Non-electric laundry room with massive drying capacity?

I've got a situation where I'd like to build a large no-electric laundry facility. The major hurdle I have is that:
1. It has to be able to operate with filtered air to eliminate pollen / allergens.
2. It needs to be able to dry in the fall and winter in Appalachian climate.
3. I need to have enough space to be able to have several loads drying at any one moment for a large multi-family setup.

The real problem I think is, probably obviously, allergies. We struggle with some pretty bad allergies to pollen. We can't simply dry outdoors and thus I need to set up a permanent area that can work in all seasons in an Appalachian climate in the midwest/northeast.

I can allocate some space as a utility room in a sheltered out building, but I have to maximize it since it's not that large.

Anyone have any thoughts on creating a passive and mostly clean (allergen free) high efficiency drying laundry room?

My home design has something like that, we don't need massive, but the idea is the air comes up out of the basement, through the floor where the drying happens and goes out the ceiling. The basement intake is dehumidified before it comes in, that's part of the whole house system, and the ceiling output goes into the house exhaust system. Rising heated air, warmed in the basement, provides the pull upward out of the house.

Something like that, adapted for your climate, perhaps? Mine's designed to work with the rest of the heating/cooling/air flow system, so my design won't be exactly what you need, but might give you ideas.

Incidentally, something else in the laundry room design is to have the washer and a drip area next to it in a 2-3 inch lowered part of the floor sloping gently to a drain. Keep water problems accounted for as you make the room, that cuts down on later issues. Washer overflow, plumbing weirdness and dripping happens, I have it accounted for.

I live on the wet coast and am concerned about you getting the amount of fabric you're implying dry before you get mould or mildew happening using a completely passive system.

We have an electric dryer, but only use it for shrinking fabric (we probably wouldn't own it if we hadn't been given it 35 years ago.)

However, we do have a top loading electric washing machine (also 35 years old, but it's had a few repairs over the years). If we are washing heavier items, I will reset the dial for a second spin cycle because the more water you can spin out, the less needs to evaporate out. There are special "spin only" machines that I've seen in laundromats that people often use for towels, but they're electric. Years ago, I saw a hand cranked wringer, and I believe there still places such equipment can be bought.

We also heat with wood in the winter. I have a clothesline hanging from hooks in front of the upstairs wood stove. However, that wood stove has an electric fan to push air over the stove from the back and out the front to make it more efficient.

All that water *has* to go somewhere. So we also run a dehumidifier in the bedroom. That provides a bit of heat in the bedroom and stopped the mould issues we were having there. The only shower in the house has a door opening to that bedroom and no ceiling fan, so after a particularly miserable night in a bed that was too damp for our body heat to dry out, I put my foot down.

I once saw an interesting system for drying wood. It had air coming in down low and exiting near the top, and the front was greenhouse plastic for solar "heat". You need a way of filtering the incoming air due to pollen, and again, doing that completely passively is going to be tricky. However, involving solar heat either directly or through solar heated water could go a long way to making this work, although electricity for pumping would again make it easier. Think of the "towel heaters" that classy bathrooms have, but made of copper pipes containing water that is solar heated. The clothes would be hung over these or above these to help keep the air and moisture moving.

Before we had electric washing machines, bedding only got washed once per year and it was hung on shrubbery to dry. Modern attitudes may also be an issue.

Greg,

What energy resources are available?  Wood?  Solar?  Wind?  Natural gas? Biogas?  Does it need to operate even during times when there is no solar/wind?

Do you know if it would be public/commercial, or private?

Does it matter how long the drying takes?  (If it’s a laundromat, a 20 minute dry cycle can be more valuable than a 50+ minute dry.)

Does the drying need to be done in-bulk by the wash-load or is there a possibility of handling each garment separately (such as putting each garment on a hanger to dry)?

Absolutely agree with Jay about the significance of wringing, whether it’s wringer or spin cycle or both, especially with cotton that holds on to water.  Synthetic fibers hold a lot less water, but it depends on what your goals are.

Why “no electric”?  Is it off-grid, or for environmental reasons, is it amish? More details needed.

