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Efficient dehumidifier makes air conditioning a breeze (2014)

362 points by jonnycomputer 4y ago

jimmar 4y ago
Published 13 months ago. Is this technology in use, yet?
- ChuckMcM 4y ago
  Signs point to no. But their web site is pretty complete. (https://www.mt.energy/wattair https://www.mt.energy/wattair) That said, given the market, I would expect about a year of analysis to get the design win, then another year or two to get first products from design into production. I find their idea of going after electric busses "first" as a stretch since a) all e-busses are currently made in China so the technology transfer would be challenging, and b) there aren't that enough municipalities committed to e-busses yet to make a viable market for Montana Energy (if they capture 100% of the E-bus market they sell about 1000 units this year, probably not enough to sustain a company). That makes me wonder about the company. If it is run by scientists who insist on going for the most efficient implementation rather than by engineers who understand getting the value of having anything on the market, the company will fail.
  - amluto 4y ago
    Comparing their system to the top Energy Star performers [0], and taking their performance (20 L/kWh) at face value, they win by over 8x. If nothing else, they should be selling dehumidifiers! A quick web search suggests that the US dehumidifier market is between $1bn and $2bn per year. If they’re anywhere near as good as they claim, they should be able to capture essentially the entire market, especially if they are competent at marketing. They could, in addition, attempt to integrate with the high end heat pump makers (Mitsubishi, Daikin, etc) and target the high end HVAC market. I would be willing to believe that electric busses are a decent market (lots of time spent with doors open), but the EV car market seems like a poor target (lots of solar heating, doors and windows mostly closed in hot or humid weather, size and weight of equipment are constrained). So I agree, they’re doing this wrong. [0] https://www.energystar.gov/most-efficient/me-certified-dehumidifiers/results?is_most_efficient_filter=Most+Efficient https://www.energystar.gov/most-efficient/me-certified-dehum...
    - ChuckMcM 4y ago
      This exactly. A long time ago I had an opportunity to interact with the highest levels of a company called "Plastic Logic" who had created a flexible e-paper display that was much more durable than the glass covered displays. They presented their business plan where they were going to market with the "Plastic Reader", basically doing the entire product and software in house. I urged and pleaded with them. I said, "You guys are brilliant at displays, you've got a killer product here. Sell it to people who make readers! You start making money right away and you get better and better at making displays. Let your customers take the market risk of getting the form factor and software right, just start by making money!" The guy with the most sway in the company was the scientist who had actually come up with the way to make transistors on plastic and integrate them into a display. He was (and still is) a brilliant guy. But he was so smart that he felt "the display is the hard bit, everything else is practically off the shelf. Why should we give up our margin and our advantage to people who can't currently get a display with these properties. When we start shipping all other e-readers will become obsolete overnight!" (Not an exact quote but close enough from memory.) I tried to explain how risk didn't care how good your display was, adding to existing risks of getting the displays reliably produced, the rest of the stack put dozens of other ways your product could get stalled on its way to market and the "other guys" were investing like crazy. They couldn't possibly match the software and design engineering talent people that already had a reader on the market had right now. I told the CEO straight up, I said, "This path leads to failure, it always leads to failure." Of course they totally failed and sold off their assets a few times to various hedge funds and guess what, their display never ever made it to mass production because the brilliant guy who designed it in the first place didn't focus on that. I'm still sad they chose that route, it could have been epic.
      - amluto 4y ago
        By this analogy, I suppose they could sell to, say, Aprilaire. On the other hand, it’s not particularly hard to stick a nice blower on their device and sell a self contained unit. Plenty of vendors will gladly sell them excellent ECM blowers. Trying to integrate with electric buses seems extremely unwise.
  - toast0 4y ago
    They might be approaching the E-Bus market because their device needs to vent outside, and an airhandling device has easy access to vent outside, whereas a home dehumidifier often wouldn't have easy access to outside air. In addition, an E-bus has an acute need for energy efficiency; reducing the need for energy for climate control lets you go more miles on the same battery and range on a large, heavy, EV is hard to increase. It makes sense for liquid fueled busses too, but liquid fuel allows for a pretty long range anyway. Getting a design win on a new(ish) transportation category could have a bigger impact than competing in an existing market; although if the E-bus market is really 1000 units, they better find other applications soon. (Although if works for E-busses, it should work for any vehicle where dehumidification is happening)
- influxmoment 4y ago
  They'll probably sit on the patent so it can't be used and we'll see the tech on the market after expiry in 10 years. Seems to be what happens with patents
  - jonnycomputer 4y ago
    What possible advantage would that give?
mdorazio 4y ago
I'm not qualified to evaluate how plausible this is, but if it does actually work out it could be a huge boost in multiple ways. Air conditioning accounts for somewhere around 10% of US energy usage [1] and probably more in southern areas. Cutting that by a third is a lot. Not to mention the potential range extension for BEVs - in some of my BEV testing earlier this year, HVAC cut range by around 20% (note this wouldn't necessarily help much for heating, which is usually a bigger range impact). [1] https://www.eia.gov/tools/faqs/faq.php?id=1174&t=1 https://www.eia.gov/tools/faqs/faq.php?id=1174&t=1
- jeofken 4y ago
  Do you have any data on air conditioning and EV range? I find nothing helps as much as going 110kmph (~70mph) rather than speeding at 130kmph (~80mph).
  - jonnycomputer 4y ago
    I'd be interested in seeing data on that too.
  - bufferoverflow 4y ago
    The peak efficiency is at around 38mph https://cdn.shopify.com/s/files/1/0196/5170/files/model_s100_range_temp_imperial_grande.png?v=1530552309 https://cdn.shopify.com/s/files/1/0196/5170/files/model_s100...
  - consp 4y ago
    My Aircon uses about 4kw (3 to 4 is typical) plus several 100s W for the fan. So ev usage time times that is the reduced power available and thus reduced range. It is just as noticeable on a petrol car especially on lower power compact versions, it won't have too much impact on gas guzzling engines since they are already inefficient and usually more powerful so it is less noticeable, though the added consumption will be more of course.
  - SoftTalker 4y ago
    Presuming that the AC condensor gets airflow from the car moving through the air, it is going to be more efficient if the car is moving faster. However after a point, the air resistance will be hurting range more than anything.
atemerev 4y ago
I can’t handle dry air, my nose immediately becomes blocked. So I hope it won’t become obligatory in every AC unit.
- pfdietz 4y ago
