data center or whatever, you can pump that heat into a high temperature fluid and send it to a sky-radiator instead of sending it to an air-exchange radiator. So heat produced in processes could be moved to radiator assemblies and “beamed” into space (I probably should have said radiated).

So it would seem, but we could also air condition the world and beam the energy into deep space instead.

by K0balt 1y ago

So it would seem, but we could also air condition the world and beam the energy into deep space instead.

Why beam it anywhere? Why not capture and make use of it? Isn't that the whole point of heat pumps? Grab energy from one locale, move it another to do useful work?

ithkuil 1y ago
You need a temperature differential.
JumpCrisscross 1y ago
“Energy” is a colloquially ambiguous term. The better terms are available energy (exergy) and entropy. The Earth radiates away almost exactly as much energy as it receives. It has to. Otherwise it would boil. Our biosphere, however, extracts a lot of available energy from that system. That results in the Sun shining low-entropy energy on the Earth, and the Earth radiating high-entropy radiation away. Put another way, a universe that is homogenous at 10 million degrees has plenty of energy. But it has zero useful energy because you have no entropy gradient.

grues-dinner 1y ago

Could that actually work? You'd have to expend energy to concentrate the heat into your power generation system to power the (I assume) a laser or similar emitter to beam the energy away. Would you be able to make sure that the extra energy used to move the heat around, plus inefficiencies in the laser power generation gets included in the outgoing photons? This seems, perhaps naively, like the entropy is going the "wrong" way. You could presumably radiate it to space by moving the heat to something that can "see" a clear sky, but you can have this happen naturally on a far huger scale by reducing GHG content in the atmosphere and increasing the radiative efficiency of the entire planet surface, as well as various passive systems like cool roofs, albedo manipulation and special materials that radiate specific wavelengths.

K0balt 1y ago
Yes, it would require radiative surfaces with sky view. Such systems are already in use, including surfaces that get much cooler than air temperature, in the sun on a warm sunny day. When you cool a building or a data center or whatever, you can pump that heat into a high temperature fluid and send it to a sky-radiator instead of sending it to an air-exchange radiator. So heat produced in processes could be moved to radiator assemblies and “beamed” into space (I probably should have said radiated).