Jay Angler wrote:Years ago, I saw a hand cranked wringer, and I believe there still places such equipment can be bought.

 https://www.lehmans.com/product/lehmans-best-hand-wringer?utm_source=google&utm_campaign=20435299634&utm_medium=ad&utm_content=&utm_term=&gad_source=1&gclid=Cj0KCQjw9vqyBhCKARIsAIIcLMFqis0PZA1Uvj699pmM08vsywSeTP426nznPPviVSvMV5-dGDDjsPgaAtECEALw_wcB
Personally I would buy a used one somewhere, but hey, it's at Lehman's if you need it.

I'm not sure about your climate. In the winter our house is so dry that we can hang our clothes off a rack in the kitchen and they are dry by morning.

Elanor Gardner wrote:

Jay Angler wrote:...

 
I'm not sure about your climate. In the winter our house is so dry that we can hang our clothes off a rack in the kitchen and they are dry by morning.

I hear you - we came from Ontario and people want *more* humidity in their houses in the winter. Hubby struggled with the concept that here the humidity is 100% all winter. Wood heat lowers that a bit, but not nearly enough. We come in from outside with sopping wet clothes that needs to dry before we need to be outside for the next task. Our house is much more comfortable with running a dehumidifier as needed. It may not be the most permie solution, but if I can't sleep, I'm not going to be much good at all the other things a homestead needs doing! An RMH with a cob bench for a bed platform might fix the problem, but our house isn't designed for that, so I compromise.

The house I am building has a 8x30 foot front porch.  It faces south and is fully glassed in.  I plan to put a clothesline in there to dry clothes in poor weather.  

J Hillman, how will any moisture get away?

I have not read all the posts so if this has been mentioned forgive me ...

My vision is a giant dehydrator.  One so large that a person can walk inside the dehydrator.

Maybe this giant dehydrator takes on the look of a greenhouse.

Lots of windows and glass roof.

And a permanent way to make the filtered air that was mentioned.

I agree with the comments above -- you're going to need a heat source and a way to pull the warm moist air outside. A tall black chimney for air exhaust maybe 16-24" diameter may help with the convection flow (sun heats pipe, hot air rises). I'm not sure it will be enough -- you can buy solar powered attic exhaust fans (not cheap, but off-grid friendly).

Do you plan to have air intakes covered with filters? This is tricky, because they require a fair bit of suction to move air through them.

If you're inclined to try DIY off-grid forced ventilation, we had a thread discussing it:

"Daylight drive" direct PV solar for equipment
https://permies.com/t/117961

I think variations of a room-sized solar dehydrator have been suggested. The thing is, direct solar on clothing destroys it quickly. So it has to be indirect heating, somehow.

We don't know how dense an intake filter would be required to control pollen in a way acceptable to the OP. IMO this is a wild card in our calculations.

John C Daley wrote:J Hillman, how will any moisture get away?

In the summer it will be wide open.  In the winter the air is dry and we want the moisture.  But if it gets too damp we could open a vent.

I built a large solar dehydrator for food, similar to this.
https://extension.usu.edu/sustainability/research/community-solar-dehydrator-plans

But air didn't flow through it fast enough.  I took an 12 volt electric radiator fan from a GM vehicle and mounted it in the dehydrator to suck air out of the box.  I wired it directly to a broken 26 volt solar panel.  So any time the sun shines the fan is moving air.  

The brighter the sun shine the more heat is made in the heat panel and the more electric the electric panel makes  causing the fan to move more air.  

The same thing could be used to dry clothes.  Just replace the food shelves with bars to hang the clothes on.  And by having the powered fan you probably have enough air flow that you could put a air filter on it.

The inside of the box is always dark so the sun can't bleach the clothing.

Depending on your location it should work in the winter too.  You just may need to add more heat panels to it.

J Hillman wrote:I built a large solar dehydrator for food, similar to this.
https://extension.usu.edu/sustainability/research/community-solar-dehydrator-plans

But air didn't flow through it fast enough.  I took an 12 volt electric radiator fan from a GM vehicle and mounted it in the dehydrator to suck air out of the box.  I wired it directly to a broken 26 volt solar panel.  So any time the sun shines the fan is moving air.  

The brighter the sun shine the more heat is made in the heat panel and the more electric the electric panel makes  causing the fan to move more air.  

The same thing could be used to dry clothes.  Just replace the food shelves with bars to hang the clothes on.  And by having the powered fan you probably have enough air flow that you could put a air filter on it.

The inside of the box is always dark so the sun can't bleach the clothing.

