CHP Woodgas Laundry Challenge

OK, here’s a project challenge for anyone who wants to try it. This occurred to me yesterday and I wanted to throw this out there.

CHP stands for “Combined Heat and Power”. For example using an engine to make electricity but also using the waste heat for a useful task, like space heating or water heating.

It occurs to me that laundry is a perfect combination of heating and power needs. Hot water. Control by electricity. Agitation. Heat for drying. Several ways you could approach this…

  • Run a small generator to power a standard electric washer/dryer (just for the controls)
  • The Amish use gasoline washing machines. Use wood to directly power the washer engine.
  • Convert a gas dryer to burn woodgas directly
  • Use a big generator to power an electric dryer
  • Use exhaust heat from the engine to heat water
  • Use direct woodgas to heat the water
  • Use surface heat from the gasifier to dry hanging clothes on a line

There’s room for charcoal to shine here! If you can make your charcoal while heating the water then power the engine from that, go for it!

The “winner” of the challenge:

  • Must actually build, document, and run at least 3 loads of wash
  • Gets the most wash done per wood burned
  • Uses no power or heat except for the wood itself
  • To keep it fair I’m excluding sunshine-powered outdoor clotheslines - dry the clothes with wood heat.
  • Maintains WAF (wife approval factor)… operator stays clean, clothes come out clean, smelling fresh, and no wood smoke anywhere around the washing area!

Can it be done? :sunglasses:


I’m not sure if this counts , but I cut all my firewood on a inverter generator running off charcoal , that charcoal was made from the slow combustion fire’s in our house , roughly about 30 litre’s a day I collect from the fires , this generator also runs a 8000 watt inverter/charger that charges up a bank of batteries that powers the washing machine , the tv and computers even after I stop the generator , this system of mine runs 5 days a week during winter mainly in the afternoon till evening times and maybe 2 or 3 times during the spring / autumn . during summer the solar panels out in the garden keep the batteries fully charged up enough to do all my jobs and may only run the generator if I have a spare amount of charcoal left over if I need that extra power .
I have a small 1kw solar system on the house roof that feeds back into the grid and they pay me 70 cents a kilowatt feed in tariff , and so during daylight hours I try and never use mains electric so that all the suns rays will at least off set my quarterly bill and daily supply charges , my last bill for the autumn months came in at $15 AU so my playing does at least help save not only money but gives me something to do .
I missed out getting my new Hydronic wood burning fire fitted before this winter but hope to have the sorted out before next winter , that will heat 6 radiators around the house .


Great Challenge, I like it. I have thought about this many times since I heat exclusively with wood, and I would like to get free from the power company. Heating appliances like the dryer and oven are the biggest consumers I have. To reduce electric use, the obvious solution is to switch these to gas. But I’m already free from the gas company and don’t intend to go back.


Bump. Bump.
A suitcase tpye enclosed little inverter generator unit can have all of its out-the-end directed heats routed into an old electric/NG cloths drier.
The inverrter-genrator unit providing the AC electrical power for the drier controls, drum and blower motors.
Ha! Ha! A “little” 2000 watt unit can and will dry a load of cloths then. Takes a fer hours with the low maximum BTU’s of available heat though.
You all did not think, that I would not try this?
J-I-C Steve unruh


Do the clothes come out acceptably nice smelling? I generally get complaints when my clothes get covered in engine exhaust…

Well I grew up with the drying part as the poor man’s laundry. We would setup a drying rack beside the wood stove in the winter. It was a win win outside of the looks of hanging cloths in the house. But you got dry cloths and added humidity inside the house which gets too dry here with wood heating. Your cloths didn’t smell bad because they dry in house air. But that doesn’t help with the washing side…


Well now Dan, looks like some people boil there clothing…

Edit: and make charcoal.