  If it reduces the humidity to just the point where condensation would form in the A/C coils, you won't see any change (except to reduce the load on the A/C).
- jhugo 4y ago
  It's not a binary "dry/wet" thing. If you live in a humid place, you can probably remove quite a bit of moisture from the air before you encounter those symptoms.
- colechristensen 4y ago
  Air brought down to ~50% humidity is quite a lot more comfortable and not at all dry.
- jonnycomputer 4y ago
  Not sure where you are located, but most people have low toleration for overly dry air. Running an air conditioner in a dry place like Arizona or California will only make it drier. Running it in a humid place like Florida or Virginia makes the humidity level tolerable. When I lived in California, we used an evaporative cooler most times of the year. Only the hottest days did we turn to AC. But here in the east coast, the evaporative coolers would probably be mostly useless.
- kube-system 4y ago
  Dehumidification is already obligatory in AC units by the nature of how they work. When you cool air down it can’t hold as much water and so that water condenses and leaves the air. The current way that we handle this is we just let that water condense on your AC evaporator coil, then expel the cool water as waste. But it’s more efficient if your AC unit spends its time cooling air instead of water.
  - 4y ago
twelvechairs 4y ago
For anyone trying to understand whether dehumidification alone is enough to make them comfortable try the link below - load the 'givoni' comfort overlay and your city's weather chart. If most of the weather is [edit] vertically above the comfort zone or possibly the natural ventilation zone adjacent [/edit i originally wrote in the 'evaporative cooling' zone shown which is wrong] its probably a good choice for you. https://drajmarsh.bitbucket.io/psychro-chart2d.html https://drajmarsh.bitbucket.io/psychro-chart2d.html
- jonnycomputer 4y ago
  Cool! So, you set the Givoni Bioclimatic Chart overlay on? Grew up in the evaporative zone, and it worked well, except on the hottest of days (which come now more often..). Now I live in a much more humid place, which seems to be in natural ventilation/mass cooling zones (overlap of the boxes is a tad confusing to read.
  - Bilal_io 4y ago
    > you set the Givoni Bioclimatic Chart overlay on? I think it depends on you and what you're comfortable with.
    - jonnycomputer 4y ago
      The overlay shows the cooling system zones.
- sonofhans 4y ago
  It’s a fascinating tool and thanks for the link! But oh my word — I need to find and download a weather station file, then upload it again to the same tool? I don’t spend much time in GIS tools, but this feels almost maliciously opaque :D These instructions are hidden behind a “Toggle Instructions” button which is hidden in a popup which is hidden in a select control: > “Once you have found the right weather station, select its indicator and click the 'Download Weather File' link in the popup. This will download the selected file to local storage so you will need to select the 'Load...' button or the 'Load Weather File...' menu item and locate the downloaded file on your system.” I mean, I UX for a living and I’ve seen some daft shit, but I’ve rarely seen a tool so useful and polished in its presentation which presents a less-clear surface area to the user. I want to put a frame around it somehow, as The Master Antipattern.
thunkle 4y ago
Being mold sensitive and living in the pacific nw we have two dehumidifiers just to keep our house from mold growth. This would save us a lot of money if it works out.
- sologoub 4y ago
  Check out mini-splits and ducted mini-splits. The latter can be setup to look like traditional forced air systems. These include heat pump system (cooling/heating) and ability to dehumidify. Zoning the home is also very easy, you do need to ensure you have a competent contractor to properly set these up if you go with the more complex/feature rich systems.
  - pmoleri 4y ago
    Dehumidify is a nice feature of splits but my understanding is that it's not as efficient as a dedicated dehumidifier.
    - sologoub 4y ago
      Depends on what you are comparing to - if a dedicated whole house system, then possibly (depends on ducting and such). Any portable systems are likely to be less efficient when compared on throughput. The major win for me is that it all just works. The units already have drains and they balance everything as they cool. No separate system to worry about or maintain.
- lotsofpulp 4y ago
  If you are west of the Cascade mountains, that sounds like an air flow or drainage issue. The humidity is already pretty low, so moisture evaporates pretty quickly, in my experience.
  - tatersolid 4y ago
    Humidity is low in Seattle?
Simon_O_Rourke 4y ago
I can understand that, I spent a holiday in Scotland one year where it hardly went above 80, but felt like Salt Lake City in a heatwave.
bilsbie 4y ago
I wonder if cooling without dehumidifying is possible. A lot of times I want it cooler in the house but it starts getting uncomfortably dry.
- dymk 4y ago
  You could run a humidifier at the same time
- verall 4y ago
  Use a swamp cooler
  - More-nitors 4y ago
    ditto this efficient dehumidifier+AC will do wonders on wet+hot regions (south-east asia)
- influxmoment 4y ago
  You are noticing a change in relative humidity even tho the cooling did not change the absolute humidity
  - lukevp 4y ago
    Relative humidity rises for the same volume of water/air as temperature decreases. The dryness of an A/C is because of the condensation accumulating from the air passed across the evaporator, it is dehumidifying at the same time it’s cooling.
  - b112 4y ago
    If that was the case, it would be more humid, not less.
    - SoftTalker 4y ago
      The air tempertature at the evaporator is cold -- maybe 40 degrees or so? The relative humidity is about 100% (as evidenced by liquid water condensing on it). But the house itself never gets that cold, heat moves in from outside by radiation, the air temperature is higher, maybe 70-80 degrees, which results in a lower relative humidity.
bilsbie 4y ago
This sounds like free energy. The desiccant absorbs water and then dries out from the heat of absorbing water?
- bell-cot 4y ago
  This. IANAP (...Not A Physicist), but condensing water vapor releases a whole lotta heat. If you could do that "free" - well, setting up a heat engine between your hot condenser and the evaporation-cooled spot where you let the water vaporize again becomes a classic perpetual motion machine. (Yes, I see that the article claims their system is a mere 10 to 30 times more energy efficient than conventional dehumidifiers. That still sounds far too good to be true.)
  - galangalalgol 4y ago
    Conventional AC and dehumidifiers remove water from air by cooling both until the cooled water drops out of solution. This is supposedly using chemical means to remove hot water from the air so that you don't have to cool it.
    - CorrectHorseBat 4y ago
      It's been a while since I've studied thermodynamics, but as far as I understand it that sounds like a violation of the second law of thermodynamics.
      - bell-cot 4y ago
        Hydrophilic chemicals are a perfectly legal way to dehumidify. You pay the price (energy) when you pry the water & chemicals back apart.
        CorrectHorseBat 4y ago
        Of course, but as far as I understand this device does exactly that?
Animats 4y ago
Contains a "novel desiccant material that has exceptional adsorption properties." But no mention of how much the material costs and how long it lasts. Is this another one of those new surface chemistry materials that doesn't last long, like the ultra-black material, the ultra water repellant material, and the exotic salt water desalination membranes?