Depending on your location it should work in the winter too.  You just may need to add more heat panels to it.

A system like I described could be built into a house as a closet for the drying chamber.  And the heat panels could be outside with the air moving from the panels to the drying chamber through large diameter pipes(drain tile comes to mind as the cheapest option)

If you want to increase capacity you could build more than one drying chamber and add more heat panels.

For drying clothes you would want to take outside air, run it through the system then vent it back outside.

But you could put in baffles so you aren't drying clothes you could take inside air, run it through the panels and then vent the warmed up air back into the house to help heat your home when you need it.

Such a system would still require you to work with nature a bit.  You wouldn't want to do 10 loads of laundry on a rainy day with a week of rain forecast, your clothes would mold before they dry.  

A assume each drying chamber(about 60 cubic feet) could hold a large washer load of clothes and would dry it in a day if the sun is shining.  I may test my food dehydrator with a load of clothes and report back.

It is overly complicated compared to just hanging the clothes to dry, but with your allergy issue it may be an option.

This is REALLY fun to think about; and, my favorite kind of post.

I will be ruminating on this and will get back~

I saw this posted in another thread and wow what a great example of what I suggested earlier, only my idea is much larger and with more windows!



source

Anne Miller wrote:I saw this posted in another thread and wow what a great example of what I suggested earlier, only my idea is much larger and with more windows!



source

A room with a view! Drying clothes wasn't the first usage that came to mind though. ;-)

I don't know what your conditions are like, but I would guess that a key factor would be understanding what your ambient temperature and humidity levels are. Here in the UK we have months of the year when you can't reliably use a outdoor line and when the humidity is near 100%. Clothes dry slowly and can pick up a mildew smell if it is slow enough - far from ideal!

The trouble is the two key factors you want - removal of huge amounts of water through evaporation, and highly filtered air are working in opposition to each other. To carry away moisture you want a large air exchange of warm dry air, but that incoming volume of air then needs to be filtered. Filter drastically reduce airflow rates and I struggle to see how you will manage to design a totally passive system that manages to ensure both high volume and good filtration.

I would suggest looking into a system that uses a fan-forced filter where the air enters as a reasonable compromise. This could be run from a solar panel if a mains connection is not viable.

Heat gain can thereafter be passive solar in some suitable configuration.

Mike Philips wrote:Greg,

What energy resources are available?  Wood?  Solar?  Wind?  Natural gas? Biogas?  Does it need to operate even during times when there is no solar/wind?

Do you know if it would be public/commercial, or private?

Does it matter how long the drying takes?  (If it’s a laundromat, a 20 minute dry cycle can be more valuable than a 50+ minute dry.)

Does the drying need to be done in-bulk by the wash-load or is there a possibility of handling each garment separately (such as putting each garment on a hanger to dry)?

Any and all options are available. The idea is to be able to do the entire wash+dry cycle without electricity when needed and to do so as efficiently as possible. But we can use electric if we wanted. My hope is to eliminate the NEED of electric entirely and still be able to dry the close of 8-20 people very easily and entirely cleanly without worry of allergens.

Michael Cox wrote:...

I would suggest looking into a system that uses a fan-forced filter where the air enters as a reasonable compromise. This could be run from a solar panel if a mains connection is not viable.

Heat gain can thereafter be passive solar in some suitable configuration.

We're in Appalachia and we have humidity to deal with. We're working on a greenhouse setup that might allow us to get creative with cycling air at variable temperatures through the house. The goal we're working with there is to eliminate all heating and cooling electric needs and then to repurpose the air for other things as well where possible. We're heating water with under-solar-panel piping as well.

Sorry for the delayed responses. Hay time is very demanding here.

So thanks, everyone, for the fantastic ideas and detailed insights so far. Here’s where I think we stand and some additional thoughts and questions to keep the discussion moving ahead:

Filtration and Airflow: Allergen control is a significant concern, so the balance between filtration and airflow is critical. I'm considering HEPA filters, but I'm worried about the suction required. Does anyone have experience using HEPA filters in a passive system? How did you manage the airflow?

Climate Adaptability: Drying in the Appalachian climate, especially during the humid seasons, can be challenging. The suggestion of using solar-powered fans or integrating a dehumidifier makes sense - but I need to reduce electric to as little as possible. Has anyone had success with passive solar designs, like solar chimneys or greenhouse-type setups, in high humidity areas? I’m particularly interested in how these systems perform in winter. I like the photo above of the "outhouse-like" building. That's pretty neat and the idea might be extrapolable into something larger, at least for a drying area.

