[08-15]

> has actual numbers for power input per liter of water

Where did you find that? All I could find is "0.8-1.8kW/hr" for a machine with capacity with a capacity of "30gal/day". This is complete nonsense, "kW/hr" is neither energy nor power nor energy per volume of product. And if it's power, why does it vary?

I'm going to read it as 1.8kW, with a capacity of 30 US gallons (113l) per day. My dehumidifier from the hardware store consumes 0.2kW at a capacity of 10l per day. They are 15% more productive... hardly a quantum leap.

[azernik]

Generally a lot of electrical appliances are advertised with kW or W actually meaning kW-hour and W-hour (and yes, this is awful, but it's pretty standard). So your interpretation as 1.8kW is about right.

It varies, as does output, because (as the numbers mention) this all varies wildly by atmospheric temperature and humidity.

(By the way, running the numbers I'm seeing it as 62.77L/kW vs. 50L/kW, which is a 25% improvement, though at much larger scale.)

[08-15]

groan

So when they write kW/hr, they mean kWh/h, which is kW, because they expect readers to be confused. But if that's the power of the machine, it shouldn't vary. Just like my car produces 70kW, not "7-70kW/hr depending on road conditions". This machine would run a max power all the time, wouldn't it?

> 25% improvement

Serves me right for trying to compute in my head. Qualitatively, it makes no difference, though: they claim a 100% improved efficiency over the competition, and they are nowhere close. The 25% difference may indeed be purely to scale; bigger machines (whether from this company or the hardware store) tend to be more efficient.

[azernik]

As someone else noted, this system functions by using a refrigerator to keep air in the condenser at the dew point; the power required to do this varies based on humidity (changes the dew point) and temperature (changes the temperature gradient your refrigerator has to maintain between the dew point and the outside temp).

Chilling below the dew point doesn't add much, if any, performance.

(And yeah, that kW = kW-h convention hurts my brain.)

[08-15]

Dehumidifiers are not a new thing, I have one right here I can observe. It either runs or it doesn't, so it either consumes 200W or it doesn't. It doesn't regulate the temperature of the condenser, the condensing water does that quite nicely. Since the machine is switched by a hygrostat, you can surely say something like "0-200W" on average, but then it also has a capacity of "0-10l/d".

Power consumption doesn't depend on humidity. Capacity does. So if they quoted "0.8-1.8kWh/l", that would make sense (but be ridiculously low). If they quoted 1.8kW and 40-100l/d, that would make sense, too. But 30gal/d and 0.8-1.8kW implies that the machine throttles the compressor in order not to exceed the advertised capacity, which it doesn't reach under real world conditions anyway.