Heat Pump Dryers

[a64pilot]

Originally Posted by senormechanico

OT, but I clog the road with my 20 year old convertible which gets 29 mpg.

When we aren’t cruising we drive a Miata, which surprisingly only gets 25 MPG.
Or we will drive the Wife’s car, a 500 HP CTS-V Cadillac, which again surprisingly gets 25 MPG.
Go figure

Neither seems to make sense does it?

Both are 15 yrs old, and I hope to keep them at least another 10.

[hellosailor]

Funny coincidence, YouTube threw a "miracle drier BUSTED!" video at me. Apparently someone has started a kickstarter campaign and raised 1/2 million for a small drier using "miracle space vacuum" yada yada to dry clothing using way less power. Except...along the way to proving it is a scam they present what are supposed to be government specs showing the relative energy efficiency of heat pump driers versus electric driers, and electric are supposed to do the job in about 1/2 the overall power consumption, when everything else is equaled out.
How this figures against the great results Dockhead has gotten, I don't know. Just saying that in the larger world, heat pump driers have the reputation for being the energy hungry ones.

[wingssail]

Cost, power requirements, reliability, space to install, complexity...

We REALLY prefer a simple vessel, maintenance and repairs are enough already without adding washer/dryer or the multitude of other conveniences which can be packed into a boat which soon turns into a ship needing a full time engineer, and a slow ship at that.

We've spent most of our time in ports or cruising between port. We have our laundry done in town. On crossings we save it.

Most places we've been it is cheap, and certainly less drudgery, than washing in a bucket and hanging on the lifelines. A load here in Mex is about $8 ($.75/kilo). A washer dryer would be nice, maybe, but then... someone is going to have to use it. Add one more household task to the weekly list. Often the laundry will pick it up and drop it off.

Each item you add, even if it seems so slight it doesn't make that much difference, eventually results in a heavy boat. And each thing which makes you slower, even if it is such a slight difference it seems like it should be ignored, eventually makes you a slow boat. And ALL of these items add to the maintenance load and detracts from the fun of sailing it.

Keep the fun in sailing, keep the boat light and simple, avoid complex conveniences that purport to make things easier, (too many of them don't actually make things easier anyhow, just more complicated).

[Dockhead]

Originally Posted by hellosailor

. . . Just saying that in the larger world, heat pump driers have the reputation for being the energy hungry ones.

No. "In the larger world", heat pump dryers obviously and objectively and measurably use much less power, roughly half, or less. I think you must have mis-read that article -- this is not controversial.

See, for example, https://en.wikipedia.org/wiki/Clothe...at_pump_dryers

". . . In this way not only does the dryer avoid the need for ducting, but it also conserves much of its heat within the dryer instead of exhausting it into the surroundings. Heat pump dryers can, therefore, use up to 50% less energy required by either condensation or conventional electric dryers. Heat pump dryers use about a 1kWh (kilowatt hour) of energy to dry an average load instead of 2 for a condenser dryer, or from 3 to 9, for a conventional electric dryer."



Whether that efficiency is worth the extra cost and complexity is a different question, with an answer which may not be the same for all people.

[dannc]

Originally Posted by Dockhead

Are you sure the run time is longer with a heat pump dryer? My land dryer takes something over an hour; just like my boat one. Only the land dryer holds 8kg; the boat one less than half of that. I don't really remember other dryers; in my other house we have a Miele condensor dryer, I believe, but a housekeeper has done all the laundry for decades, and I don't use the appliances there, so I don't know how long it takes, but I would think it's over an hour...

Am I sure? No, since I do not own a heat pump dryer and have not compared it to our current dryer. Some of the various reviews I read/saw mentioned the longer run time.



Later,
Dan

[Dockhead]

Originally Posted by wingssail

Cost, power requirements, reliability, space to install, complexity...

We REALLY prefer a simple vessel, maintenance and repairs are enough already without adding washer/dryer or the multitude of other conveniences which can be packed into a boat which soon turns into a ship needing a full time engineer, and a slow ship at that.

We've spent most of our time in ports or cruising between port. We have our laundry done in town. On crossings we save it.

Most places we've been it is cheap, and certainly less drudgery, than washing in a bucket and hanging on the lifelines. A load here in Mex is about $8 ($.75/kilo). A washer dryer would be nice, maybe, but then... someone is going to have to use it. Add one more household task to the weekly list. Often the laundry will pick it up and drop it off.

Each item you add, even if it seems so slight it doesn't make that much difference, eventually results in a heavy boat. And each thing which makes you slower, even if it is such a slight difference it seems like it should be ignored, eventually makes you a slow boat. And ALL of these items add to the maintenance load and detracts from the fun of sailing it.

Keep the fun in sailing, keep the boat light and simple, avoid complex conveniences that purport to make things easier, (too many of them don't actually make things easier anyhow, just more complicated).

Light is good, but if carrying the gear you need is weighing down the boat too much, you can solve that with a larger boat.


Whether you need a washer/dryer on board or not depends on how and where you cruise. If you're doing coastal cruising in Mexico where you can get laundry done for $8 a load, then obviously you don't need a washer/dryer. But for my use case, which is totally different -- extended cruises in sometimes wild places and sometimes weeks off grid and away from any kind of laundry facilities, in latitudes where lifeline drying often doesn't work -- I wouldn't want to be without it, not at all. I would give up any number of other "conveniences" on board, before I gave up the washer/dryer, for my use case.


And anyway, the weight is not a big deal -- less than the weight of 100 liters of water. The big issue is VOLUME, but my boat was designed for it and the washer/dryer was installed as part of the original build of the boat, so it's not an issue. YMMV.

