> Is this because of geothermal energy leaking upwards
No. The heat energy comes from the sun. Power flux from geothermal is measured in milliwatts per square meter, while the sun can provide more than a kilowatt during the day. So real geothermal heating is negligible at the surface. That's why the temperature a few feet down equals the average annual temperature at the surface.
The only reason people call this "geothermal" is because marketing people realized that this sounds more impressive than "ground source heat pump". It really should not be called "geothermal", because that's something very different. Real geothermal involves extremely deep drilling (not feasible for residential use) or unusual geology.
> Air source heat pumps are the most common models, while other types include ground source heat pumps, water source heat pumps and exhaust air heat pumps.
Heat pump > Types:
- SAHP: Solar-assisted heat pump; w/ PV
- acronym for a heat pump with TPV thermophotovoltaic heat to electricity:
- acronym for a heat pump with thermoelectric heat to electricity:
FWIU archimedes spiral turbines power some irrigation pumps in Holland at least. Is there an advantage to double/helical archimedes spirals in heat pumps if/as there is in agricultural irrigation?
Noiseless double-helical Achimedes spiral wind turbine on a pivot like a pinwheel: Liam F1 average output with 5m/s wind: 1500 kWh/yr (4.11 kWh/day);
Weight: ~100 kg / ~220 lbs;
Diameter: 1.5 m / 4.92 ft
What about CO2 and heat pumps? Would a CO2 heat pump make sense?
There's also buoyancy. The pyramid builders may have used buoyancy in a column of heated bubbly water to avoid gravity, in constructing the pyramids as a solar thermohydrodynamic system with water pressure.
Yes, the you can put "thick" insulation over top of any buried plumbing and the exposed bottom will gain geothermal heat from the below and it can prevent freezing.
Its a bit of both, but its primarily due to the high insulation.
There are 2 gradients: The surface gradient is what I mentioned about and its quite steep(only a few meters to drop tens of degrees). After that, you reach approximately the average annual surface temperature, but do continue to get small drops due to the geothermal gradient. The geothermal gradient is relatively shallow - you need to go down a thousand meters to see tens of degrees drop.
Is this because of geothermal energy leaking upwards? If so, it's not the dirt, it's the geothermal energy.