5 ms·

Is 5kW not enough to heat the cabin? I guess it must be really cold where you are. Modern heat pumps should unproblematic handle -25°C (air to air), and provide

by Epa095 5y ago

Is 5kW not enough to heat the cabin? I guess it must be really cold where you are. Modern heat pumps should unproblematic handle -25°C (air to air), and provide 4-5kWh of heat for each kWh of power used.

adrianN 5y ago
Which heat pump reaches that kind of efficiency when the temperature differential is so high?
- kwhitefoot 5y ago
  None as far as I can tell. Some people I know here in Norway turn off the heat pump when the outside temperature is below -25°C, but those pumps were installed some years ago. New ones do have a significant gain at that temperature. For instance this Samsung Nordic Home: https://www.elkjop.no/product/hjem-og-husholdning/oppvarming/varmepumpe/215947/samsung-nordic-home-25-varmepumpe-nordichome25 https://www.elkjop.no/product/hjem-og-husholdning/oppvarming...
- Epa095 5y ago
  Good point, I did not think about the fact that the effeciency went down. But it seems to me (as a noob) that modern heat pumps specialising in low temperature conditions still can get around 2.5 at -25°, which gives you more than 10kWh of heating at 5kW, which is quite a lot.
CorrectHorseBat 5y ago
5kW of panels don't produce 5kW in winter, that's the issue I guess.
- Epa095 5y ago
  What does the 5kWh of energy turn in to, of not heat?
  - jacquesm 5y ago
    It says '5KW', not '5KWh'.
    - Epa095 5y ago
      I just now realised that "panels" was solar panels, not the ovens (we call them "panel ovens" in my language). My fault!
      - jacquesm 5y ago
        Np, it is an easy mistake to make.
- jacquesm 5y ago
  Correct, they will produce more. Solar panels produce the most power on cold winter days. The 'rated power' is for 20 degrees ambient at full (90 degrees, no cloud) incidence at sea level.
  - notahacker 5y ago
    In practice it's kWh you care about, and you get significantly fewer hours of sun in winter. No cloud days are rare in some regions in winter too.
    - jacquesm 5y ago
      Sure, but the time factor wasn't present in the above comment, it was just instantaneous power.
      - CorrectHorseBat 5y ago
        It was about how that could heat (or not heat) a cabin, time is definitely a factor in that.
        jacquesm 5y ago
        "5kW of panels don't produce 5kW in winter" -> there is no 'time' factor in there. What you could say is that solar panels in the winter do not produce the same amount of power in an average day as they do in the summer due to the shorter day and the bigger chance of occlusion as well as the longer path the suns rays have to travel through the atmosphere.
  - CorrectHorseBat 5y ago
    That really depends on how far north you live. Where I live a good winter day's production is ~10% of a good summer day's. (Also depends on the orientation, but it's never even close, let alone more)
    - 5y ago
deleted 5y ago
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by Epa095 5y ago

adrianN 5y ago

Which heat pump reaches that kind of efficiency when the temperature differential is so high?

kwhitefoot 5y ago
None as far as I can tell. Some people I know here in Norway turn off the heat pump when the outside temperature is below -25°C, but those pumps were installed some years ago. New ones do have a significant gain at that temperature. For instance this Samsung Nordic Home: https://www.elkjop.no/product/hjem-og-husholdning/oppvarming/varmepumpe/215947/samsung-nordic-home-25-varmepumpe-nordichome25 https://www.elkjop.no/product/hjem-og-husholdning/oppvarming...
Epa095 5y ago
Good point, I did not think about the fact that the effeciency went down. But it seems to me (as a noob) that modern heat pumps specialising in low temperature conditions still can get around 2.5 at -25°, which gives you more than 10kWh of heating at 5kW, which is quite a lot.

CorrectHorseBat 5y ago

5kW of panels don't produce 5kW in winter, that's the issue I guess.

Epa095 5y ago
What does the 5kWh of energy turn in to, of not heat?
- jacquesm 5y ago
  It says '5KW', not '5KWh'.
  - Epa095 5y ago
    I just now realised that "panels" was solar panels, not the ovens (we call them "panel ovens" in my language). My fault!
    - jacquesm 5y ago
      Np, it is an easy mistake to make.
jacquesm 5y ago
Correct, they will produce more. Solar panels produce the most power on cold winter days. The 'rated power' is for 20 degrees ambient at full (90 degrees, no cloud) incidence at sea level.
- notahacker 5y ago
  In practice it's kWh you care about, and you get significantly fewer hours of sun in winter. No cloud days are rare in some regions in winter too.
  - jacquesm 5y ago
    Sure, but the time factor wasn't present in the above comment, it was just instantaneous power.
    - CorrectHorseBat 5y ago
      It was about how that could heat (or not heat) a cabin, time is definitely a factor in that.
      - jacquesm 5y ago
        "5kW of panels don't produce 5kW in winter" -> there is no 'time' factor in there. What you could say is that solar panels in the winter do not produce the same amount of power in an average day as they do in the summer due to the shorter day and the bigger chance of occlusion as well as the longer path the suns rays have to travel through the atmosphere.
- CorrectHorseBat 5y ago
  That really depends on how far north you live. Where I live a good winter day's production is ~10% of a good summer day's. (Also depends on the orientation, but it's never even close, let alone more)
  - 5y ago

deleted 5y ago

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