Crazy Idea for new hydronic appliance...

larry

Just want to throw this idea out there as crazy as it might be - has anyone heard of a hydronically heated cloth dryer? It would essentially be a fan coil setup within a dryer. Has anyone ever prototyped such a beast? I would guess it would be a much safer appliance than the direct heated gas or electric versions of today. On a weekly basis the average cumulative runtime of a cloth dryer probably exceeds the cumulative fire time or even draw time of an indirect DHW tank. This is to say it's an appliance that gets alot of use. If it makes sense, there is the obvious infratructure issue in that folks just don't have boiler loops running to their laundry room. Would such an appliance potentially save energy compared with existing technology? Of course in the USA, there isn't any energy star classification for cloth dryers so a mechanism to create incentives for improvements doesn't readily exist. Any comments?

Geo_2

cloths dryer

I heard there coming out with a microwave cloths dryer !!!.

larry

Will have to check your pockets for coins and chicken nugget pieces with this one!

hr

Yep

have a friend in W Virginia that has one. It runs off his wood fired boiler. Just like you describe a HW coil in the air stream. Sounds simple

hot rod

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Dan Peel

drying degrees

Steam dryers maybe, hot water not so good. Even with 180 to 200 degree water your fan and tumble run time is more than double a conventional dryer. Heat recovery from the exhaust of a conventional dryer may have some possibilities. Enjoy....Dan

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David_5

Who makes it?

I would be interested in it. Is it hard piped or flexible? I have thought of this but, never went anywhere with it.

David

Jason Horner

Home-made solution:
Take an old electric dryer, rip out the heating coil. Hook up a duct from a fan coil to the dryer plenum. Install a relay to call for heat when the dryer is turned on. ;-)

Only problem I see is do you run it like DHW priority in the winter? Typical laundry load takes what, 30-60 minutes to dry? Not sure I want 'laundry priority' for an hour when its -40F outside.

Best bet is front load washer - wrings more water out on the spin cycle so dry cycle in the dryer is shorter. Miele and Asko both make washers so efficient at extracting water that the dryer does not need an exterior vent in order to vent excess moisture from the clothes - the amount released into the house is negligible and easly handled by an ERV.

Unknown

When I was in the

Navy we had what was called the "drying room" for clothes. You could hang a wash there at 6:00 pm at night and by 4:00 AM it would be all dry. It was just a bunch of steam pipes all around the walls that made the room about what seemed like a hundred degrees.

Weezbo

Yes there is a dude who made one....

he's an retired plumber electrician kinda guy:) he has a few other fancy things hes made also , a table that folds allweird and loses theplates ,knives ,forks,and spoons into a dish washer that some how is hooked to another oven refridgerator deal he made so essentially it stores dinner ,cooks it and washes the dishes and resets the table the next time a round! Sounds almost bettern a wife:))) well,... almost

Dean_7

dryer

About 30 years ago when I was in college the father of a friend of mine had a wind generator, solar panels, wood burning boiler, etc.. All homemade at the time. He also had a dryer like the one your talking about. He used a heater core from a car installed it into an old electric dryer and piped it to the boiler. It actually worked.

Cliff Brady

I had the same idea

but was not crazy enough to post it. Regardless, I would appreciate an objective Wall discussion of the costs, performance, and feasibility.

Here are some issues I have had in the back of my mind:

1. Looking at it numerically from the point of my 22,000 BTU (max input) gas dryer, what size fan coil would you need to output that BTU and at what supply and return temperatures. Lower return the better for us condensing boiler users, so a larger coil I assume could be more efficient?? 22,000 BTUs is about half the minimum modulation rate of my boiler and could easily be a zone but may cycle the boiler if can't dump its minimum BTU output. Comments?

2. Does the moisture produced in gas dryer combustion go through the clothes too, reducing efficiency?

3. Would a fan coil hookup be noisier. Could the suction/blower fan in the dryer pull the air through the coil of the "fan" coil?

4. Would a fan coil hookup take much more space?

hr

They make some sense

in the case of the outdoor wood boilers, as these sit there most all winter at 180-200° anyways. Any heat energy not used is lost up the flue or to the surrounding air.

To use a gas or LP fired appliance to heat water, then heat air, then dry clothes... I think when you look at all the energy exchange and losses, you may be better (cheaper)just direct firing the dryer with the gas or LP.

I'd still like to tinker with one myself, however, kinda low on the list as our laundry frequency has dropped a lot with Max off to college!

