OWB powered dryer. With pics!

[rx7145]

Well I have been working on my OWB dryer for a couple weeks now and It is up and running. I used a 9x9inch HX that I got at a surplus store for $20. I then made a "box" for one end and a 4" outlet. The heat exchanger came with a 120v fan so I wired that to the dryer so that it came on when the dryer was running. The HX and fan stay in the basement next to the main PEX line. I Also put the dryer heater elements on a switch so I can turn them on/off.

It takes about twice as long with the HX. (I was expecting this to be the case.) Also the way I have the HX air blowing into the dryer the electric elements over heat because there is no air flow. Also the dryer is always turning off because it "thinks" the laundry is dry when it is not. My need to add a always on switch or a aftermarket timer. I'm running my water temp at 165* now I'm going to turn it up to see if that helps.

I have about $100 in to so far which is more than I wanted but Oh-well.

 

[iCreek]

That's a heck of an idea, I remember you mentioned this a few weeks ago in another post. Looks great, to bad it's taking twice as long to dry the clothes. Curious what the inside the dryer temps are via electric (original source?) versus HX? Get an IR temp gun and see if you have alot of loss? Great Job so far.

 

[jer427]

well, if anything else, i think that's a pretty neat setup you got going there. A little time to figure it out it will work ok.

 

[urhstry]

Think Patent!!!!

 

[urhstry]

and the lint?

 

[cityevader]

and the humidity?

 

[wdchuck]

Cool setup, sure beats a pedestal fan in the basement near the woodburner, and your clothes will come out softer from the tumbling.


[/QUOTE=cityevader;1243348]and the humidity?[/QUOTE]

Might be a good thing.

 

[LarryTheCableGuy]

Cool setup, sure beats a pedestal fan in the basement near the woodburner, and your clothes will come out softer from the tumbling.

and the humidity?

Might be a good thing.

Around here it sure would be!

+1 Cool setup!

I hope that you get it working the way that you want it to.

 

[MATTYB11]

and the humidity?

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

 

[Laird]

Looks like an outstanding idea!
I have never worked on a dryer before, but am I wrong is assuming that the lint and humidity are dealt with the same as always? Do you still have the dryer vented/exhausted to the outdoors with the exhaust air going through a lint trap?

 

[mtfallsmikey]

Are the indoor lint trap setups still available? You could get one with a container which held water to trap the lint. My CB dealer set his dryer up in a similar fashion.

 

[rx7145]

Looks like an outstanding idea!
I have never worked on a dryer before, but am I wrong is assuming that the lint and humidity are dealt with the same as always? Do you still have the dryer vented/exhausted to the outdoors with the exhaust air going through a lint trap?

The dryer is still vented outside. Was thinking about venting it inside. I have a whole house humidifier so the house dose not get too dry.

 

[rx7145]

That's a heck of an idea, I remember you mentioned this a few weeks ago in another post. Looks great, to bad it's taking twice as long to dry the clothes. Curious what the inside the dryer temps are via electric (original source?) versus HX? Get an IR temp gun and see if you have alot of loss? Great Job so far.

I don't have A IR gun but I do have a older temp gauge I got 160* air with the electric only set up. I'll check that today.

 

[Paso One]

Awesome Idea RX7145 nice aluminum welding as well

Where is the inlet to the dryer ( from your HX ) Same location as the electrical element??

 

[rx7145]

Awesome Idea RX7145 nice aluminum welding as well

Where is the inlet to the dryer ( from your HX ) Same location as the electrical element??

No it is not. I should have so I can use both at the same time. Click on the "backofdryer" pic.

 

[rx7145]

Update!

Well after over a week of using the "new" dryer it is still working good. We can dry three loads a day even if one is cloth diapers (which take forever to dry, even with the old electric set up). Only problems are the electric elements over heat do to no air flow (design flaw on my part) and the dryer turning off when the laundry is still wet. The dryer has a "dampness" sensor but it does not seem to work.

I will up date when I get the next electric bill.

 

[Jkebxjunke]

one thing i might suggest is to get rid of the flex pipe and try to go with hard smooth pipe.. you will get better airflow... the flex pipe creates alot of turbulence in the air flow and slows down the air flow...
another thing... is the fan blowing the same volume of air as the dryer blower?

 

[KsWoodsMan]

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

Well after over a week of using the "new" dryer it is still working good. We can dry three loads a day even if one is cloth diapers (which take forever to dry, even with the old electric set up). Only problems are the electric elements over heat do to no air flow (design flaw on my part) and the dryer turning off when the laundry is still wet. The dryer has a "dampness" sensor but it does not seem to work.

I will up date when I get the next electric bill.

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 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.

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.

The fan on the exchanger might actually be a restriction to the airflow.

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

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

 

[rx7145]

one thing i might suggest is to get rid of the flex pipe and try to go with hard smooth pipe.. you will get better airflow... the flex pipe creates alot of turbulence in the air flow and slows down the air flow...
another thing... is the fan blowing the same volume of air as the dryer blower?

The flex pipe was kind of temp set up anyway. They do make rigid flex pipe that I might switch it over to.

No the dryer is about 250cfm from what I have read. The fan on the heat exchanger only draws about 40watts so I'm sure that it is less than 250cfm.

 

[Jkebxjunke]

maybe you might have to have a larger HX and fan or 2 of the ones you have... I understand the the temp thing... its alot easier to route and play with... if you went with a larger fan or 2 of them... I have seen that pipe in 6" or maybe the pipe is reduced down to small for the fan .. maybe a squirrel cage blower would be better... just thinking out loud here... because I have been thinking of doing that to one of my dryers
I just looked at you pics again... and I had some more thoughts... what if you went with a larger supply pipe... removed the electric coils all together... one reason it may take so long could it be that the air flow is restricted? by not enough supply of hot air? also could the hot air be back flowing out the bottom of the air intake for the coil box?