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.
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.
You're taking flak for being too harsh, but I'm glad you posted, because without your second sentence I don't think I could have figured it out. It's too counterintuitive to select a file, download it, and then upload it. My mind would have rejected it before even considering it if I hadn't read your comment before I clicked.
It's a neat and interesting visualization, though, once you get past that. I could see it being useful.
Not sure if this is the case here, but lots of weather APIs cost money, so if they tried to integrate the full process themselves they would no longer be providing a free service, and instead losing money. So by outsourcing the download portion to you, each IP may get a few free downloads and then you just provide the data yourself saving the creator money and allowing the tool to be free...
Me neither, but are there any GIS tools, that get it right?
My (limited and possibly outdated) experience with them is kind of horrible. Buttons and information overload and the workflow of experienced users is strictly memorized. I know some people (used to) make their living, just by knowing where to click around in ArcGIS and helping others who do not know the interface structure so well.
Guarantee you that over 50% of people who visit this site turn away in frustration, and over 90%+ of the people who aren't computer scientists on Hacker News lol. Yep this is a beautifully-functional tool but the UX is ridick! Also - Select your city by dragging through the map? Weird chart with blue boxes result one has no idea how to read without digging for further instructions?
I don’t think this is intended to be used in isolation. Cooling dry air is much less energy intensive than cooling dry air + a bunch of water. So, this device efficiently removes the moisture from the air, allowing the ac system to do less work.
AC systems are pretty good at dehumidifying as well. I'm going to be replacing my home AC system soon (it's 13 years old) and was asking our AC maintenance guy about getting an oversized system. In central Texas days approaching 110 seem to be the norm these days. In this weather, my "correctly" sized system can only drop the temperature around 25 degrees different than the outside. He advised against going oversized because apparently a big system cools faster than it removes moisture and you can end up with a block of ice at the exchanger or get condensation and then mold inside.
I was thinking a smarter thermostat should be able to monitor humidity in the air and run the AC at a low level, ramping up as moisture goes down, but that doesn't seem to be a feature in any of them (product idea?).
Maybe a separate dehumidifier like the one in the article combined with an oversized system could work?
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.
I'm thinking there is a lot of context here I am missing as a layman. you can shift all the zones (including comfort zone) up and down the chart by adjusting the "mean outdoor temp" slider. people don't really work that way, unless we are assuming that they keep wearing their outdoor clothes inside maybe?
> whether dehumidification alone is enough to make them comfortable ... if most of the weather is in the 'evaporative cooling' zone shown its probably a good choice for you.
That doesn't seem right - the evaporative cooling zone includes conditions like 40C 1% humidity.
What would dehumidification alone do under those conditions?
Sorry my bad brain explosion writing evaporative cooling. Should read 'vertically above the comfort zone' is good for evap cooling. Ive edited the above comment too. Thsnks for pointing out my mistake
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.
I live in south-eastern Canada today it was 35C which is something I've never seen here. And the humidity at one point was 90% which is typical since I am on an island. Thankfully it went to about 70%.
I felt tired it wears you out even 35C is OK but any humidity over 60% is terrible. My entire childhood up until ten years ago a 30C day here was a very hot day that came maybe once per summer but most years never.
So that 10C difference only feels like 2C difference, but comes with the complications of being all sticky, which might make you feel more miserable overall despite being technically cooler.
Also, I don't know enough about wet bulb, but would it be possible that if humidity is higher, that sweat evaporates more slowly, and accumulates rather than just evaporating? If sweat drips off your body rather than evaporating off, do you still get the cooling effect (is it the releasing of sweat, or the evaporating that cools you?). Walking through a park on a summer day and a lab environment are going to be a bit different.
Basically, my question is, does wet bulb temperature accurately represent the human body, or is this a spherical cow moment?
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.
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?
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.
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.
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).
I'm not qualified either, however, we can see from [1] that in southern states summer energy use jumps like crazy--almost all because of AC--peaking when solar production drops to about half around 6pm [2]. Given that humidity affects both the efficiency of AC, and personal comfort (sometimes I run the AC just to dehumidify), and the fact that it's only going to get hotter with GW, and more humid (because warmer air can hold more water), targeting AC efficiency is a BFD.