Non-Electric Solutions: The hand-cranked wringer idea seems promising for removing excess water before drying. Does anyone recommend a specific model or a DIY solution that’s durable and effective? I'm open to all suggestions, from commercially available options to innovative DIY solutions. It might be worthwhile, for convenience and for when electric is viable, just put a drum "wringer" (like a traditional washing machine, but a spin cycle only) to reduce water content.

Practical Implementation:

1. Prototype Testing: Maybe build a small-scale prototype to test the feasibility of some of these ideas. Any suggestions on key elements to include in this prototype would be helpful. Specifically, how should I set up the airflow system and integrate filtration without compromising on efficiency?

2. Heat Source: For winter, wood heating might be practical, but we couldn't tolerate the smell of wood fire smoke. Maybe this could be reduced through a rocket mass heater with more efficient combustion. I’m thinking about setting up a clothesline in such a construction with heat coming in from either a wood stove or rocket mass heater, but probably will keep the burning area outside of the drying area and thus have the exhaust chimney only pass through the drying area... perhaps similar to what Jay mentioned. Any thoughts on how to optimize this setup to maximize drying capacity without causing a safety hazard?

Additional Questions:

1. Greenhouse Integration:  The idea of a greenhouse for solar heat gain is going to be a big winner for me. What are the best practices for integrating drying racks within a greenhouse? How do I ensure adequate air circulation without letting allergens in? I might integrate earth tubes and basement ventilation to increase the heat gradient differential for some kind of convection flow setup.

2. Moisture Management: For those who have used enclosed porches or similar setups, how do you manage moisture buildup? Any tips on ventilation strategies that have worked well when you especially want to retain / block temperature transfer outside for maximum temperature retention?

3. Energy Resources: I have access to various energy resources (wood, solar, wind, natural gas, biogas (in planning) and maybe hydro (in planning)). How can I best leverage these to create a flexible and efficient drying system that remains mostly non-electric but can use electric power if absolutely necessary? I'm working on setting multiple inputs up to multiplex them into a battery bank for consumption (and probably both separate AC & DC circuits to reduce energy loss for electronics that can directly consume DC).

Again, appreciate the contributions so far and look forward to hearing more about your experiences and ideas.

If you want HEPA filtration, you will need forced air from electric fans. These can be powered by off-grid solar, but there's no way it will work with passive convection flow.

Edit: This post turned into multiple brain droppings as I drink tea, sorry for the additive thinking :D

I agree, HEPA filters are HARD to get air through. You are willing to have at least some electric at some times, using it to draw the air through the filters might well be your best use of it.

The problem with solar chimneys etc is where does your input air come from? They can pull a lot of air through them easily, and work very well, but the incoming air is going to be the problem. Is it dry? Is it filtered? Humid, pollinated air is easy to find, clean dry is not. And if you have clean dry, you don't want it dumping out at a furious pace.

Look up Masonry heaters, the kind of heat dispersal they do hooked to a rocket mass heater type system might be most effective, have your burn and exhaust outside, and the masonry heather type radiator system inside.

If you can hook a drum type spinner to a pedal system, you could probably do some serious spinning out, especially if you have kids who can pedal.

Adding a greenhouse to it all will INCREASE the humidity in the area, if your goal is drying a lot of things, the last thing you want is to have to keep it good for plant to grow. I'd say those are incompatible goals, greenhouse needs to be separate from a problematic drying area. You have too many design challenges as is without mixing in stuff that requires the exact opposite conditions. You can easily make a building with two sections, one with the drying area, one with greenhouse, and route your air flow through drying first, then greenhouse, then into house. That would let you keep the problems separate.  There is a time to function stack, and a time to separate problems to solve them.  :D

The major problem I see with any of this design is the HEPA filters. Here's an interesting exercise, figure out the least air restrictive filters you can use. HEPA is REALLY fine, T shirt fabric might be entirely enough to keep out allergens. Look up particle size of your main allergens, and see what kind of filtration you actually need to design for. T shirt fabric is a LOT cheaper, washable, and a pretty good filter, most pollens etc are going to be caught by it, Making a filter system that uses something akin to T shirt cloth that has several layers each with an air space behind it (not layered tight on top of each other, 1/2 inch or so) will be VERY effective, and might be worth considering. HEPA filters also cost a small fortune, and have to be changed very often, few wash well. I have few I can wash, but they require the force of a vacuum to get air flow through them, and they don't last long.