ChrisKY for the Honda 2000 suitcase units there are kit offer’ers on the Net for screw-on ducting for when these units are marine below deck installed, and for RV compartments mounting. These- the engine exhaust is NOT separated out from the engine/gen heads heats flows.
Other Net offer’ers have clamp-on/weld-on muffler/exhaust stubs for those who wish to use these Honda 2000’s in-garage; in-shop; in-green house, isolating the exhaust flow for piped outside.
Combine the two kits to farm out heats for blowing into the dryer cabinet. Or course the engine exhaust heat just-in-time separated out cannot be fully recovered for cloths drying.
Yep. Yep. Relatively expensive kits; with just this one purpose, application. YOUR IDEA PATTERNS to make up your own for a DIY project and other generator applications.
The little 2000 unit actually loaded down to a continuous 1600 watt electrical output is at best is only able to make ~3000 watts of heat. Less than 1/10 of what the electric/gas drier BTU heating capability. So takes a long time to dry a load.

A loaded down 3500-5500 engine generator could do much better.
J-I-C Steve Unruh

Don’t enter me in the laundry challenge, a simple close-line cannot be beat, albeit that depends upon fair weather.

I’m just posting these pixs for a laugh…because this is what I did to my old gas dryer!


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My grandparents ran the clothesline in the basement in the winter by the furnace, which was oil so a dry heat too.

Menke is almost done using the hot water boil method. He just needs the clothesline or rack around the retort to dry them. :slight_smile:

Great challenge Chris. It incorporates all the heat recycling power generation and wood gas production one could want for his homestead. While I am equipped to do it with my WK and 15 kw Onan, electric water heater and electric clothes dryer ,efficiency doesn’t enter the equation. This is all something on my plate but logistics in my home is not on my side. Working on a charcoal producing boiler design now as the next step.

There is a very good reson the topic starter Chris Saenz excluded out solar outside line drying.
AND virtually excluded out next to woodstove racked drying.

My wife is the still full time working one here. So I DO most of the laundry.
A typical basket of washed, rung-out wet clothing will run about 40-60 pounds (18-27 kg). Depending on the size of the basket and the fabric contnet of the clothing.
This will sun/forced heat-dryer down to just 15-18 pounds (7-8 kg).
The weight difference is all wet waters!!
Very easy then to calculate just how much heat energy range you will need to vaporize and blow-away all of that.

And although indide house drying MAY be OK for some mid-continental frozen down dry-dry folk for some of the time in no sun-winter. Even YOU folks will over humidify your houses for months in late winter/early spring.
Inside house hung-open clothes drying is just so very 19th century! A time of in-house made tuberculosis’s, phnomoia’s and such.
Yeah a real “fun” cough-cough century. With crying shame child mortality rates.

Really? Want to go back to ONLY horses as the primary personal transportation? Wonderful manure for the vegi’s growing, eh-yah. Horrid diseases human transmission spreading flies and worms problems!

Come’on. Step up to a real 21st century challenge.
I am out of this challenge as I am already a Lifetime member.
J-I-C Steve Unruh

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This thing Menke talked me into making will produce enough heat to dry your clothes with racked drying and no smoke at barrel level. It singed a few of the leaves on the bushes (and possibly the leaves on the tree 30ft up) which is why I am discontinuing my use of it. I don’t think it has a lingerie setting though.

If you want something more couth, the soaking wet towels I wrapped around the condenser pipe to help it cool dried to damp in about 45 minutes and the t-shirt rag was dry in the same amount of time, which you can kind of see in the background. It got a little smoky because of the gaps in the stovepipe, and the joints, but those are fixable with clamps and like a silicone sealant. It is only super hot the first couple of feet. You might be able to use a roll or two of flexible foil ducting which comes in like 20ft rolls and is fairly cheap.


:fearful: :joy:

This stuff may work for that too.


and get your wife back too! Thanks for sharing, that was hilarious. :slight_smile: And actually it would probably work,

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Eating chilli con carne and watching this add realy made my day right now :smile: thsnks for srareing :wink:


If I had the time I would try some winter laundry by making charcoal and boil a load of laundry. Next freeze dry them out side on the line. Should still dry froozen.


i am somewhat sad that we don’t have winters here…
i have some idea’s in my sleeve to participate in this laundry challenge…
but no cold here…

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Hi Koen, just sharing your thoughts could be helpful to others that are doing the challenge, and I’m sure they would be appreciated.

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