[HN Gopher] Research on harvesting electricity from humidity in ...
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       Research on harvesting electricity from humidity in the air
        
       Author : wglb
       Score  : 29 points
       Date   : 2023-05-29 11:12 UTC (11 hours ago)
        
 (HTM) web link (techxplore.com)
 (TXT) w3m dump (techxplore.com)
        
       | tedunangst wrote:
       | I'm still waiting for the sound deadening paint that will also
       | power my home by absorbing ambient vibrations.
        
       | mikro2nd wrote:
       | OK, I'll bite: _How much_ energy can they harvest? While
       | realising that this is still highly experimental, early days and
       | bleeding edge (and also very exciting!) it would be very
       | interesting to get some idea of the actual energy harvest, even
       | though this will surely be an area of intense future research. I
       | did not see any mention of it in the article, though, and the
       | original paper seems to be paywalled.
        
         | dafelst wrote:
         | It is in the article:
         | 
         |  _Finally, because air humidity diffuses in three-dimensional
         | space and the thickness of the Air-gen device is only a
         | fraction of the width of a human hair, many thousands of them
         | can be stacked on top of each other, efficiently scaling up the
         | amount of energy without increasing the footprint of the
         | device. Such an Air-gen device would be capable of delivering
         | kilowatt-level power for general electrical utility usage._
        
           | ilyt wrote:
           | That seems like something that would be insanely easy to clog
           | up by just dust in the air
        
             | fbdab103 wrote:
             | Maybe it could be pre-filtered air in a closed loop?
             | However, this already seems like magic to me, so I am
             | unsure if it is possible to filter/recycle the air and
             | still come out net energy positive. Alternatively, maybe
             | there could be some kind of washing step where the plates
             | are washed/air forced through/voltage applied to remove
             | debris.
        
             | pengaru wrote:
             | Indeed, but at utility-scale you also likely have some
             | energy to spare for powering an electrostatic dust filter
             | at the intakes...
             | 
             | My parents' house had a Honeywell brand electrostatic air
             | filter in front of the air handler that wasn't cost-
             | prohibitive to operate, and didn't have a drip pan or
             | anything so I don't think it stripped moisture either. We'd
             | just toss the large metal filter cartridges in the dish-
             | washer periodically, which barely fit. They didn't pose a
             | significant air restriction, unlike conventional pleated
             | physical filters.
        
         | jaclaz wrote:
         | There was a thread from another article on the washington post:
         | https://news.ycombinator.com/item?id=36091615
         | 
         | It is essentially the usual "breakthrough" that won't likey
         | have any practical use for many years, the experimental device
         | is tiny and produces very little power.
         | 
         | It seems you need one billion of these devices to get 1 kW.
         | 
         | >The device, the size of a fingernail and thinner than a single
         | hair, is dotted with tiny holes known as nanopores. The holes
         | have a diameter smaller than 100 nanometers, or less than a
         | thousandth of the width of a strand of human hair.
         | 
         | >While one prototype only produces a small amount of energy --
         | almost enough to power a dot of light on a big screen --
         | because of its size, Yao said Air-gens can be stacked on top of
         | each other, potentially with spaces of air in between. Storing
         | the electricity is a separate issue, he added.
         | 
         | >Yao estimated that roughly 1 billion Air-gens, stacked to be
         | roughly the size of a refrigerator, could produce a kilowatt
         | and partly power a home in ideal conditions. The team hopes to
         | lower both the number of devices needed and the space they take
         | up by making the tool more efficient. Doing that could be a
         | challenge.
        
           | giarc wrote:
           | Some googling and napkin math. 1 fridge = 1 kW
           | 
           | A fridge is 25 cubic feet, so 40 watts per cubic foot. A Dell
           | E2422H monitor uses 13 watts while powered on. So a box 0.325
           | cubic feet could power a monitor, or a cube of 8.25" edge
           | length. Assuming it was 100% efficient and endless supply of
           | humid air etc.
        
             | importantbrian wrote:
             | > and endless supply of humid air etc.
             | 
             | Floridians are getting really excited right now.
        
       | shrx wrote:
       | Wouldn't the water just condense inside the nanopores due to
       | surface energy, and render them useless?
        
       | ttul wrote:
       | Do these devices have the effect of cooling the air? The energy
       | has to come from somewhere... If so, that would potentially serve
       | two purposes for the price of one: cooling and power generation.
       | Or, is the side effect to make the air less moist. Also a useful
       | function, particularly in humid places where drying the air is
       | desired.
        
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       (page generated 2023-05-29 23:00 UTC)