OWB powered dryer. With pics!

[woodlumn]

great idea, great work!

 

[rx7145]

I like the idea and looking forward to hearing any results.



A few thoughts that may help.

Disable the heater element and block off the opening at the bottom of the intake. You might be able to get away with just using "Fluff" cycle and the element doesnt get powerd that way. Or replumb the input to underneath the heating elements so they have airflow and will kick out with the overtemp sensor at the top of the duct.
The heater elements are disconnected now with a switch. I should have plumbed it to the bottom of the heating elements


The dampness sensor might be shutting things off early if the temps arent high enough to raise the humidity of the exhaust enough to gauge dryness properly.
Good point I bet thats it.


One good question mentioned earlier is if the fan from the exchanger is moving as much air as the dryer blower ? If not , low airflow can cause slow drying times. You will want very little restriction of airflow. Enough heat in the drum is only part of what dries them, the moving air carrying the moisture away is the other part.
Very good points. I'm sure that more air flow would help. But more air flow would force more air outside.


The fan on the exchanger might actually be a restriction to the airflow.
It might be but there is still not enough air flow through the electric elements with the current set up which makes me think that this is not the case.


How much heat are you losing with metal ducting going to the unit ?
Can this ducting be shortened or eliminated ?

I'm not sure. This would be a last resort as I don't want to mess with the boiler lines any more.

Like I said earlier, I like the idea of it and think you are on the right track with it.

Thanks

 

[KsWoodsMan]

You're Welcome.

The fan on the exchanger might actually be a restriction to the airflow.
It might be but there is still not enough air flow through the electric elements with the current set up which makes me think that this is not the case.

The way I looked at the pictures, the opening under the electric elements is still open to draw in cold air. Mixing this cold air with the hot air from the exchanger provides only luke warm air.

If I did nothing else to it, I would plug off the inlet to the coils as much as possible so only the hottest air from the exchanger can be pulled through the machice. Even if it is restricted it will still be hotter than from both sources and possibly aiding the drying time. Drying them faster means less cold air is drawn into the house.


Re-routing the water supply and return lines would be troublsome, but if the exchanger could be mounted directly to the back of the drum instead of the current sheetmetal setup you wouldn't have any losses from the flexline.

Great work so far prototyping this idea.

BTW, spare sheetmetal parts can be had at some scrapyards for the price per pound. Around here it has dropped considerably and they are letting scroungers back in to scavenge parts. This is handy since the sheet metal ducting inside is very common among Kenmore, Whirlpool and Roper dryers for the last several years. Actually nearly all of it is the same and interchangeable from one brand mentioned to the next.

 

[urhstry]

Have we got any further on this project? My wife likes her dryer so much I think she camps out inside it. I quiver when I see the electric bill come.

 

[rx7145]

Have we got any further on this project? My wife likes her dryer so much I think she camps out inside it. I quiver when I see the electric bill come.

I have not worked on it any. Still is working fine with about a two hour dry time. I see about a $10-15$ dollar difference on my electric bill. I'm going to work on it more this summer/fall when I'm useing the "summer" dryer. (all electric model)

 

[ant]

great post. is it worth it to do?

 

[Iska3]

That's a great idea for sure. I was thinking on the same lines with a transmission cooler mounted inside a box so I could mount a furnace filter to the back side of the box to keep the exchanger clean That will be a summer project. The Honey-Do list is long enough the way it is.

Nice set up.

 

[cantoo]

Would you be better off starting out with a gas dryer at least then it would have proper air flow designed into it. We dry our clothes either on an outside line or hanging in the basement beside the furnace. We have an electric but it's only used for rush jobs or 4 day rains in the summer.

 

[rx7145]

great post. is it worth it to do?

I would say that It wasn't worth it. However I like to tinker, so I had fun doing it.

I'm going to try and pre heat the air and see how that works. With three kids and two-three loads a day it was just taking too long.

 

[Geez]

The added humidity indoors would be a nice bonus in the winter months.

Be careful what you wish for. I used a lint trap and tried to recapture that heat and humidity one year. The next summer I remodeled the only wall in the house that didn't have a poly vapor barrier installed yet. It is an older house with tarpaper on the outside under the siding. The humidity was drawn through the drywall until it hit the tarpaper (which is in effect a vapor barrier on the wrong side of the wall) and consequently soaked the insulation. I could literally grab a handful and wring the water out! :censored:
Another fella I know who did it had an A frame house. The excess humidity went through the drywall to the properly installed ceiling vapor barrier and condensed there. The water collected, then ran downslope, soaked the lower sheetrock until it caved in.
Sorry to throw this off topic but I do home improvements for a living and should have known better. I want to make sure you guys are aware of it. People tend to add more humidity in their house than is good for it. A rule of thumb is if you see condensation on your windows or colder wall surfaces, chances are your house humidity is too high and is causing structure damage somewhere (hidden) and by the time you find out, it is too late.
In the old days when walls weren't insulated and didn't have vapor barriers, this wouldn't have hurt a thing, because the walls could breathe. Well insulated houses are a good thing, but they come at a price. The air by necessity has to be dryer than is comfortable.