[Dockhead]

Originally Posted by dannc

Am I sure? No, since I do not own a heat pump dryer and have not compared it to our current dryer. Some of the various reviews I read/saw mentioned the longer run time.



Later,
Dan

Ha, ha. OK, fair enough.


I guess it depends on the particular examples, also, doesn't it? The one on my boat needs about an hour and uses 2.2kW/h. The heat pump dryer at home takes about the same amount of time, but uses about 0.7kW/h for a load 2.5x the size (8kg vs 3kg). This is not necessarily representative -- the boat one is primitive and very small; a larger one would probably dry more clothes for the same amount of power, and a condensor dryer probably use less power.

[dannc]

Originally Posted by Dockhead

..
I guess it depends on the particular examples, also, doesn't it? The one on my boat needs about an hour and uses 2.2kW/h. The heat pump dryer at home takes about the same amount of time, but uses about 0.7kW/h for a load 2.5x the size (8kg vs 3kg)....

Just noticed I had left a page open to Consumer Reports about an LG heat pump dryer, LG DLHX4072V.

CR's Take

This electric dryer combines conventional vented drying with a heat pump to cut energy by recycling heat generated during drying. It's Energy Star qualified. It was superb at drying, has a large capacity, and is quiet. The dryer can be used in regular mode, the same as a standard dryer, or use the EcoHybrid option, which uses the heat pump to save energy. We found it used 50 percent less energy but took almost three times as long to dry our 12-pound load of mixed cottons. Note that this dryer needs a drain for the water that's extracted from the laundry.

I read some other reviews that mentioned longer runs times as well though I don't think they said three times as long.

Later,
dan

[Q Xopa]

Not knowing specifically about Heat pump dryers.

But Heat pumps generally are a much more energy efficient way of producing heat than an Electric resistance wire. They work on the principle of moving/ pumping heat from one place to another. So they are only moving heat they are not actually producing it, which is far less energy required. Generally 50% less is a conservative number.

So assuming it is just a different way of producing heat to dry clothes, I'm not sure why it should take longer. Perhaps they dont produce as much heat?

It also works well for producing Hot water. But of course is more expensive to produce a compressor and 2 heat exchangers than a resistive wire.

This can be done with devices called 'Desuperheaters', a fancy name for a heat exchanger. For example you could attach a desuperheater to the condensor coil at the back of your house fridge to heat your house water.

This also has the advantage of not pumping the heat from inside your fridge to the kitchen. So saves on Aircond and fridge efficiency. Of course this is all extra cost and complexity but is easily possible.

As someone also mentioned the exhaust of a heat pump is cold.

So theoretically you could have your fridge, air cond and hot water heater connected. Moving heat from your fridge to your hot water heater etc.

Why isnt this done. Well mostly because the way we do it is the accepted way we've always done it. It's good enough, so why bother changing. But if we were serious about energy reduction we would.

Sorry for the slight thread drift.

[Dockhead]

Originally Posted by Q Xopa

. . . So assuming it is just a different way of producing heat to dry clothes, I'm not sure why it should take longer. Perhaps they don't produce as much heat?

Well, heat pump dryers are not indeed just dryers with the heat produced a different way. The air is recirculated and the heat is not blown out -- the air (and any heat) is kept within the machine -- basically the water is pumped out. The heat is mostly conserved, because the hot moist air is recirculated right back over the cold evaporator. It's actually a much cooler process than it seems like at first glance, and I would think that the theoretical possible efficiency is way more than double a normal dryer.


Whether it takes longer or not I don't know -- it doesn't take longer than my boat machine, but that may not be representative. I would tend to believe CR that comparing like for like, heat pump dryers do take longer. I wouldn't think that this is inherent to the process -- just probably the result of working the process at a lower temperature, which is good for the clothes.

Originally Posted by Q Xopa

Sorry for the slight thread drift.

Most of the best stuff on CF is thread drift

[Montanan]

If cruisers were to have such washer / dryer modcons on board that would seem to destroy the entire marine laundry pick up and delivery boat services. I like the service boat that comes by as needed or on a set schedule which boat delivers water and / or fuel, pumps out the waste water(s), pickups up the trash and laundry, returns with cleaned / folded / pressed laundry, and delivers groceries. Of course said service boat uses a different tank for dispensing clean potable water than the one that it uses for pumping out the waste water tanks, or at least I hope they do.

[Q Xopa]

Hmmm interesting take on this.

It's like saying having home cook top and oven will kill the restaurant trade.

Because you have the home capacity doesnt mean you wont treat yourself to a night out.

However when your in remote locations with no laundry services available it might be handy to be able to roll your own.

Or you can wait until you get back to someone to bring you folded laundry.

I reckon its nice to have the option.

As you like.

[Dockhead]

Originally Posted by Montanan

If cruisers were to have such washer / dryer modcons on board that would seem to destroy the entire marine laundry pick up and delivery boat services. I like the service boat that comes by as needed or on a set schedule which boat delivers water and / or fuel, pumps out the waste water(s), pickups up the trash and laundry, returns with cleaned / folded / pressed laundry, and delivers groceries. Of course said service boat uses a different tank for dispensing clean potable water than the one that it uses for pumping out the waste water tanks, or at least I hope they do.

Service boat?





Enquiring minds want to know -- what that even is.

[Montanan]

Originally Posted by Dockhead

Service boat?


Attachment 193585


Enquiring minds want to know -- what that even is.

A service boat is a vessel that is a cross between a garbage scow and a megayacht, soon to become autonomous drones vessels which one can receive same or next day service by Amazon Prime membership.

There being full service vessels and specialized, limited service vessels.

My favorite limited service vessels being versions of these: