h a l f b a k e r yThere goes my teleportation concept.
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In a conventional dehumidifiyer (the type using a heat pump,) air from the room enters the machine, is chilled to it's dew point, and is then cooled further.
That "further" cooling results in condensation of water from the air.
The air then passes through the hot part of the heat pump, bringing
it to just above it's original temperature, and then it leaves the machine, going back to the room.
What I propose is very similar, but with one key difference:
Air enters the machine, passes through an entropy exchanger (where it loses heat and gains both absolute and relative humidity). The air coming out of the entropy exchanger has a relative humidity of nearly 100%.
The air then goes through the cold part of the heat pump. Here, the air is chilled, of course, but since the air is nearly at 100% humidity, we don't need to pre-cool the air much before condensation begins. After this, the *absolute* humidity has decreased, but the *relative* humidity is 100%.
Then the air passes through the entropy exchanger a second time. Naturally, since it's cold, it will be in good condition to absorb heat from the other flow of air through the exchanger. Less obviously, since the relative humidity is 100%, it is in good condition to transfer humidity to the other flow of air. This is because entropy exchangers absorb or release moisture based on relative, not absolute humidity.
After the air leaves the entropy exchanger, it's temperature will be close to, but lower than, the original air's temperature, and of course it's humidity will be close to, but less than, the original air's humidity.
Then, as in a conventional dehumidifiyer, the air passes through the hot part of the heat pump, and goes back to the room.
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do these entropy absorbers defeat conservation of energy? So in effect you saturate the air, then you condense the water back out of it. Brilliant. The bit about one air mass transmitting its moisture to the other air mass is a little mystical but surely possible using these new thermodynamics ignoring "absorbers". |
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I must argue however that if you propose a mystical way to do things that assails both math and science it is better to make it more effective, rather than less effective, than the physics-respecting current state of the art. |
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Last week while driving (LOTS of driving) My sinuses wished I could cool the air without pulling all the moisture out. |
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I invite anyone who desires to know more about the reality of "entropy exchangers" to simply google the phrase. |
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Conservation of energy (It's the law) |
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This doesn't necessarily break any laws; there is inefficiency in the need to reduce the temperature to the dew point before any water is removed, and this seems to address that. You could also gain some efficiency with a simple heat exchanger between the cooled air and the inlet air. Again, no laws broken. |
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It is the very definition of inefficiency to add more moisture to the air before we try to dehumidify it. And if by doing so we saved energy then, yes, we would also be violating thermodynamic laws. It's like saying that supersaturated air will absorb less energy getting dry then air with a R. Humidity of 50% because the wetter air gets down to business immediately, rather than waiting to get colder. |
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Also, after a few reads I suspect that the author simply intends to make the room hotter using his heat pump, thus reducing the R. Humidity. |
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Yes, if this mythical entropy exchanger adds energy to the equation, you would be correct. |
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If water were added to the incoming air from another source then efficiency would obviously be reduced, but here the water to be added to the incoming air is from the outgoing air - some of the dehumidifying uses the potential of the incoming air to absorb water up to its dew point (assuming the incoming air is not already saturated). The cooling part gets to work with saturated air, and therefore proportionally more of the energy is used in removing the heat of condensation rather than cooling the air to its dew point. |
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I would like some explanation of this "entropy exchanger", and I'm not convinced of any greater efficiency improvement than a simple heat exchanger would provide (since that would also reduce the energy cost of the cooling to dew point) but I'm not yet ready to side with the naysayers. |
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(later) I think this could be achieved by a long trough of brine, divided laterally into several sections, above which is a matching air duct, divided lengthwise into two such that two counter-current air streams contact the brine, but not each other. The brine in each section would allow heat and humidity to pass from one air stream to the other but prevent the air streams from mixing. The temperature and concentration of brine would gradually increase from one end to the other. |
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There are probably better ways to do it. |
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It increases efficiency by allowing both heat and humidity to move at close to equilibrium, rather than across large changes, so the efficiency can come closer to the maximum thermodynamic efficiency. No magic involved. |
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