Heat pump clothes driers

[RalphVa]

This morning there was a This Old House segment on heat pump clothes driers. Only exhausts water. All the air is kept in.

Richard's estimate is 40-50% energy savings. Sent them a note saying this is probably low. The COP of heat pumps is usually 3 to 4. That would mean 67-75% energy savings for air once through.

The water pump would consume energy unless you buy a stackable one and put atop the clothes drier and let the water gravity drain (to your garden).

How many have one?

Ralph

 

[JDAOWNER]

MY CENTRAL AIR FINALLY DIED, SO I HAD A HEAT PUMP PUT IN. IT SEEM TO WORK OK, BUT IT'S NEW TO ME. I'VE NEVER HEARD OF A HEAT PUMP CLOTHS DRIER, HOW DOES THAT WORK? IS IT DIFFERENT THAN AN A/C--HEAT--HEAT PUMP?

 

[3Ts]

Never heard of them until now. Whirlpool claims 67% efficient and the water is put in a container at the top of the machine with an option for a drain hose - no pump. BUT, it will take longer to dry the clothes, so how is the energy efficiency calculated? Is it energy consumed per hour or per load? If it's per hour and it takes longer, how much is the real savings?

 

[Diggin It]

And how much more expensive are they? How much more expensive are parts and service? Do they need frequent maintenance like some of the new washers?

And why would TOH hawk appliances instead of renovation projects? OH, yeah, they got commercialized into being a venue for product placement ads, one of the many reasons I stopped watching TV.

 

[Diggin It]

MY

Push it again.

 

[JDAOWNER]

SORRY DIG IT--I'VE POSTED BEFORE, BUT AGAIN NERVE DAMAGE TO MY HAND DOSN'T ALLOW ME TO REACH SHIFT BUTTON, SO IT'S JUST EASIER TO LEAVE IT LOCKED IN.

 

[CADplans]

This morning there was a This Old House segment on heat pump clothes driers.

That would mean 67-75% energy savings for air once through.

Sorry, I believe I know enough about thermodynamics to refute the energy savings claims,,
I doubt that there is ANY savings,,

This is not a heat source fore a home,, that is where a heat pump produces savings,,

A clothes dryer? Hmmmmmmmmmm,,,,,,,,,
A conventional clothes dryer MAINLY drys clothes by air exchange, the same as hanging the clothes on a rope,, except less walking.
blow low humidity air over the fabric, exhaust the high humidity air outside,, the conventional dryer moves moisture.
stand outside next to the vent when the clothes dryer is running, and note how humid the exhaust is.
The dryer does add heat, to speed up the process,,

Heck, that is EXACTLY why a house heat source heat pump is efficient,, it MOVES heat, rather than add heat.

The heat pump clothes dryer,, another creation from Europe,, much like their pushing of diesel cars,, as better,,
Guess what? Many Europeans are now going BACK to gasoline cars,, I just read that in the last 6 months,,

I would bet the Europeans created the heat pump clothes dryer to eliminate the exhaust vent.
They live MUCH closer together than we do,,,,

 

[KennyG]

The calculations on this would be pretty interesting. Is it just operating like a dehumidifier? If it captures the water, that would seem likely.

 

[Rebeldad1]

maybe you could leave the cap lock off. i do just lazy i guess. it is much quieter this way.

 

[radios1]

here's how it works. YouTube I've been reading it takes 15 minutes longer to dry clothes in a heatpump clothes dryer, but it saves a lot of energy in exchange.. the manufacturers would be losing a lot of money on returns if it didn't work properly!.. and these can cost $1000 and up for a large capacity dryer.