- trebligdivad 4y ago
  The video talks about a metal-oxide framework; no idea of the lifetime of them but they seem to be the cool new tech used in everything at the moment.
- dgacmu 4y ago
  You could probably build something similar using zeolite (if that's not already what they've using). The form factor undoubtedly matters but there are existing water absorptive materials that are long lasting and effective.
- grigri907 4y ago
  This sounds like a retooling of the dessicant air dryers [0] that have been used for years in industrial compressed air systems. [0] https://en.m.wikipedia.org/wiki/Compressed_air_dryer#Desiccant_dryers https://en.m.wikipedia.org/wiki/Compressed_air_dryer#Desicca...
  - KennyBlanken 4y ago
    That's not the novel part, the novel part is thermally connecting the regenerating and saturating sides. I think the tldr is that the regenerating side is evaporating and thus cooling? The work input into the system (aside from fans) is the vacuum pump. They're using vacuum to dry the desiccant; the mechanism to seal the two chambers well enough to pull a vacuum seems like a high failure point.
    - jamiek88 4y ago
      Ah! They are using vacuum thus inputting energy to move the regen and sat sides around otherwise this would have a distinct whiff of ‘perpetual motion’ about it. I was skeptical but had missed that bit!
Terretta 4y ago
Incidentally, staying on a beach island last 3 summers, and this summer the AC isn’t working right, only “cooling” about 1C. Set system to de-humidify instead, and air to room is 5C-7C lower temp than air at return. (As measured by a laser temp sensor.) Note that ambient humidity is above 80% so there’s plenty dehumidifying available.
WaitWaitWha 4y ago
An evaporative cooling solution by "Tech Ingredients" seems to be more efficient (correct me if I am wrong) [0]https://www.youtube.com/watch?v=7w4rg3UcsgI https://www.youtube.com/watch?v=7w4rg3UcsgI
- Bloating 4y ago
  evap cooling doesn't work (well) in humid climates
ezoe 4y ago
Prove it that it will work in a very humid environment or this product just make dry air from already dry air.
udev 4y ago
I am rusty on my thermodynamics, but could this cycle be reversed for heat-pumps? In the summer dehumidify air for more efficient cooling. In the winter humidify the air for more efficient heating? This would be a win-win-win because where I live summers a hot and humid, and winters are dry, and my heat-pump dries the air even more.
- alliao 4y ago
  daikin had this premium residential series called ururu sarara 7 which does this. albeit with some performance upper bounds to keep costs sane. somewhat complicated setup, and i think it would be a brilliant unit if your local weather is within the designed performance envelope
- Izkata 4y ago
  Why not just use a regular humidifier? Evaporative humidifiers are just a fan with a special filter that's good at absorbing water and has a very high surface area so it also evaporates quickly.
- jve 4y ago
  > In the winter humidify the air for more efficient heating? I'm rusty too, but the more mass you have, (or things that takes heat) the more energy you need to heat up. But then you have inertia. That's why people put bricks around simple wooden stove - so after the wood has burned out, those bricks still give you heat.
freemint 4y ago
I am kinda struggling with the thermodynamics of that mechanism. Can someone explain where the energy saving comes from using Thermodynamic Integration or comparing the (almost) cyclic processes of this one with a conventional air conditioners cycle?
- space_fountain 4y ago
  I think this is similar to the difference between a heat pump and a heater. Normally to dehumidify we strip the humidity out of the air and turn it into water, but all the embedded energy in the water vapor needs to go somewhere and it ends up heating up the house. Here instead they have a device that on net pumps humid air out of a structure. It doesn’t try to pull it all out of the air, just to move it from one bit of air to another so it doesn’t have to pay the full price of removing it
- toast0 4y ago
  A traditional dehumidifier is more or less an air conditioner, where you run inside air over the cool side, so that humidity condenses and is collected, then the air exits over the warm side and into the room. This device uses two chambers with a dessicant and alternates between running inside air through the chamber to adsorb humidity from the air into the dessicant and then using a vaccum to pull water vapor from the dessicant and pump it into the outside air. There's no energy intensive phase change of the refrigerant, and if I understand it correctly, the adsorbtion and deadsorbtion of the water vapor into and out of the dessicant isn't very energy intensive either. Note that this system doesn't work without access to outside air to vent the water vapor, whereas a traditional dehumidifier runs within a space, although the condesate may drain to outside. The effectiveness will likely depend on the humidity and temperature and the properties of the cooling system this device is paired with. An air conditioner will generally provide some dehumidificiation anyway (unless the cold side doesn't reach the dew point...) and maybe that's enough, in which case additional dehumidification isn't helpful. In some places, temperature reduction isn't needed and just dehumidification, this system could help reduce humidity without providing cooling.
jonnycomputer 4y ago
I believe this is a link to the submitted patent: https://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=/netahtml/PTO/srchnum.html&r=1&f=G&l=50&s1=%2220210055010%22.PGNR.&OS=DN/20210055010&RS=DN/20210055010 https://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2...
- udev 4y ago
  From what I can see this is a patent application for the dehumidification part only, which can be added to a pre-existing HVAC system. The website claims the system can eliminate the compressor and refrigerant completely. Not sure if they have a separate patent for that.
  - deleted 4y ago
    [deleted]
  - mannykannot 4y ago
    As far as I can tell, the article does not claim (or no longer claims) that this device can eliminate the compressor and refrigerant from an A/C system. It does claim that it can eliminate condensation on the evaporator, which is plausible, and it does eliminate the compressor and refrigerant used in conventional heat-pump dehumidifiers.
trebligdivad 4y ago
Would this work for clothes drying?
Maursault 4y ago
You know what else would make cooling your home energy efficient? If your home was not absorbing as much heat from the sun. Most roofs are black petroleum product, because oil everything! For not a whole lot of money, the cost of some digging, running pipes, and a pump, one could encase their home inside a closed loop 5mm tall waterfall during summer, which would drop their energy bill significantly. The idea is a little water runs over all outside surfaces of your home, taking whatever heat the surface of the home has with it (but also taking heat through evaporation) back down under the ground surface where it exchanges the heat. Add water as it is lost through evaporation. Really, if civil engineers and builders had made everything a water wonderland instead of heat absorbing black top, it would be a lot fn cooler.
- abstract_put 4y ago
  Is this an actual construction technique in real life (beyond DIY-ers)? Is there a name for it?
  - Maursault 4y ago
    I'm not aware of any installs or of any official name for this, but I like to call it wet roof.
- cjalmeida 4y ago
  An even simpler method is painting your rooftop white/light gray.
- alliao 4y ago
  wouldn't most of that water evaporated away? water's hard enough to come by nowadays...
- rcxdude 4y ago
