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by azernik 2799 days ago
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.)

1 comments

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.

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.)

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.