I posted to here because (a) government lab, so has some credibility, and (b) getting feedback from the HN community who might have informed opinions about it.
Your second citation does not show AC peaking at 6, it shows Solar and Wind use averages over time of day.
I don’t know when AC use peaks but total use tends to peak before 6PM while residential use peaks in the morning and evening [1]. Solar does fall off around then and rather suddenly for any given longitude. But what you see with the duck curve (slouching midday prices with a 6PM peak) in California is reduced grid demand. Grid demand is not the same as energy use because of behind the meter generation (e.g., rooftop solar). The duck curve shape is caused by replacement energy use from solar not reduced energy use.
I recently got back from a few hundred mile road trip in >100F temperatures in an EV with decently high (40%+) humidity. Climate was <5% of the energy usage as reported by the car. Even when driving around town in 114F weather, its rarely been >15% of my overall energy usage.
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).
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.
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.
Kona EV has a page on power consumption, which at 30C ambient temperature and a long drive said I used about 4% on AC. Same amount goes to "electronics" which I find surprising.
“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,” said Matt Jore, CEO of Montana Technologies.
__extend their driving ranges by up to 75 percent__
> 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.
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.
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
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)
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.
Readit News
https://drajmarsh.bitbucket.io/psychro-chart2d.html
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.
It's a neat and interesting visualization, though, once you get past that. I could see it being useful.
Me neither, but are there any GIS tools, that get it right?
My (limited and possibly outdated) experience with them is kind of horrible. Buttons and information overload and the workflow of experienced users is strictly memorized. I know some people (used to) make their living, just by knowing where to click around in ArcGIS and helping others who do not know the interface structure so well.
Its one of those cases where you need some techincal knowledge and its not going to make money so gets missed despite its importance.
I was thinking a smarter thermostat should be able to monitor humidity in the air and run the AC at a low level, ramping up as moisture goes down, but that doesn't seem to be a feature in any of them (product idea?).
Maybe a separate dehumidifier like the one in the article combined with an oversized system could work?
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.
I think it depends on you and what you're comfortable with.
It’s endlessly fascinating how different we can all be.
That doesn't seem right - the evaporative cooling zone includes conditions like 40C 1% humidity.
What would dehumidification alone do under those conditions?
I felt tired it wears you out even 35C is OK but any humidity over 60% is terrible. My entire childhood up until ten years ago a 30C day here was a very hot day that came maybe once per summer but most years never.
38C@30% humidity = 24.4C
28C@60% humidity = 22.2C
Also, I don't know enough about wet bulb, but would it be possible that if humidity is higher, that sweat evaporates more slowly, and accumulates rather than just evaporating? If sweat drips off your body rather than evaporating off, do you still get the cooling effect (is it the releasing of sweat, or the evaporating that cools you?). Walking through a park on a summer day and a lab environment are going to be a bit different.
Basically, my question is, does wet bulb temperature accurately represent the human body, or is this a spherical cow moment?
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.
Dew point determines how much body cooling you can achieve through sweating.
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?
[0] https://en.m.wikipedia.org/wiki/Compressed_air_dryer#Desicca...
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.
Deleted Comment
https://youtu.be/R_g4nT4a28U
[1] https://www.eia.gov/tools/faqs/faq.php?id=1174&t=1
I posted to here because (a) government lab, so has some credibility, and (b) getting feedback from the HN community who might have informed opinions about it.
[1] https://www.eia.gov/todayinenergy/detail.php?id=36692
[2] https://jrenewables.springeropen.com/articles/10.1186/s40807...
I don’t know when AC use peaks but total use tends to peak before 6PM while residential use peaks in the morning and evening [1]. Solar does fall off around then and rather suddenly for any given longitude. But what you see with the duck curve (slouching midday prices with a 6PM peak) in California is reduced grid demand. Grid demand is not the same as energy use because of behind the meter generation (e.g., rooftop solar). The duck curve shape is caused by replacement energy use from solar not reduced energy use.
[1] https://www.eia.gov/todayinenergy/detail.php?id=42915
https://cdn.shopify.com/s/files/1/0196/5170/files/model_s100...
“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,” said Matt Jore, CEO of Montana Technologies.
__extend their driving ranges by up to 75 percent__
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.
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.
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.
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)
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-h...
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.