  energy efficient but not water efficient. Also unless you're in an area with plentiful soft water you're gonna create some impressive mineral deposits. You're better off painting things white and insulating the house better (which helps with both heating and cooling it).
m3kw9 4y ago
Once I see my local HVAC specialist start selling one with rebates, then I know this is legit and scalable
rr808 4y ago
When looking at dishwashers Bosch were selling some that had Zeolite cyrstals that magically seemed to create heat out of moisture absorption, which seems to good to be true. I guess this is similar crystal? https://www.bosch-home.com/us/experience-bosch/crystaldry https://www.bosch-home.com/us/experience-bosch/crystaldry https://en.wikipedia.org/wiki/Zeolite https://en.wikipedia.org/wiki/Zeolite
calvinmorrison 4y ago
So is the concept basically to pump air over a very hydrophilic mesh and suck that water out? i don't really get it honestly
jillesvangurp 4y ago
I just experienced 38 degrees heat with 30% humidity here in Berlin just a few days ago. and then 28 degree heat with 60% humidity. I'll take 38 degrees at 30% humidity every time. It was fine. At 60% humidity, you are sweating non stop and it's uncomfortable because not enough of it evaporates. You feel sticky, hot and miserable. At 30% humidity, sweating cools your body really effectively and while taxing, you recover quickly in the shade. 38 degrees (slightly warmer than you) is no joke. But at that humidity, I prefer it over much cooler temperatures with higher humidity. The combination of high temperatures and humidity is lethal.
- ant6n 4y ago
  I grew up in Berlin as well and never minded the heat, because it was usually dry. But in the last decade or so we seem to have more of these hot and humid days, which makes me wonder… why doesn’t this startup target consumer dehumidifiers first, it would seem like an easier market when u have some newfangled technology with magical properties. Unless it’s really expensive.
- acchow 4y ago
  Curiously, if you do the wet bulb conversion: 38C@30% humidity = 24.4C 28C@60% humidity = 22.2C
  - zagrebian 4y ago
    What do the numbers on the right hand side mean?
    - bisby 4y ago
      From https://www.omnicalculator.com/physics/wet-bulb https://www.omnicalculator.com/physics/wet-bulb > Wet-bulb temperature is the lowest temperature a portion of air can acquire by evaporative cooling only > Our bodies sweat to cool off, but, because water evaporates slower in more humid conditions, we cool down a lot slower in humid conditions. Basically, "what is the absolute coolest you can get from evaporative cooling via sweat."
  - 4y ago
dzhiurgis 4y ago
IIRC there are some dew points where you wanna be using both AC and heat in a vehicle. On an EV you'd have to use resistive heater since you just can't flip the valve while AC is running and turn it into heat pump instantly.
DannyBee 4y ago
The mechanism they describe is exactly how desiccant compressed air dryers already work. It is hard to believe that they really have come up with some super novel desiccant. If they did, it would be instantly useful in this already existing commercial application and trivial to integrate. In practice, we already have good rechargeable desiccants that work well for a very long time (ie 10+ years at constant duty cycles)
- jonnycomputer 4y ago
  Here is their patent submission: https://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=/netahtml/PTO/srchnum.html&r=1&f=G&l=50&s1=%2220210055010%22.PGNR.&OS=DN/20210055010&RS=DN/20210055010 https://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2... Not sure which desiccant they're using. They have several papers on their site, e.g. https://www.pnnl.gov/publications/graphene-oxide-membranes-high-permeability-and-selectivity-dehumidification-air https://www.pnnl.gov/publications/graphene-oxide-membranes-h...
  - DannyBee 4y ago
    Yeah, this reads like a standard dessicant dryer applied to HVAC. I can believe that it costs less to run the dessicant dryer and then cool the air than a standard AC. This is often very true in compressed air, because you are trying to compress air, and if your air is saturated with water, you are producing a much smaller volume of compressed air vs using dry incoming air. Water is relatively incompressible, so it's actually somewhat remarkable how true this is (IE what volume of air you get out of 80% humidity intake air vs 30% humidity intake air) The main issue they are likely (IMHO) to hit is contamination. Compressed air is filtered before being dessicant dried to avoid getting oil/dust/etc on the dessicant, because it will reduce efficiency and destroy adsorption capability over time. Compared to compressed air, residential HVAC systems are not that well filtered (commercial can be). There are lots of people using nothing or random low-MERV fiberglass filters. That will destroy dessicant capability very quickly. So i have to imagine they are starting commercial first.
    - 4y ago
deleted 4y ago
[deleted]
alliao 4y ago
HVAC industry is such a huge market primed to be disrupted. The way they wanted to "size" your room properly is really used to calculate cooling/heating capacity to achieve a comfortable relative humidity. But back in the days they didn't have DC inverter, units were either on 100% full power or shut off at 0%. Nowadays with linear inverter units cooling/heating can be ramped up and down, but we also have a lot more requirements now like greenhouse potential etc. Ignoring all that, it is in theory possible with 3rd party sensors + algorithm to coordinate all assets to achieve a satisfying outcome. Chug in vent control then you'd have a pretty decent solution. So if you only have AC units, it'd cool from one end with shade and fan the hot end. If you have humidifier units, then it can coerce air to be dried first before being conditioned etc. Just by turning on/off vents and units and learning from sensor data.
0x53 4y ago
There is a great podcast by a company called positive energy that covers a lot of topics relating to this. Here is the one on how important dehumidification is to cooling: https://positiveenergy.pro/building-science-podcast/2021/11/4/keep-it-dry- https://positiveenergy.pro/building-science-podcast/2021/11/...
nikolay 4y ago
From their model, the vents are on the ground, which means they will lift all the dust.
deleted 4y ago
[deleted]
rasz 4y ago
>“There’s a huge opportunity in electric vehicles (EVs) and particularly electric buses because integration of our dehumidifiers in their air conditioning systems can extend their driving ranges by up to 75 percent,” so its a scam then, ok
- digdigdag 4y ago
  "up to" means it can be as little as 0%. Not sure where the scam is.
Izkata 4y ago
Image caption: > Traditional dehumidifiers are too large and too energy intensive to install in vehicles, but AirJoule’s compact size and zero net energy penalty makes dehumidifying air before cooling it in a vehicle not only possible but creates huge energy savings. Uh, what? Pretty sure most vehicles have AC, which functions the same as a traditional dehumidifier. The only difference is the cooled air AC would output is run back across the "exhaust" pipes to reheat it, instead of ejecting the heat outside. (No comment on the energy saving aspect, just the first part caught my eye)
aaron695 4y ago
Kosirich 4y ago
Few years ago I was in Phoenix,AZ when it was 40 most of the day with I'm guessing 0%-10% humidity. As our hotel had a pool I went for a dive and returned back to the shade and to my surprise I started shaking from being cold as evaporative cooling effect was so intense. Similar to other HN user, I would prefer this kind of heat aka 40 degC with 0-10% humidity than what we have in Denmark during few summer days with 28 degC and 70% humidity.

