Zero-energy Attefall. How would you have done it?

[Ulltand]

Absolutely, but it feels like asking for trouble. Don't complicate it

Well, it's rather an innovative solution to reduce energy use. If you do it right, there won't be any problems. If you don't, there won't be any savings.

 

[Ulltand]

Shouldn't the house be connected to the power grid?

Yes, it should be, but the idea is that it should be able to continue functioning even if the grid disappears!

 

[nybyggarn3]

Well, it's more of an innovative solution to reduce energy use. If done correctly, there will be no problems. If not, there won't be any savings.

So, is it a refrigerator in an uninsulated niche in the wall that provides the savings? The potential energy savings are part of the 200 kWh/year the refrigerator consumes, which becomes heat.

 

[nybyggarn3]

Yes, it should, but a thought is that it should be able to continue even if the network disappears!

Maybe a kamin?

 

[Ulltand]

Fireplace maybe?

Yes it becomes a must!

 

[nybyggarn3]

Yes it becomes a must!

Then you don't need 500 mm in the walls. Then you'll be lighting a fire with kindling at a time

 

[Ulltand]

Is it a fridge in an uninsulated niche in the wall that is the saving? The possible energy savings are part of the 200 kWh/year that the fridge consumes, which turns into heat.

Not quite. There is value in the fridge operating without electricity from December to April.

The fridge also runs on pure electrical energy, so the heat addition is 1/4 of what I get from the heat pump. So 4 times more expensive.

 

[Ulltand]

Then you don't need 500 mm in the walls. Then you can light a fire with kindling one at a time

Can go down to 300 mm if I can use real wood

 

[nybyggarn3]

No, not quite like that. There is value in having the refrigerator work even without electricity from December to April.

The refrigerator also runs on pure electric energy, so the heat gain is 1/4 of what I get from the heat pump. So 4 times more expensive.

Then maybe 150 kwh per year in losses remain in the refrigerator. Say you can save half, the gain is 75. The risk is that by building in a thermal bridge, the consumption increases more than you save.

 

[Ulltand]

Then perhaps 150 kWh per year in losses in the refrigerator remains. Let's say you can save half, the gain is 75. The risk is that you create a thermal bridge and increase consumption more than you save.

The risk of creating a thermal bridge only exists if you do it wrong, right? In my idea, I assume it is done correctly.

The gain is not only an energy saving but also a significantly reduced need for the power grid to function half the year. A bit like prepping.

 

[fribygg]

The risk of creating a thermal bridge only exists if you do it wrong, right? I assume in my idea that it will be done correctly.

Do you intend to carry out the construction work yourself? Do you have the experience and knowledge?

 

[nybyggarn3]

The risk of creating a thermal bridge only exists if you do it wrong, right? In my idea, I'm assuming it's done correctly.

The benefit is not just energy savings but also a significantly reduced need for a functioning power grid, a little prepping.

If you want to avoid a thermal bridge, you'll need 500mm on the sides and door, or equivalent of another material. And a door with no losses at all. Otherwise, it will take from the approximately 75 kwh per year that can be saved.

The prepping aspect is interesting, but what if the war or crisis happens during the summer half of the year? Maybe a jordkällare could be an alternative?

 

[Rabbithole]

Cool idea anyway, even if I would have preferred a small fridge/freezer inside and building so there's the possibility for a passive cold storage, old school style.

Bosch has a fridge/freezer combo that consumes 104kWh per year
https://www.bosch-home.se/produktli...ogglebox=manuals/Togglebox=accessoriesOthers/

 

[Ulltand]

To avoid thermal bridges, you should have 500mm on the sides and the door, or equivalent of another material. And a door completely free from losses. Otherwise, it will take away from the approximately 75 kWh per year that can be saved.

The prepping aspect is interesting but think if the war or crisis comes during the summer months. Perhaps an earth cellar could be an alternative?

That's the thing with building the refrigerator into the wall. The insulation on the sides is already in the wall!

The door is like a regular refrigerator, 6 C on the inside and room temperature on the outside.

The backside against the exterior wall provides free cooling from December to April.

During the summer months, there is a good supply of electrical energy from the solar panels on the roof to run the refrigerator on compressor cooling.

 

[nybyggarn3]

500mm on the door, where did you get this from?
I've never seen a door that thick in a passive house😉

True. But the door is probably a weak point in the shell.