① Battery Guy now ② Doctor of Engineering -- Metallurgy and Ceramic Science @ Tokyo Institute of Technology (Institute of Science Tokyo since Oct. 01, 2024) *The ultimate goal was the photo-induced B-E Condensation.
(cf. 1) Japanese technologies are also still attractive. For example,
Microwaves are also inverter-controlled in Japan -- Global: ON/OFF;
Induction-heating (IH: P ∝ [ρμf]^1/2 (NI)^2, where P is the power, ρ is the resistivity of the conductor, μ is the absolute magnetic permeability, f is the frequency of the alternating current, N is the turn of the coil, and I is the current.) rice cookers, which are, needless to say, inverter-controlled, are changing heating areas three-dimensionally every 40 microseconds. The frequency, f, has been increased to, e.g., 60 kHz or 90 kHz. In addition, N has been increased and the copper loss, related to ρ^1/2 I^2 that can be thermally increased, has been decreased. Then, you can "generally" use non-magnetic hardware for IH cookers. For IH rice cookers, the multi-layered hardware, including a stainless metal layer, is used.
This does not just mean Japanese cooking-machines are convenient.
The difference between energy levels of molecular rotations is small, thus, microwaves having the energy ranging 10^-6 - 10^-3 eV can excite molecular rotations. Because of the small energy difference between the levels, the probability density function on rotational energies can be described by using Maxwell-Boltzmann statistics at room temperature having the energy of 2.6 × 10^-2 eV.
In contrast, molecular vibrations having the energy ranging 10^-3 - 1 eV cannot be excited by microwaves, instead, can be excited by infrared.
At the cryogenic temperatures, even molecular rotations can be at the lowest energy level, called the ground state.
In order to decrease the temperature, at which molecular rotations can be at the ground state, Stirling refrigerator, Gifford-McMahon refrigerator, Pulse-Tube refrigerator etc. can be used:
(a) The displacer is located at the bottom. The low-pressure valve is closed, and the high-pressure valve is opened. Then, the high-pressure gas (e.g., helium) is filled into the room-temperature side of the displacer (right).
(b) The displacer is going up toward the top. Helium is cooled at the regenerator (left), and filled into the low-temperature side of the displacer.
(c) The displacer is located at the top. The high-pressure valve is closed, and the low-pressure valve is opened.
(d) The displacer is going down toward the bottom. The helium filled in the low-temperature side of the displacer is exhausted through the regenerator. Since helium experiences the adiabatic expansion, the temperature is further decreased. The regenerator is cooled.
The stretching/shrinking standing wave of the gas pressure is used as the displacer, instead of the mechanical one. The progressing mass-transfer wave, which has the phase delay to that of the pressure wave, carries the energy (the heat). The appropriate pressure-vibration source design, the regenerator design, and the tube design can result in the practical-level entropy-flow: this is a kind of dissipative structure, which should be considered from a viewpoint of fluid mechanics, thus, goes beyond the scope of this post.
Cooling the refrigerant via forced alignment of Cu nuclear-spin (I = 3/2) followed by spontaneous dealignment, resulting in the Cu nuclear-spin entropy increase to N k log4 (resulting in the corresponding refrigerant entropy decrease).
The compressor 4 increases the refrigerant gas pressure and temperature to a higher temperature than the outside temperature.
At the condenser 1, the refrigerant disposes the heat to the outside.
At the expansion valve 2, the refrigerant experiences Joule–Thomson expansion, then the pressure of the refrigerant is decreased and the temperature of the refrigerant is decreased to a lower temperature than the room temperature.
At the evaporator 3, the refrigerant is warmed by the room air, thus, the room air is cooled by the refrigerant.
The refrigerant reaches the compressor 4, again.
At the temperatures lower than the inverse temperature, the temperature of the refrigerant experiencing Joule–Thomson expansion is decreased, since:
At the temperatures lower than the inverse temperature, intermolecular attractive force is dominant, since the kinetic energies of molecules are low and the pressure is low, thus intermolecular collisions frequency is low.
Then, Joule–Thomson expansion (= adiabatic expansion) results in the loss of intermolecular attractive force (= the cause of the negative potential energy is lost),
However, the total energy must be kept, since it is an adiabatic process. Then, the molecular kinetic energy (= temperature) is decreased in order to compensate the above-mentioned loss of the negative potential energy.