362 points by jonnycomputer 4y ago

jimmar 4y ago

Published 13 months ago. Is this technology in use, yet?

ChuckMcM 4y ago
Signs point to no. But their web site is pretty complete. (https://www.mt.energy/wattair https://www.mt.energy/wattair) That said, given the market, I would expect about a year of analysis to get the design win, then another year or two to get first products from design into production. I find their idea of going after electric busses "first" as a stretch since a) all e-busses are currently made in China so the technology transfer would be challenging, and b) there aren't that enough municipalities committed to e-busses yet to make a viable market for Montana Energy (if they capture 100% of the E-bus market they sell about 1000 units this year, probably not enough to sustain a company). That makes me wonder about the company. If it is run by scientists who insist on going for the most efficient implementation rather than by engineers who understand getting the value of having anything on the market, the company will fail.
- amluto 4y ago
  Comparing their system to the top Energy Star performers [0], and taking their performance (20 L/kWh) at face value, they win by over 8x. If nothing else, they should be selling dehumidifiers! A quick web search suggests that the US dehumidifier market is between $1bn and $2bn per year. If they’re anywhere near as good as they claim, they should be able to capture essentially the entire market, especially if they are competent at marketing. They could, in addition, attempt to integrate with the high end heat pump makers (Mitsubishi, Daikin, etc) and target the high end HVAC market. I would be willing to believe that electric busses are a decent market (lots of time spent with doors open), but the EV car market seems like a poor target (lots of solar heating, doors and windows mostly closed in hot or humid weather, size and weight of equipment are constrained). So I agree, they’re doing this wrong. [0] https://www.energystar.gov/most-efficient/me-certified-dehumidifiers/results?is_most_efficient_filter=Most+Efficient https://www.energystar.gov/most-efficient/me-certified-dehum...
  - ChuckMcM 4y ago
    This exactly. A long time ago I had an opportunity to interact with the highest levels of a company called "Plastic Logic" who had created a flexible e-paper display that was much more durable than the glass covered displays. They presented their business plan where they were going to market with the "Plastic Reader", basically doing the entire product and software in house. I urged and pleaded with them. I said, "You guys are brilliant at displays, you've got a killer product here. Sell it to people who make readers! You start making money right away and you get better and better at making displays. Let your customers take the market risk of getting the form factor and software right, just start by making money!" The guy with the most sway in the company was the scientist who had actually come up with the way to make transistors on plastic and integrate them into a display. He was (and still is) a brilliant guy. But he was so smart that he felt "the display is the hard bit, everything else is practically off the shelf. Why should we give up our margin and our advantage to people who can't currently get a display with these properties. When we start shipping all other e-readers will become obsolete overnight!" (Not an exact quote but close enough from memory.) I tried to explain how risk didn't care how good your display was, adding to existing risks of getting the displays reliably produced, the rest of the stack put dozens of other ways your product could get stalled on its way to market and the "other guys" were investing like crazy. They couldn't possibly match the software and design engineering talent people that already had a reader on the market had right now. I told the CEO straight up, I said, "This path leads to failure, it always leads to failure." Of course they totally failed and sold off their assets a few times to various hedge funds and guess what, their display never ever made it to mass production because the brilliant guy who designed it in the first place didn't focus on that. I'm still sad they chose that route, it could have been epic.
    - amluto 4y ago
      By this analogy, I suppose they could sell to, say, Aprilaire. On the other hand, it’s not particularly hard to stick a nice blower on their device and sell a self contained unit. Plenty of vendors will gladly sell them excellent ECM blowers. Trying to integrate with electric buses seems extremely unwise.
- toast0 4y ago
  They might be approaching the E-Bus market because their device needs to vent outside, and an airhandling device has easy access to vent outside, whereas a home dehumidifier often wouldn't have easy access to outside air. In addition, an E-bus has an acute need for energy efficiency; reducing the need for energy for climate control lets you go more miles on the same battery and range on a large, heavy, EV is hard to increase. It makes sense for liquid fueled busses too, but liquid fuel allows for a pretty long range anyway. Getting a design win on a new(ish) transportation category could have a bigger impact than competing in an existing market; although if the E-bus market is really 1000 units, they better find other applications soon. (Although if works for E-busses, it should work for any vehicle where dehumidification is happening)
influxmoment 4y ago
They'll probably sit on the patent so it can't be used and we'll see the tech on the market after expiry in 10 years. Seems to be what happens with patents
- jonnycomputer 4y ago
  What possible advantage would that give?

mdorazio 4y ago

I'm not qualified to evaluate how plausible this is, but if it does actually work out it could be a huge boost in multiple ways. Air conditioning accounts for somewhere around 10% of US energy usage [1] and probably more in southern areas. Cutting that by a third is a lot. Not to mention the potential range extension for BEVs - in some of my BEV testing earlier this year, HVAC cut range by around 20% (note this wouldn't necessarily help much for heating, which is usually a bigger range impact). [1] https://www.eia.gov/tools/faqs/faq.php?id=1174&t=1 https://www.eia.gov/tools/faqs/faq.php?id=1174&t=1

jeofken 4y ago
Do you have any data on air conditioning and EV range? I find nothing helps as much as going 110kmph (~70mph) rather than speeding at 130kmph (~80mph).
- jonnycomputer 4y ago
  I'd be interested in seeing data on that too.
- bufferoverflow 4y ago
  The peak efficiency is at around 38mph https://cdn.shopify.com/s/files/1/0196/5170/files/model_s100_range_temp_imperial_grande.png?v=1530552309 https://cdn.shopify.com/s/files/1/0196/5170/files/model_s100...
- consp 4y ago
  My Aircon uses about 4kw (3 to 4 is typical) plus several 100s W for the fan. So ev usage time times that is the reduced power available and thus reduced range. It is just as noticeable on a petrol car especially on lower power compact versions, it won't have too much impact on gas guzzling engines since they are already inefficient and usually more powerful so it is less noticeable, though the added consumption will be more of course.
- SoftTalker 4y ago
  Presuming that the AC condensor gets airflow from the car moving through the air, it is going to be more efficient if the car is moving faster. However after a point, the air resistance will be hurting range more than anything.

atemerev 4y ago

I can’t handle dry air, my nose immediately becomes blocked. So I hope it won’t become obligatory in every AC unit.

