V Zug Dishwasher with Heat Pump

[logixx]

Not on any home page but a member from the German forum found the manual.

 

Nice to see that most cycles are still under two hours, it has a cutlery drawer and water storage tank - just the final rinse temp of 55C is a little low for my taste. Here's the English manual:

http://www.vzug.com/medias/sys_master/usermanuals/8838332907550/J41001.013-1.pdf

 

[T5-RSergeant]

A DW with a heat pump, I don't understand..

 

[mielerod69]

Video of new V-Zug dishwasher

here is a video showing the new heatpump dishwasher in action.

 

[cuffs054]

Looked at vid and read manual. I still don't understand how/why the heat pump system works.

 

[henene4]

The heatpump is used to heat the water by pulling energy out of the surrounding into the water heaiting it up, just as it works on their heatpump washer and on a heatpump dryer. More efficient as conventional heaters, but still pretty expensive!

 

[logixx]

These V-Zug dishwashers are nice... and fast! Unfortunately, they're also very expensive.

 

Here's the patent: http://www.google.com/patents/EP2446795A2?cl=en&hl=de

 

[dj-gabriele]

In the whole lifetime of the machine you will never ever recoup the additional cost of the heat pump system in the dishwasher compared to any other "normal" dishwasher of extremely high quality, plus you add a complicate, failure prone system in a domestic appliance.

Surely I wouldn't want it, just like for the heat pump washing machine.

 

[cuffs054]

I've got to be missing something here. Been around heat pumps for 40 years. I can't imagine how the system could pull enough latent heat out of the air to warm the water more than a few degrees. How does it dispose of the cold it produces?

 

[logixx]

The patent explains is rather clearly. The dishwasher uses the heat pump to generate heat, it doesn't take it from the ambient air. While one part of the heat pump generates heat, the other side generates cold. There is a pipe in the base of the dishwasher that stores water. This water is cooled while the heat pump runs. During each drain cycle, this pipe is flushed with the waste water from the current step in the cycle. The heat pump then extracts heat from this water and transfers it to the tub. This process is repeated until the cycle is done. The final rinse water, if clean enough, is stored in a separate tank to be used for the next prewash.

During the drying cycle, the heat pump comes on to heat the base of the tub - similar to heated dry on US dishwashers. While the base of the dishwasher is heated, another part of the heat pump cools the tub wall for the condensation drying cycle.

Sounds rather complex. Bosch has been using a similar principle for the last 15 years or so but with a water tank attached to the tub.

 

[cuffs054]

logixx, thanks for the info. While I understand the concept now, the complexity worries me! I guess I'll stick with my clunky US DW.

 

[washer111]

If its a REAL Heat-Pump

I.e. The type that utilises a compressor, then I would steer FAR away from it!

 

Compressor-driven heat-pumps in typical installations can barely produce air hotter than around 120º, let alone anything like 150º like you might need for a final-rinse on Euro models without a heated dry. 

 

However, if the system is just like heat-pipes used in computer processors, I don't see why it couldn't be used to save some energy.

Although, encouraging people to have hot-water recirculators (with insulated pipes) and dishwashers connected to a HOT water supply (Where the hot water is generated from Solar, Gas, Heat Pump, Geothermal (etc) sources) would probably save FAR more energy then 3-4L of Hot water stored for the next fill when filling from cold - since the water temperature will equalise. I.e. If the incoming temperature is 15º and the tank is 50º, then the water will probably get to about 30º at best, I imagine. 

If you have a 50º tank and hot water ready at the tap (at 50º or hotter), you can maintain the tank temperature during the rinsing phases for the final rinse, and even get a "leg up" if your water is hotter than 50º. Instead of heating water from 15º - 60º for the final rinse, you are heating just 22.2% of the time - and with a heating phase 10-15 minutes long, this equates to substantial savings - especially with the cost of European/Australian electricity. 

 

Just my typical "against everyone else" 2 cents  

 

[logixx]

The dishwasher has a traditional flow-through heater as well.