I happened to get a tour of our geothermal district heating building last week, it was really interesting.
The entire neighbourhood of about 2200 houses is heated and cooled by this installation.
About 60% comes from the heat pumps that get their water from two well pairs, about 40 and 80 meters deep. It's not a closed system and the ground water flows about 50-100 meters to either pair.
The remaining capacity comes from a gas turbine that generates electricity to sell back to the net, and the residual heat is captured and used to heat the district. If the demand isn't there, it's pumped back into the ground for future use.
The third method is what amounts to basically a giant electric kettle, which has the worst COP factor, but there are times here in The Netherlands when energy prices are negative, and that's when they shut down the gas turbine and use the electric heater instead.
There are three pipes going to every house in the district, one with hot water, about 70 degrees and used for both floor heating and hot water, one with cold water for cooling in the summer, and a return pipe.
It removes a lot of infrastructure from your house, the hot water goes directly in your floors, so no boilers or furnaces. There's a small heat exchanger that warms the tapwater for showers, and you have zero maintenance.
That's too bad. What is known here as geothermal and ground heat are completely different. What should actual geothermal (nuclear decay heat) then be called in the USA?
From what I understand geothermal itself refers to heat of the earth (crust) while geothermal energy refers to energy generated within the earth mainly but not exclusive, nuclear decay. Calling ground heat geothermal is therefore correct, calling it geothermal energy is not.
(see: https://education.nationalgeographic.org/resource/geothermal...)
Yea, there’s also leftover energy from the earth’s formation. Nuclear decay + moon + sun (tides and sunlight) + residual heat together all contribute to the amount of available energy.
That's pretty amazing. Is floor heating enough in the winter? Can you turn up the temperature if needed? In the house I am in right now the floor heating is not enough, they had to add radiators. All electric.
That is amazing. I would have made a special trip to see that - I just got back from NL. How involved is it there to get the new pipes into those homes? If you could supply any URLs or geo clues I’d appreciate it!
Edit: was this a new from scratch development or a retrofit? I realize my plumbing question might be irrelevant.
Two heat exchangers, one big for the hot water, one smaller for the heating. Heat comes in the form of water at 10bar/75°C. Everything is packed in a box having the a size of 1m (H) x 50cm (L) x 30cm (D). Isolated delivery pipes are all under the city block.
We have that at home, this is great. No noise, no maintenance, no emissions. The only downside is that you are "locked in" with a single heat provider.
My best friend family built a house 15 years ago, when the tech was new-ish, and the pipes are under the cement and inaccessible without huge costs. Then their house settled a little over the years and it lead to maintenance issues.
I suppose new installation don't have the issue, but for stuff I'll use for a long time (basically house, computer and car), if I don't know how to repare it, I prefer old tech.
Wouldn't you need pipes anyway for regular plumbing? That would have lead to issues anyway, right? Also I doubt somewhat the tech was new 15 years ago, it's quite common in germany to use district heating, especially if there's a source nearby you can use or it's a bigger city. So I am pretty sure district heating is very old-tech, just geothermal source is new. German wikipedia says:
> About 9 % of the total heat demand in Germany is covered by heat grids today and 14 % of the demand for residential buildings.
It's less efficient than lower temperatures, but this district is built without gas lines to the houses (as is normal in The Netherlands till recently), and it's more efficient than everyone having an electric boiler in their house.
The pipes are well insulated and apparently the energy loss quite manageable.
The efficiency mostly comes from _moving_ heat that already exists, instead of creating new heat.
Depending on the specifics, that's often about 5x more efficient.
Counterintuitively - the "heat" source doesn't have to actually be hot. In theory as long as it's above absolute zero it can be used as a heat source to heat up the inside of your home. It's the same for cooling - even if it's hot indoors and really hot outdoors, you can still use a heat pump to make it even colder inside the hosue.
The entire neighbourhood of about 2200 houses is heated and cooled by this installation.
About 60% comes from the heat pumps that get their water from two well pairs, about 40 and 80 meters deep. It's not a closed system and the ground water flows about 50-100 meters to either pair.
The remaining capacity comes from a gas turbine that generates electricity to sell back to the net, and the residual heat is captured and used to heat the district. If the demand isn't there, it's pumped back into the ground for future use.
The third method is what amounts to basically a giant electric kettle, which has the worst COP factor, but there are times here in The Netherlands when energy prices are negative, and that's when they shut down the gas turbine and use the electric heater instead.
There are three pipes going to every house in the district, one with hot water, about 70 degrees and used for both floor heating and hot water, one with cold water for cooling in the summer, and a return pipe.
It removes a lot of infrastructure from your house, the hot water goes directly in your floors, so no boilers or furnaces. There's a small heat exchanger that warms the tapwater for showers, and you have zero maintenance.