pfdietz 4y ago
If it reduces the humidity to just the point where condensation would form in the A/C coils, you won't see any change (except to reduce the load on the A/C).
jhugo 4y ago
It's not a binary "dry/wet" thing. If you live in a humid place, you can probably remove quite a bit of moisture from the air before you encounter those symptoms.
colechristensen 4y ago
Air brought down to ~50% humidity is quite a lot more comfortable and not at all dry.
jonnycomputer 4y ago
Not sure where you are located, but most people have low toleration for overly dry air. Running an air conditioner in a dry place like Arizona or California will only make it drier. Running it in a humid place like Florida or Virginia makes the humidity level tolerable. When I lived in California, we used an evaporative cooler most times of the year. Only the hottest days did we turn to AC. But here in the east coast, the evaporative coolers would probably be mostly useless.
kube-system 4y ago
Dehumidification is already obligatory in AC units by the nature of how they work. When you cool air down it can’t hold as much water and so that water condenses and leaves the air. The current way that we handle this is we just let that water condense on your AC evaporator coil, then expel the cool water as waste. But it’s more efficient if your AC unit spends its time cooling air instead of water.
- 4y ago

twelvechairs 4y ago

For anyone trying to understand whether dehumidification alone is enough to make them comfortable try the link below - load the 'givoni' comfort overlay and your city's weather chart. If most of the weather is [edit] vertically above the comfort zone or possibly the natural ventilation zone adjacent [/edit i originally wrote in the 'evaporative cooling' zone shown which is wrong] its probably a good choice for you. https://drajmarsh.bitbucket.io/psychro-chart2d.html https://drajmarsh.bitbucket.io/psychro-chart2d.html

jonnycomputer 4y ago
Cool! So, you set the Givoni Bioclimatic Chart overlay on? Grew up in the evaporative zone, and it worked well, except on the hottest of days (which come now more often..). Now I live in a much more humid place, which seems to be in natural ventilation/mass cooling zones (overlap of the boxes is a tad confusing to read.
- Bilal_io 4y ago
  > you set the Givoni Bioclimatic Chart overlay on? I think it depends on you and what you're comfortable with.
  - jonnycomputer 4y ago
    The overlay shows the cooling system zones.
sonofhans 4y ago
It’s a fascinating tool and thanks for the link! But oh my word — I need to find and download a weather station file, then upload it again to the same tool? I don’t spend much time in GIS tools, but this feels almost maliciously opaque :D These instructions are hidden behind a “Toggle Instructions” button which is hidden in a popup which is hidden in a select control: > “Once you have found the right weather station, select its indicator and click the 'Download Weather File' link in the popup. This will download the selected file to local storage so you will need to select the 'Load...' button or the 'Load Weather File...' menu item and locate the downloaded file on your system.” I mean, I UX for a living and I’ve seen some daft shit, but I’ve rarely seen a tool so useful and polished in its presentation which presents a less-clear surface area to the user. I want to put a frame around it somehow, as The Master Antipattern.

thunkle 4y ago

Being mold sensitive and living in the pacific nw we have two dehumidifiers just to keep our house from mold growth. This would save us a lot of money if it works out.

sologoub 4y ago
Check out mini-splits and ducted mini-splits. The latter can be setup to look like traditional forced air systems. These include heat pump system (cooling/heating) and ability to dehumidify. Zoning the home is also very easy, you do need to ensure you have a competent contractor to properly set these up if you go with the more complex/feature rich systems.
- pmoleri 4y ago
  Dehumidify is a nice feature of splits but my understanding is that it's not as efficient as a dedicated dehumidifier.
  - sologoub 4y ago
    Depends on what you are comparing to - if a dedicated whole house system, then possibly (depends on ducting and such). Any portable systems are likely to be less efficient when compared on throughput. The major win for me is that it all just works. The units already have drains and they balance everything as they cool. No separate system to worry about or maintain.
lotsofpulp 4y ago
If you are west of the Cascade mountains, that sounds like an air flow or drainage issue. The humidity is already pretty low, so moisture evaporates pretty quickly, in my experience.
- tatersolid 4y ago
  Humidity is low in Seattle?

Simon_O_Rourke 4y ago

I can understand that, I spent a holiday in Scotland one year where it hardly went above 80, but felt like Salt Lake City in a heatwave.

bilsbie 4y ago

I wonder if cooling without dehumidifying is possible. A lot of times I want it cooler in the house but it starts getting uncomfortably dry.

dymk 4y ago
You could run a humidifier at the same time
verall 4y ago
Use a swamp cooler
- More-nitors 4y ago
  ditto this efficient dehumidifier+AC will do wonders on wet+hot regions (south-east asia)
influxmoment 4y ago
You are noticing a change in relative humidity even tho the cooling did not change the absolute humidity
- lukevp 4y ago
  Relative humidity rises for the same volume of water/air as temperature decreases. The dryness of an A/C is because of the condensation accumulating from the air passed across the evaporator, it is dehumidifying at the same time it’s cooling.
- b112 4y ago
  If that was the case, it would be more humid, not less.
  - SoftTalker 4y ago
    The air tempertature at the evaporator is cold -- maybe 40 degrees or so? The relative humidity is about 100% (as evidenced by liquid water condensing on it). But the house itself never gets that cold, heat moves in from outside by radiation, the air temperature is higher, maybe 70-80 degrees, which results in a lower relative humidity.

bilsbie 4y ago

This sounds like free energy. The desiccant absorbs water and then dries out from the heat of absorbing water?

bell-cot 4y ago
This. IANAP (...Not A Physicist), but condensing water vapor releases a whole lotta heat. If you could do that "free" - well, setting up a heat engine between your hot condenser and the evaporation-cooled spot where you let the water vaporize again becomes a classic perpetual motion machine. (Yes, I see that the article claims their system is a mere 10 to 30 times more energy efficient than conventional dehumidifiers. That still sounds far too good to be true.)
- galangalalgol 4y ago
  Conventional AC and dehumidifiers remove water from air by cooling both until the cooled water drops out of solution. This is supposedly using chemical means to remove hot water from the air so that you don't have to cool it.
  - CorrectHorseBat 4y ago
    It's been a while since I've studied thermodynamics, but as far as I understand it that sounds like a violation of the second law of thermodynamics.
    - bell-cot 4y ago
      Hydrophilic chemicals are a perfectly legal way to dehumidify. You pay the price (energy) when you pry the water & chemicals back apart.
      - CorrectHorseBat 4y ago
        Of course, but as far as I understand this device does exactly that?

