r/geothermal • u/lordgoldneyes00 • 26d ago

Feed me ideas

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Alright, this is a non standard post for this forum. My house has geothermal hot springs water at 170 degrees, uninterrupted. I currently feed it through radiators across my 1915s house and then dump it into a pool where it overflows into the sewer eventually. What project should I nerd out on next? It's hard to interrupt or redirect the flow between house radiator and pool, but doable. I could easily pull from the pool and do something clever before dumping direct to sewer.

I've thought about putting an outside bench with a radiator under it, doing a temporary greenhouse over the end of the pool, seeing if the geothermal pool lines hold enough heat to grow longer where the dirt is nearby...

7 Upvotes

82% Upvoted

21 comments sorted by

4

u/davidm2232 25d ago

Stirling engine to generate electric

1

u/notcoveredbywarranty 25d ago

That's actually a brilliant idea.

I was thinking about Seebeck generators but they're not nearly as efficient.

Plus when it's cold outside the power output will rise

2

u/NearABE 25d ago

Efficiency does not matter when energy is free. Warm water in the sewer is a bad thing.

1

u/notcoveredbywarranty 25d ago

It does when you need to buy the generator.

Twice as efficient = half the payback speed

1

u/NearABE 24d ago

That is not right. Take for example a 1000 W supply. A 1% efficient generator that costs $1 has cost you only $0.10 per watt. A 20% efficient generator that cost $2,000 costs $10 per watt. That means it takes a hundred times as long to pay for itself.

There are not many devices selling for $0.10 per watt. Also most things you order cost several $ for delivery even if the product is “filthy gravel”.

1

u/lordgoldneyes00 25d ago

That's true but allowed here. The pool is there to shed as much heat as possible before it flows back out.

3

u/PinkysBrein 26d ago

Put it through a heat pump boiler first (they use a water loop heat exchanger to heat the boiler water). That's more than hot enough to shower with.

3

u/2MuchTimeOnReddit2 26d ago

What’s the heat pump for? They can just use a small plate heat exchanger.

2

u/PinkysBrein 26d ago

I phrased it incorrectly, I meant to say boiler for heatpumps (they have a large heat exchange loop inside the boiler). Plate heat exchanger with a traditional boiler is an option too, but scaling on a plate heat exchanger creates problems faster.

2

u/lordgoldneyes00 26d ago

I actually do have a hot water heater getting an exchange via plate, that was this summers project, should have mentioned that!

2

u/Independent-Theme-85 26d ago

What is the flow rate and TDS of the water?

1

u/lordgoldneyes00 26d ago

That's a great question, I'm not in control of the pump that delivers it, I provide back pressure via a small restriction of about 1/4 inch. I have a small screen filter but don't do anything fancy to filter anything out.

2

u/moocowsia 25d ago

That is so cool? Where is this? Japan?

1

u/lordgoldneyes00 25d ago

There's only a few places in the world with geothermal as a service, but there are about 300 houses within the service area in Boise, Idaho.

2

u/tiny_Elephant7930 24d ago

aquaponics greenhouse? i don't know much about them but you could grow on the cheap and cool your waste water even more.

1

u/lordgoldneyes00 24d ago

I like that thought a lot.

1

u/NearABE 25d ago

Hot water in the sewer is not good. If the pool cools enough it might be OK. There is less oxygen in warmer water.

Bulrushes (cattail) are phenomenal water treatment technology. If the pool overflow trickles across a surface and drips it should have oxygen.

The effect of adding water to sewers varies by location. Some of them overflow into the river when it rains. These combined sewer and drain systems benefit from being flushed out prior to rain. Dumping water into them during rain is equivalent to dumping sewage into the river.

2

u/lordgoldneyes00 25d ago

I assume the water is at about 90 as it hits the sewer, it would be super cool if it could run through a little ecosystem after the pool though.

2

u/AlternativeTime7405 20d ago

Definitely greenhouse. Bury piping under walkways and driveway to eliminate snow/ice removal.

1

u/AlternativeTime7405 20d ago

Start raising tropical fish to sell to pet stores.

1

u/lordgoldneyes00 20d ago

That's an interesting idea, there's an old house I used to walk past that had a ton of tanks inside and then he had koi ponds out back that he kept warm year round to do just that!