Google spinoff Dandelion uses ground energy to heat and cool homes

My understanding of their data innovation is on the marketing side. What I heard is they're narrowing their marketing to only homes on heating oil or propane, essentially not going after houses on the natural gas infrastructure. The gas distribution data at the residence level is not super public.

I'm curious how much this affects the price. I'm not a homeowner any more, but when I was, I longed to replace my furnace with a ground-source heat pump. It is not too much of an efficiency win over gas for heating, especially since we used little heat, but it's great for cooling. But I was really put off by the price. There was no way to justify it even under the most pessimistic assumptions about energy prices, except perhaps if my furnace and AC were to break at the same time.

Well, that is what they say (without telling anything about the actual drilling method).

A typical water well drilling machine is on the back of a large truck and will bore a 30-40 cm hole for (prices here in Europe) 80-90 €/m.

There are smaller drill rigs (nothing that actually needs to be invented, only "normal" micropiling rigs) that can bore 10-20 cm diameter holes for a price of 60-70 Euro/m.

Let's say you need two holes 80 m deep, at 20 €/m difference (80-60=20 or 90-70=20):

28020=3,200

which represents roughly 10% of the actual price for the dandelion system (the real, not subsidized price) of 35,500 US$.

A typical small micropiling rig has a boring rate of around 100 or maybe 120 m per day so either they are really using a new, ultrafast technology (which I personally doubt) or are using less deep bores, and in any case the depth depends on the geology of the site, so everything is probably "averaged".

A geotermic pump with inverter with 20-30 kW of heating/refrigerating power should be around 15,000-18,000 € so, without more data 30,000 € or 35,000 US$ don't seem such a breakthrough (most probably they have huge savings due to the "massive" scale of operation, instead).

Reduced cost, but still the expense of a ground-source setup (20k is quoted in article).

:applause Seriously, it's a great idea and a shame it hasn't been adopted more widely.

I would take issue with their terminology though. To me, geothermal energy is extracting energy from hotspots in the earths's crust, as in Iceland, hot springs, and so on.

This is just using the stable temperatures below the surface as a source/sink for a heat-pump - no energy is being extracted. Hence ground-source heat-pump.

They don't depend on geothermal activity. They depend on the relatively constant temp of the ground below the freeze line. In most places if you go down a few feet the earth is 40-50 degrees F. Its basically a heat pump that uses water instead of air.

My sister outside of Pittsburgh, PA has had a https://www.waterfurnace.com for 17 years. Her system has paid for itself a few times over. She has 1500 ft of plastic tubing burried in her front yard.

They don't rely on any special geological phenomena. They work like a regular air conditioner or heat pump (compressor, refrigerant, condenser, evaporator) but instead of pumping heat to/from the outside air, they pump it to/from the ground.

The advantage is that, while the outside air is almost always the wrong temperature (hot in the summer when your pump needs it to absorb heat, cold in the winter when you need to pull heat out of it), the ground is basically always the right temperature.

The disadvantage is install costs because you have to put piping underground by either trenching or drilling.

Geo-thermal is a little misleading because the systems you are talking about use very high temperatures found in volcanic parts of the world, which is obviously pretty easy. A ground source heat pump only requires 10 degrees or more of heat difference, easily found 30 metres below ground in most moderate temperature countries - it then uses the same technology as air-conditioning. Loads of them are already installed in the UK.

Iceland gets a pretty nice chunk of their power from geothermal, and the cost effectiveness of geothermal power on a volcanic island (combined with a cold air temp that makes cooling easy) makes it a remarkably cheap place to mine bitcoin, as the case happens.

Another fun thing made possible by geothermal: Some roads and sidewalks in Reykjavik are actually heated to prevent icing over.

(And before someone says it: Yes, Greenland is colder, but Iceland still gets pretty freaking cold. After walking two miles or so in an Icelandic blizzard once, I feel like I can claim some expertise on the subject.)

There is at least one old house right here in Atlanta, GA that uses geo-thermal.

I wonder how their economic viability changes if interest rates double. A lot of these kinds of companies seem to have assumptions of historically cheap money baked in.

You're right that does prevent some drilling depending on the city and it is a shame as it locks out a lot of downtown properties. I'm also not a big fan of horizontal systems and prefer vertical fields whenever possible.

Still, I'm excited because I think there is a big market for residential and commercial spaces that don't have the footprint or alley access to fit a conventional rig.

Maintenance will be a recurring cost (amortised) cutting into the yield percentage.

That wasnt really my point. My point was twofold, that 1. the tech exists, so way praise google X etc? 2. Its already outdated.. air to water heatpumps are moore efficient, cheaper and easier to install. The ground based heat system require a very large yard or similar to lay pretty massive amounts of pipes to be effective. Thats also a very big part of the cost.

I wonder, how "compatible" this is with solar.

I.e. if you install solar by itself, you save X dollars/month. If you install this by itself, you save Y dollars a month. If you install both, is it close to X+Y, or is there some substitution there?

On one hand, you can sell solar back to the grid, but you can't always sell it back at retail, so I would guess your savings would be smaller, but how much smaller? Or would you be able to achieve the same ROI with a smaller rooftop solar installation?

TBH, I'm not really a big fan of rooftop solar, it seems like a hack to deal with shitty environmental policy that undermines the electricity grid itself.

FWIW: I had geothermal in my house in maryland, and loved it. The system consistently beat the listed performance specs, which were detailed and complete and easily findable. See the submittable data at https://www.waterfurnace.com/residential/products/literature

This is compared to air heat pumps, where they give you a single number with no factors, and your system rarely will get that number given your set of variables. You can get the full performance sheets if you nag the crap out of them or you are a contractor and have access to the service site.

It is significantly more common in areas on the east coast (which has a good climate for it) and also areas where wells need to be drilled anyway.

It's less common in areas with city water/sewer.

When i talked with the well drillers, they were doing a bunch of residential geothermal installs each week, so ...

It appears they are using a better drilling method https://blog.x.company/introducing-dandelion-2706eded169a I was being cynical as we have a nest that underperforms and sometimes behaves erratically. The website focuses on exploiting subsidies to install. I'd like to know more about Dandelion in case I missed something, will be interesting to get feedback on effectiveness, performance and noise levels