Animats 4y ago

Contains a "novel desiccant material that has exceptional adsorption properties." But no mention of how much the material costs and how long it lasts. Is this another one of those new surface chemistry materials that doesn't last long, like the ultra-black material, the ultra water repellant material, and the exotic salt water desalination membranes?

trebligdivad 4y ago
The video talks about a metal-oxide framework; no idea of the lifetime of them but they seem to be the cool new tech used in everything at the moment.
dgacmu 4y ago
You could probably build something similar using zeolite (if that's not already what they've using). The form factor undoubtedly matters but there are existing water absorptive materials that are long lasting and effective.
grigri907 4y ago
This sounds like a retooling of the dessicant air dryers [0] that have been used for years in industrial compressed air systems. [0] https://en.m.wikipedia.org/wiki/Compressed_air_dryer#Desiccant_dryers https://en.m.wikipedia.org/wiki/Compressed_air_dryer#Desicca...
- KennyBlanken 4y ago
  That's not the novel part, the novel part is thermally connecting the regenerating and saturating sides. I think the tldr is that the regenerating side is evaporating and thus cooling? The work input into the system (aside from fans) is the vacuum pump. They're using vacuum to dry the desiccant; the mechanism to seal the two chambers well enough to pull a vacuum seems like a high failure point.
  - jamiek88 4y ago
    Ah! They are using vacuum thus inputting energy to move the regen and sat sides around otherwise this would have a distinct whiff of ‘perpetual motion’ about it. I was skeptical but had missed that bit!

Terretta 4y ago

Incidentally, staying on a beach island last 3 summers, and this summer the AC isn’t working right, only “cooling” about 1C. Set system to de-humidify instead, and air to room is 5C-7C lower temp than air at return. (As measured by a laser temp sensor.) Note that ambient humidity is above 80% so there’s plenty dehumidifying available.

WaitWaitWha 4y ago

An evaporative cooling solution by "Tech Ingredients" seems to be more efficient (correct me if I am wrong) [0]https://www.youtube.com/watch?v=7w4rg3UcsgI https://www.youtube.com/watch?v=7w4rg3UcsgI

Bloating 4y ago
evap cooling doesn't work (well) in humid climates

ezoe 4y ago

Prove it that it will work in a very humid environment or this product just make dry air from already dry air.

udev 4y ago

I am rusty on my thermodynamics, but could this cycle be reversed for heat-pumps? In the summer dehumidify air for more efficient cooling. In the winter humidify the air for more efficient heating? This would be a win-win-win because where I live summers a hot and humid, and winters are dry, and my heat-pump dries the air even more.

alliao 4y ago
daikin had this premium residential series called ururu sarara 7 which does this. albeit with some performance upper bounds to keep costs sane. somewhat complicated setup, and i think it would be a brilliant unit if your local weather is within the designed performance envelope
Izkata 4y ago
Why not just use a regular humidifier? Evaporative humidifiers are just a fan with a special filter that's good at absorbing water and has a very high surface area so it also evaporates quickly.
jve 4y ago
> In the winter humidify the air for more efficient heating? I'm rusty too, but the more mass you have, (or things that takes heat) the more energy you need to heat up. But then you have inertia. That's why people put bricks around simple wooden stove - so after the wood has burned out, those bricks still give you heat.

freemint 4y ago

I am kinda struggling with the thermodynamics of that mechanism. Can someone explain where the energy saving comes from using Thermodynamic Integration or comparing the (almost) cyclic processes of this one with a conventional air conditioners cycle?

space_fountain 4y ago
I think this is similar to the difference between a heat pump and a heater. Normally to dehumidify we strip the humidity out of the air and turn it into water, but all the embedded energy in the water vapor needs to go somewhere and it ends up heating up the house. Here instead they have a device that on net pumps humid air out of a structure. It doesn’t try to pull it all out of the air, just to move it from one bit of air to another so it doesn’t have to pay the full price of removing it
toast0 4y ago
A traditional dehumidifier is more or less an air conditioner, where you run inside air over the cool side, so that humidity condenses and is collected, then the air exits over the warm side and into the room. This device uses two chambers with a dessicant and alternates between running inside air through the chamber to adsorb humidity from the air into the dessicant and then using a vaccum to pull water vapor from the dessicant and pump it into the outside air. There's no energy intensive phase change of the refrigerant, and if I understand it correctly, the adsorbtion and deadsorbtion of the water vapor into and out of the dessicant isn't very energy intensive either. Note that this system doesn't work without access to outside air to vent the water vapor, whereas a traditional dehumidifier runs within a space, although the condesate may drain to outside. The effectiveness will likely depend on the humidity and temperature and the properties of the cooling system this device is paired with. An air conditioner will generally provide some dehumidificiation anyway (unless the cold side doesn't reach the dew point...) and maybe that's enough, in which case additional dehumidification isn't helpful. In some places, temperature reduction isn't needed and just dehumidification, this system could help reduce humidity without providing cooling.

jonnycomputer 4y ago

I believe this is a link to the submitted patent: https://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=/netahtml/PTO/srchnum.html&r=1&f=G&l=50&s1=%2220210055010%22.PGNR.&OS=DN/20210055010&RS=DN/20210055010 https://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2...

udev 4y ago
From what I can see this is a patent application for the dehumidification part only, which can be added to a pre-existing HVAC system. The website claims the system can eliminate the compressor and refrigerant completely. Not sure if they have a separate patent for that.
- deleted 4y ago
  [deleted]
- mannykannot 4y ago
  As far as I can tell, the article does not claim (or no longer claims) that this device can eliminate the compressor and refrigerant from an A/C system. It does claim that it can eliminate condensation on the evaporator, which is plausible, and it does eliminate the compressor and refrigerant used in conventional heat-pump dehumidifiers.

trebligdivad 4y ago

Would this work for clothes drying?

Maursault 4y ago

You know what else would make cooling your home energy efficient? If your home was not absorbing as much heat from the sun. Most roofs are black petroleum product, because oil everything! For not a whole lot of money, the cost of some digging, running pipes, and a pump, one could encase their home inside a closed loop 5mm tall waterfall during summer, which would drop their energy bill significantly. The idea is a little water runs over all outside surfaces of your home, taking whatever heat the surface of the home has with it (but also taking heat through evaporation) back down under the ground surface where it exchanges the heat. Add water as it is lost through evaporation. Really, if civil engineers and builders had made everything a water wonderland instead of heat absorbing black top, it would be a lot fn cooler.

abstract_put 4y ago
Is this an actual construction technique in real life (beyond DIY-ers)? Is there a name for it?
- Maursault 4y ago
  I'm not aware of any installs or of any official name for this, but I like to call it wet roof.
cjalmeida 4y ago
An even simpler method is painting your rooftop white/light gray.
alliao 4y ago
wouldn't most of that water evaporated away? water's hard enough to come by nowadays...
rcxdude 4y ago
energy efficient but not water efficient. Also unless you're in an area with plentiful soft water you're gonna create some impressive mineral deposits. You're better off painting things white and insulating the house better (which helps with both heating and cooling it).

