[m4rky_m4rk]

Hi,

I am planning on building a dedicated HC room as part of a new house build project in Austria, -15 to +30C is common . Heating will be underfloor heating using deep bore ground source heat pump (or maybe air source) and solar. I have heard that the underfloor heating pipes can also be used for cooling, which I might need due to many large south facing windows in the house. Does anyone know how effective this passive cooling method is? Is some sort of air circulation required? Is condensation a problem. ie is it any good?? I should not need air con due to the improved insulation and the concrete construction.

The work office is a also new build and they have installed ceiling mounted passive cooling radiators. Cold air sinks. So, is this the laest thing in cooling?

[neilball]

Underfloor cooling is used more on the continent although I have also seen (and controlled) some systems in the UK. If you have a clear summer/winter seasonal change then it can be useful, although as you have hinted, the surface temperatures are limited to prevent condensation. They also do not cool the air directly, but work as a radiant cooling source instead. The best thing you could do is to use external solar shading to prevent the sun from creating a large solar gain in the room to begin with otherwise the floor cooling is unlikely to have enough output to cope.

[colburn]

The best passive cooling effect is from the ceiling but it needs to be made of concrete and in direct contact with the air. Walls also have a good effect if they are thick and have good thermal mass. If cold air is brought in at the coolest point during the night then the surfaces will store it up to 10cm depth. The cooling energy will then be released during the temperature rise of the day in a process called heat flow reversal. The floor slab can act as a thermal sink but not as effectively as the walls or ceiling - it will depend on whether the floor is exposed of has coverings.


The downside to having hard concrete surfaces is the acoustic properties, you may need to consider dampening and other acoustic treatments.