How can I use 90 F degree water to heat my new house?

dfrazer · May 13

I have a well-insulated 2,000 square foot house on a ranch in northern Nevada that has a hot spring nearby. I can deliver as much 90 degree water to the house as needed. I've thought about using the water as input to a ground source heat pump, but was told a heat pump couldn't take water that warm. I could also use the water for hydronic floor heating, but was told it wasn't warm enough. I've been trying to find someone that I could pay to help me design something that might work, but can't find anyone so far. What about running the warm water through a hydronic floor system to provide most of the heat and having a boiler as a backup? The ranch is 4 - 5 hours from big cities like Reno or Salt Lake, so its hard to find someone to take on the project. I'm also concerned that if it breaks down, it will be hard to find someone to come out. Any suggestions would be appreciated.

Thanks.

Robert O'Brien · May 13

At best you can get 10 Btu/sq/ft from 90F water if that. What's the heat loss?

ethicalpaul · May 13

It looks to me on casual research that they can handle 90 degrees. Some can go to 120 it appears.

Even if they couldn't, I would consider some kind of bypass loop that recirculated some of the water exiting the heat pump back into the supply in order to moderate/cool the incoming temperature. That nice warm water is too valuable to ignore IMO

https://forum.geoexchange.org/threads/new-geothermal-heat-pump-system-entering-water-temp-is-high.3236/

pecmsg · May 13

in four radiant heat

and a small heat pump to make up the very little difference

Jamie Hall · May 13

How well insulated is well insulated?

The only type of system which offers any hope is radiant floors or ceilings — or more likely, both. You need to have a very clear idea as to how much heat is required to heat your house, and that means doing a careful and thorough heat loss calculation. Then you can begin to wonder if you can meet that heating load with water at that temperature — and, not irrelevant, if you have enough water available. You may find that you need essentially all of the floor and ceiling surface to be heated. You may also find that you will need 20 plus gpm of flow, 24/7 , to maintain the temperature — 30,000 gallons per day. Do you have rights to that much water?

hot_rod · May 13

The first thing you need to know is the heatload of the home, ideally room by room

This graph shows some common retrofit options and expected btu/ ft output. Radiant walls are about the high output, and you have a lot if surface area availade

Running that water through a plate HX you would only loose a few degrees, do call it 88 degree supply water

A hp adds a lot of cost to boost maybe 10-15 degrees

The biggest issue is that Nevada geo thermal water is very hard, so continual descaling of the hx may be needed

leonz · May 13

https://forum.heatinghelp.com/discussion/204375/how-can-i-use-90-f-degree-water-to-heat-my-new-house

If you were to use the hot spring with a heat pump you have to understand that if you have an oil leak or refrigerant leak it will contaminate the hot spring.

What you need in order to make use of the heat from the hot spring is to use an insulated buffer tank to store hot water and also deliver it to the home using multiple copper coils in the large storage tank,

Using 2 small circulators where one can feed the hot water from the spring to the tank and the other feeding the hot water from the copper coils to cast iron or steel tube radiators with the cooler water allowed to drain back to the hot spring.

The thermal mass built into the cast iron or steel tube radiators along with the thermal mass in the water from the hot spring can be used to its fullest advantage.

JUGHNE · May 13

Is this a flowing well or coming down from an elevation?

How would you get rid of that much water?

hot_rod · May 13

I visited the Peppermill in Reno a few years back and got a tour of their geothermal system which heats and provides DHW for the entire resort, 2.1 million feet of space. They pump and dump.

One pump pulling 176° F from the well, another discharge to help pump back down a well across the property.

Jamie Hall · May 13

So… we have two critical paperwork steps here. First, does this property have the necessary rights to use enough water? For those unfamiliar with Western water law — like anyone east of the Mississippi! — it is well to remember that just because there is water on a property — or beneath it — does NOT mean that the property owner has the right to use it! Water rights (and mineral rights for that matter) do NOT run with the land.

Then second, how much heat does this place need? Can water at that temperature (85 F mean temp) provide that much heat with a reasonable surface area?

Answer those two, then we can begin think about practicalities…

EBEBRATT-Ed · May 13

Put a boiler in with baseboard heat as a booster a stand alone system.

use the 90 degree water through a heat exchanger to run radiant heat and preheat your domestic hot water.

