“PREPPING” THE AIR

By “prepping”, I mean pre-heating or pre-cooling, but couldn’t think of a word to describe those two things at the same time…any suggestions on a postcard please.

I’m going to tell you now about an exciting little innovation that we have built beneath the cellar of the house - a labyrinth heat exchange! Because the temperature more than 1 metre underground remains at a constant 12(ish) degrees centrigrade all year round, we are able to use it to pre-heat our air before it comes into the MVHR; or cool it in summer.

Low level heat energy from beneath the earth is used in many contexts, but when we were designing the house, we did not find an example of it being installed in a cellar. This is interesting because there are plenty of properties with cellars/basements, but no gardens, for whom a cellar heat exchange could be a helpful energy source.

Including the 6 metre long inlet pipe that brings air in under the kitchen floor, there are 28m2 of surface area for the air to come into contact with before entering the MVHR. We have placed various sensors to measure incoming air temperature (i.e. temperature outside), ground temperature and the temperature of the air when it comes out of the heat exchange. We haven’t turned the MVHR on yet, and anyway it hasn’t exactly been cold, but we are hoping that the labyrinth heat exchange will bring the incoming air up to 12 degrees in the winter, or down to 20 degrees in the summer.

We have addressed condensation issues by sloping the surface inwards to a central drain channel, which runs to a sump.

It is insulated on top and now all covered up, so let’s hope it works because I don’t want to have to take the floor up to fix it!