m3kw9 4y ago

Once I see my local HVAC specialist start selling one with rebates, then I know this is legit and scalable

rr808 4y ago

When looking at dishwashers Bosch were selling some that had Zeolite cyrstals that magically seemed to create heat out of moisture absorption, which seems to good to be true. I guess this is similar crystal? https://www.bosch-home.com/us/experience-bosch/crystaldry https://www.bosch-home.com/us/experience-bosch/crystaldry https://en.wikipedia.org/wiki/Zeolite https://en.wikipedia.org/wiki/Zeolite

calvinmorrison 4y ago

So is the concept basically to pump air over a very hydrophilic mesh and suck that water out? i don't really get it honestly

jillesvangurp 4y ago

I just experienced 38 degrees heat with 30% humidity here in Berlin just a few days ago. and then 28 degree heat with 60% humidity. I'll take 38 degrees at 30% humidity every time. It was fine. At 60% humidity, you are sweating non stop and it's uncomfortable because not enough of it evaporates. You feel sticky, hot and miserable. At 30% humidity, sweating cools your body really effectively and while taxing, you recover quickly in the shade. 38 degrees (slightly warmer than you) is no joke. But at that humidity, I prefer it over much cooler temperatures with higher humidity. The combination of high temperatures and humidity is lethal.

ant6n 4y ago
I grew up in Berlin as well and never minded the heat, because it was usually dry. But in the last decade or so we seem to have more of these hot and humid days, which makes me wonder… why doesn’t this startup target consumer dehumidifiers first, it would seem like an easier market when u have some newfangled technology with magical properties. Unless it’s really expensive.
acchow 4y ago
Curiously, if you do the wet bulb conversion: 38C@30% humidity = 24.4C 28C@60% humidity = 22.2C
- zagrebian 4y ago
  What do the numbers on the right hand side mean?
  - bisby 4y ago
    From https://www.omnicalculator.com/physics/wet-bulb https://www.omnicalculator.com/physics/wet-bulb > Wet-bulb temperature is the lowest temperature a portion of air can acquire by evaporative cooling only > Our bodies sweat to cool off, but, because water evaporates slower in more humid conditions, we cool down a lot slower in humid conditions. Basically, "what is the absolute coolest you can get from evaporative cooling via sweat."
- 4y ago

dzhiurgis 4y ago

IIRC there are some dew points where you wanna be using both AC and heat in a vehicle. On an EV you'd have to use resistive heater since you just can't flip the valve while AC is running and turn it into heat pump instantly.

DannyBee 4y ago

The mechanism they describe is exactly how desiccant compressed air dryers already work. It is hard to believe that they really have come up with some super novel desiccant. If they did, it would be instantly useful in this already existing commercial application and trivial to integrate. In practice, we already have good rechargeable desiccants that work well for a very long time (ie 10+ years at constant duty cycles)

jonnycomputer 4y ago
Here is their patent submission: https://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=/netahtml/PTO/srchnum.html&r=1&f=G&l=50&s1=%2220210055010%22.PGNR.&OS=DN/20210055010&RS=DN/20210055010 https://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2... Not sure which desiccant they're using. They have several papers on their site, e.g. https://www.pnnl.gov/publications/graphene-oxide-membranes-high-permeability-and-selectivity-dehumidification-air https://www.pnnl.gov/publications/graphene-oxide-membranes-h...
- DannyBee 4y ago
  Yeah, this reads like a standard dessicant dryer applied to HVAC. I can believe that it costs less to run the dessicant dryer and then cool the air than a standard AC. This is often very true in compressed air, because you are trying to compress air, and if your air is saturated with water, you are producing a much smaller volume of compressed air vs using dry incoming air. Water is relatively incompressible, so it's actually somewhat remarkable how true this is (IE what volume of air you get out of 80% humidity intake air vs 30% humidity intake air) The main issue they are likely (IMHO) to hit is contamination. Compressed air is filtered before being dessicant dried to avoid getting oil/dust/etc on the dessicant, because it will reduce efficiency and destroy adsorption capability over time. Compared to compressed air, residential HVAC systems are not that well filtered (commercial can be). There are lots of people using nothing or random low-MERV fiberglass filters. That will destroy dessicant capability very quickly. So i have to imagine they are starting commercial first.
  - 4y ago

deleted 4y ago

[deleted]

alliao 4y ago

HVAC industry is such a huge market primed to be disrupted. The way they wanted to "size" your room properly is really used to calculate cooling/heating capacity to achieve a comfortable relative humidity. But back in the days they didn't have DC inverter, units were either on 100% full power or shut off at 0%. Nowadays with linear inverter units cooling/heating can be ramped up and down, but we also have a lot more requirements now like greenhouse potential etc. Ignoring all that, it is in theory possible with 3rd party sensors + algorithm to coordinate all assets to achieve a satisfying outcome. Chug in vent control then you'd have a pretty decent solution. So if you only have AC units, it'd cool from one end with shade and fan the hot end. If you have humidifier units, then it can coerce air to be dried first before being conditioned etc. Just by turning on/off vents and units and learning from sensor data.

0x53 4y ago

There is a great podcast by a company called positive energy that covers a lot of topics relating to this. Here is the one on how important dehumidification is to cooling: https://positiveenergy.pro/building-science-podcast/2021/11/4/keep-it-dry- https://positiveenergy.pro/building-science-podcast/2021/11/...

nikolay 4y ago

From their model, the vents are on the ground, which means they will lift all the dust.

deleted 4y ago

[deleted]

rasz 4y ago

>“There’s a huge opportunity in electric vehicles (EVs) and particularly electric buses because integration of our dehumidifiers in their air conditioning systems can extend their driving ranges by up to 75 percent,” so its a scam then, ok

digdigdag 4y ago
"up to" means it can be as little as 0%. Not sure where the scam is.

Izkata 4y ago

Image caption: > Traditional dehumidifiers are too large and too energy intensive to install in vehicles, but AirJoule’s compact size and zero net energy penalty makes dehumidifying air before cooling it in a vehicle not only possible but creates huge energy savings. Uh, what? Pretty sure most vehicles have AC, which functions the same as a traditional dehumidifier. The only difference is the cooled air AC would output is run back across the "exhaust" pipes to reheat it, instead of ejecting the heat outside. (No comment on the energy saving aspect, just the first part caught my eye)

aaron695 4y ago

Kosirich 4y ago

Few years ago I was in Phoenix,AZ when it was 40 most of the day with I'm guessing 0%-10% humidity. As our hotel had a pool I went for a dive and returned back to the shade and to my surprise I started shaking from being cold as evaporative cooling effect was so intense. Similar to other HN user, I would prefer this kind of heat aka 40 degC with 0-10% humidity than what we have in Denmark during few summer days with 28 degC and 70% humidity.