Here's a silly question.  If you sink heat from the ground in the summer and pull heat in winter why wouldn't you want to insulate the ground loop from the top by placing an insulating layer let's say 1 ft above?

Thanks for your input
Paul

This works as long as your heating load matches your cooling load--which is rarely the case in residentail applications unfortunately. Still it is being done for some large commercial applications where loads can be precisely balanced in Europe and Canada, often called borehole thermal energy storage or aquifer thermal energy storage.

-Adam

5-6 foot deep horizontal loops get benefit from solar gain in heating dominated climates in the winter. While this is less than beneficial in the summer, it is among the reasons horizontal loops have less applications in cooling dominated climates.
good luck,
joe

I don't see how it would be cost effective. Most insulation works by trapping air and the ground would crush the insulation thus making it have a very low effectiveness. Other concerns:
- This would trap the heat above the insulation in the summer and kill off any vegetation above it.
- Vegetation roots would likely break the insulation
- Bacteria would likely break it down also thus
- You might lose heat gain from the sun thus making it less effective for heating dominated climates

Speaking from a heating dominated climate you want the earth to warm up in summer as much as it can. In winter we have snow, which is a pretty darn good insulator. I remember as a kid going around our house with my dad and shoveling snow up against the house to about 5 feet high. It made a noticeable difference when it was really wind and cold.

And at least in our area it is amazing how much water is in the soil and I would imagine even putting a "blanket" over it you would still get a lot of heat transfer sideways and down and as water moves past the field.

One could keep grass clipped short in the summer and let it grow long in the winter. No idea if there is enough savings to be worth it.

The ground is actually a pretty good insulator as it is with an average R value of about .25 per inch (R value = thermal resistance which is the reciprocal of thermal conductivity). A few feet of soil is equivalent to any insulation you are going to add anyway.

-Adam

Brock you are a never-ending source of off-the-wall but technically correct thermodynamic data and info.

It never occurred to me until now that shoveling snow up against a house could serve any useful purpose but it makes perfect sense now that you mention it. Snow is an excellent cold weather insulator