You can go oversize on the radiant tubing to maximize use of the 90 degree water which will probably do the job for a good portion of the winter.

What the radiant can't do the boiler will

.Nice and simple and not overloaded with controls.

hot_rod · May 14

so the house is already built and you want to maybe add a hydronic system?

I’m in the Salt Lake area and to get a building permit you need to have a heating and cooling load calculation. Maybe that was the case in your area?

Without that load calculation, it is just a guesstimate as to what could work.

There are a lot of good hydronic companies around Nevada. They tend to be near the resort areas, but quite a few in the Reno area.

Western Nevada Supply in Reno has an excellent hydronics division. I know hydronic reps in that area that may have contractor options. What town are you in?

dfrazer · May 14

Thanks for the ideas.

We have more than enough hot spring water to feed a system. Our hot spring normally just flows out to our meadows. I'm just diverting a part of the flow to the house and back to the fields.

Its and old house stipped to the studs. I live in a county with no building permitting requirements.

I like the idea of radiant tubing with the 90 degree water with a backup boiler for very cold times. I need to do heat loss calculations for the house and the radiant tubing to see how it adds up.

Scaling in the heat exchanger is likely to be a problem given the high mineral content of the water.

Thanks also for the suggestion for Western Nevada Supply in Sparks.

Jamie Hall · May 14

That water diversion may — or may not — be permitted. Don't assume. ASK. People have been shot for less — and I'm not joking.

pecmsg · May 14

in Colorado I owned the property. Someone else owned the mineral rights. I had to negotiate with them to drive a well!

Check the local regulations!

EBEBRATT-Ed · May 14

@dfrazer.

If the HX might scale you could size the boiler for say 80% of the heat loss. That would be plenty to keep things operational even if you hit design temp. You could also have a spare HX on site.

hot_rod · May 15

Here is an example of limescale and a plate hx.

A simple cleaning method is install a flush ball valve on each port. Then connect one of the descaler kits and pump it for an hour. No need to disconnect, loose fluid or pressure this way.

DCContrarian · May 15

I suspect the water may be hotter underground. Even a shallow well may give hot enough water to simplify things.

ethicalpaul · May 15

Also consider a closed loop in the area. The hot spring would heat the surrounding earth and make the closed loop very efficient to the heat pump. You could make the well or trench loop very much shorter than I had to where the ground water temperature was 50 degrees.

You might have some trouble using it for cooling in the summer, but possibly not. After all, air to air heat pumps (air conditioners) cool quite well when the outdoor temp is 100 degrees. Or maybe you aren't using this heat pump for cooling at all.

When I lived in Michigan I had a couple friends who had pump and dump systems so the comment above "what would you do with all that water?" made me chuckle…they ran it to a hose in their back yard and let it run off! Not viable here on the east coast given our more dense lot divisions!

Plus those systems hurt themselves with the minerals as stated above…a closed loop system is better for several reasons

JUGHNE · May 15

We can heat our "sun" room with 90+ water in slab. Does well to -20 degrees overnight. Same for the basement floor, painted concrete.

Northern Nebraska, "super insulated" somewhat, house construction.

EdTheHeaterMan · 2:11AM

Not sure about western water rights but if you take that water and give it right back at a lower temperature is it really taking it at all? Water is water and I doubt that anyone thought about the temperature of the water when they were talking about water rights laws 150+ years ago when when Marshall Dillon was in charge of Dodge City. But @ethicalpaul has the better idea using a closed loop full of better quality water dug into the ground next to the hot water that is coming out of that spring.

hot_rod · 2:17AM

Readily available information, possibly you qualify for a minor domestic exempotion, worth a phone call.

https://water.nv.gov/uploads/water-rights-docs/Water_Rights_FAQs_Final.pdf

EBEBRATT-Ed · 2:40AM

I think @hot_rod just rained on the OPs parade.

hot_rod · 4:25AM

I know there is private use of geothermal water in Utah and Colorado, you just need to apply for the proper permits. The State DNR decides if you are able to get a permit.
Nevada reads like there is a minor domestic exemption available.

The DNR in Utah is helpful with their phone support. At some point they suggest you retain a water rights attorney, for legal questions, however.

There are water shares and water rights, typically. Sometimes water shares come with the property but they can be bought and sold, they are similar to a stock certificate. Once you have shares you can have access to water. If it is available to the property.

How can I use 90 F degree water to heat my new house?

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