On that thought, I said if you do have power, using it to pull air through the filters might be your best use of it, look at scavenging old vacuums for the motors to pull the air, get a lot of bang for your electrical buck there. Because of the lack of electric I have not suggested a Rainbow Vacuum type water filtration system, if you run them on low air flow, they add humidity, but if you can run them at high flow, they filter VERY WELL without adding much water to the air. Look them up, water IS a great filter, it just complicates the dryness need. Wonder if you could slow bubble air through water and use it in the house, then pull that to the drying area afterward? Hmm... Humans add moisture to air though... Maybe passing it directly in front of a masonry radiator would heat it enough to make it dry enough to be effective

And on THAT thought, count on circulating the air a lot in the room, not just one pass through, as dry and filtered are an issue. Making your air flow go across your heat source every time it can will help a lot.

In winter, once air temperature goes below freezing, the air you pull in will be dry, but freezing the water into the clothes is not effective :D Dry air coming in and masonry radiator will make it most effective in winter. Summer is more of the problem, as that's when the pollen etc is high. The problem almost wants to be broken into two parts to solve, winter and summer drying, as they are really different parameters....

Masonry heater innards:


What I mean when I say use that kind of design is to take your rocket mass heater air flow and zig zag it upward through a flat panel as wide as you can get away with, keeping each line tilted upward, to spread the heat out the absolute most effectively you can, rather than design it to hold the heat as well in the mass, disperse it as much as you can in the area you need it to.

One more thought (I have to get to work, this is more fun though) is consider using hot water radiant panels instead of rocket mass, not sure if that would work for your world, but if you have hot water in the house, you already are heating it somehow, consider piping it through flat radiant panels (in a CLOSED LOOP, do NOT mix heating water with house use water! Temperature changes breed some NASTY critters in water tubes, keep them self contained and it doesn't matter. Mix them and it's VERY VERY VERY bad!!)  My house design has radiant heat, and two water heating systems, that never interact, that, as well as floors, will heat flat panels that are basically thermal mass standing up, to make wall radiators. Those in a drying space would add a lot of easy heat, and separate the warm air flow complications into a separate issue to solve.

Complex problem you are designing for! Great fun to think on!! :D

Soooo... let's turn our thoughts the other direction.

What are some passive methods of dehumidifying air?

I've mentioned that we run a dehumidifier, and that uses electricity. There are places that use "fog nets" to collect water for drinking etc. Let's hope this drying room doesn't get humid enough for that concept to work...

However, as I mentioned the concept of running warm water through pipes that the clothing was hung over as one way to dry the clothes, would a network of pipes that one ran cold water through, with a trough under it that led the water to a container of some sort, work to help remove the moisture? I suspect the issue would be actually getting the water to form large enough droplets to roll down the pipes at a reasonable water temperature. Fridge water happily condenses a little water from our air. Ice water condenses much more.

In some weather, single glazed windows do a pretty good job of collecting water. Before we started using the dehumidifier, the bottoms of the aluminium-framed sliding double glazed doors behind a drape in the bedroom, collected water every morning in the winter.

It gets complicated - a lot has to do with "dew point" and that's a moving target.

But I thought it would exercise Pearl's brain to think about this side of the equation! I think some sort of external system feeding heat into the room would be the easiest, but since we don't want to use high air flow along with that due to allergens, I figured we should at least consider the options.

And yes, what Pearl said about needing a "green house for plants" and a different "greenhouse for drying clothing" is what I had been picturing all along. Greenhouses can easily turn into mould experiments, and most people who are sensitive to pollen, probably don't want to deal with a lot of mould either.

Ah, I inspired commentary!

The ways I like best for dehumidification require certain conditions. If those conditions are available, they are incredibly useful. If not, perhaps something may strike a chord.

