Thread Number: 94181  /  Tag: Modern Dishwashers
So, there are more DWs with heat pumps now - and they aren't from who you might think
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Post# 1188719   8/28/2023 at 08:37 by henene4 (Heidenheim a.d. Brenz (Germany))        

VZug has been the leader in using heat pumps in appliances other than refrigeration and dryers.
They first launched their DW with an heat pump after cooperating with an university program on designing it and not much later introduced their washer with a heatpump.

Owning a heat pump equipped washer from them, I can say that system does indeed save significant amounts of energy - though never enought to justify the cost with it being a VZug.

But - besides their machines being in the most TOL category and thus pricey - their heat pump systems are quite "complicated".
They use something they call a "latent heat storage" system, which is basically a water tank filled with tap cold water.
The heat pump pulls the heat from there, dropping its temp to almost freezing. Because freezing water takes a lot more energy than just cooling it, that allows them to raise wash temps without causing much condensation or taking much heat from the room.

All of that made them rather expensive.
And - I was thinking, but never checked - they had a patent on that.

Further their HP equipped DW is somewhat of a weird thing. It's even taller than their tall tub DWs - but has a regular height interior.

So, with IFA coming up, I was looking around at some stuff, and rather by accident stumbled onto something.

"Otto" is a german online retailer. And they usually make their product photographs.
And I was highly confused by one little detail:
Any heatpum device, that has a coolant charge of a flammabel gas like R600a or R290a has to have a sticker that displays a "Caution Flammable" sticker and the charge amount.

And this DW had such a sticker on the kick-plate:

The parts website I usually use does only list an inverter for a specific compressor - a TEE VNTZ 165 M.
An incredibly small compressor, varaible speed.
Not the compressor itself.

If you scroll through the pictures on the website, at the back bottom middle, you see a heatexchanger outlet.

The manual also states a few things about heat pump operations.

But the only cycle more efficent is the Eco cycle - it reaches an A.
They don't even make a huge hype about it - though from what I see they are the only company using heat pumps in DWs besides VZug.

Miele and BSH just use special insulations and specific programming plus their TOL drying systems respectivley and reach A-class efficencys.

So Arcelik just did that - and said nothing.

Even the sizing appears to be the exact same - inside and out.

So weird that they do not make any comment about that.

Post# 1188722 , Reply# 1   8/28/2023 at 09:01 by henene4 (Heidenheim a.d. Brenz (Germany))        
Found their patent

It appears Arcelik applied for a patent in 2017 in the US:

Interesting design and idea.
Still super confused as to why only the Eco cycle is rated as more efficent.
Heat pumps are a great addition to any water heating application - but if they only help in one specific cycle, they are just complicated additions that aren't used to their complete potential.

Miele has similar patents, and I bet basically anybody making DWs is currently working on a similar design.

It's just so odd a budget brand makes it to amrket first - and does not mention anything in any promotional material.

Post# 1188723 , Reply# 2   8/28/2023 at 09:08 by henene4 (Heidenheim a.d. Brenz (Germany))        
Just for refference

Here is the original design VZug uses (and has a patent for until 2029):

They basicaly created a second base unit containing the heat storange, compressor and entire coolant circuit.
All that crosses between the 2 base units are water pipes and a few electrical connections - so servicing anything is just detaching the 2 base units so you get acess to both the "normal" machine components AND the heat pump system without having any need to do anything on the coolant circuit.
During production, both a "normal" DW with some minor changes in water pathing and the heatpump base unit are just connected up and placed ontop of each other.

Arcelik appears to just use heat from the room directly and to manage condensation with a condensation drain system of some sort, getting around the patent that way.

Post# 1188728 , Reply# 3   8/28/2023 at 10:28 by appnut (TX)        

appnut's profile picture
Although it's not actually, I consider BSH Crystal Dry something like a heat pump.

Post# 1188732 , Reply# 4   8/28/2023 at 11:11 by Mrlaundry1011 (South Wales, UK)        

I understand this isn’t a dishwasher related but do you find the Vzug to be much more efficient than mieles PW2.0 or about the same? I assume the biggest difference is when both machines are fully loaded and miele cannot perform the PW style of wash and reverts back to a ‘normal’ wash style. I done about a 3/4 towel/white load in my w1 on cotton quick 60 and it used 0.6kwh. Although the Vzug will be reaching selected temps instead of mieles algorithm

Post# 1188735 , Reply# 5   8/28/2023 at 11:53 by henene4 (Heidenheim a.d. Brenz (Germany))        

So, the best I can say there is my 2 typical loads.

A 40C load in the VZug will run between 0.4kWh and 0.7kWh.
My typical T-Shirt/Underwear load would use about 1kWh in the Miele, where in the VZug it's usually just 0.6kWh.

At 60C, the VZug rarely needs more than 1kWh, but can go as low as 0.7kWh with partial loads.
My huge towels load uses about 1kWh in the VZug.
In the Miele, it would be 1.3kWh at least.

Even most boilwashes don't need more than 1.5kWh.

So 30% savings on every load on average are about what you would see, regardless of how you wash.

Post# 1188740 , Reply# 6   8/28/2023 at 12:29 by Tomturbomatic (Beltsville, MD)        

I remember the Grundig brand from HiFi and stereo equipment from the early 60s. Good to see it again.

Post# 1188852 , Reply# 7   8/29/2023 at 23:06 by GELaundry4ever (Nacogdoches, TX, USA)        
heat pumps in dishwashers

I have never seen a heat pump in a dishwasher. Since when did they do that? I thought they had a concealed heating element but most with exposed ones.

Post# 1188864 , Reply# 8   8/30/2023 at 05:14 by henene4 (Heidenheim a.d. Brenz (Germany))        

Grundig is one of the higher end brands by Arcelik, with Beko being their main brand.
They bought the name some time ago.

VZug started building these HP equipped DWs in 2013 or 2014 if I ain't mistaken.
These DWs do have additional heaters aswell, so the heat pump does not replace the heaters entirely.

I did some more reaearch over the past few days.

VZug does not state what compressor they use, but looking at their parts diagramm, it leads me to belive they use a pretty large compressor rated at about 800W or so.
Their DWs have a pump with integrated heater, their MOL and TOL machines have an additional heater before the pump and the heat-pump-model has the heatpump on top.
You can run the MOL and TOL on single phase 230V with either 10A and 2.2kW or 16A and 3.2kW. But they come by default set up for 2 phase 400V operation.
That brings the HP version to a connected power of 4kW.
The BOL model can only run single phase 10A since it only has the wash pump heater.

The parts diagramm lists the additional heater as 1kW.
The main heater in the wash pump would be about 2kW.
Which leaves about 800W for the compressor, which would mean the heat pump would have an effective heating power of something like 2kW at the top end, going down to something like 1.2kW at the low end.

The Arcelik on the other hand - if the parts list is correct - has a heat pump with the incredible heating power of about 250W at the top end.

AND they actually tested it already in the current german test magazine edition - and it SUCKS.
Got a 4.0 (barely passing), mainly due to its bad cleaning performance.
Arcelik's DWs never were "great" performers, but this is apparently even worse than usually.

I'll be purchasing the test magazine some time this week and see how they scored what.
That should include data on how much energy the Auto cycle actually uses.

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