(cf. 4) In contrast, at the temperatures higher than the inverse temperature, the temperature of the refrigerant experiencing Joule–Thomson expansion is increased, since:
At the temperatures higher than the inverse temperature, intermolecular repulsive force is dominant, since the kinetic energies of molecules are high and the pressure is high, thus intermolecular collisions frequency is high.
Then, Joule–Thomson expansion (= adiabatic expansion) results in the loss of intermolecular repulsive force (= the cause of the positive potential energy is lost),
However, the total energy must be kept, since it is an adiabatic process. Then, the molecular kinetic energy (= temperature) is increased in order to compensate the above-mentioned loss of the positive potential energy.
So, a potential, which is somewhat similar to Lennard-Jones potential must be considered:
For example, the mean free path of N2 is 67.6 nm at 298 K and at 1 atm (the inverse temperature of N2 is 851.7 K at 1 atm): under this condition, intermolecular attractive force is dominant. Then, Joule–Thomson expansion (= adiabatic expansion) results in the loss of intermolecular attractive force (= the cause of the negative potential energy),
However, the total energy must be kept, since it is an adiabatic process. Then, the molecular kinetic energy (= temperature) is decreased in order to compensate the above-mentioned loss of the negative potential energy. This is the behavior characteristics of N2 at 298 K and at 1 atm.
In contrast, the mean free path of H2 is 130 nm at 298 K and at 1 atm (the inverse temperature of H2 is 224.0 K): under this condition, intermolecular repulsive force is dominant. Then, Joule–Thomson expansion (= adiabatic expansion) results in the loss of intermolecular repulsive force (= the cause of the positive potential energy),
However, the total energy must be kept, since it is an adiabatic process. Then, the molecular kinetic energy (= temperature) is increased in order to compensate the above-mentioned loss of the positive potential energy. This is the behavior characteristics of H2 at 298 K and at 1 atm.
Note that the temperature is increased when H2 is filled into the 70-MPa high-pressure tank: initially, via Joule-Thomson expansion (an adiabatic expansion process); finally, as the result of the increase in the intermolecular repulsive force (not via an adiabatic process). Thus, pre-cooling is required.
(cf. 5) Gas Science ガスの科学 (pupukids.com): Above the inverse temperature line, Joule–Thomson expansion results in the temperature increase. Below the inverse temperature line, Joule–Thomson expansion results in the temperature decrease.
The compressor increases the refrigerant gas pressure and temperature (a higher temperature than the outside temperature),
At the condenser, the refrigerant disposes the heat to the outside.
At the capillary tube exit, the refrigerant experiences Joule–Thomson expansion, then the pressure of the refrigerant is decreased and the temperature of the refrigerant is decreased to a lower temperature than the store room temperature,
At the evaporator, the refrigerant is warmed by the store room air (the store room air is cooled by the refrigerant), then,
The refrigerant reaches the compressor, again.
In the capillary tube, the refrigerant pressure is decreased in accordance with Bernoulli's principle, (1/2)v^2 + p/ρ = const.
The ice, which grows on the evaporator, must be eliminated. So, the radiant heater is located near the evaporator. Infrared light is reflected by the Al foil located under the radiant heater. The plasma frequency of Al, which results from the electronic configuration of Al, is much higher than the frequency of infrared light, thus, infrared light cannot be absorbed.
The frost can be white, since the ice crystal size is much smaller than the wavelengths of the visible light, thus, all of the visible light can result in Rayleigh scattering.
The latent heat of ice-melting, dQ = TdS, is all used for the entropy increase dS > 0, thus, the temperature, T, does not change.
(cf. 7) Although BIOS program is stored in FLASH, BIOS startup needs SRAM. The charge-backup (meaning 0 or 1) for SRAM by a small battery is required for the quick start -- SRAM is not a non-volatile memory, but the data can be retained for a relatively long time because of the flip-flop. Therefore, a small battery is enough to back up the charges (meaning, not a single-electron transistor) in the SRAM.
Note that e-Apple (e.g., JPY1,000,000) and e-mo (JPY547,800), are not shown here, since they are, strictly speaking, categorized as 1-seater motorized bicycles (< 0.6 kWh, e.g., 0.59 kWh).