There are still functioning thousand year old systems in the middle east for water harvesting. The ones that fascinate me most are long underground tubes that slope downhill. The air comes in the bottom, and has to move slowly to a small output up top, and the cool underground pipe condenses water out of the air and it flows out the bottom of the pipe. I lived in New Mexico, and I saw the city drainage system rainwater runoff pipes doing this on their own. They were concrete pipe, always nice and cool, and if you went in them deeply, it was cool and always wet at the bottom, as there was not enough slope to remove the slow trickle water, they were designed for fast moving rain water. (Of COURSE I'm not the kind of person who crawls around in drain pipes! Heaven forbid!! But it WAS a lovely cool place on hot days....  :D  )

Fast forward to me buying land in Missouri. LOTS of humidity, a sloped piece of property, and I bought a LOT of 4 inch schedule 80 PVC pipe very cheaply. The design is... ah! I have a picture in my project file threads (linked in my signature)



The design is to have pipes that go from the house, buried in the north slope, with shady plants above them, that slope down from the house. The air intake for the house comes in them (there's more than 2, I only drew 2 for ease of communication) and it moves slowly up, to let the water condense out, and flow out the bottom where it can end up in a small animal drinking pond. There are clean outs, so the whole mess can be washed out if needed, and also farther down the slope so if needed baffles to add turbulence to the air can be slid in. I'm thinking baffles that make the air flow spiral might be useful. This is what I designed to work for ME and MY parameters, your mileage will DEFINITELY vary!  

Incidentally NEVER NEVER NEVER run any air you plan to breathe through corrugated pipe! The dust etc at the bottom turns to mold, and houses have been made toxic to the point of having to be bulldozed down by using corrugated pipes as earth tubes! Make them something you can CLEAN! And design in a way to clean them. And make them slope at least enough that they don't accumulate water.

So, in the laundry drying room, if long air pipes could be used down a sloped run, properly shaded, buried if possible, the water harvesting feature of it all will result in drier air coming in. But it comes in slowly, cannot be moving fast. My 4 inch pipes will each have an output of about 1-1.5 inch square, not 4 inch diameter. Take that into account, how much air input do you want? The longer the pipes, the better the drying, mine are designed at 80-120 feet, and as deep as I can get them with a ditch witch.

Back to Jay's post, she suggested water condensation off pipes of cool water, that ABSOLUTELY works. The problem is how to have water cool enough to do it. As I type this, it's just after noon in Missouri in the summer. The air temperature is 88, the relative humidity is 60%, the heat index is 97, and the dew point is 70 degrees. I would have to have water consistently under 70 degrees, if not colder, to be condensing water out of the air. If I have that, I could do it. I am on city water, pipes that run under the ground to get here, and at the moment, the cold water in the kitchen is at 80 degrees. If I were working off a water storage tank, that would be a different number, probably hotter. Cold water is not easy to make off grid like hot water is.

BUT! If I had it.... In something like the laundry room, I'd go for the thinnest metal pipes I could get water through without leaks, (watch water pressure changes, it can break pipes easier than you'd expect!) and put multiple rows of them into a tight cabinet, and run my room air through it and have a water run off at the bottom. I have a "in case of power outage" system like that designed and the parts out in my garage, using a car radiator as my pipes.  Hot air holds more moisture than cold air, if I was using a mass heater of some sort, I'd be pulling the heat from it off into the condensing cabinet.

It might be VERY worth your time to look up old water harvesting designs. The middle east, India, and Australia all have quite a few neat rabbit holes to go down.

:D

Pearl Sutton wrote: Back to Jay's post, she suggested water condensation off pipes of cool water, that ABSOLUTELY works. The problem is how to have water cool enough to do it. As I type this, it's just after noon in Missouri in the summer. The air temperature is 88, the relative humidity is 60%, the heat index is 97, and the dew point is 70 degrees. I would have to have water consistently under 70 degrees, if not colder, to be condensing water out of the air. If I have that, I could do it. I am on city water, pipes that run under the ground to get here, and at the moment, the cold water in the kitchen is at 80 degrees.    :D

Wow - that's pretty warm "cold" water! People make a big deal about insulating hot water pipes for energy efficiency, but nobody talks about insulating cold water pipes to make the water nicer to drink (and possibly safer - 80F seems warm enough to start growing some things???)

I admit, I tend to drink "room temperature" water under most conditions. However, my "room thermometer" claims it's 70F, not 80F or even higher!