The very best clothes drying "bang for the bucks" is to hang them outside on a sunny day. SOLAR, baby! Doesn't get any cheaper than that! A couple posts, some line, and clothes pins, remember them Use the dryer to fluff them up a bit after the clothes line

hot rod

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larry

It didn't and still doesn't make sense to me to go through all sorts of efforts to seal your house and be as energy efficient as possible and then end up with an appliance that takes about 200 ft3/min of your hard earned heated or cooled air and eject it outside. I know the issues with indoor dryer venting, and in no way am I advocating that as a solution. Condensing dryers exist, but I don't believe you gain any system (i.e. dryer + house) energy improvement with their use as they use slightly more energy (about 15%) and take longer to dry.

A while back I was playing with a heat calc program and tried to do a simple simulation of what impact a vented dryer had on your heating bill. I constructed a 12,000 ft3 house with some windows and doors that had a .4 ACH rating. Since a dryer outputs about 200 ft3/min, it will do a complete air change of this sample house in one hour giving the house a 1.4 ACH while the dryer is running. Looking at some historic weather data for average monthly temperature, and assuming the dryer operates about 6 hours/week I used the heat calc program to simulate the incremental BTU loss due to the increased infiltration while the dryer was running. I didn't consider any impact on cooling in the summer. The bottom line was that your heating system needed to consume an additional 1,300,000 BTUs (assuming 85% efficient heating system) due to the dryer. This certainly isn't a large $ amount.

Has any thought ever been given to a dryer friendly HRV? I guess it would have to be a sealed combustion system with a fresh air inlet. Dealing with lint that made it past the first trap would be a huge issue. But then companies like Fisher & Paykel are doing some interesting things like lint traps that automatically clean themselves and deposit the lint in a bulk bucket.

Constantin

There may be a simpler solution...

... I would shy away from HRV's on the dryer vent exhausts simply because of the lint and fire risk.

I posed a similar question some time ago at a different web-site: Does anyone make a sealed-combustion capable dryer? The answer, apparently, is no. Here then my proposal to make your house more energy efficienct while the dryer is running:

Run a 4" pipe through the exterior wall. Put a rain-cap terminal with a mesh screen on it to keep the creepy-crawlies out. Indoors, bring it into a U-trap that is at least 18" high. That will help reduce infiltration. Now put a flap-cap on the inside (like the external dryer vents that self-close when not in use). Then seal the laundry room with an exterior door. Voila, no more infiltration.

As an alternative, consider a motorized flue damper that runs on a simple logic. You turn it on... the flue opens... the dryer is allowed to energize (relay)... when the dryer shuts down, the flue damper uses that signal to close again.

Either option may be more trouble than it's worth though. I am considering my opportunities WRT the Vitoflame 100 which apparently does not allow a direct connection to an exterior air supply and my gas dryer, which doesn't either.

The combustion air requirements for the 150k Vitola spec out at 6" of duct. At first glance, the size seems excessive considering the minimal opening in the Vitoflame to admit air in the first place (something like 1.5x3.5"). However, I presume the "excess" duct is for the benefit of the barometric damper on the flue.

Mark Eatherton1

What HR said...

You have to ask yourself, "How efficient is the gas flame thats heating the air going into the dryer drum?" I'd say it's pretty close to 100% efficient. Then you have to ask yourself, "What would be the advantages of taking a boiler at 85 to 95% efficient, hooking it up to a coil, providing a pump and control logic to make it work..." Then you have to ask yourself, "Is it worth it?" My gut tells me that your time would be better spent in other endeavors, but it IS fun to let our minds wander...

Go SOLAR! use a backyard clothes dryer. Save energy and end up with clothes that feel great and smell good.

JMHO

ME

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Rudy

A similar concept...

Years ago, got a call from Bill Spohn, he had a family member who was replacing a furnace, he said I might be interested in getting it.

Turns out it was a combination forced air furnace/clothes dryer. It was called the 'Herbster'.

Had a lever that simultaniously moved a damper to direct air flow through the drum and engaged a belt to turn it.

It was probably 30 - 40 years old - built like a tank - real nice!!

tim smith

hydronic clothes dryer

One of my clients has a very old house that had a large dryer in it, about 12ft x 16ft. Had a overhead conveyor that would run the clothes on hangers through it. Heated water coils, pretty cool.

tim smith

hydronic clothes dryer

One of my clients has a very old house that had a large dryer in it, about 12ft x 16ft. Had a overhead conveyor that would run the clothes on hangers through it. Heated water coils, pretty cool.

