Has anyone reused waste heat from a gas dryer?

[beanie357]

Wondered if anyone has figured a way to salvage the heat up the stack without pulling the burnt hydrocarbons into the working environment. Same query goes for electrics.

[Northland]

A heat exchanger is the only safe way to do it... that gets pricey.

It's not just the CO and CO2 that are concerns.... there's a lot of water vapor too.

[Rockers]

Wondered if anyone has figured a way to salvage the heat up the stack without pulling the burnt hydrocarbons into the working environment. Same query goes for electrics.

Check the following link
http://www.cpnuk.com/Clean%20Burn%20Brochure%20-%20NEW%20June%202010.pdf

Page 2 at the bottom.
They cost around $5000 but save you a lot of cash during the winter on heating the workplace.

[Gilligan]

Never thought about this but it's a GREAT topic.

one thing you could do is look at something like what you can do in an upstairs shower.  Wrap some copper tubing around the stack (drain pipe) and it will heat the water in the pipe.

You could set up a storage tank and use thermal siphoning to collect even more heat and store it if you are operating that dryer all day... I would guess you could go even further in this situation and make a custom exhaust with some plumbing INSIDE the vent so you could collect even more.  It would need to be over sized to keep the same air flow as well as you would need to monitor it for it clogging up with lint (you should be doing this anyway).

[jasonl]

My M&R tech was telling me about a shop that had a radiator system connected to his dryer and it heated all the water for the shop.  We had a cap on our exhaust that we would take off on the freezing mornings and let the heat blow into the shop for short periods of time.  It worked and nobody died.

[RICK STEFANICK]

thats how it is in most shops..i guess over the years it can take a toll though.

[Frog]

Sounds like a CO monitor/alarm would be in order.
They are now required in California homes, but probably not businesses.

Years ago, kerosene heaters were all the rage for relatively cheap heat, but, of course, many did not heed the warning to vent.

[inkman996]

I bet if you got together with a havoc company they could rig a system up with some basic equipment maybe even spare stuff that could work well, surely those guys would know the most efficient and safest way to do it.

[Frog]

You may mean HVAC (unless you then intend to unleash the dogs of war) lol!

But, yes, those would be the guys.

[inkman996]

Gotta love apples auto correct lol.

[GraphicDisorder]

Our shop is over 6k sqft.  We don't use the "wasted" heat, there is plenty of heat without using the "wasted" lol.  It's HOT even in the winter out there.

[ZooCity]

A timely discussion for me- I have a meeting tomorrow am with an HVAC guy in our new space and was planning on getting a bid for a heat exchanger installed.  The concept is so fundamentally simple that I don't see these costing an arm and a leg.  Seems to me that you could use a variety of reclaimed materials to build one of these and I have access to a lot of that.  I'll post here regarding the final verdict.  My figuring is that the exchanger just has to 'help out' the rest of your heat system and not be anything overly fancy.   Although, like GD says I'm expecting our old beast to radiate out plenty of warmth without this feature.

I extra like the idea of using it to warm up the water so long as the line was all PEX and had a good filter on the end to keep it clean.  I find that cold water is sufficient but luke warm water really speeds up a lot of the screen making and cleaning process.  This also sounds like a pretty easy thing to add on.

Those Clean Burn dryers look excellent.  I especially like the hinge top and the cool down section.   It's about time someone started thinking about it more. 

[ScreenFoo]

I think the expensive part with heat exchangers is just the huge amount of surface area needed to make them efficient.  Seems like it would be a great project for DIY, if you have the materials, and an expert to double check it.

[arttex]

"Most drying processes use heat and air to remove moisture from a process. The moisture is absorbed by the hot air. The hot and moist (and extremely energy-rich!) exhaust air is removed through exhaust gas ducts and chimneys and out into the atmosphere. Very efficient drying indeed! Or is it? Many companies are blowing tens of thousands of kWh of energy per year straight into the air. 
For example recovery of 100 kW of heat from exhaust air operating for 6000 hours per year will with an energy price of say, $0.02 per kWh, be equivalent to a loss of $12,000 per year."


Personally, I've had talks with some guys from this field and according to them using hot air from the dryer to keep screen drying cabinet warm at around 40C (around 100 F) won't be any problem trough the simple heat exchanger. Fan heater in my drying cabinet is working almost 5-6 hours a day (drying after reclaiming, drying after coating) and this should be a solid saving for the start.   

[ZooCity]

"Most drying processes use heat and air to remove moisture from a process. The moisture is absorbed by the hot air. The hot and moist (and extremely energy-rich!) exhaust air is removed through exhaust gas ducts and chimneys and out into the atmosphere. Very efficient drying indeed! Or is it? Many companies are blowing tens of thousands of kWh of energy per year straight into the air. 
For example recovery of 100 kW of heat from exhaust air operating for 6000 hours per year will with an energy price of say, $0.02 per kWh, be equivalent to a loss of $12,000 per year."


Personally, I've had talks with some guys from this field and according to them using hot air from the dryer to keep screen drying cabinet warm at around 40C (around 100 F) won't be any problem trough the simple heat exchanger. Fan heater in my drying cabinet is working almost 5-6 hours a day (drying after reclaiming, drying after coating) and this should be a solid saving for the start.   

Great point.  Ours is the same most days and those little heaters suck up juice.  I am switching to a dehumidifier though.