I think if I had lots of water, I'd consider something like this post shows: https://permies.com/t/256307/tech-evaporative-cooler-produce-charcoal
And I'd put a water tank inside it?  However, this might not work with the high humidity that this discussion is working with. There are smaller versions of the same concept made of 2 nesting clay pots with sand between them which is kept moist. Food is put in the inner pot and stays cooler - not necessarily fridge cool, but significantly better than ambient temperature.

This is not intended as a thread hijack - there are multiple sides to drying clothing. One is speeding up evaporation through some sort of heat application. Another is decreasing the ambient humidity around the clothing. And a 3rd is the movement of the air. Since outdoor air introduces problem pollen, keeping the existing air requires a way to get the water out of the air without exchanging it.

Jay: those kind of water coolers and food coolers do not work with high humidity. They are evaporative, and if it's too wet, there's no evaporation going on.

What about a version of the food dehydrator that is featured here on the site.  I’ve always just hung my clothes outside in the line in the summer during the winter they get on a rack by the fire.  But double duty the rocket mass food dehydrator when it’s not being used for food?   Hang on hangers and load it up.

I plan to inhabit my land in a few weeks. I, too, am plagued with allergies. I often use the remedy attached to help with them.
I will build a dome home with areas for laundry and drying in one of many sections. See main picture; the dwelling can be as large or small as you want to build it.
You may want to look into aircrete to build with. I’ve done my research and it is a great option for allergy sufferers. There are ways to pipe in heat without smoke, but I don’t have a picture to post.

So the guy who invented air conditioners had terrible allergies and was trying to dry out the air to remove most allergen particles. If you could rig up something with an AC unit on your intake that would help dry and filter your air. After that point I'd create a mass heater bench with drying racks above it for your clothes with a sterling engine blowing the warm air for more movement. The wood heat chimney I'd run through the middle of your room vent pipe so it's heat radiation would help pull a draft for your vent. the sterling engine and vent draft would be passive but only work  when you fire the mass bench but when you'd need to dry NOW they'd kick things into overdrive. I see the previously mentioned baffles as a way to control what parts of the chain need to be used, you don't need the ac to dry & filter air as much in winter, you might not need the mass bench to fire in summer or maybe just for a couple hours and let the mass slowly dump its heat all day.

An unusual situation to start with. What is the actual allergy situation? With the up to 20 people living there, is it a sanctuary/community for people with allergies? I've heard of similar where people want to live perfume free. Or is it extended family with a genetic allergy? Can you tackle the allergy side of things? What makes you all allergic? The culprit may not be what triggers reactions but some underlying problem. How many of those people living there actually have allergies? If only a few, can you reduce the amount of laundry requiring those conditions, i.e. do it separately in a smaller, more easily run system? Tackling another root problem; would you be better off moving to a more suitable climate? It requiring the most extreme approach, but barring any permanent cure,  also offers the most permanent solution.

I also agree with Jay that modern attitudes to cleanliness can be an issue. What applies to germs may apply to allergen exposure in making you more susceptible when limiting exposure.

A few more ideas about the laundry setups suggested, and tackling humidity.

The rocket mass heater assisted dehydrator is an excellent idea. It's somewhat similar to a chamber behind a Tromb wall. It could be situated down-wind from the prevailing wind and have an extended chimney to remove any smoke away from the dwelling. If it goes onto skids or wheels, it could be moved if the wind occasionally blows in the opposite direction.

My mother had a regular front-load washing machine but used a separate spinner after the washer spin cycle. It would still extract more water. They are certainly more powerful in removing water.

I have an off-grid no-electric laundry setup using a mangle. It also does a very good job, but I would suggest that some items that are slower drying (typically cotton jersey, or bulky fabrics) are put through twice. I tend to let things with zippers and bulky buttons like jeans drip dry. I only wash them on sunny, breezy days, as they would take too long to dry. My climate here in west Wales, by the way, is similar to the PNW.

Lastly, an amusing thing I saw in an advert for double glazing for cold climates or periods. It showed a single-glazed window with condensation and the window sill was fashioned into a mini sink with drain. It was meant to be disparaging, but my permy/Heath Robinson/Rube Goldberg brain saw a brilliantly simple dehumidifier. It could be a small window or even a metal plate high on an external wall where warm, moist air rises to. The bottom would simply be fitted into a channel with a tube moving the water outside. You could place some insulated panel in front to reduce some heat loss as well as prevent warming of the panel by radiant heat, but allowing the air to go behind it around the edges.