Ray_9

Miele/Asko washers

Miele & Asko are condensing dryers - that is why hno exterior vent is required. However,you MUST have cold water running all the time they are running to cool the condensingh coil. LG and Malber also use this technology in their combo washer/dryer - both functions in one machine.
As Constantine posted some time ago, most energy & water efficient washer is the Fisher Paykel GWL11 - 1/2 the water of most top loaders and 1/2 or less the cost of a front loader.

larry

The standalone condensing dryers available in the USA (Asko, Miele, Eurotech, Malber, Bosch and AEG (via Canada)) all use air-based heat exchangers. All these manufacturers also sell vented dryers as well. Most of these condensers have 5 kg capacity although 6 kg units are available in Europe. This is small compared to most vented dryers out there today. AEG makes a unique condenser only available in Europe (Lavatherm WP) that actually has a heat pump built into the dryer (big $$$ and probably no reasonable ROI). The combo washer dryers (LG, Malber, Asko/Eurotech) are the ones that use a water cooled heat exchanger as they have an available supply of cold water.

As for the Fisher Paykel GWL11... it's an interesting and fine machine indeed, but I couldn't say it's the only one to consider. It really depends on your needs. The GWL11 doesn't have an internal heater, and still uses considerably more water than a front loader (Energy Star water use of 9,937 gal/yr vs. 5,345 gal/yr for the Bosch Nexxt WFMC6400UC). We have a 12 year old Asko, and find the internal heater very useful. Last week needed to do a wash at 90C to get some profoundly dirty stuff clean - can't get there with straight domestic hot water.

Bob Daros

sounds great but most laundry rooms are on the second floor now. It woild be a pain to pipe.PEX could make it a little less troulblesome.
Gas company will really love this one.

Ray_9

condensing dryers

Larry, the other? problems with condensing dryers that use cold water is that the clothes are not DRY - there is just a little dampness left that the mfrs say is desirable- huh?? I sell appliances for a living, and most people won't pay the up costs of an internal heater washer over one without - they don't miss it as they never had one.

Constantin

That's not what I recall...

... A GWL-11, IIRC, is not comparable to all front loaders.

...when I was involved in writing the new energy efficiency standards for 2004 and 2007 (this was in 2000), the GWL-11 was the only washer on the market in 2000 that already met the 2007 standards. It is entirely possible that the washers introduced since then offer better efficiency... particularly on former EU-only models that we did not consider.

If top-loading is your thing, the machine cannot come simpler than the GWL-11. As we all know, the fewer parts something has, on average, the less likely it will be to break. Some of the front loaders are beautiful studies in electromechanical design but as a result will probably enjoy a shorter trouble-free life than their simpler bretheren.

doug_10

I just installed a commercial 30lb "hydro-dryer" made by American Dryer. It has a 60,000 BTU coil which seems to be somewhat undersized but the thing works- Eb

larry

Constantin,

Since you were part of the standards writing, could you say why there isn't any Energy Star standard for dryers or hot water heaters? Not that Energy Star always tells a complete and accurate story around energy efficiency, but atleast it's one comparable metric.

In general I agree with you that simplicity breeds reliability. Some of the newer FL washers are also using these expensive ECM motors as does F&P. The other side of washing machine reliability is the electronics used these days. In a real sense, washing machines are a hostile environment for microprocessor motherboards, so although the F&P machines are very simple they rely almost 100% on two expensive high tech parts. Another machine worth considering for pure no nonsense reliable design are the new home models from Speed Queen. After 5 years they are back in the home market basically selling a version of their commercial product. Certainly isn't a fancy looking feature ladden product offering, but it should be very solid.

Constantin

Can't say... sorry!

I don't know why there aren't any EnergyStar categories on the dryer and WH side. I imagine that it's because they all have similar energy consumption and hence do not stand out from each other. But I'd have to call a former colleague to find out for sure.

As for ECM reliability, you have to balance the reliability gains due to having much less in terms of a tranny, etc. vs. the added complexity of electronics. Then, consider where the electronics are located. Some US models feature the driver boards below the drum, right in the path of water, should it leak. Take a F&P apart and tell me the likelyhood of the electronics getting wet considering the number of gaskets in the design, where the tub penetrations are, and the location of the drive electronics.

I agree that washing machines are a hostile environment for motherboards and such. That's why the ones I dealt with were conformally coated and then sealed in a plastic sheath of some sort (some better than others). Yet, for me the limitus test are not the solid state electronics, its the myriad of switches in some of the more sophisticated designs that would give me pause. That's a lot of electromechanical stuff that can go wrong...

Ken_8

We serviced a steam

driven dryer system in a laundra-mat here in NJ.

~50HP boiler and steam to air HX. I forget the manufacturer, but it was OEM and worked well. They pre-heated outside air so the HX would not get jammed up with lint. It was over 30 years old when we dumped the guy for poor payment record. That was about two years ago.

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mp1969

Steam heated dryers

I hooked up steam heated clothes dryers in the 70,s at a hospital in Hayward , Wisconsin. This was an institutional application and they worked great!

MP 1969