It's one thing to talk. It's another to get a shovel and start digging long 6 feet deep trenches all around your back yard --if you have a backyard at all.

Indeed, far better to defer any problem to future generations rather than absorb any inconvenience or cost ourselves.

I re-energized my house last year using German subsidies.
Retooling with a heat pump would have been much too expensive.

But I've been thinking a LOT about heat pump (in this case geo-thermaly supported) technology. Why ain't it the silver bullet we've been looking for?

The only answer I have is that you can't bottle it and sell it to your neighbor. If you use it in your own home, you might "save" money in the long run. But you can't "make" money by producing electicity and putting it back in the grid.

Or does anyone have a way of using a heat pump to create electricity or charge a battery? Sort of a refrigerator in reverse??

Thanks, Dom

If I dig a 6 foot hole in my back yard, or front yard, I hit water.

Excellent. That probably means you have hit the water table. You can use the specific heat properties of water in your water table as a heat sink in the summer and as a heat source in the winter.

My smallish back yard is a 250 million year old coral reef, with about 4 inches of dirt dropped on it by the developer of the neighborhood. Hard to dig in. The HVAC guy I use follows the conventional logic: unless I'm going to live in the house for decades, I should just install oldfashioned air-sink units and leave it to the next owner of the house to fix.

So a geothermal project could go vertical, but I've been told that Austin (and Texas) has some funny environmental rules about withdrawing groundwater. (Edwards Aquifer and all that; apparently San Antonio and the salamanders both have some sort of claim on it) Or even drilling. Also, I don't know anyone with a backhoe, let alone drilling equipment.

So it looks like a little more research will be needed. My own vision for this particular climate was a pile of rocks with a little fountain to keep them wet. Let that be the heat sink for your cooling loop. Looks like I have to move out of the city to build a thing like that, though.